[RE-wrenches] FLA battery problelm

Fri Dec 12 11:33:52 PST 2025

I second the chronic undercharging suggestion. We have a client with a 64
kWh FLA battery bank that only has 2.4 kW of PV. When they bought these
batteries two years ago, they thought they could solve all of their energy
woes by just buying a bigger battery. It is astonishing how many people
don't understand that batteries themselves do not generate electricity -
they just store it. They must think it's magic!

Anyway, with that kind of PV to storage ratio, they were probably barely
getting past the internal resistance. The batteries are completely toast
now, and the client is moving to LFP (with more solar per my demand).

Jason Szumlanski
Principal Solar Designer | Florida Solar Design Group
NABCEP Certified Solar Professional (PVIP)
Florida State Certified Solar Contractor CVC56956
Florida Certified Electrical Contractor EC13013208

On Fri, Dec 12, 2025 at 1:32 PM Michael Morningstar via RE-wrenches <
re-wrenches at lists.re-wrenches.org> wrote:

> Chronic undercharging, electrolyte dilution, lack of informed
> equalization, and adding water without knowledge of the how’s, whys, and
> when’s will kill those batteries in no time. I’ve pulled out to many of
> those heavy bastards to count, most of them at a fresh young  age because
> the installer didn’t educate the clients properly.
>
>
> On Fri, Dec 12, 2025 at 10:21 AM David Coale via RE-wrenches <
> re-wrenches at lists.re-wrenches.org> wrote:
>
>> Hi Wrenchers,
>>
>> I have a client with an old off-grid Trace system and he is having
>> trouble with the batteries.  He has HUP Solar One FLA batteries that are
>> about 4 years old, so they should be in good shape.  The last set lasted
>> almost 20 years with a fair amount of abuse.
>>
>> Here is he history and what I think is going on. 7/21 they got new
>> batteries after about 19 years of use.
>>
>> 7/22 I get a call saying the batteries are not charging up all the way.
>> When I check out the system, the batteries needed cleaning, and I found
>> three low cells, and the charger settings were back to default, not set
>> high enough to charge the batteries all the way (it’s always multiple
>> problems).  The client (now a new renter, new to the system) said he was
>> filing the batteries once a month and experienced some overflowing when the
>> batteries were charged up.
>>
>> I cleaned things up, reset the charging parameters and set up an
>> equalizing charge to even out the cells. Hopefully this will fix things.
>>
>> 11/25. The client calls and said the batteries don’t charge up all the
>> way and he is running the generator a lot and worried about getting though
>> the wintertime.
>> When I check things out, there are three bad cells and there is soda on
>> the batteries. It is hard to get a good voltage readings because of the
>> soda. Most of the cells are reading 2.1 volts under about a 40 amp load.
>>
>> Yesterday I check things out, and all the cells are reading between 1.93
>> to 1.98 under a 40 amp load in the morning, and I don’t find any bad
>> cells.  The charging voltage is never going over about 52 volts so the
>> system is never getting fully charged up.  The charge setting look OK, so
>> not sure what is going on. This is acting like an old battery pack but
>> these batteries are relatively new.
>>
>> My guess at this point is that maybe the batteries lost acid with the
>> overflowing event and lost capacity.  Maybe adding acid back in would bring
>> them back up to working order.  The SG measured at 1.150 or less.
>>
>> At this point the client (renter) has had enough of these battery
>> problems and is wondering every morning if the batteries will last long
>> enough to until the sun comes up.  The renter is pushing for a replacement
>> LFP battery, but there should be lots of life left in this battery pack.
>>
>> Let me know what you all think.
>>
>> Thanks,
>>
>> David
>>
>>
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>> --
>
> Michael Morningstar
>
>
> Morningstar Electric Inc
>
> PO Box 1494
>
> Mount Shasta, CA 96067
>
> 530-921-0560
>
> CSLB 1116835
>
> mjmorningstar at gmail.com
>
>
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