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As per title , this happens at least once a week from what I can tell.
This morning , it has just jumped from 73% to 100% , solar PV only just started kicking in , system voltage is way below still at 53.80 volts , absorbtion is set for 55.70 on MPPT controllers and in Multiplus is set to assume 95% SOC at 55.70 volts.
Any ideas?
I have just downloaded the data in excel where it confirms this as well.
Please see attached screenshots
Are you using "2 signal BMS" assistant or ESS with this settings set in it?
Voltage is not the best way to measure the SOC of the LFP battery.
If you want the SOC properly measured use SmartShunt or BMV.
BTW.
If you do not have a "clever" or other method of signaling to your chargers that the LFP battery cannot be charged or discharged for any reason, your battery will not last long.
You can of course relay on internal BMS (if it has one) that have a way to disconnect the battery from chargers/loads, but it is very poor way.
I will have to disagree for the most part.
The reason I don't want any " clever " method is not to overcomplicate things unneccessarily.
There is one and ONLY thing can and does determine state of charge in my setup.
The figure is set in black and white in Inverter settings as " state of charge when bulk is finished = 95% "
So , when batteries reach 55.7 volts , whatever the current reading of SOC , this changes to 95% , which is what supposed to happen and works like this , as it should , most of the time.
But , this issue occurs in random timeframes , not exactly sure how often , but probably once a week or once in 2 weeks.
SO , this is clearly a glitch , out of the blue for SOC to jump to 100% , when it is NOWHERE near absobtion voltage.
MPPT chargers are all Victron , and they have clear parameters to what voltage they will charge the batteries up to, this is " clever " enough for me.
Have been running this system over a year , works great , apart from this weird issue.
All things you are talking about have nothing to do with help understand the reason " jump " of the SOC to 100% nor they can have any effect on this.
There are different ways to skin a cat. I don't need or want Smartshunt or BMV as both of these are within a degree of accuracy is already integrated in Multiplus II.
PS , of course I have a BMS on my battery banks , with cutoff etc. voltages set ...
That also has nothing to do with the reason for the SOC jump , as they cannot dictate what Multiplus shows me as SOC.
I appreciate you may be trying to help , but I think you should look at exactly what I am reporting , rather than diverging into irrelavant things.
Did you consider the internal resistance (IR) of your cells?
Battery voltage is directly related to IR under load or charge.
Same with temperature and its influence on the IR.
To be able to measure SOC based on voltage of the battery, it has to be disconnected from load or charge for couple minutes.
Also IR is getting higher as battery ages.
Method that you are using is good for Lead Acid battery.
You can do whatever you want with your battery. After all it is your battery.
My batteries are just fine.
If they were NOT , I would be having this issue every day.
They are fully balanced , Delta is never higher than 50mV even under hig load or high charge.
Please re-read what I am asking / describing , if you understand what it is , come back and make relevant comment.
Otherwise no need for you to send response.
Unless you want to boost your forum post count for brownie points with totally irrelevant replies.
@mvader or other Victron Gurus , would you mind looking at this to see what might be causing the issue?
You won’t get any official help for batteries that aren’t on the compatible list.
Having lithium batteries without a bms or a properly setup shunt will just cause issues.
There are tons of topics here you can search for with all the information you need.
Its not a glitch, you just haven’t set it up right.
Why are you complaining? You clearly don't care about actual battery SoC since you're using one that can't count the incoming current from the PV.
Contact your reseller for support.
