I have just finished my new solar setup and passed final inspection in California. I have a sol ark 15k directly connected to my 200 amp main panel with 5.8 k of solar panels. I have 1.5 k of dc pv and the rest ac coupled all going to the sol ark. The technical support from sol ark and enphase has been awesome. I bought six Pytes E-Box-48100R, four them would have one cell constantly going over voltage. The Pytes tech guys tried to fix this with firmware and software updates but to no avail, so they replaced them and I have six working batteries now. So I was wondering if there is a way of dealing with the errant cell in each battery and restoring them to be usable, without tearing the batteries apart. I have a 5 amp 60 volt bench power supply and I am trying to top balance slowly to see if that would work. Any suggestions would be very much appreciated.
One cell going over voltage
- Thread starter Leodoggie
- Start date
sunshine_eggo
Happy Breffast!
Likely simply imbalanced. VERY common with new batteries of all brands.
Regular use over time would likely have brought them into balance.
Charging low cells with a power supply is a common approach to addressing imbalance, but that requires physically accessing cell terminals.
Regular use over time would likely have brought them into balance.
Charging low cells with a power supply is a common approach to addressing imbalance, but that requires physically accessing cell terminals.
Thanks for the response, with closed loop when one battery goes over voltage the master goes into protection mode. I ran at least ten cycles on each battery and the same cell kept going over voltage, that’s why they were replaced, the new ones are working fine.
wpns
Solar Joules are catch and release
They let you keep the old ones? In that case, float charging at an appropriate voltage that will cause them to balance for a few weeks (!) might be your first/easiest fix.
sunshine_eggo
Happy Breffast!
The common solution is to put the unit in a lead-acid battery type and manually set conservative absorption and float voltages.
I didn't glean that from the post, but if so, heck yeah... use that 60V/5A supply to hold them at 55.2-56.8V for several days and see if they improve.
Yes, they let me keep the four batteries that went over voltage, the Pytes tech guys did their best to correct the issue, but ended up replacing them. Good to know that it is possible to rehabilitate the batteries. When my power supply is connected to the battery, I can change the amps but not the voltage, so I don’t know why that is. Therefore I am charging very slowly at 0.250 amps and the voltage slowly goes up.
Hedges
I See Electromagnetic Fields!
- Joined
- Mar 28, 2020
- Messages
- 21,188
How many kW of PV panels AC coupled?
What model GT PV inverter, and is it set for Rule-21 and frequency-watts?
Is that on output of inverter or on Gen port?
I'm wondering if SolArk is having trouble controlling the amount of power it has to stuff into the batteries.
What model GT PV inverter, and is it set for Rule-21 and frequency-watts?
Is that on output of inverter or on Gen port?
I'm wondering if SolArk is having trouble controlling the amount of power it has to stuff into the batteries.
wpns
Solar Joules are catch and release
Perfect, give that a try and see what happens. Best case the batteries come back to life and that’s a tax on their Tech Support guys who have no clue.
I don’t know if those batteries are welded or bolted, but you could certainly pull the cover off and take a look. Worst case you can scavenge some good cells out of one of the batteries and repair all the others.
sunshine_eggo
Happy Breffast!
It's because you can't adjust the voltage above the current battery voltage. Only set voltage when disconnected from the battery. When the battery voltage is lower than the set point, it will display the actual voltage, not the set point.
Disconnect power supply.
Set voltage
Attach to battery
Set max amps.
Great suggestion, it worked. So I set the voltage to 56 volts and 0.250 amps. I will try that and see what happens, thanks.
sunshine_eggo
Happy Breffast!
Bro... 5A... don't be skeered. There's still a BMS in there protecting/balancing. Once you hit your peak and BMS protection engages, it may make sense to dial the current way back to 0.05-0.10A to give a positive input while it balances, but until you hit cutoff... give it all the electrons you can!
Ampster
Renewable Energy Hobbyist
That is 3.5 per cell and may keep that runner shunted enough to let the others catch up.
Yes you are right, I am little gun shy, with batteries going over voltage. I did have the amps higher earlier but with the battery showing 100% SOC I dialed the amps down.
56 volts is what you suggested when we talked, so I will try that and hopefully the cells will balance.
Ampster
Renewable Energy Hobbyist
The only thing that we don't know how much current that BMS can shunt.
DIYrich
Solar Wizard
Charge, and note the voltage where the bms goes into OVP.
Set amps to 2, and charge up to that voltage.
Keep upping by 0.10v until it OVP again.
Back off by 0.10v, and hold for 2 hours for top cell to balance down. If you can see voltage of high cell, wait until it drops by 0.010v, or 0.015 under OVP.
Raise charge voltage by 0.10v. Repeat until you hit 57.6v, or the BMS limit.
Set amps to 2, and charge up to that voltage.
Keep upping by 0.10v until it OVP again.
Back off by 0.10v, and hold for 2 hours for top cell to balance down. If you can see voltage of high cell, wait until it drops by 0.010v, or 0.015 under OVP.
Raise charge voltage by 0.10v. Repeat until you hit 57.6v, or the BMS limit.
I would set voltage to 55.2V first.
If the bms keeps locking you out, and you end up needing to cell balance, take pics of you opening up the case and we can help you manually balance the cells.
sunshine_eggo
Happy Breffast!
I'm pretty shocked they just let you keep them... you paid for 6 but got 10 batteries? They must have some crazy margins.
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