LiFePo4 Batteries not charging to capacity

LivingTheDream · Oct 7, 2022

System
- 24v 560Ah total
- MPP Lv2424
- 1620W of panels

Hello everyone,
I just plugged into shore at 50A and my Overkill BMS is showing that the batteries aren’t charging to the full 280Ah/each. Any idea why this would happen? I also noticed that my Delta is way out of whack compared to what it was prior to plugging into shore. I’ve attached a screenshot of one of the batteries as well as it’s settings.

sunshine_eggo · Oct 7, 2022

Because:
your charge voltage is too low, should be 28.8V
Your "cell full voltage" is too high. set to 3500
Set "Cell 100%..." to 3500

Did you test your cells and they only had 224Ah? If that's the case, then that's fine. If not, you need to set total cycle capacity to 90-100% of rated.

LivingTheDream · Oct 7, 2022

sunshine_eggo said:
Because:
your charge voltage is too low, should be 28.8V
Your "cell full voltage" is too high. set to 3500
Set "Cell 100%..." to 3500

Did you test your cells and they only had 224Ah? If that's the case, then that's fine. If not, you need to set total cycle capacity to 90-100% of rated.

Where is the “charge” voltage? I corrected the cell 100% to 3500.
When I topped off and balanced, they were at the 280 mark. At least per the BMS.

sunshine_eggo · Oct 7, 2022

LivingTheDream said:
Where is the “charge” voltage?

In your charger(s)

LivingTheDream said:
I corrected the cell 100% to 3500.
When I topped off and balanced, they were at the 280 mark. At least per the BMS.

When was that?

LivingTheDream · Oct 7, 2022

sunshine_eggo said:
In your charger(s)

When was that?

Just did it when I read your comment. I’ll look at the MPP settings when I get back home.

LivingTheDream · Oct 7, 2022

Oh wait, you mean the 280. Maybe 3-4 months ago.

sunshine_eggo · Oct 7, 2022

LivingTheDream said:
Oh wait, you mean the 280. Maybe 3-4 months ago.

Yeah. If you're not charging to true 100% at least a couple of times a month, the BMS will go out of sync with the true SoC of the battery. Additionally, extended periods of inactivity (storage) will almost guarantee your cells will lose their top balance.

LivingTheDream · Oct 8, 2022

Is there some sort of reset I can do for the BMS?

Ampster · Oct 8, 2022

sunshine_eggo said:
Yeah. If you're not charging to true 100% at least a couple of times a month, the BMS will go out of sync with the true SoC of the battery.

LivingTheDream said:
Is there some sort of reset I can do for the BMS?

That may depend on the BMS. I can adjust the parameters on my BMS (Orion) so that it resets to 100% even though I charge to 3.45 V per cell. I had to adjust parameters on my BMS and my Inverter so they both sync at the top of my normal charge cycles. No matter how I tweaked them they drifted apart if not reset at least weekly.

sunshine_eggo · Oct 8, 2022

LivingTheDream said:
Is there some sort of reset I can do for the BMS?

Yes. Charge to full so that all cells are above 3.5V

TomC4306 · Oct 8, 2022

Also, change "Cycle Capacity" to 280.
Remember, SOC is a derived number. It is not a direct measurement. The most reliable way I have found to reset it to 100% is a nice hard charge to my absorption voltage and hold there for an hour before dropping into float
Go through the manual for your LV2424 setting by setting.

ghostwriter66 · Oct 8, 2022

Love that LV2424 ... great little go to SCC (if you set it up right)(Hey lots of good youtube videos also on how to set it up right)(lots of settings on it that if you don't know what they are - don't touch them)

LiFePo4 Batteries not charging to capacity

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