Hello guys.
I have noticed a interesting warning on my install, I am getting a high voltage alarm on the Pi Venus, but its at voltages that I would consider perfectly safe?
Pylontech reports High Voltage from a single sell but display Average voltage of the bank.
Best way to fix, discharge nice and low and recharge to full for a few days. Error will clear after a few days.
Thanks, I will try that, I set the minimum SOC to 40% now, with a little loadshedding tonight I should get it down to 30% SOC.
If what Jaco suggest does not clear your alarm, then you can also follow the same procedure I gave to fix the hubble imbalance by reducing your max battery voltage and then slowly increasing it.
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I ended up employing a combination of things to get the alarm away, first I started cycling a bit deeper, then I dropped the max charge voltage and increased it by 100mV per day.
But I think it was the last trick that @plonkster also suggested in another thread that finally fixed everything, I dropped the battery charging current to 2A in DVCC and after 2 days the alarm was gone 
Thanks guys!
Hi Guys.
We have had this problem on a set of Pylontech’s, one site in particular where no matter what you do and how long or deep you have discharge (and held there for 48H’s) and slowly re-charge and at any voltage or current, the alarms of high voltage (even when only at 50.5Vdc) still continues to show up after a few hours. Any Ideas on how to resolve?
Don’t keep them discharged, they need to cycle constantly.
You will still get alarms for a week or 2 but eventually they will go away, limit the charged voltage to 52V and try limiting the charge amps to say 3A and just have them cycle.
The part about charging slowly only really comes into play once the balancer becomes active, which is when the highest cell reaches 3.45V or thereabouts. In other words, when the battery is already close to full.
By far the easiest method remains the one @PJJ mentioned. Just cycle them, keep the charge voltage down for the first two weeks. You can maybe raise it slowly over time. What you want to do is keep the highest cell under 3.55V.
Hi all,
Sorry to necro this one!
I also started seeing this one in the last month on my VenusGX, Multiplus 1 5KVA and 3x US3000b Pylontechs. First time I’ve ever seen it in the almost ~4 years running the system.
I charge the batteries to almost full every day (I have Home Assistant logic to charge from the grid if the sun doesn’t cut it). Most of the days they do go down to 25% (my normal) but sometimes when there’s loadshedding I tend to keep them at 50% as can be seen below.
Is the advice to correct this still the same? E.g. @PJJ suggestion to cycle them fully empty and fully full, and limit the charge voltage for 2 weeks?
Do I need VE Configure to set this (Jaco did my setup, I only ever adjust ESS settings)? Should I go lower than 25%?
EDIT: oh wait, these parameters?
Look under Settings → DVCC to override the limits
This?
Yes.
You can lower your charge voltage (the lowest value between this and the battery’s parameters CVL will be used)
You can limit the charge current (the lowest value between this and the battery’s parameters CCL will be used)
So if you have issues lower the charge voltage until you see you don’t get cell imbalance errors. Also limit the charge current to ~5A or less and set the battery to Keep Charged.
Then as things settle increase the charge voltage 0.5V at a time until you go above the battery CVL without errors.
So to start fixing battery imbalances:
- Set the min ESS SOC to say 10%? 15%? and let the batteries disharge.
- Set the DVCC charge current limit to 5A and voltage limit to 52v (which is lower than CVL @ 53.2v and CCL @ 22.2A currently) and will thus become active overwriting the other
- Set the batteries to “keep charged”. This will of course trigger a charge from the grid.
- Let it slowely recharge until 100%
- Repeat
- When battery high voltage warnings start disappearing, increase the charge voltage 0.5V at a time until above battery CVL again.
Yes that is about it.
You only need to discharge to around 70-80% before the charge to start as the balancers normally dont work until you reach ~3.4V depending on the BMS and settings.
Some say that it helps to discharge fully, but the top part is what really matters. So I would do that a few times before trying discharge and full charge if your battery still need work.
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When discharging to very low SOC to recharge, one has to have access to the BMS to set the balancing start volts also lower so that it balances all the way to the top.
Helps me naught if my balancing starts at 3.45v yet I drain to 10% … I have to set the balancer to also start balancing at like 3.2v, at a lower charge amp etc.
Not all can do that.
Well spotted Louis. 
A battery that is cycled every day already does this, if you think about it. It is strange that a battery that is in daily use would develop a balance issue.
Yeah, I hope this isn’t a bigger issue.
Thanks all, will then do 75% or so and let it slowly recharge.
I mean loadshedding is still a thing, so it is going to run from the batteries somewhere in any case.
My gut feeling: Wait a few more years. It will become more common.
Seen it on my escapades, Will and Andy at one time or another alluded similarly I recall, hence where I got the idea, that using Eskom to recharge a batt is more “controlled” than 100% MPPT.
As such, if I want to recharge for balancing purposes, I use 100% Eskom. Slow and controlled, consistent all the way.
… we are still learning.
EDIT: And not recharging daily to 100%, also seems to have a cumulative impact.
Mine usually does, I force charge it to 95% daily (I gradually lift the min SOC in 5% increments every 30 mins until I get to 95% - so if it isn’t there yet from the MPPTs it will pick it up from Eskom). Then at night I let it run down unti 50% or 25% (depending on loadshedding).
As an aside, I also noticed my batteries’ health is on 90%, not sure if it is related.
Interesting.
At least you have a plan now. Caught it early. Can be a faulty cell, I hear Pylontech is good with warranty/support too.