My Sol-Ark 12K just developed bad habit of mis-reporting SOC

[DougfromdaUP]

My Sol-Ark reported SOC now jumps up to 100% long before the batteries are charged. The charge cycle continues normally, but I hate not being able to monitor it. I haven't made any programming changes recently, and can't think of any reason for it to do this. Any ideas?

This is typical for the last week or so:

 

[houseofancients]

Are you using comms between your BMS and Sol-ark ?

 

[DougfromdaUP]

No comms for the Sol-Ark, but I do monitor the 5 bms regularly. I'm using voltage and not SOC for the Sol-Ark "time of use" settings, since I'm well aware of the problems the Sol-Ark (and bms) have estimating SOC after a few cloudy days.

I've been running this system for a year and a half.

 

[Cmiller]

My Sol-Ark reported SOC now jumps up to 100% long before the batteries are charged. The charge cycle continues normally, but I hate not being able to monitor it. I haven't made any programming changes recently, and can't think of any reason for it to do this. Any ideas?

This is typical for the last week or so:

View attachment 179374

This is an issue that I'm seeing over, and over, and over........ with so far zero help from Sol-Ark! The issue with using Voltage based Time Of Use settings is that will also limit gen charging in a grid down scenario... so let's say you set TOU to 52V... now if grid is down and a gen auto starts with the auto start relay, it will charge to 52V and shut down. That isn't even remotely close to being practical!

I'm just ready to make a new thread showing these issues in hopes of getting Sol-Ark's attention... after emailing 4 weeks ago and receiving a response saying they will need a few days.... and now nothing but crickets ever since!

 

[Cmiller]

Well, I got a very disappointing email back from Sol-Ark. I am extremely disappointed at their lack of trying to help with this issue!

Check this out:



I am just blown away by the lack of putting any effort into resolving the issue.....

Here are 2 pics from our one job. These were taken yesterday morning, and the Sol-Ark is showing 50% when the battery is at 25%. The system is a 15K with 1,000AH LifePo4 batteries. The screens on these batteries are actually shunt based and have always been very accurate!





And Sol-Ark says setting TOU to 50% while in SOC based mode does a good job of discharging to 50%.....

This is insane!! I sent them TONS of screenshots showing how the SOC jumps around....... And this is their response!

 

[DougfromdaUP]

Thanks for posting Cmiller. It’s certainly disappointing that they are so uninterested in fixing a software glitch.
They have the hardware, and it works in one mode, more-or-less. One would think it shouldn’t consume too much programming time to fix.

 

[Danke]

I think this is the problem a person I know is having with his 3 paralleled 12Ks. The generator turns on, but input to the Sol-Ark quickly cycles on and off, never charging batteries.

 

[houseofancients]

Well, I got a very disappointing email back from Sol-Ark. I am extremely disappointed at their lack of trying to help with this issue!

Check this out:

View attachment 181366

I am just blown away by the lack of putting any effort into resolving the issue.....

Here are 2 pics from our one job. These were taken yesterday morning, and the Sol-Ark is showing 50% when the battery is at 25%. The system is a 15K with 1,000AH LifePo4 batteries. The screens on these batteries are actually shunt based and have always been very accurate!

View attachment 181367

View attachment 181368

And Sol-Ark says setting TOU to 50% while in SOC based mode does a good job of discharging to 50%.....

This is insane!! I sent them TONS of screenshots showing how the SOC jumps around....... And this is their response!

well, actually they are very clear on WHY they recommend comms...
always have been....

 

[HighTechLab]

Sol-ark was frank, concise and to the point. It may not have been the answer you were looking for, but I think that's a case of managing your own expectations, not a case of poor support on their part.

Nothing is to say your batteries did not briefly stop accepting charging - for example, if low-temperature protection was triggered - that caused a voltage spike to make the sol-ark think the batteries were actually full. The Sol-Ark cannot know if this is happening without communication. But here we are upset with Sol-Ark when nothing is to say it's not the battery's fault.

 

[RCinFLA]

Colomb counters are the best way to keep track of state of charge. It is a cumulation of amp-seconds of current in and out of battery.

Discharge and charging efficiency of battery comes into play as battery losses are also a function of the magnitude of the battery current. For LFP this is not a big factor as their charging and discharging efficiency is quite high for the typical less than 0.3 C(A) current range.

Biggest source of Columb counter inaccuracy is the dynamic range of current measured by current shunt. Best to set the calibration of the current measurement value for the users statistically average discharge current and charge currents.

All Columb counters accumulate errors over time and need to be given a reference reset periodically by a known full charge re-referencing point of battery. Think of SoC Columb counting like dead-reckoning navigation, every so often you need to find a known reference point to wash out errors.

I would not recommend terminating battery charging based solely on Columb counter state of charge. When Columb counter accumulates too much error it may result in over or under charging of battery if SoC computation is relied on for charge termination. Full charging current taper down and absolute battery voltage are commonly used to reset Columb counter to full charge reference point.

The actual capacity of battery must be known for Columb counter to compute the remaining SoC. This can be manually set by user based on given battery capacity or done semi-automatically by computing AH's between battery fully charged and fully discharged reference conditions based on battery voltage. If battery capacity computation is done semi-automatically it is best to do it for a complete discharge cycle of battery immediately after a full charge reference reset when Columb counter has the least amount of cumulated error.

If you do not do a full charge re-referencing for months, the Columb counter will continue to accumulate more error.

 

[Cmiller]

well, actually they are very clear on WHY they recommend comms...
always have been....

So tell me why their spec sheet says they have a shunt and that they track SOC...? I know they want closed loop comms, but I have seen quite a few situations where closed loop comms did NOT work right... That in itself is all dependent on the software in the battery, and I have seen a bit of issues on that end!

But to be honest, that is actually beside the point! If you say your software tracks SOC , then you should probably deliver! It's not like it's not possible to do.... I mean only every other battery monitor out there seems to work way better.

The issue is the lack of that working!

The issue is NOT "I'd rather not use closed loop comms", or anything like that. The fact remains that Sol-Ark says they track SOC, but it isn't accurate.

 

[houseofancients]

The fact remains that Sol-Ark says they track SOC, but it isn't accurate.

and EXACTLY the reason why they want Comms, same goes for Deye and Sunsynk...

SOC tracking by voltage for lifePO4 is iffy at best ( as explained by RCinFLA), and all inverters that do, fail miserably at it...

 

[Cmiller]

and EXACTLY the reason why they want Comms, same goes for Deye and Sunsynk...

SOC tracking by voltage for lifePO4 is iffy at best ( as explained by RCinFLA), and all inverters that do, fail miserably at it...

If that were the case, closed loop comms wouldn't work either!! How would the battery track SOC internally????

There are 2 ways that LifePo4 batteries track SOC internally.

#1 is by running the negative current from the battery through the circuit board of the BMS, and tracking what goes in or out.
#2 is by having a shunt, and the negative current runs through the shunt, then by watching the millivolts read across the shunt they track what goes in or out....

(I know there may be other variations, but these 2 are the basic jist of it!)

Both scenarios are a "columb counter" as explained by RCinFLA.

Both scenarios use algorithms to calculate the columbs, AH, or whichever form of power measurement you prefer to put it as, going in and going out. Both scenarios use the same type of algorithm that Sol-Ark does. Sol-Ark is using a shunt. I have seen it, their docs state it.

And furthermore, if SOC tracking on LifePo4 batteries is iffy at best, then explain to me why it works for me with Schneider, Midnite, Outback, Victron, Magnum, Tri-metric........ all of these brands I have set up battery monitors ON LIFEPO4 and got them to track pretty accurately!

No battery monitor is perfect! Every last one will at times run off, especially when the batteries don't get completely full for weeks at a time!

On Sol-Arks I see the SOC run off even when the batteries were full 2 or 3 days ago!

I still stand by what I said. If Sol-Ark says (especially on the spec sheet) that they have a shunt "for Accurate % SOC", and that is exactly the wording on the spec sheet, then they should do better than they do!

 

[Cmiller]

Sol-ark was frank, concise and to the point. It may not have been the answer you were looking for, but I think that's a case of managing your own expectations, not a case of poor support on their part.

Nothing is to say your batteries did not briefly stop accepting charging - for example, if low-temperature protection was triggered - that caused a voltage spike to make the sol-ark think the batteries were actually full. The Sol-Ark cannot know if this is happening without communication. But here we are upset with Sol-Ark when nothing is to say it's not the battery's fault.

It took them 4 weeks to get back to me with that response! And that response came only after I kept emailing them asking for a response! Don't tell me it wasn't poor support!

I can say with 100% certainty that the issue is NOT the batteries! I know that sounds pretty high and mighty, but it is true!

#1 I have seen it on MANY installs!
#2 it wasn't low temperature protection, these installs are virtually all inside people's homes!
#3 the jumping around of SOC happens from any given SOC and/or voltage!
#4 at times it has seemed like even a cloud passing in front of the sun and dropping charge rate to batteries caused SOC to jump to 100% (even from say, 40%..... and then later it dropped again by the way.)

Also, my expectations are tempered off of what Sol-Ark says their products do.

What is extremely frustrating to me is that when their SOC runs off, I lose the ability to use the Sol-Ark to auto start a backup generator, because.... well, if the Sol-Ark says SOC is 50% when it is actually 15%..... I mean how is that supposed to work. And I can't use voltage based settings because.... well using 52V in TOU doesn't really give any room for generator charging.... you hit 52V in short order, causing cycling of the generator.

I'm not some new kid on the block! I have set up hundreds of systems! I know this is an inverter issue! I have a thousand other setups with other devices to compare with!

Any other brand of inverter that I am familiar with, I can depend on the gen start working, and the SOC monitoring to be relatively accurate probably 99% of the time. (I know there are always cases that are out of the ordinary.) Not so with Sol-Ark.

We have installed 100+ Sol-Arks, and many of them work fine. It's just when we try to use TOU everything goes screwy!

 

[Solar Guppy]

We have installed 100+ Sol-Arks, and many of them work fine. It's just when we try to use TOU everything goes screwy!

The issue with TOU is typically there is a lot of partial charge / discharge cycles and running open loop the inverter has no way to know true state of charge of the battery bank especially with parallel batteries with uneven distribution of energy between them.

The only way this will work is with closed loop communications and each battery reporting columb count values, I'm not familiar with Sol-Ark and how there software implements this but would assume that it can aggregate the reported battery values.

For what this is worth, the concept of accurate battery SOC has been a multi decade challenge and close loop communications is the best it can get so as an installer, you need to learn the tools given for your customers.

 

[Cmiller]

The issue with TOU is typically there is a lot of partial charge / discharge cycles and running open loop the inverter has no way to know true state of charge of the battery bank especially with parallel batteries with uneven distribution of energy between them.

The only way this will work is with closed loop communications and each battery reporting columb count values, I'm not familiar with Sol-Ark and how there software implements this but would assume that it can aggregate the reported battery values.

For what this is worth, the concept of accurate battery SOC has been a multi decade challenge and close loop communications is the best it can get so as an installer, you need to learn the tools given for your customers.

Actually, when the inverter has a shunt to measure the current going in and out it can indeed be pretty accurate! The Sol-Ark has a shunt..... it measures the current going in and out, it has battery efficiency settings to compensate for that, it has temp comp (not used with LifePo4, but needed for FLA), but obviously their algorithms need some improvement!

How is closed loop comm any different/better than any other battery monitoring system that tracks what goes in and out?? The only difference is that the batteries themselves are tracking the power, and then the master battery "tells" the Sol-Ark (or whatever brand inverter) what the combined average % SOC is of the batteries vs. having a stand-alone shunt with something reading those values to track SOC.

You say accurate SOC has been a multi decade challenge, that may be so, but I know that for the last 12-13 years I have worked on literally hundreds of systems with ACCURATE battery SOC monitoring!

I would argue any day, all day that closed loop communication has no functional benefit over a quality inverter system with a dependable battery monitor, tracking SOC using a shunt and proper algorithms! If you know where to set your charge voltages, and you have quality equipment, you can 100% have an outstanding end result!

As I have been trying to say, my problem with Sol-Ark is the lack of delivering what they promise!



Notice the "integrated" part.... that would mean no closed loop comm needed.....

And their Time-of-use settings need an accurate SOC in order to function correctly!

 

[Solar Guppy]

A single shunt can't report accurately a multi battery ( parallel ) system, that's the issue. So what happens is one or more batteries, especially with partial charge / discharge TOU get further away from each other in net charge, is shown as large and sudden drops of pack SOC as the weaker batteries drop off under load due to LifePo4 knee curves.

Closed communications is the tool to mitigate this.

 

[Quattrohead]

Any other brand of inverter that I am familiar with, I can depend on the gen start working, and the SOC monitoring to be relatively accurate probably 99% of the time.

Can you give us examples please.

Oh the horror, someone found a problem with Sol-ark ?

 

[Cmiller]

A single shunt can't report accurately a multi battery ( parallel ) system, that's the issue. So what happens is one or more batteries, especially with partial charge / discharge TOU get further away from each other in net charge, is shown as large and sudden drops of pack SOC as the weaker batteries drop off under load due to LifePo4 knee curves.

Closed communications is the tool to mitigate this.

A single shunt does indeed track accurately. Mine at home does..... as well as many others.

Closed loop comms actually doesn't keep the batteries in sync either in terms of parallel configurations.... it just reports the aggregated total % of pack, total allowed charge amps, total allowed discharge amps, charge voltages, etc. to the inverter.

And if you are tracking power in and power out you absolutely won't have sudden drops in pack SOC! You are counting AH in..... and AH out..... voltage drop doesn't determine what the SOC reading is on a battery monitor! The whole point of the shunt is to count those AH's or Columbs of power!

You could theoretically see sudden drops in voltage! But that most definitely is not what I have been seeing on the many systems with these issues! The only time that battery volts should be a factor in the SOC numbers is to re-calibrate at 100% when the batteries are above X volts and charge rate drops below X rate.... and also at a pre-set empty volts it should auto calibrate to 0%. anything between there is solely determined by tracking AH in and AH out through the shunt!

 

[mvonw]

I may not be fully comprehending this thread, but my SolArk 12k (no comms) SOC shunt is very close (usually < 5%) different to my victron smart shunt on my bank of 6 48v 120AH batteries. The SOC reported out on the BMS's are WAY off from reality, however.