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Charge Controllers and Clippers => The "Classic" charge controller => Topic started by: 2flit on March 26, 2011, 04:45:01 PM

Title: Tare Losses, Cut-in Power Level
Post by: 2flit on March 26, 2011, 04:45:01 PM
Hi There,
I am measuuring 380ma parisitic draw with the array breaker off. This is a huge winter time loss on a small system, heck, I can almost run two littlite's on that much power!

I would like to know what the nightime tare losses are and how this thing knows when to stop being a load?
In my system.... what is the aproximate array wattage at which the controler will cut-in? 
In real world conditions for our system there is often ridiculously little power comming in >> In these conditions (ie 20 array watts for 8 hours, dark the rest) At some point the night time tare losses result in net loss from having the Classic turned on...... At what point would this occure?  Express this in watt-hours/ day input to the controler.

Thanks!

I have a very early version Classic200 with three 200W Sanyo's connected in series. Array is Tree mounted but still suffers heavy shadding in the maritime pacific nortwet.  24VDC Battery with 5amps and 123vpm on the array, 160' #6 cu 1-way array run
Title: Re: Tare Losses, Cut-in Power Level
Post by: boB on March 26, 2011, 05:13:23 PM
QuoteI am measuuring 380ma parisitic draw with the array breaker off. This is a huge winter time loss on a small system, heck, I can almost run two littlite's on that much power!

Yes, you're right !   LED lights for sure !

384 miliAmps at 25V is ~almost~ 10 watts and I have never seen the idle tare loss (Classic off) that high.
BTW, what are you using to measure this current with ?   Are you using say, A Fluke meter ?

Does the display say "Resting" when that input breaker is off ?  The reason I ask is that if the Classic
is running and you turn off the input breaker, it may still be running for a minute before it
turns itself off.  When it is not resting and the switching circuitry is running, it will draw more power.  That draw
at lower power output will be reduced fairly soon in software so will at least be upgradeable.


If it i indeed  is drawing Resting current this high, give me or Ryan an email or phone call or message and we will see what we can do.

Right now, it shouldn't draw more than around 5 Watts or so when Resting.  On the high side, I have heard 5.5 Watts
and around 4.25 to 4.5 and 1/2 Watts on the low side.

I realize that even 5 Watts is higher than it should be and we are reducing that.  Some of that will be done with just
Software and even more with hardware for future units.  Not too long from now, while the Classic is in Wind mode and
waiting for wind, if the cut in voltage is fairly high, the Classic will draw a bit much power just sitting there for a
minute until it turns off.  This can and will be reduced by about 1/3 with a software only fix fairly soon.

Right now, if the Classic is not producing at least around 15 Watts, that is when it should turn off.
This rule may be made better soon too since the Classic's current sense circuitry is fairly accurate.


boB

Title: Re: Tare Losses, Cut-in Power Level
Post by: niel on March 26, 2011, 06:29:12 PM
shuts off at 15w? arbitrary figure or how did you arrive at that? curiously, mine is still going as it's outputting .4a on mppt float. not complaining mind you.
Title: Re: Tare Losses, Cut-in Power Level
Post by: Vic on March 26, 2011, 07:49:38 PM
Hi Niel,

I am not a designer of this kind of stuff,  but my guess is that the power to run the converter vs power produced must corss over at about this point,  and the exact value probably depends upon the system voltage and PV voltage.   BUT,  whatta I know ?!

73,  Vic
Title: Re: Tare Losses, Cut-in Power Level
Post by: boB on March 26, 2011, 10:38:12 PM

Nahhh....   15 watts is arbitrary, but this value will be changed to  match tare losses at the operating voltage.

If the controller is holding the battery at Absorb, Float or EQ Voltage, it will stay running no matter what the
power output is because that's what it is supposed to do in that case.    In MPPT, (current) mode, that's when
you want it to turn off when there is not net positive output current.

Night time tare loss (Resting) is a totally different story, but should strive to be as low as technically possible.
There's a lot of stuff in the Classic and that doesn't help things, but it can be made a couple Watts or so better.
I'd be happy with, say, 3 Watts or maybe 3.5 Watts.

boB
Title: Re: Tare Losses, Cut-in Power Level
Post by: niel on March 27, 2011, 02:01:42 AM
sounds good boB. let us know when you've made that improvement and then i'll have to learn how to do the software upgrade.

speaking of software upgrades, you just came out with one, but i thought it not imperative for me to do the upgrade at this time. for the next upgrade to take hold should the current upgrade be done or will it just be ok to go straight to the next upgrade? i have to ask for once i got behind on windows upgrades and those it turned out didn't take all at once (i think i had like 20+ updates to download all at once and it was on another lesser used pc i have if you're wondering) and i had to load each upgrade singly until up to date.
Title: Re: Tare Losses, Cut-in Power Level
Post by: Halfcrazy on March 27, 2011, 06:06:42 AM
Niel
You can skip any software upgrades you like and when you do one it will bring you up to current. This will not add to the time at all it is still about the same amount of data. We promise to never be like windows ;D
Title: Re: Tare Losses, Cut-in Power Level
Post by: Vic on March 27, 2011, 01:18:22 PM
Hi boB,

Thanks for the clarification ...  too much assuming on my part.  My comments mostly based on watching the MX-60 do something very similar (latest 5.11 FW) -- late in the day with fading sun the MX would do its wake-up  charge at 20 or 15 watts for a bit,  then go back to sleep for a bit.  My assumption was that it must have been programmed to sleep at poweer levels @/below 15-ish watts,  as it was a net zero production,  else why not just keep on charging down to about nil charge (?).

All assumptions on my part.  Altho the net gain on a system like mine,  where each of the two inverters consume 20 Wh,  it makes no real difference on the net charge.   For a petite system,  the small net gain of charging to the bitter end of evening sun might be more important ...  again whatta I know ?

73,   Vic
Title: Re: Tare Losses, Cut-in Power Level
Post by: 2flit on April 05, 2011, 06:32:38 PM
Bob,
Yes I was using a Fluke 87 for that 385ma tare loss with the PV breaker off.  I would say that even 3 watts quiescent losses are  too high in a small off-grid system in the wintertime pacific northwest >> (compared to the competition anyway).  The Tri-Star published  is 1.3 watts and the FM60/80 published is under 1 watt. Blue-sky is even lower from my measurements.
If we are seeing even a 5 watt quiescent draw (instead of the 10watts measured) then that 5 watts amounts to 10 amp-hrs/day! (12v system).  That is a stupendously huge load for the little guy with a small off-grid system. In our climate it would take a minimum of a 120 watt module to keep up with this thing in winter sunlight conditions in the Northwest!  (allowing for a 1.6hr average day and .8% charge efficiency, but it is actually worse than this since the controller during the 6 or less hours of low light conditions is robbing more than 5watts while sweeping and tracking).  It is fairly clear that this is not the best choice MPPT for small systems with minimal wintertime input. For the normal size systems that rack up 20 watt standby losses on their Inverters like it was duck soup..... well heck, another 5-10 watts may not even matter.  I am a bit tongue in cheek here but we are learning to treat tare loss like they almost didn't matter.
Title: Re: Tare Losses, Cut-in Power Level
Post by: boB on April 05, 2011, 09:36:51 PM
2flit,   was that 385mA at 12 Volts battery or 24V ??

Also, I know the PV breaker was off, but was the Classic "Resting"  ??

I'm not sure if it was 5 watts (12V) or 10 Watts (24V)

I would agree that the Classic is not the best for real SMALL systems (< 300 Watts or so)

I would be happy to have its tare losses as low as 3 Watts, but hopefully we can
get it down lower than that eventually.  It's not real easy, but possible.

boB
Title: Re: Tare Losses, Cut-in Power Level
Post by: SteveK on April 13, 2011, 06:58:41 AM
2flit, I'm one of those little guys at ~1KW in a not so perfect location. I also see a higher tare loss but not quite as high as yours (5.5W). Initially I had thought of a contactor to time the on/off of the Classic. Then after I scratched my head a bit and looked in the mirror I decided I really had no business using such a large (and full featured) controller with my lowish inputs. I had lost touch with my intentions for owning the Classic. If I intended to stay low input I should've stayed with what I had.

Having said that I had always intended larger inputs for the Classic, be it wind, hydro or more solar. With that being the case the 3W or so tare boB spoke of would be minimal. So for now here in the better weather it matters very little but winter is right around the corner.

Speaking from my own personal observations, the Classic becomes par with my other cc at 170W input levels and gathers more across the day than the other lower power cc...
Title: Re: Tare Losses, Cut-in Power Level
Post by: niel on November 25, 2011, 01:00:13 PM
i just thought i'd bring this up again to ask about what you guys may have gotten it down to? i still haven't updated my software as of yet and did download the latest to the pc, but i just haven't gotten around to trying it yet. i guess i've got cold feet here as i'm a believer in that guy murphy.
Title: Re: Tare Losses, Cut-in Power Level
Post by: boB on November 25, 2011, 02:23:57 PM
Quote from: niel on November 25, 2011, 01:00:13 PM
i just thought i'd bring this up again to ask about what you guys may have gotten it down to? i still haven't updated my software as of yet and did download the latest to the pc, but i just haven't gotten around to trying it yet. i guess i've got cold feet here as i'm a believer in that guy murphy.

I think that the lowest we are going to see is about  3 Watts.    Some of getting down to that level
is software, but I don't have that part quite done yet.   We might get down to just under 4 watts
by software alone.

Hope you had a good thanksgiving !
boB


Title: Re: Tare Losses, Cut-in Power Level
Post by: niel on November 25, 2011, 09:23:49 PM
yes, i was told by ryan in a pm that you guys made some inroads into this area. 8)

my holiday was good and i hope it was good for you and everybody else here too. :)
Title: Re: Tare Losses, Cut-in Power Level
Post by: Willyarnold on June 19, 2013, 11:27:18 PM
Hi.  I posted this over at wind-sun.com and was told to repost the question over here.  This seemed to be the appropriate thread, even though it too is over 2 years old.

Thanks in advance for your response,


Willy

-----

Originally Posted by halfcrazy 

"The idle draw is important to us and I can assure you we will work to bring that way down. Possibly even having a super sleep mode based on sunset and sunrise where we turn almost everything off."

Sorry to dig up an old thread, but 2 years later has there been any progress on this issue? It is very important to me.

Thanks,


Willy
Title: Re: Tare Losses, Cut-in Power Level
Post by: TomW on June 19, 2013, 11:41:11 PM
Quote from: Willyarnold on June 19, 2013, 11:27:18 PM
Hi.  I posted this over at wind-sun.com and was told to repost the question over here.  This seemed to be the appropriate thread, even though it too is over 2 years old.

Thanks in advance for your response,


Willy

-----

Originally Posted by halfcrazy 

"The idle draw is important to us and I can assure you we will work to bring that way down. Possibly even having a super sleep mode based on sunset and sunrise where we turn almost everything off."

Sorry to dig up an old thread, but 2 years later has there been any progress on this issue? It is very important to me.

Thanks,


Willy

Willy;

Not sure I understand your question?

I would suggest you start a new thread on this and be as detailed as possible with information.

Someone here probably has the information you need.

Tom
Title: Re: Tare Losses, Cut-in Power Level
Post by: mtdoc on June 27, 2013, 01:18:05 AM
Quote from: Willyarnold on June 19, 2013, 11:27:18 PM
Hi.  I posted this over at wind-sun.com and was told to repost the question over here.  This seemed to be the appropriate thread, even though it too is over 2 years old.

Thanks in advance for your response,


Willy

-----

Originally Posted by halfcrazy 

"The idle draw is important to us and I can assure you we will work to bring that way down. Possibly even having a super sleep mode based on sunset and sunrise where we turn almost everything off."

Sorry to dig up an old thread, but 2 years later has there been any progress on this issue? It is very important to me.

Thanks,


Willy

Since no one was answering and I was curious I went ahead and measured this on both of my Classics during "Resting".  Using a milliamp resolution clamp meter I got 112 milliamps at 55 Volts or just over 6 watts.  I confirmed this reading on one of my Classics with my Fluke 87V.   Not bad, but I'm not totally up to date on my firmware (I've missed the last few updates) so maybe it's lower now.
Title: Re: Tare Losses, Cut-in Power Level
Post by: boB on June 27, 2013, 03:32:42 AM

Well, there has been a hardware change that makes it able to turn off the arc fault board at night (remove power)
and of course the Classic Lite doesn't have an arc fault board OR an MNGP.  The MNGP draws a watt or so.
Without those two items, the power draw is more like 3 watts.
When the arc fault board gets powered off and the MNGP goes to sleep, power draw should
be around 3.5 watts  (maybe 3.75 at most ???)

How old is your classic hardware ?

Eventually, at night, the Classic itself and MNGP can go to sleep  (low power processor mode) and
should drop the power down to 4 watts or so from your measured 6 watts just from software.
There had to be hardware changes to really drop the power though which happened around
1/2 a year ago.  That was the arc fault board turn off circuitry and another internal
power supply rail from the aux switcher.

Eventually, when power down at night is selectable, this will stop the Ethernet from running
at night which is a compromise.

boB
Title: Re: Tare Losses, Cut-in Power Level
Post by: mtdoc on June 27, 2013, 01:03:57 PM
OK thanks boB

My first classic is about 2 yrs old (serial no about 1000) and my second is about 18 months old (serial no about 1800 I think).  I have another  classic not installed yet that is about 1 yr old.

I'm actually fine with a 6 watt idle draw since I am grid tied and have a fairly large system - though of course lower is always better.  But for those with smaller, off grid systems every little bit is important.  I know that the poster Willy seemed quite concerned about this number as he had posted over at the NAWS forum as well.
Title: Re: Tare Losses, Cut-in Power Level
Post by: Willyarnold on August 14, 2013, 07:59:56 PM
Sorry it took me so long to get back to this. I got sidetracked.  :-\

I bought my Classic 150 on Black Friday of last year (2012) and when I checked, I believe it was drawing about 4 watts on idle (Klien clamp meter). I guess if you have a big system or a grid tie system, that's not a big deal, but right now I have a standby/emergency system and until I go out and invest in a battery bank, just one 4D battery. 4 watts x 16? hours will cycle my single battery (which is not otherwise being used) more than I would like. And please forgive me for bringing up the competition, but Outback has got theirs down to less than 1 watt on standby. I had read the above quoted statement when (or maybe before) I bought my Classic believing that in time you could bring the idle draw down in firmware.

"The idle draw is important to us and I can assure you we will work to bring that way down. Possibly even having a super sleep mode based on sunset and sunrise where we turn almost everything off." - Halfcrazy

I guess at this point I am asking if there is anything I can do to bring my idle draw down as much as possible. For instance, if arc fault is a constant draw, can I disable it completely? (even by cutting a wire?)

If nothing else, maybe I can set up a way to just disconnect it every night.

Thanks in advance for any input you guys can offer.


Willy
Title: Re: Tare Losses, Cut-in Power Level
Post by: Rybren on August 14, 2013, 08:28:20 PM
You can turn arc fault off through the menu settings. I believe that it's in Tweaks.

I can't, however, say whether the software on/off will affect the power draw.
Title: Re: Tare Losses, Cut-in Power Level
Post by: boB on August 14, 2013, 08:56:17 PM
Quote from: Rybren on August 14, 2013, 08:28:20 PM
You can turn arc fault off through the menu settings. I believe that it's in Tweaks.

I can't, however, say whether the software on/off will affect the power draw.

Right now the Arc fault does not go "OFF" as far as its power.

Next revision should change that if the hardware has the capability.
i.e.  if the serial number is over a certain #.  The hardware to be able
to reduce that draw has been in there for a while now...  maybe a few
thousand Classics.

So for those and the next firmware rev, turning off AF should also un-power it.
That will bring your tare losses down some.

As far as Classic Lites' go, they draw somewhere between 2.75 watts and
3.25 watts depending on battery voltage


boB
Title: Re: Tare Losses, Cut-in Power Level
Post by: Willyarnold on August 14, 2013, 10:12:28 PM
Quote from: boB on June 27, 2013, 03:32:42 AM
Eventually, when power down at night is selectable, this will stop the Ethernet from running
at night which is a compromise.

boB

That sounds promising.  Any idea when this will be available?
Title: Re: Tare Losses, Cut-in Power Level
Post by: zoneblue on August 15, 2013, 11:48:56 PM
If 4W * 24h deep cycles your bank, have you thought about getting a smaller controller at all?
Title: Re: Tare Losses, Cut-in Power Level
Post by: Halfcrazy on August 16, 2013, 06:14:12 AM
Well 4w times 16 hours is 48Wh so at 12 volts that is 4AH So if one looked at a pair of golf cart batteries that are 220AH the Classic could run for 330 hours and still be above 50%, 110AH*12V=1320WH/4W=330Hours

Ryan
Title: Re: Tare Losses, Cut-in Power Level
Post by: boB on August 16, 2013, 05:50:38 PM
Quote from: Willyarnold on August 14, 2013, 10:12:28 PM
Quote from: boB on June 27, 2013, 03:32:42 AM
Eventually, when power down at night is selectable, this will stop the Ethernet from running
at night which is a compromise.

boB

That sounds promising.  Any idea when this will be available?

No, I do not have an idea at this time.   This option would only meant that the main
processor itself may go to sleep at night and will not reduce consumption as much
as actually turning the power off to the Ethernet electronics...  But it should
certainly help and lower the idle/tare losses.

boB


Title: Re: Tare Losses, Cut-in Power Level
Post by: Willyarnold on August 26, 2013, 07:31:46 PM
Yeah, I guess it's time to just break down and buy some batteries.  Found a place in Miami that has GC-2 225 AH (off brand) for only $79 each. But I still look forward to any updates that will bring down the idle draw.

Thanks everyone for the input.


Willy