[RE-wrenches] Low voltage lithiums

Jeff Clearwater jeffc at villagepowerdesign.com
Sat Nov 19 06:14:11 PST 2022

Hi Kris

What voltage do you have your charge settings at?  

I recommend that bulk or absorb voltage for lithium iron phosphate not be set above 56 V  - there is no reason for it even though many manufactures suggest higher settings.      In cases where total storage is sized generously enough I  often use 55.6 or even 55.4 in order to target 95% as full instead of 100% in order to extend cycle life.   and for float there’s no reason to ever go over 54 V and better maybe even to be in the mid-53s. 

See if that helps assuming you had it higher. 

The other thought is you have one bms that is perhaps not protecting overcharge  and allowing a temporary spike when the others do limit. 

Hope that helps!  

Best Jeff C. 
Village Power Design

Sent from my iPhone

> On Nov 19, 2022, at 6:32 AM, Kristopher Schmid via RE-wrenches <re-wrenches at lists.re-wrenches.org> wrote:
> Greetings all,
> I have seen an issue on two different systems that I am hoping someone can shed some light on for me.  One was a 48 volt pack of 12 volt Battle Bornes and the other was a 24 volt pack of SOKs.  What happens is when reaching the end of the bulk charging stage, the battery voltage spikes and sends the inverter into an overvoltage error.  Can anyone explain what is happening and a solution?
> Thanks,
> Kris
> Shine On!
> Kris Schmid
> Legacy Solar, LLC
> 137 West 1st Avenue
> Luck, WI 54853
> www.legacysolar.com
> 715-653-4295
> NABCEP Certified PV Installation Professional
> Licensed Wisconsin Master Electrician
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