Leaving new batteries unused then charging and maintaining them.

[WNCGUY]

After purchasing two SOK 100ah batteries in June of 2022, I now have the time to move forward with their intended use but am concerned it may not have been in the batteries best health interest to leave them setting in the box unmaintained. I charged one of the batteries today using a Victron IP22 30-amp charger.

The Victron app shows a 4hr 17min charge time, 78.7Ah, 13.5v

Do I need to be concerned about any damage to the batteries if so, what can I do now?
What should I have done with these batteries as soon as I received them?
Going forward what should be done to maintain battery health?

 

[cs1234]

What settings were you using on the Victron charger? Some of the cells probably aren't balanced. 78.7ah is just what the battery hit before it hit overvoltage on the cells most likely. Hard to tell without bluetooth on the battery, which is why I hate batteries without cell readouts.

I would suggest letting the battery rest for a few hours, then connect it again. Rinse and repeat until it is fully charged and balanced. Perhaps at a reduced voltage, and then increase it .1 volts at time until you are back up to 14.2 or 14.6 charging voltage.

It will probably correct itself automatically over time if you just hook them up and use them though.

 

[mikefitz]

If you are saying the Victron charger put Into the battery 78.7 Ah, then that seems about correct. The batteries will not have been shipped at full charge , around 50% in usual. With some self discharge and power use by the BMS it's possible the battery was around 20% before you started charging.
Charge up the other battery and see how much power it takes.
Idealy batteries should not be stored at a high SOC so you won't have causes any damage.

4 hours for a 30 amp charger to Input 78 Ah suggests a long absorbtion time so I doubt there is a balance issue.

Mike

 

[cs1234]

@mikefitz

Doh, I for some reason thought they were at 0% empty.

 

[WNCGUY]

If you are saying the Victron charger put Into the battery 78.7 Ah, then that seems about correct. The batteries will not have been shipped at full charge , around 50% in usual. With some self discharge and power use by the BMS it's possible the battery was around 20% before you started charging.
Charge up the other battery and see how much power it takes.
Idealy batteries should not be stored at a high SOC so you won't have causes any damage.

4 hours for a 30 amp charger to Input 78 Ah suggests a long absorbtion time so I doubt there is a balance issue.

Mike

78.7 Ah, Victron manual states Charge = Total capacity provided during the recharge stages (Bulk and Absorption). Reviewing all charger settings, I found I inadvertently set the absorption time for 2hr when SOK spec is 1hr, corrected this setting, put the battery back on the charger, no additional charge added to battery, voltage is 13.60 volts.

Second battery put on charger, Charge added is 77.80 Ah, battery voltage is13.64 volts.

 

[cs1234]

Do you have a shunt? If so, drain the battery at a low constant current using a load of some sort. The shunt will tell you how many amps come out of it total.

Will Prowse reviewing a Victron Shunt.

 

[WNCGUY]

Do you have a shunt? If so, drain the battery at a low constant current using a load of some sort. The shunt will tell you how many amps come out of it total.

Will Prowse reviewing a Victron Shunt.

I do have a shunt, but I have not assembled the system, only charged the batteries in preparation.

 

[Bluedog225]

I got 4 of the SOK server rack batteries as I recall about the same time. Currentconnected.com indicated they were at a special, early adopter price. And that the price would increase. Then they decreased the price. Not cool.

Anyway, I called and asked if they needed to be maintained as they are still sitting in my closet. They said, no problem.

 

[AmyG]

I did the same thing with a couple of 206 AH SOK batteries. They arrived at 13.03V (~ 30% SOC) which I believe is how SOK ships them - that would put your ~ 78 Ah about right.

Mine sat for almost a year (wired in parallel for the last 6 months) and stayed at 13.03 V that entire time. When I was finally able to put them in series and charge them (on SCC, no grid power) the BMS cut off at 28.5V (14.25V), which is significantly lower than the 29.2V (14.6V) charge voltage recommended by SOK. I reduced my charge voltage settings and increased the boost/absorb time and have slowly been able to get them better balanced so I can get up over 28.8V (14.4V) now without the BMS cutting off the charge. It would help if I could cycle them more often but for right now I have limited PV.

I wish I understood why the SOK-recommended charge settings are significantly higher than what you typically see recommended for LiFePO4 batteries. I'm not concerned about capacity as I don't really need it right now, but I do want to make sure I'm getting charge voltage up high enough for the BMS to balance the cells, which SOK says is 14.4V (28.8V or 3.6V per cell).

Do you have the batteries with bluetooth BMS so you can see the individual cell voltages and differential? Wish I did - bought mine just before those became available.