Author Topic: SOC, efficiency, and Battery capacity temperature compensation  (Read 251 times)

Resthome

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Re: SOC, efficiency, and Battery capacity temperature compensation
« Reply #15 on: January 04, 2019, 01:37:34 AM »
Yeah another thing I don’t like about the SOC reading is on days when I run Equalization and a lot of positive NET AH get accumulated. It really screws up the SOC because the net AH do not get reset to zero to a O as the loads start to reduce the NET AH at night it has to reduce all that positive Net AH accumulation from the equalize charge.
John

10 x Kyocera KC140, Classic 150 w/WBJr, Link10 Battery Monitor, 850 AH @ 12v Solar One 2v cells, Xantrex PROwatt SW2000
Off Grid on Houseboat Lake Don Pedro, CA

boB

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Re: SOC, efficiency, and Battery capacity temperature compensation
« Reply #16 on: January 04, 2019, 03:11:14 AM »
Yeah another thing I don’t like about the SOC reading is on days when I run Equalization and a lot of positive NET AH get accumulated. It really screws up the SOC because the net AH do not get reset to zero to a O as the loads start to reduce the NET AH at night it has to reduce all that positive Net AH accumulation from the equalize charge.

That doesn't make sense unless maybe you have found a bug.  And who knows ?   
The NET AH can count up and up and up BUT the Remaining Amp-Hours should not go any higher than the capacity unless the battery temperature tells it to.

EQ "should" act just like Absorb as far as accumulating AH and changing SOC%.

Will have to look further.
K7IQ

Vic

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Re: SOC, efficiency, and Battery capacity temperature compensation
« Reply #17 on: January 04, 2019, 10:16:19 AM »
YES,  after an EQ finishes or is Stopped,  there is some non-zero AH showing.

We only do Manual EQs,   Auto EQ finishes might not behave this way.

One other thing,   is,   that if one Starts a manual EQ when the Classic is in Absorb,   upon the ending of EQ,   the Classic returns to Absorb  (at least when the EQ was manually stopped).

BTW,   in the Local App,  there is no way to zero Net Ah (that I've found),   so one needs to make the trip to the Classic CC to do so manually.   As John said,   this accumulated positive Net Ah does disturb the Ah removed on the following discharge,   and the SOC reading,  as well.

FWIW,   Vic
Off Grid - Two systems -- 4 SW+ 5548s, Surrette 4KS25 1280 AH X2@48V, 11.1 KW STC PV, 3X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  Thanks MN for Great Products/Service/Support!

boB

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Re: SOC, efficiency, and Battery capacity temperature compensation
« Reply #18 on: January 04, 2019, 12:31:31 PM »

OK.  Not sure what is happening but I will look at it.

Doing an EQ should NOT screw up the SOC%

Thanks guys.

K7IQ

Vic

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Re: SOC, efficiency, and Battery capacity temperature compensation
« Reply #19 on: January 04, 2019, 12:54:25 PM »
boB,

Believe that Resthome John was saying that in the discharge following that EQ,  the SOC IS disturbed because the SOC calculation is based upon a starting point that is more positive than zero.   And that zero would be the proper beginning point for beginning.

To me,  really pay NO attention to SOC,   only Ah removed from the battery in the discharge/s that follow a complete charge,  so zeroing Net Ah  IS  important  --  have not looked at the effect of a positive Net Ah on the SOC calcs resulting from 50 or 80 Net Ah starting point of a discharge cycle  ...

Just the read on things here.   73   Thanks,   Vic
Off Grid - Two systems -- 4 SW+ 5548s, Surrette 4KS25 1280 AH X2@48V, 11.1 KW STC PV, 3X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  Thanks MN for Great Products/Service/Support!

boB

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Re: SOC, efficiency, and Battery capacity temperature compensation
« Reply #20 on: January 04, 2019, 04:52:07 PM »

SOC is based purely on Amp-Hours Remaining.

NET Amp-Hours is supposed to be a supplemental statistic, not necessarily used for SOC calculation.

So, It has been quite a while since I have even thought about this so that's why I will have to take a look again.
K7IQ

Resthome

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Re: SOC, efficiency, and Battery capacity temperature compensation
« Reply #21 on: January 05, 2019, 12:27:44 AM »

SOC is based purely on Amp-Hours Remaining.

NET Amp-Hours is supposed to be a supplemental statistic, not necessarily used for SOC calculation.

So, It has been quite a while since I have even thought about this so that's why I will have to take a look again.

boB

Unfortunately we have closed up for the winter so can’t look at this right now. I may have mis spoke on the SOC but I also thought it was off. Trying to remember exactly which reading I was looking at on the Local App which I had a picture of the LA, but believe it was the Status page where the WBjr info shows. Found one picture and both remaining and net show. I don’t pay much attention to remaining so I believe it the net. And since it is so far positive with the Eq cycle and does not reset to zero then is does not show a true picture of what is removed form the batteries that evening and what get gets put back in the next day because you don’t really know the starting point because it wasn’t zero like when it hits float. Seem like it takes another day without Eq to sort of get back to reality. I usually compare the LA reading to my Link 10 meter and they are usually close but not when there was an Eq.


Yeah, Vic manual Eq here also, never use Auto. And thank for the conformation.
John

10 x Kyocera KC140, Classic 150 w/WBJr, Link10 Battery Monitor, 850 AH @ 12v Solar One 2v cells, Xantrex PROwatt SW2000
Off Grid on Houseboat Lake Don Pedro, CA

Resthome

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Re: SOC, efficiency, and Battery capacity temperature compensation
« Reply #22 on: January 05, 2019, 12:38:29 AM »
Always Eq from Float. Not sure what Stage it goes to after Eq completes or stopped. Pretty sure it goes to Resting until the charge bleads off unless there is a good load at the time. If It does return to Float it doesn’t reset the Net Amps like it does going from Absorb to Float.
John

10 x Kyocera KC140, Classic 150 w/WBJr, Link10 Battery Monitor, 850 AH @ 12v Solar One 2v cells, Xantrex PROwatt SW2000
Off Grid on Houseboat Lake Don Pedro, CA

boB

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Re: SOC, efficiency, and Battery capacity temperature compensation
« Reply #23 on: January 05, 2019, 01:37:08 AM »
If It does return to Float it doesn’t reset the Net Amps like it does going from Absorb to Float.

Now THAT would be a bug but not surprising actually.  At least the next time the Classic goes from Absorb to Float normally, it will zero out.
The will most likely not be any fix for that right away but will put that into the notes.  I appreciate knowing about that  one !

BTW, as I remember, NET Amp-Hours, when it counts up, will not take efficiency into account.  And AH+ Lifetime doesn't either pretty sure.

If you started EQ when in Absorb and then manually STOP, the stage should return to Absorb.  If you let the EQ run, it should return to Float.

If you started EQ from Float, it will also return to Float if you manually STOP the EQ or let it EQ for the preset time.

K7IQ

rmak

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Re: SOC, efficiency, and Battery capacity temperature compensation
« Reply #24 on: January 05, 2019, 04:52:13 PM »
Is there a way for the Net Ah to reset to zero when the Classic goes into resting? Does it have to be done manually?

Ray
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boB

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Re: SOC, efficiency, and Battery capacity temperature compensation
« Reply #25 on: January 05, 2019, 05:18:49 PM »
Is there a way for the Net Ah to reset to zero when the Classic goes into resting? Does it have to be done manually?

Ray

I think that the NET AH (which really doesn't play into SOC% or Remaining Amp-Hours ?) can be reset
whenever the Classic goes from Absorb to Float if the TWEAK option is set. 

If this bug is real, then NET AH doesn't get set when going from EQ to Float automatically.

The other way to reset the NET AH is to either manually do it or by way of an external computer that can make almost anything happen for any reason. 

I will look at the code though and see how easy it is to fix this bug.  It's probably very easy.  BUT, I don't think this is a large enough bug to warrant a new release of Classic code just for this.  It sure could be rolled into the next release though for whatever other reasons.

« Last Edit: January 05, 2019, 05:23:26 PM by boB »
K7IQ