[RE-wrenches] Low voltage lithiums

[Ray Walters]

To add to Jeff's suggestion of targeting 95%, many Li+ batteries have a 
spike in voltage as they reach 100%.  We just don't have to worry 
anymore about sulfate damage from under charging.

Ray Walters
Remote Solar

On 11/19/2022 7:14 AM, Jeff Clearwater via RE-wrenches wrote:
> 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 <http://www.legacysolar.com>
>> 715-653-4295
>> NABCEP Certified PV Installation Professional
>> Licensed Wisconsin Master Electrician
>> BSEE
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