[RE-wrenches] Aging Batteries

[Howie Michaelson]

Hey Will,

At the risk of being overly simplistic and obvious, have you kept good
specific gravity records over the years? Are they showing lowered or uneven
readings?  I've often been able to get some more life out of flooded
batteries by raising the charge and equalize voltages, particularly if
these are Rolls 2- volts. I've been known to run the bulk charge as high as
31 sometimes and equalize up to 32 with longer run times (2.5 - 3 hours)
for off grid, assuming that there aren't any particularly weak cells.

You can also do a simple load test on each individual battery and if you
find a very weak or dead one, taking it out of the string often improves
capacity (if you've already tried recovering it through extra charging). Of
course, you would would need to adjust the inverter and CC settings
appropriately.

Which model of 2-volts are these?

Again, sorry if this is all too obvious for you.  Just getting back to
basics.

Good luck,
Howie

On Fri, Oct 27, 2023, 11:27 AM Mac Lewis via RE-wrenches <
re-wrenches at lists.re-wrenches.org> wrote:

> Hi Will,
>
> I'd keep inching the start voltage down and see if it helps.  Sometimes
> old batteries just operate at a lower voltage and will sag more under load
> but they will still carry the load OK
>
> Of course you can:
> 1.  Do all of your high power stuff when the sun is out.
> 2.  Disable the generator start at night and see where the voltage goes by
> morning, perhaps a load kicks on and the voltage is sagging enough to kick
> on the generator from voltage.  It helps if you can plot the voltage over
> night to see what is happening.  (Victron battery monitors are really cool
> for this).
> 3.  Load starting can help limit overall run time.
>
> Sometimes you can do inventive things with Quiet time that will limit
> generator starting.  Not sure what inverter system you have.
>
> On Fri, Oct 27, 2023 at 9:03 AM White, Will via RE-wrenches <
> re-wrenches at lists.re-wrenches.org> wrote:
>
>> Hello Wrenches,
>>
>>
>>
>> I installed my off-grid system in 2008. It’s 24 V using 2 V industrial
>> FLA batteries. As you can imagine after 15 years the capacity of my battery
>> bank is significantly less than it used to be.
>>
>>
>>
>> For logistic reasons, I won’t be able to replace them till around June of
>> next year, but it’s not even into winter yet and my generator is already
>> running every day.
>>
>>
>>
>> Does anyone have any tips on how to get through the winter on these
>> batteries while minimizing generator run time? I’ve got two FM80’s with 3.8
>> kW of PV, two VFX3524 inverters, and a Kohler RES12 generator. I haven’t
>> changed any settings since I installed the system.
>>
>>
>> Thanks,
>>
>> Will
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> --
>
>
>
> Mac Lewis
>
> *"Yo solo sé que no sé nada." -Sócrates*
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