[RE-wrenches] FLA battery problelm

Fri Dec 12 10:56:49 PST 2025

As a long time HUP dealer,  I've dealt with stuff like that for quite a 
while.  FYI, HUPs are no longer being made, thanks to the tariffs.

As Steve mentioned, renters are Not the best off grid customers. They 
really don't understand the system, and how to properly maintain it.  My 
guess is they have a bunch of phantom loads, extra junk plugged in, and 
the system is never reaching full charge.  2nd, as noted, they are over 
filling the water.  I have several customers that get fixated on 
filling, and forget to check SG, and actually fully charge the batteries 
too.  You didn't mention some key info: battery size, or array size.  If 
its a bigger HUP, it could take over a week with no loads to come back 
up.  HUPs have a minimum charge rate requirement that is very important 
in this situation.

So, based on the age, this should be recoverable.  It will take some 
extreme EQing for possibly a couple of days.  I'd EQ at 61 v for 2 
hours.  Monitor temperature and don't let the batteries exceed 95F.  
Check SG.  If you're not up to 1.265 on the lowest cell, EQ again.  
Rinse/ repeat, until you get to 1.265.  Then this renter may need to go 
on an energy diet too, so this doesn't happen again.  I've had so many 
renters ruin good systems that worked for the original owners for 
decades.  They just leave stuff on, and it never comes to full charge.

Ray Walters
Remote Solar

On 12/12/2025 11:35 AM, Steve Higgins via RE-wrenches wrote:
>
>
> The SW series inverters don't have non-volatile memory, so if the 
> renter discharges the battery below the low-voltage point, all 
> settings will be reset to default.   That will definitely cause 
> charging issues.
>
> If they were overfilling the batteries, this would push sulfate out of 
> the battery, diluting the acid mix and lowering overall capacity.  
>  You can try adding more back, but it will require a lot of premixed 
> acid. It might help to drain 1/2 out and add back premixed 1.265-1.280 
> acid to correct. If the sulfate levels are already low and there is 
> mostly just water in the battery, corrosion can occur within weeks, 
> resulting in permanent damage.
>
> Also, if you add too much or the sulfate has precipitated on the 
> plates, this will increase the sulfate in the battery and lead to a 
> significant loss of overall capacity.
>
> My guess... is this battery is done for... You can try the above, but 
> you'll likely spend a lot of time adjusting electrolyte levels and 
> many hours of cycle charging to recover.  Even if you recover to some 
> capacity, the SGs will always be "All over the place," and the bank 
> will likely remain questionable until they are replaced.    In the 
> end, the "Renter" probably killed these due to lack of 
> interest/education...
>
> Steve Higgins.
>
> 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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