this is what happened last weekend. i received this new 48v/400ah lifepo4 battery. i temporarily connect the midnite classic to 3x 24v panels in series leaning on the wall. they charged up the battery and the midnite classic went to float. having confirmed that the system all nicely worked, i disconnected the 3 solar panels.
here we come to the interesting fact:
the input voltage remained at 117/118v. after a couple of hours i thought "holy duly midnite really installs super quality caps". however i also noticed that the midnite used 0.4a. and the temps were quite warm for doing nothing: 44.2 and 48.4 degrees. also periodically the fan in that midnite came on. whereas the first midnite classic connected to the 12v system worked at 500watts and the temps were lower.
note: the input was not connected to anything. so i disconnected the battery and reconnected. the input voltage went to 39volts, and whizbang jr shows the normal 0.1a use. and stayed like this the last two days.
i vaguely remember somebody mentioning this very same fact on the forum here.
to me it looks like the midnite was running in reverse. however i did not check if it could be used as a stepup switchmode device. i suspect the current would have not been very big. but it was doing something to warm up to trigger the fan.
just wondering if midnite is aware of this.
greetings urs
Were you reading the voltages on a meter or on the display of the Classic - or Local Status app ?
Larry
i was reading them first on the midnite classic display, then with the voltmeter, the voltages corresponded. i was tempted to shorten it out, but refrained from that impulse, just in case.
like i wrote, there were absolutely no solar panels connected. when it went to float, the input voltage went up to 118v or the like. there is nothing connected to battery. so no usage. after i disconnected the panels the voltage just stayed up there for hours until i disconnected the midnite from the battery. reason says the midnite classic was reversing.
i imagine it is not a problem as such, but still an interesting fact.
Weird is what id call it. Theres no way that a classic with no input connected should be in float. Are you sure? Try to take a photo of the MNGP when it occurs.
It is however normal for some voltage to be present on the input when not charging, thats just the way the buck oncverter works.
Hi,
I'd strongly recommend you turn everything off and sort out all the wiring before you end up blowing something up (eg the Classic) or starting a fire somewhere.
There is just no way the Classic can go into Float, and as expected the input voltage rise, without there being any PVs connected.
dgd
hello you guys
ok, just to make it clear, absolutely clear:
i hooked up the array (3x 24v panels.
the midnite went first to bulk charging
then absorption
then, the battery was fully charged
THEN the midnite went to float (arrays still connected)
however as the battery was now full:
the voltage went about to something like 118v (because the midnite was in float and no usage of the battery, no connection, please note again, because the inverter has not arrived yet, note is not ordered yet, nowhere anywhere close to my midnite classic!!!!!!
i turn off the breaker with the temporary array
then, EVERYBODY pleas take note!!!! disconnected the solar panels physically. ok, so no physical connection at the input anymore
so the only connection was to the lifepo4 battery, and the dc solar breaker and whizbang jr etc.
again please read correctly here:
the voltage stayed up at 118v
the whizbang jr showed using ( to make it clear for everybody, electricity flowing from the battery to the midnite classic) 0.4 amps. now, resting it only uses 0.1.
the temperature reading showed 44.2 and 48.4 degrees celsius. the fan (inside the midnite classic, to be precise) came on periodically.
for the fellow with the advice about checking the wiring:
please note : AFTER DISCONNECTING THE MIDNITE CLASSIC FROM THE BATTERY, THE MIDNITE TURNED OFF, ZILCH, NADA, ZERO, I MEAN ABSOLUTELY NOTHING ON THE DISPLAY.
turned the midnite classic breaker back on to reconnect to the battery. now, input voltage showed 38.9 volts
whizbang jr 0.1amps, the temp reduced down 35.5/42.2 degrees celsius after a while, probably more later on. (and no solar panels connected, if anybody should be wondering)
it seemed to me the midnite classic missed going into resting mode.
ok to repeat, the only thing that was connected, was the battery. and take my word, the polarisation is connected correctly.
for the blowup theory fellow: i reconnected today for a short while to the solar array, again 3 panels at 24 volt nominally, polarization correct, it charged in bulk mode, however did not wait for float. the reason is, as mentioned before, there is no use of the battery and i do not like to keep the voltage in the lifepo4 up in absorption voltage.
programmed to specs of the lifepo4 : absorb: 56v, float53.6 (the lifepo4 battery is 48v and 400ah, just in case somebody is wondering about that)
this is probably for the midnite classic people to look into.
now if anybody is interested i can give them my mymidnite username and password. just in case there is still somebody out there thinking i should check the wiring.
whats more, i vaguely remember somebody mentioning a similar case on this forum as well.
i hope i cleared some uncertainties for the sceptics
greetings urs
please don't forget that the Classic is powered by the battery, not solar, so that small amount is to be expected... ;)
the whizbang jr showed using ( to make it clear for everybody, electricity flowing from the battery to the midnite classic) 0.4 amps. now, resting it only uses 0.1.
westbranch!
on resting the midnite classic uses 0.1A according to the whizbang jr
(as i described above)
however, in the case described above, the whizbang showed 0.4A and as described above, nothing was connected to use that kind of current. so, i mean, to make it quite plain and simple and i hope most of the readers understand that, this current must have been used up inside the midnite classic. and warmed up the fets and all the things inside the midnite classic to trigger the fan.
and even if there was some parasitic current, say a spider or a fly connecting the battery terminals, or sawdust, the 0.4 A should not warm up the midnite classic. besides that current would have come from the battery.
to me it seems logical, if there is no electricity going into the midnite classic none can come out. ( do i have to describe that more clearly??) as a logical progression that current warming up the midnite classic came out of the battery. so besides keeping all the circuits running inside the midnite classic on standby it was doing some other mysterious action. now this mysterious unknown action, that is what i am wondering about.
westbranch, i am aware of all those facts. i have two midnite classics. they are being watched all the time when i am anywhere near the computer or the shed. or on the team viewer or mymidnite page when at work.
now i am aware that this is a weird case. i in no way want to fault the midnite classic engineers. all i want is letting them know of this fact. and i am not too keen to replicate it. i am quite happy having a working midnite classic. so it might not do that symptom when panels keep connected. like in the evening when it goes to sleep. maybe it does not like the panels being disconnected. however when i disconnected the pv, the current was 0.
I think the latest firmware may have fixed this...
Try to be a bit patient with us. Most of the folk on the forum are volunteers, but between us we do have decades of expereince with RE. It is possible there is a fault with your controller, but it will help to rule out any system issues, which is why were asking for clarification a bit.
Firstly what firmware are you running?
Quote
however as the battery was now full:the voltage went about to something like 118v
Which voltage? And how did you measure it?
Quote
i turn off the breaker with the temporary array
then, EVERYBODY pleas take note!!!! disconnected the solar panels physically. ok, so no physical connection at the input anymore
Its not a faulty breaker or anything? How did you disconnect the array, esp given its a fairly high (shockable) Voc?
Quoteagain please read correctly here:
the voltage stayed up at 118v
the whizbang jr showed using ( to make it clear for everybody, electricity flowing from the battery to the midnite classic) 0.4 amps. now, resting it only uses 0.1.
the temperature reading showed 44.2 and 48.4 degrees celsius. the fan (inside the midnite classic, to be precise) came on periodically.
Please can you clarify if the controller is remains in float, when you disconnect the array.
The classic only uses that low few watts when it is truly resting. The non resting non charging draw is somewhere up in the 15W area. Whats your ambient temp? Classics run warm in float, its just how they work.
If you remain confident that there is an issue with your unit, you are adivsed to open a support ticket, to make sure that tech support gets to look at this. They sometimes dont see things on teh forum for a day or two.
Quote from: zoneblue on November 25, 2015, 03:11:45 AM
If you remain confident that there is an issue with your unit, you are adivsed to open a support ticket, to make sure that tech support gets to look at this. They sometimes dont see things on teh forum for a day or two.
The description of the "fault" is absolutely identical to that which Steve reported oh, 8, perhaps 12 months ago.
He made videos of it. Everyone seemed to think he was bonkers too.... yet it was demonstrable and repeatable.
And now we have someone unrelated, on the opposite side of the world, seeing the same thing.
Inneresting, 'aint it?
May be an "unusual" situation, but it isn't "unique". australsolarier may have identified something you've not seen, and is not "supposed" to happen, but he's not bonkers. Not if someone else got the same thing almost a year back!
I believe Jim is right, The latest firmware should put a 90 second time out on that if it isnt making real power.
Ross, noone is calling anyone bonkers. Is this the thread youre talking about:
http://kb1uas.com/mnsforum/index.php?topic=2280.msg22674#msg22674
zoneblue,
i am sure you are meaning well. however, if the sun panels are removed, it does not matter whether the breaker is working, you can put bullets into it, dip it in acid, smash it with a hammer: IT IS TOTALLY IRRELEVANT. as for your other questions they are amply answered if you only read the whole thread. i cannot possibly get much more implicit.
for the other folks:
thanks for taking me serious. i am not actually saying the midnite classic is faulty.
bye the way, i noticed when you turn off the breaker to the solar panels, the classic goes into some intermediate state. some high pitched sound i can just about hear comes from the midnite classic. and again a higher voltage than the battery at the input. and higher current use (current from the battery into the classic midnite) on the whizzbang. but then a few seconds later it drops into resting. so maybe the midnite forgot to get into resting mode. i am sure there is probably a LOGICAL explanation for it, but it is way beyond my knowledge. i am pretty sure the midnite classic engineers probably already know why.
firmware is 1923/1839. i was on planning to update the firmware. however. however. the laptop is windows 10. so i was not going to waste 3 hours then find out somewhere along the 30 step update procedure, that it does not work with windows10. so i will wait till that promised easier update procedure is reality.
so thanks again for all the folk reading the thread and actually taking me seriously of what i was describing
all the best to all of you and lots of sun shine
greetings urs
From what others have said W10 is a GO, way easier than W7 or W8...
don't have experience as I am on W7 still
http://kb1uas.com/mnsforum/index.php?topic=2753.0
not according to this.
unless there is something new - Windows 10 doesn't work for firmware updates. I tried.
Ryan said they were working on something new that will work with Windows 10 .
Larry
This may not be on target ...
But about seven years ago, was running an Outback MX-60 MPPT CC, and it developed the capability of making "power from darkness";
The MX said that it was delivering about 50 - 60 watts output, the Vin was about 10 volts above Vbat, the MX was warm, and its fan would run periodically.
Returned it to OB, and the Repair Report was that there were some leaky FETs.
But, the above may well have nothing to do with this situation. FWIW, Vic
HELLO AGAIN
being of an inquisitive mind, i charged the lifepo4 battery again just a few minutes ago. (this time with the permanent wiring) it went into float.
aha!
it said float on the display, the midnite used 0.7amps and?? you guessed it, the 117 volts at the input. turned off breaker to the solar panels, the 117v stayed. i waited a few minutes just to make sure. then disconnected the battery and restarted the midnite. now in resting mode.
for the unbelieving thomasses i took some pictures of the midnite status panel and the display.
after midnite blokes are ready with the simplified update i will do more tests.
i haven't actually checked the other midnite in 12 volt configuration if it is doing the same thing. as there is a converter connected to it, pulling down the battery voltage might trigger the midnite to come out of his "rebellious state".
interesting to say the least.
greetings urs
Quote from: australsolarier on November 25, 2015, 06:24:14 PM
aha!
it said float on the display, the midnite used 0.7amps and?? you guessed it, the 117 volts at the input. turned off breaker to the solar panels, the 117v stayed. i waited a few minutes just to make sure. then disconnected the battery and restarted the midnite. now in resting mode.
Why is this a surprise to you?
When the controller moves from Absorb to Float the current required from the PVs reduces as the controller now only needs to maintain the Float voltage.
So the voltage from the PVs increases up to near the PVs open circuit voltage (117v in your case).
This is absolutely normal.
There is no need to disconnect the PVs as the controller is working normally, its preventing the batteries over charging.
And the 117v on input after you disconnect the PVs... have you considered the Classic's PV input capacitors?
dgd
dgd,
you absolutely missed the point of this thread.
IT IS ABOUT THE MIDNITE CLASSIC REVERSING
ACTUALLY CREATING 117V FROM THE 52 VOLT BATTERY.
now i repeat this here for you: it is not about disconnecting the panels because i am worried the midnite is not doing the right thing in float.
it is about, when you disconnect the panels after float, that the midnite keeps outputting 117v for hours on time without any panels connected at all
is it too much asked for you to read the whole thread?
and as described above:
THE LATEST UPDATE IS SUPPOSED TO REMEDY THIS INTERESTING FACT.
Australsolarier,
I have absolutely NOT missed the point of this thread.
That somehow the Classic has a voltage boost function operating in the direction from battery output stage to the PV input stage is, for me, just incredible. Such a feature has never been mentioned by the designers of the Classic but if this is a secret feature then I look forward to the designers explanation of its purpose.
You appear yo have reached this conclusion based on a few watts of battery power being consumed by the Classic and the PV input reporting 117v even though the PVs are disconnected. I can't follow your logic in how you have come to this conclusion.
I would hazard an explanation for what you see as below.
That 117v you see is really suspiciously identical to the PVs near OCV.
Even when you disconnect the PVs then the Classics input stage caps will remain charged at 117v (they are, I guess, several thousand uF at 200v), they are probably discharging very very slowly if there is no output current going from Classic to battery bank.
Hence you see the 117volts for some time after the PV input is disconnected.
Perfectly normal, no problems.
The WBjr current into the Classic will be different from cool and resting when compared to hot and just come off Absorb to Float. Hot electronics consume more energy and if the fans are activated to provide cooling then more current ill be used.
The 0.1 amp to 0.4 amp range you originally posted again is completely normal for resting AND DOES NOT mean the Classic is operating in some weird reverse voltage boosting mode to show the 117volt input reading you see.
dgd
PS when you see 117v input that does not mean there is 117 volts being output by the classic to your batteries
The true output voltage is the battery voltage you see on the Classic's display
And I will bet the firmware upgrade you mention is not fixing any reverse voltage boost
Its probably just timing out a FLOAT with zero current output and reverting to RESTING mode
So the classic will go either way :o
We use it in boost mode in burn in to feed its neighbor, There is also a couple hidden modes (Well semi hidden) for using it in boost.
Basically (I don't understand the software/hardware reason) with a Asynchronous rectifier (I think I got that right) any time the output of the classic sees the voltage above the target it tries to go the other way. Of course we have reverse current limits etc for that BUT if the battery is full and you disconnect the PV in a regulated state (IE Float or absorb) the Classic will basically set in that neutral state holding the PV at the last voltage it was running at. Normally if in bulk for instance there would be a sweep and it would catch it but in regulated states it does not sweep so it never finds this issue. We never had software in there to watch for low wattage only and shut down I guess, so we now have that added in there.
Ryan
halfcrazy
i really really appreciate that you take me seriously.
rather than writing half a page trying to refute my observations.
thanks thanks thanks
greetings urs
Nobody is refuting your observations
Just the conclusions you are coming to based on those observations
You seem to be reaching these conclusions without any evidence
Dgd
dgd,
are you trying to take the micky out of me because i am an australian?
No, I leave that to our rugby and cricket experts
But I'm please you see the funny side of this thread
I started laughing when I noted the use of 'bonkers' in a posting - not from me :D
Dgd
ok dgd,
as you are in this nick of the world, and you need proof,
i invite you to come over to australia and observe for yourself. i pick you up at sydney airport, you may stay in my house in the spare bedroom, free food, etc. bring your own multimeter, just in case. then we can look at it together. promise not to entertain you with silly new zealand jokes. don't like them. i lived in NZ for about two years myself and liked it there.
shall we leave it at that?
Hi,
Thanks for the offer, however I don't dispute what you are observing on the Classic screen.
I just think there is a better explanation than saying the Classic is taking voltage from your battery and boosting it to the 117v you see on the display for input volts.
Did you not think my explanation for your observations was credible?
I think its time for me to defer to the Midnite engineering expertise who will, no doubt, resolve this.
dgd
dgd,
you are not observing anything, i am doing the observation. please read the thread again. it is all explained. multiple times.
i really do not know how to explain it more to you. i am starting to think you are just trolling.
30 watts go into the midnite from the 52 volt battery. the input shows 117 volts or thereabouts. the whizzbang jr shows -0.7 amps. the midnite is getting warm. every so often it turns on its internal fan. the 117v remain for hours. without any solar panels connected at all. i mean, the solar panels were moved, i carried them away on the porch. disconnected. 10m away from the nearest cable.
there is only so many times i am going to explain this.
i might be australian but that does not mean i am absolutely without any minimal amount of intelligence.
if you are serious about refuting my observation, why don't you try it yourself.
i mean, i used to work in electronics, though many years ago.
i mean you can believe australia is part of new zealand ..............
i am not going to answer to you personally anymore.
now i feel a bit aggravated. sorry about it.
snapshot when midnite classic was reversing
Well what can you say... the moral of this thread, and one i linked to for that matter, is that if you muck about with anything long enough youll discover new things. Most people actually connect their arrays, and thus never find such interesting and useful things. Enjoy!
Quote from: australsolarier on November 25, 2015, 06:24:14 PM
HELLO AGAIN ...
i haven't actually checked the other midnite in 12 volt configuration if it is doing the same thing. as there is a converter connected to it, pulling down the battery voltage might trigger the midnite to come out of his "rebellious state" ...
greetings urs
Believe that the "converter" that you mentioned, that is connected to another "midnite", is a battery charger, connected to a MidNite Classic CC.
If this is true, this is not a recommended practice, in general. Power supplies, connected to the input of many/most MPPT CCs are often too "stiff" for these types of CCs to find Vmp, when they Sweep. This could damage the CC.
Also, believe that one approach that CCs use for Thermal management, is to move the Vin away from Vmp, to limit current/power/heat.
Depending upon the nature of the external power source, you may need to place a series resistor in the Vin lead to the CC, to help protect the CC. Believe, that having a power source with an output voltage near that of the battery will help reduce the risk, at least somewhat.
FWIW, Vic
vic,
well, as a matter of course i presumed that everybody knows an inverter is connected to the battery and not the pv input.
what i was trying to say, when the midnite goes to float whilst a load is connected to the battery (the inverter connected to that battery) that reversing might not occur. like i said i have not checked it yet.
MY INVERTER IS CONNECTED TO THE BATTERY NOT THE PV INPUT. and the solar panels are oriented towards the sun .......... if anybody doubts it, i can send pictures as evidence.
one interesting fact with the lifepo4 batteries is, when the charging falls from absorption to float, for about 30 seconds or there abouts, all the electricity for the inverter (hooked up to that battery) comes from the battery and non from the midnite classic. until the battery voltage drops near the programmed float voltage.
as far as i am concerned i am pretty sure the midnite engineers and designers know about that reversing.
vic, i hope i cleared up the problem thinking i hooked up an inverter to pv input and i sincerely hope i did not hook up the inverter to the pv input whilst thinking it is hooked to the battery. and i sincerely think you did not even in your wildest dreams think of hooking up your inverter to the pv input.
as far as i am concerned this thread should be about the reversing of the midnite and not where people think i hooked up the inverter or if a breaker is broke. i can actually replicate it. and i can understand some people do not believe it. then again i do not believe the earth is flat also.
greetings from a somewhat frustrated urs
You don't have to shout ! More people might help you if you had a better attitude.there I said it for all the great members that give there time and info for free! I will not respond to this thread so if you got something nasty to say inhale and suck it up.
Quote from: australsolarier on November 25, 2015, 06:24:14 PM
HELLO AGAIN <snip> ...
... i haven't actually checked the other midnite in 12 volt configuration if it is doing the same thing. as there is a converter connected to it, pulling down the battery voltage might trigger the midnite to come out of his "rebellious state".
interesting to say the least.
greetings urs
Hello again australsolarier,
Well, the above is a "quote" that was edited to try to focus on just that one part.
This quote came from australsolarier, regarding part of his/her system. In NA, converter commonly means a battery charging device used in our RVs (Caravans).
I did not mention an Inverter, or where anyone's inverter happened to be connected, or not connected.
The word "converter" does NOT mean an Inverter to us, here in this other country. Perhaps it does have that interchangeable meaning, there.
There is almost no one here, that is doing anything other than trying to help others. There will usually be a lack of information in posts from those asking for help, and often, there is some ambiguity in the way some "information" is written. Believe australsolarier made a statement about disconnecting the PVs from the "midnite" input ... this implied to some of us, that a wire had been disconnected, rather than flipping the DC input breaker to Off. This might lead some of us to believe that disconnecting a HOT DC cable could have caused some transient condition in the "midnite", and so on.
Not all of us are perfect! Imperfect Vic
Well living with them every day and relying on them to keep the house running. I like to know all the quirks of the classics charge controllers.
I'm from Australia (QLD) I also run 400ah 48v (calb lifepo4 lithium batterys) . So perhaps I can try and replicate your finding. Perhaps the issue is stimulate by how stiff the voltage is on the lithium's when they have no load in float though I wouldn't think so.
As you mentioned I also notice that there is a period of time after the end of absorb befor the charge controllers need to do anything to maintain float V . Its nothing unexpected as the voltage is so stiff on the lithium's that even with a small base load it takes a surprising amount of time to bleed the surface charge off. Lead acid plummets almost instantaneous as soon as you take the charge off.
Though that's not the issue. This (self consumption) state you have triggered looks like it's something to avoid. Not a common situation to be in but still it's a situation you found your system in and the results are worth mentioning. Thanks for sharing.
I will let the battery hit float and then switch the breakers off for the PV input and see what happens. I guess you will want no DC loads on the battery other than the classic So I will switch the inverter off to then.
Will report back over the weekend. Though I am using 1849 firmware.
Kurt.
hi kurt,
i know you well from the australian energy matter forum. naturally i was following your threads with your system and programmed it to similar voltages, absorb 56, float 53.6v. i will take the opportunity here to express for all your and gordon's pioneering work. sincere thanks!!!!
as i mentioned several times before, there is nothing hooked up to the battery, yet, except of course the midnite and the blue ev power bcu pack, which draws maybe 40mAs.
however it was mentioned before on this thread that the latest firmware limits that reversing state to 90 seconds. i can defenitively replicate it, but i totally agree with you, it is not good to let the midnite classic run in that state.
the 400ah/48v lifepo4 (i got the green coloured cbs )battery is brand new, the inverter not here yet. so i hooked it temporarily up on three panels leaning on the wall. after float, the battery being fully charged and the system working, i turned of the breaker, dismantled the temporary wiring, and carried the 3 panels away onto the floor of the veranda.
however i then noticed that intermediate state between float and resting. and that lasted several hours. turning the midnite of and on it then went to resting mode.
at the moment i am grid connected. when the 60cents feed tarif is cancelled end of next year, i then will fully use the new system. i am a bit ahead timewise with the purchases and installation, as the ossi dollars seems to be on a downhill course.
thanks for your support kurt
greeting from nsw
urs
vic,
i am sorry if i confused you with the word converter. i did mean inverter
all the best
urs
I think I head about an old version of firmware, that under certain conditions, could allow some sort of backfeed as you described.
Normally, battery voltage, or something lower is present at the solar terminals after dark..
Just for the record, I believe Halfcrazy (Ryan) answered the OP's question a few posts back. While I haven't seen a post from boB you can take Ryan's word for it that this situation you have created apparently has been corrected in later firmware. He works for MidNite and was previously the Tech Support Manager.
And yes I can confirm Win10 did not work for firmware updates for me and we are waiting for Ryan to let us know when a new and simpler firmware update method is available.
Australsolarier,
Next time you see this 'reverse' would it be possible for you to use a mutimeter and see if the voltage is 117v at the Classic PV terminals when the PVs are disconnected?
And perhaps again after 30 minutes or so.
This would ensure there is a maintained voltage present and the reading you see is just not a meter reading not being cleared by the Classic's cpu.
A further test would be to place a small load over the PV input terminals in the Classic, something that just draws a few watts and again see if the multimeter shows the 117 volts is being maintained.
A GU10 230v 20 watt halogen light should be ok as it will draw about 5 watts at 117v, it may even glow dimly
dgd
Before the Classic came onto the market , one of the things being mentioned was that it would have a snow melting mode where the Classic could reverse some power back into the panels to heat them up a bit. This feature never came into being . But I just remembered this and perhaps the reverse power being seen is some part of the hidden features Ryan mentioned , maybe some part of the code for that activates under the conditions Astralsolarier creates ?
snow melt thread
http://kb1uas.com/mnsforum/index.php?topic=660.0
Larry
Quote from: ClassicCrazy on November 27, 2015, 10:18:17 PM
Before the Classic came onto the market , one of the things being mentioned was that it would have a snow melting mode where the Classic could reverse some power back into the panels to heat them up a bit.
Larry
So how would that work with panel having blocking diodes installed in them ?
I have seen one 300W Canada Solar that was damage on shipping (fork from lift truck pierced it) And on disposing of it , I noticed black diodes in the wire combiner box.
Other was a few small Asian no brand that also had diodes .
VT
dgd,
i did measure it with the fluke voltmeter. just to give you an idea, when i first discovered this reversing, it lasted from from 10.58 to 16.48 hours. then i disconnected and reconnected the battery. it then fell into resting mode and 39.odd volts (as recorded on the mymidnite website).
and yes i was tempted to see how much power i could draw. however, i am not in the situation of ryan serial blowing up of midnite classics. i have to pay for them. this one set me back 1350AUS$ with the whizzbang jr. it gets quite warm doing it.
i was watching the 12v system (also has lifepo4 battery, 12v/300ah) today falling into float mode. it did it rapidly, no intermediary reversing state. the inverter was drawing 750 watts though.
turning off the breakers on the 48v system during bulk, it goes into that intermediary state for about 30 seconds before hitting resting mode.
both midnite classics have the same software, 1923 loaded.
greetings urs
Quote from: CDN-VT on November 27, 2015, 11:33:46 PM
So how would that work with panel having blocking diodes installed in them ?
I have seen one 300W Canada Solar that was damage on shipping (fork from lift truck pierced it) And on disposing of it , I noticed black diodes in the wire combiner box.
I seem to remember the diodes installed in solar panels are usually bypass diodes and not blocking diodes.
Blocking diodes are usually installed externally
http://www.solar-facts.com/panels/panel-diodes.php (http://www.solar-facts.com/panels/panel-diodes.php)
dgd
Ok , I read that , So how is the panel fed power to use for heat ? reversal is / has been posted .Both Diode pix are one way & anti reversal , Zener diodes are Bi /till voltage .
Please explain ,
So I need to see what & what im missing , of how to back feed heat /power or to feed in flow power ? that I can't see heat on a factor of % to make the power input worth the heat .
VT
Can't spell
If you elevate the panels voltage above VOC it will generate heat, the higher above the VOC the more current it will conduct.
(http://www.solar-facts.com/panels/bypassdiode.png)
So from Ryans explanation , there would be no blocking diode .
I can see the cells receiving power with just bypass diodes .
Must be some amount of power to overcome some VOC on series wired panels
and then shed amps to heat them .
Thanks for the update.
VT
This feature of solar panels can be put to use. As boB mentioned some time ago the PVs can be used to clip an attached wind turbine with the Pvs OCV becoming the clipping voltage. As turbine output exceeds this the excess is used to heat the PVs and slow the turbine
It would need some thought to get the design right with the voltages but would enable a PV array and a paralled wind turbine to be connected to inputs of a Classic.
dgd
Yes that used to be done a lot with hydro. Make sure the PV is larger than the hydro and make sure the pv vmp and hydro vmp are similar. Then as the battery gets full the MPPT lets go and the hydro heats up the panels slightly but the panels become a clipper
So if I lived somewhere where snow covered my PV array AND there was wind to get a turbine really moving then clipping the turbine voltage using the PV array would also clear the snow off the array.
Then we would not need a 'reversing' Classic :D
dgd
Here we use a rubber edge snow rake if need be. (https://encrypted-tbn2.gstatic.com/images?q=tbn:ANd9GcQusKaa47FFFnxqVsldvdy8tPbPLTsZh3W6os5L1NFyqMZQNnX8vw)
(http://www.burlyproducts.com/store/images/uploads/snowrake1.jpg)
If we do have a build up of snow it's direction off the panels is still downward , so I'll need to blow it somewhere .
After the panels are semi clear the sun can do the rest , if it's still snowing then i don't think you can beat the melt with powering the panels HERE.
VT
I've tried to use a snow rake, but not the rubber edged one. I have a brush about 16" wide on a pool cleaning extension rod for panel cleaning now. The snow rake would get caught on the roofing screws on the steel roof, and on the panel mounting hardware on the arrays. The brush doesn't.
Ralph
Ralph gets much fluffier snow than us on the wet coast .
Our snow is heavy wet pack . I modified the snow rake in the posted Pix ,
I went to a janitor type store & got a replacement floor squeegee rubber & then drilled & used aluminum strip to secure .
on the handle side I installed a wing so the rake only go's down 6-8" in the snow.
For us wet-coasters , we need to remove the snow evenly from the roofs, take off 1/2 on one side & then 1/2 off the other till you have unloaded evenly .
We don't normally get snow , but with them fooling with the weather , 3 years ago we were hit with 6' in a week .
I had both snowblowers going & 2 roof rakes while we were on pruning ladders pullin ,pushin & blowen for a month .
Snow belongs in the mountains or back EAST !! :o
I posted the Pix of the snow rake for W Auckland,many might think I was pushing their chain with snow snakes & rakes ..
Hard to see white snakes , but if ya ski , them-el trip ya up every time ;)
Quote from: dgd on November 29, 2015, 05:06:50 PM
So if I lived somewhere where snow covered my PV array AND there was wind to get a turbine really moving then clipping the turbine voltage using the PV array would also clear the snow off the array.
Then we would not need a 'reversing' Classic :D
dgd
Unfortunately, with enough snow on the panels and anything lower than 20 some degrees F outside, you will most likely blow the PV's series fuse when trying to melt snow :(
BTW, the newest Classic firmware (2079) will not stay on with zero forward watts (into the battery) for very long.
What happened before was that if the Classic was in Float or Absorb (or EQ) with little or zero output watts/amps,
like if the battery voltage was being held up by another charger or whatever, it would stay on.
Merry Christmas, almost.
boB
Bob, 2079 looks to me very much like the firmware that throughly put the icing on the christmas cake.
Quote from: zoneblue on December 01, 2015, 03:41:08 PM
Bob, 2079 looks to me very much like the firmware that throughly put the icing on the christmas cake.
This is great to hear !! (I think it's good, anyway ? )
Quote from: boB on November 30, 2015, 11:23:15 PM
BTW, the newest Classic firmware (2079) will not stay on with zero forward watts (into the battery) for very long.
What happened before was that if the Classic was in Float or Absorb (or EQ) with little or zero output watts/amps,
like if the battery voltage was being held up by another charger or whatever, it would stay on.
I'm not sure this is a great idea, it may be for a system with a single Classic but what happens if there are two or more Classics charging the same battery bank?
Since there is no charge balancing between Classics where they share the charge requirement between them then what happens now is that one Classic will maintain the Float charge needed by the battery and the other(s) will stay in Float but have zero amps out to the battery. If the one providing the Float current falls below the required amps then the other(s) will start moving out amps to make up what is required.
Now if you are going to force the zero output Classic to resting then how can it waken up in Float state to make amps to maintain the battery Float state?
Will it come out of Resting and go into Bulkmppt mode? which would then have the potential to overcharge the battery.
And 'follow-me' would not be a viable solution for this as the Classic that was maintaining Float would move to zero amps output as the woken-up Classic did Bulkmmpt. In turn then the Float Classic would go to Resting andbe woken up again in Bulkmppt mode.
As they say SNAFU :o
dgd
Quote from: boB on November 30, 2015, 11:23:15 PM
BTW, the newest Classic firmware (2079) will not stay on with zero forward watts (into the battery) for very long.
Perhaps a modbus register could be used to enable/disable this feature
With the LA having a config line to do this?
Or have it disabled if follow-me is not implemented?
Or better still, get charge sharing implemented
And get follow-me implemented over ethernet using an ip-number table on each Classic so that the serial ports can be used for proper applications (inc W10 firmware updates) ;)
dgd
Quote from: dgd on December 05, 2015, 05:42:27 AM
Quote from: boB on November 30, 2015, 11:23:15 PM
BTW, the newest Classic firmware (2079) will not stay on with zero forward watts (into the battery) for very long.
Perhaps a modbus register could be used to enable/disable this feature
With the LA having a config line to do this?
Or have it disabled if follow-me is not implemented?
Or better still, get charge sharing implemented
And get follow-me implemented over ethernet using an ip-number table on each Classic so that the serial ports can be used for proper applications (inc W10 firmware updates) ;)
dgd
Did I add a flag bit to choose this ? Hmmm... Will have to look.
It doesn't turn off until it sees it sitting there for at least 15 minutes and then just goes to resting...
If the battery voltage is above the set-point, then it will not turn back on. If the battery voltage is
below the set point, then the Classic will wake up again and start charging.
This was mainly intended so that the Classic would not just sit there and waste energy when there
was no need to be on and running. Going to Resting will make sure it wakes up only if it needs to
and 15 minutes should be long enough where it doesn't keep clicking on and off.
I will see about adding that enable flag if I didn't already.
boB
ok, so for the people thinking i am mucking about, i hooked up the battery bank (lifepo4 48v/400ah) to the new selectronic 7.5kw inverter. then charged up the battery. the midnite classic went to float and was reversing again. even though i turned on the water tap to trigger the pump. after 5 minutes isolated the midnite, turned it on again and then normal again. i did not find out how far down i had to discharge the battery for the midnite to volunteer to go into proper float mode.
just wondering how the midnite classic guys are going on with that easy to install windows10 firmware update.
ok here more tests:
this morning charged the battery with the selectronic inverter charger. pv panels disconnected at the breaker. midnite classic connected to the battery. after charging finished check the midnite classic. and loh and behold, it was reversing.
then
discharged the battery somewhat and another charge this time with the midnite. went to float, was reversing. hooked up the 2000w kettle to the selectronic inverter and turned on. battery voltage goes slowly down. when it went past the programmed float voltage, in my case 53.6 v, it thought better of reversing and started charging. turned of the kettle: battery voltage rose again with the result of the reversing effect. turned on kettle, normal float.
so the result is in my case between absorb voltage and float voltage it is doing the reversing
might i add here
the midnite classic is not miss behaving because i am "mucking" around.
rather the "mucking" around is a consequence of trying to figure out what is going on.
i also might add, that this reversing effect is not necessarily a bad thing for the lifepo4 batteries, as they get pulled down to float voltage faster when there is no use of electricity.
however, i am not able to say whether or not this state is good for the midnite classic, as it warms it up to over 48 degrees and the fan turns on.
the midnite classic designers might perhaps let me know whether this reversing state is detrimental to the health of the midnite classic.
thanks for any answer from the more knowledgable people here.
I would see if you could swap the classic another one. That's not normal behavior. As you already know I have a almost identical setup 400ah lithium battery, two classic 150's and a selectronic 6000w inverter.
I don't get the reversing (classic consuming 30w and heating its self up) you are describing at all In the transition period from absorb to float.
Didn't you mention you had a 2nd classic on another12v system. Could you swap that one over and try that one.
Kurt
yes i could swap the midnite classics over. however that is about a days work. what with them really small terminals in the midnite classic. the 12v system has 50mm2 cable into the midnite and i crimped reducers on the end so to fit into them really small terminals. they are bent as well. i mean even a 35mm2 wire you have to 50% trimm back to fit into the terminals in the midnite.
plus then reconfigure the settings.
so i think i wait with that experiment till the midnite classic guys come back with an opinion and that new update is available for windows10. then see what's happening afterwards.
Just a thought, is your classic float voltage near to or lower than the battery rest voltage? Someone else pointed out that this would cause a quite a lot of reverse potential. What the new firmware does in this situation is a bit unknown becasue if it goes to sleep, then wakes up and repeats it could be interesting.
FTR, i looked at the 1s monitoring data, and my bank upon float, reverses for exactly 2 seconds. Then the voltage stablises.
See beta 10 installer here:
http://kb1uas.com/mnsforum/index.php?topic=2794.msg26912#msg26912
well yes you want the float and "rest" voltages to be the same, as recommended by the manufacturer and other people on the fora do.
as mentioned before, the lifepo4's are quite stiff. after changing to float there is some seconds or even minutes or hours when no use of the battery where it hoovers between absorb and float.
so what happens your agm's drop down to float much faster and even in float might consume some residual power.
basically if i would use 500w or so electricity that reversing would be much shorter also. it's just that my 48volt system is at the moment in the commissioning stage and not connected to the house yet. like i wrote bringing the kettle to boil brings down the battery's voltage fairly quickly and the midnite starts to work in float mode again.
so it is quite possible that there will not be much of a problem when the thing is in use.
Yes -seems like you really should try out the newest firmware to see if it fixes your problem. Ryan said though that if for some reason that Beta Windows 10 installer doesn't work, it will leave your Classic without any firmware.
I think he said that using a Windows 7 computer could fix it up in case Windows 10 beta uploader messed up.
So is it not possible to borrow a Windows 7 laptop ( probably your best option at this point ) from someone to use to install the newest firmware ?
Larry
Yeah so far we have tried the 10 updater on 12 pcs. 1 failed but it also has a couple driver issues. The failure simply leaves the classic with NO firmware so updating with a different pc would work but you have to have the other pc
i think i wait till that windows10 updater is secure. the system is not at proper use now. so i can wait. at the moment my new system is just idling. with a socket to tap into the 240 volts. it has yet to be connected up to the house. (the electrician !!!!!!!!!!!!!!!!!!!!!!!!!!!!)
anyway thanks for the helpful answers
urs
Quote from: Halfcrazy on December 18, 2015, 11:19:00 AM
Yeah so far we have tried the 10 updater on 12 pcs. 1 failed but it also has a couple driver issues. The failure simply leaves the classic with NO firmware so updating with a different pc would work but you have to have the other pc
Probably sideways of the topic, but...
Just have to ask:
Just wonder if a super basic Linux system [with the update files] in a USB image that is written to a stick that boots the PC, finds The Classic, installs the update with a python script like the Linux updater does??
Would bypass the seemingly continuing MickeySoft issues? Probably not all that hard to do. Might be a very good way to distribute updates? At least should eliminate software issues?
Just been thinking of this as a solution to an ongoing issue with Windows versions.
Tom
Quote from: australsolarier on December 17, 2015, 06:38:13 PM
ok here more tests:
this morning charged the battery with the selectronic inverter charger. pv panels disconnected at the breaker. midnite classic connected to the battery. after charging finished check the midnite classic. and loh and behold, it was reversing ...
Hello austral..
You might want to try what almost all of the rest of us do, when we wish to not have a Classic active -- We go to the Mode menu for that Classic, and switch Mode = Off.
This allows the PV to remain connected, but the Classic will be in Rest, until the Mode is again switched to On.
FWIW, Vic
yes i agree if the midnite classic is turned off, it will not do reversing. say your car is using 2 liters of oil for every 100km. it will not use any oil if you turn off the car. however turning off the car will not result in fixing the problem of loosing oil.
basically what i am saying is my midnite is doing reversing between float and absorb voltages, no matter whether the battery is charged with an outside source or with the midnite itself. then rebooting it will go into proper mode, say resting. until bulk charging again. etc
as far as i am concerned that reversing has something to do with a soft ware glitch.
another thing i like to mention, say you charge the car battery. the charging is finished. you unplug the charger at the mains socket. you would not expect to be zapped by the prongs of the plug whilst the charger is still connected to the battery.
so this reversing is inherently dangerous. i like to work with the pv wiring when the sun is not shining (at night). because the pv panels do not generate voltage. then you go up the ladder and get zapped. or the bloody wires spark or whatever.
as a matter of fact the midnite should not do reversing at any circumstance. not even if it is faulty. or the rain gets to it. the caterpillar go inside and chew wires. a dust storm. a tsunami. mud wasps build their cocoons inside. etc
say your car is breaking down, the gearbox breaks. you would not expect the car to have 5 reverse gears and only one forward gear, because something is wrong. or suddenly the brake pedal turns into the accelerator and vice versa.
I thiink you have proved your point about the reversing and everyone believes you and Midnite said it is possible and that they made a firmware update to fix it hopefully. So just waiting for you to do that update.
just waiting for that windows10 update
I have the updater but it is "BETA" If you try it and it fails do you have access to a windows 7 or 8 PC? So far it has only failed on 1 PC and that has a USB driver issue but it still worries me as it erased the firmware and wouldn't update. So if you did not have a backup pc to update with then it would be an issue
Let me know if you want to try it or wait for a few more to play with it
well yes the pc is windows7. but it is about 20m from the shed. it would take hours if not days to set it up in the shed, not even thinking then returning it into the house. i mean it is heaps easier carrying the laptop to the shed and plug it in.
like i wrote before, the system is not in full use yet. i can charge the lifepo4 with the selectronics using power from the grid. so i am happy to wait till that windows10 updater comes out of beta.
anyway, thanks for the offer.
Quote from: ClassicCrazy on December 19, 2015, 04:54:59 PM
I thiink you have proved your point about the reversing and everyone believes you and Midnite said it is possible and that they made a firmware update to fix it hopefully. So just waiting for you to do that update.
I have had time to try and duplicate this 'reversing' using six different Classics, c150 150lite c250
With 24v 1025FLA, 800/48 SLA and 300ah 48v LiFeYPO4
In all cases the high PV input voltage faded away after a minute or so
No holding on to voltage for hours or apparent reversing (reverse voltage boosting)
So 'proven'. Definitely not.
Various Firmwares before 2079
Dgd
just by coincidence, just when i received the last message, my 48v system went into float, with no load and was doing the proven/unproven reversing. i waited a few minutes. in the status panel turned off "mppt mode".
and yes the pv voltage started to sag. turned on again. remained in resting mode.
my offer for seeing the fact for yourselves still stands.
have a good christmas holiday season
greetings urs
Quote from: ClassicCrazy on December 19, 2015, 04:54:59 PM
I thiink you have proved your point about the reversing and everyone believes you and Midnite said it is possible and that they made a firmware update to fix it hopefully. So just waiting for you to do that update.
Quote from: australsolarier on December 19, 2015, 07:36:48 PM
well yes the pc is windows7. but it is about 20m from the shed. it would take hours if not days to set it up in the shed, not even thinking then returning it into the house. i mean it is heaps easier carrying the laptop to the shed and plug it in.
like i wrote before, the system is not in full use yet. i can charge the lifepo4 with the selectronics using power from the grid. so i am happy to wait till that windows10 updater comes out of beta.
anyway, thanks for the offer.
Quote from: dgd on December 19, 2015, 08:01:57 PM
Quote from: ClassicCrazy on December 19, 2015, 04:54:59 PM
I thiink you have proved your point about the reversing and everyone believes you and Midnite said it is possible and that they made a firmware update to fix it hopefully. So just waiting for you to do that update.
I have had time to try and duplicate this 'reversing' using six different Classics, c150 150lite c250
With 24v 1025FLA, 800/48 SLA and 300ah 48v LiFeYPO4
In all cases the high PV input voltage faded away after a minute or so
No holding on to voltage for hours or apparent reversing (reverse voltage boosting)
So 'proven'. Definitely not.
Various Firmwares before 2079
Dgd
Maybe it's the controller!! It seams to me that this discussion has become very heated and I would think if the controller was sent in to midnite for a search and discovery it would benefit everyone! After all, the controller isn't in service yet and Im sure something can be worked out that will allow australsorier to get a controller in working order when the panels are ready and in place. australsorier, if you need a controller Ill send you one that works and is safe, I would just like to see your controller sent back to midnite for them to play with!
Walt
yes there is the possibility the midnite classic is faulty.
however i think we should wait till that promised easy windows10 update procedure eventuates. some people here on the forum think that might solve the problem.
then, we go out from there.
That is fair enough! As long as you can be patient for the windows 10 update to be proven not to cause further issues. ;)
Walt
I'm confused here a bit... as once this LFP system is actually put in use... the whole problem is moot. We who have LFP packs know that the voltages are stiff and that when the Classic moves from ABSORB to FLOAT that it will take a moment for it to catch up. None of it is actually detrimental to our Lithium packs. You can either wait for it to do it on its own after a few minutes or a quick 15 seconds of a Kettle on would settle it.
My system has been up since June 2013 and it has never been an issue in a system being used.
How many times is that pack going to be recharged if it is not actually being used. Also, if someone is going to go on vacation and leave their system to not be used while away one would simply turn off all components and the breaker to the battery pack to keep from either charging or discharging. Lithiums are better off just sitting there by their lonesome rather than needing to be "Topped Off" like Pb cells.
Comply different chemistry here. Whole new set of quirks and nuances.
My two cents.
Cloud
ok
i updated the firmware to 2079. (with that new super easy straight forward beata updater.)
and
like the more knowledgeable members of this forum predicted, this 2079 update actually solved the problem. like ryan said earlier, the reversing times out after 90 seconds. (i actually timed it)
we can now let this go to rest.
i like to thank for the people here on the forum that contributed in a positive way to solve my concern.
the people that actually understood what i was talking about.
thanks again
and wishing everybody here a good year with much sunshine
greetings from down under
urs
Urs
Glad it all went as we hoped.
Ryan
Glad all worked out, Im sure many learn't from all the postings .
I did at least .
Good-day Mate !
VT
Great ! Good news for a change !
boB
real happy ti see it all worked out and with the understanding of the concernes 8)