Starting a new thread, want to leave the Update via Win8.n thread less cluttered. [ http://midniteforum.com/index.php?topic=1912.0 ]
Anyway. I've now got 2 arrays and 2 controllers side by side. 3Kw / 120V into a MS-TS-MPPT-60 which seldom runs any more than warm. Been in place for 3 years .
Adding the classic, on a 2Kw / 160V array, into the same battery bank, and it's running 10deg (C) over ambient (my battery temp sensor is currently in free air)
My battery/inverter shack runs 5-15F over ambient, the roof eves are open for flow thru ventilation, the XW inverter sometimes has it's fan come on when I'm pulling over 1.5Kw in loads
But the Classic is roasting, when the sun is up. When it falls back to float, and the cool controller is "taking up the load", it's still cycling it's fan while providing 0 watts. And at night, it's drawing power from the batteries, staying 10C over ambient.
Hi Mike,
Classics do run a bit warmer than some other CCs.
Higher String Vmps will increase the losses in just about any MPPT CC.
When running a Classic 200 or 250, it may not be fair to compare CC heat with CCs that do not have this capability, and are running considerable lower Vins.
The CC loss vs increased Vin is not a linear function -- increasing Vin by 25% does not mean that there is only a 25% increase in CC power dissipation (within the CC), based on observations here.
When one needs the capability of a Classic 200 or 250, there are few alternatives. And a bit less efficiency comes with this decision. Am sure that you did carefully consider losses in the PV cabling vs cost, and these losses/costs vs decreased efficiency in a Classic running at the higher Vins. Sometimes these trade-offs are difficult to make.
Recently was looking at a Classic 200 with a fairly high Vin vs large cable and a Cl 150 for a 300 Ft run. Have been leaning toward the Cl 150, but the jury is still debating.
Do not know if the Buck Converter in your Classic 200 shuts off after a period of minutes, when in Float at 0 watts out, with another CC carrying all of the charging load. But just running the Converter with very high Vin is going to make things run hot, IMO.
And, when you note that the Cl 200 has a 160 V input, is this String Vmp, or Voc, and on the TS is at 120 Vmp, or Voc?
And, when you note that the Classic 200 is 10 C over ambient at night, does the Classic state it is Resting? And you are sure that the Classic is NOT experiencing Insomnia?
Your Power Shed is pretty hot ... if you could force some air flow, or move it to a cooler location, this should help some. 33 C-ish batteries is probably not good for them, although I know little of NiFe batts.
Vic
Floating at 63.5 volts for a 48V battery bank ??
Is this the required float voltage for an NIFE bank? What is the Absorb voltage and do you time this or use end amps value to terminate? and what is EQ voltage if these cells are EQable :)
dgd
Quote from: dgd on June 21, 2014, 10:26:01 PM
Floating at 63.5 volts for a 48V battery bank ??
AND at 0 watts and 0 amps AND still in Float and NOT Resting... I have an idea here.
With the Float voltage on this 0 watt output Classic set to a lower 54 or so volt Float setting
and the battery being pushed up to 63 volts (presumably by the other controller ?), what might
be happening is the Classic is pushing some negative current into the PV array and heating
up. This will not hurt anything but would possibly cause this result.
You can see if the Classic is pushing out negative current into the PV array by looking
at the middle - numbers in the "secret screen" from main status... Hold he left arrow key
down and tap the ENTER key to get into this display from main status. If the BATT - number
is higher than around 50, then this may just be the issue.
When you see this happening, please try setting this Floating Classic's mode to OFF so
it goes to Resting and wait a little while to see if the temperature drops down.
I don't understand either though why the battery is at a high voltage unless maybe you are
EQing or as DGD eludes to, is because of a special battery type or arrangement.
Thanks,
boB
Thank you DGD for noticing this !
Mike has said elsewhere that his NiFe battery bank charges at about 65 V.
FWIW, Vic
Quote from: Vic on June 22, 2014, 02:15:38 AM
Mike has said elsewhere that his NiFe battery bank charges at about 65 V.
I suppose it depends on the number of NiFe cells to make up 48v. AFAIK a cell is 1.4v and loads down to 1.2v with constant voltage charging at 1.65v per cell.
So 48v configured as 40 cells at 1.2v is 48v and charge at 65 volts.
Again AFAIK theres no float or eq just constant voltage charging timed to replace used Ah on an 80% efficiency - use 8Ah replace with 10Ah.
This would answer why the Classic is in Float with zero output if absorb is metered then float is set very low or zero.
Or I could be completely wrong ;) perhaps Mike will explain his battery configuration and the charging regimen.
dgd
summertime daytime temps in the upper 90's thru low 100's. Eves are not blocked in, just screened to allow for air flow and hydrogen evacuation. I could put a fan on a timer to move air around. The battery temp sensor is NOT attached to the batteries but just in the air next to them. NiFe does not tend to "runaway" during charge. Batteries are a large thermal mass sitting on the concrete floor.
So for my NiFe bank, I absorb up to 67-68V, and float at 64v. This uses about 15 gallons distilled monthly, which I'm told is average for NiFe. I can discharge as low at 46V in dire conditions, so that would be the range I run at. I have "daisy chained" cables and conduits, and have used the largest wire I can pull thru existing filled conduit. So I'm stuck at the 160V. Designed myself into the corner and am trying to live with it.
About the only thing now I'm uncertain about is the LIMITS in the Advanced menu (Local App) I currently have
Min Volts = 45.9v Max 69.1V 52A output 49A input any pointers appreciated.
Mike
As we spoke about on the phone. The night time PCB and FET temps are about normal. The Classic will draw ~3 watts at rest to keep the display, Ethernet and other items going. The Temp sensors are on the circuit board and thus get some false heating from those components.
Sorry you are unhappy with your Classic.
I would also point out that the Classic "Appears" to run hotter than other chargers and a lot of that is the fact you can actually grab ahold of the heat sink as it is smooth. With a finned heatsink like the Morning star the heat is dissipated faster thus appearing cooler.
Quote from: mike90045 on August 06, 2014, 02:21:38 AM
About the only thing now I'm uncertain about is the LIMITS in the Advanced menu (Local App) I currently have
Min Volts = 45.9v Max 69.1V 52A output 49A input any pointers appreciated.
mike,
My opinion is that these Limits are (now) in the Limits menu for Sealed LA batteries. But, do not know about the desired limits for NiFe batteries.
From observations, here, the upper voltage Limit is set automatically from what has been entered as the EQ voltage. AND ... let's see, was the lower limit automatically set from the Float voltage entered ... ?? ? Forget, but, for FLAs, this does not work at all well, and can cause problems when one believes that they are correctly charging FLAs that are cold (as a minimum).
It took me a while to figure out just why my FLAs at one remote, unattended site, were very undercharged, when things finally turned cold ... This had been caused when VMMing after a FW Update, and not realizing that the Limits menu had changed, and that the Temp Comp charge voltage values had been limited to a very narrow range, and that in time would result in quite inadequate compensation, particularly for cool/cold batteries ..
It is my belief that the low voltage limit in the Limits menu is the point where temperature compensation STOPS when batteries are hot. And, the upper voltage in this Limits menu is the point where temperature compensation STOPS for cold batteries.
Personally, often set EQ to Vabs + 0.1 V (this is as low as the Classic will allow), when am not interested in EQing the battery. When FW is updated, and one does VMM, then the Limits voltages are CHANGED to these values, which are not at all appropriate for FLAs (in my case) ... one more thing to try to remember to reset to some safe value for non SLA batteries.
Personal belief is that this change to voltage limits on VMM is not a good thing for FLAs ... and something to keep in mind, for those with FLAs ... not to rag on MN too much.
I do not know what are the needs of your NiFe batteries regarding compensation of charge voltages.
Opinions, YMMV. Good Luck, Vic
Quote from: boB on June 22, 2014, 01:02:44 AM
.....You can see if the Classic is pushing out negative current into the PV array by looking
at the middle - numbers in the "secret screen" from main status... Hold he left arrow key
down and tap the ENTER key to get into this display from main status. If the BATT - number
is higher than around 50, then this may just be the issue......
Numbers are jumping around in the mid 40's watched for a minute, never saw any 50's
Got the clamp-on meter rigged up, and it's reading about 0.14A (140mA) which at the 54V at the batteries,
gives me about 7.5w Dang, it sure seems like that case is cooking along at about 40 watts, but that's what
my meter claims, 7.5W
There is power leaking from the classic to the Array, because the PV breaker will turn the SPD on or off, but 5mA into an LED will light that up.
However, in contrast, the Morningstar consumes 20mA in night mode, 40mA when the display is lit. That's about 1 watt dark, 2 watts with display backlight, and it's web server is running too.
I'm relieved that I don't have a problem to solve for winter (low power days, long nights, counting every watt) and surprised how much 7.5 watts warms up the case. My meter does not have enough resolution to see the effect of turning the SPD on / off via PV breaker.
I've not heard the Turbo fan come on. I think at boot time, it's just the 2 main fans that do a test spin?
Even though the daytime temps hit mid 90's, the battery jugs only get to 75 from their thermal mass, night times it's mid 50's
Quote from: boB on June 22, 2014, 01:02:44 AM
Quote from: dgd on June 21, 2014, 10:26:01 PM
Floating at 63.5 volts for a 48V battery bank ??
AND at 0 watts and 0 amps AND still in Float and NOT Resting... I have an idea here.
With the Float voltage on this 0 watt output Classic set to a lower 54 or so volt Float setting
and the battery being pushed up to 63 volts (presumably by the other controller ?), what might
be happening is the Classic is pushing some negative current into the PV array and heating
up. This will not hurt anything but would possibly cause this result ...
... When you see this happening, please try setting this Floating Classic's mode to OFF so
it goes to Resting and wait a little while to see if the temperature drops down.
I don't understand either though why the battery is at a high voltage unless maybe you are
EQing or as DGD eludes to, is because of a special battery type or arrangement.
Thanks,
boB ...
OK, have wondered just why Classics seem to not rest when something is holding Vbatt above Float voltage compensated setting. Believe this happens when the Classic transitions to Float from Absorb. Do not recall hearing the input relay opening, and the Classic resting until the surface charge is removed from the batteries and the Vbatt descends to the correct float voltage.
Seems like this can cause concerns here (even though it may not really be a problem), and when there might be Wind or Hydro inputs able to charge the battery bank after the PVs are shaded or it is dark.
My guess is that when the Classic is in Float, the Converter is running, and therefore the Classic is consuming more power than when Resting.
Mike, so you have NO Hydro, Wind, or other charging source when the Classic is "roasting" in the evening/night??
And, as has been noted earlier, fans running in a Classic does not mean that there is an abnormal situation (IMO). The LA Screen shot shows that the FETS are about 20 degrees C above ambient. That might represent some power that is not charging the batteries, but probably not a huge deal ... easy for me to say, with FLAs and only PV as the RE charge source.
Pardon the opinions, Vic
Mike, try unplugging the MNGP/Remote and re-check the current draw. I have another idea too but
will require the serial number of the Classic to see if its hardware can use the idle power draw lowering
idea. 7.5 watts is very high for a Classic. These days they are "usually" almost but maybe slightly
higher draw than half of that. OK, so much for idle draw.
On the input side, the PV terminals are supplied from the battery by a 10K resistor plus a diode drop
and is "normally" around half of the battery voltage if PV side is left open circuited.
If the relay was NOT opening while resting, then the PV input will be "almost" battery voltage... i.e. Vbatt minus
a diode drop.
Also, when you see that number go up to 50 while "Resting", that is a bit high but not by very much.
That would typically be a bit higher than 0.14 amps higher than 0.0 amps, or more like 0.5 amps from
zero offset. There is a hardware wired in offset from those current sense numbers of around +4.0 to
+4.5 amps or so.
boB
42 cell NiFe battery bank 67V absorb
(https://www.facebook.com/120212794718849/photos/a.904365872970200.1073741844.120212794718849/904367002970087/?l=248d08d893)
(link to facebook was here)
Screen shot of the "secret screen"
https://www.facebook.com/120212794718849/photos/a.904365872970200.1073741844.120212794718849/904367002970087/?l=248d08d893
Other charge controller is holding the battery at Float @ 64.5V
Classic Float set to 64.6V but today is warm at 30C so the BTS has lowered the actual "desired" voltage to something a bit less.
Today @ 30C, the fan is running 100% while 0 watts being produced.
FET 48.1C
PCB 49.2C
BAT 31C (free floating at ambient air temp, about 90F today. battery jugs a bit cooler)
Took a 10 sec video of the screen with the numbers jumping around
Nighttime there is no other charging source
24hr battery graph:
Oh No ! You showed the "secret screen" !
Since the Classic evidently in Resting or Float mode here, there is some current being drawn to run the Classic which is why the positive current #36 is lower than the #40 or so that you would normally see.