I spent decades talking folks through recovering HUPs that had been chronically under charged.   The fact that the batteries are just hovering around 52 v and not breaking out above that is another sign that there is capacity left.  Its when they charge right up to 58 v and go into float before 10 AM that you have no capacity left. That hovering at partial SOC is because there is not a high enough charge rate.

They need to start the generator in the morning, so that both the generator and the solar can work together to have a high enough charge rate.

Equalize, Equalize, Equalize, they will come back to full charge, but yes they will have lost some capacity from when they were new. These batteries could easily last another 5 years if recovered.

We're not talking 2 to 4 hours of generator charging either, we're talking like 12 hours a day possibly, for 3 to 4 days.  You just keep going until the SG comes up.  Period.  Then bring them to full charge every week to 10 days, and don't let them sit chronically under charged again.


More solar or a drastic weight loss program is the only way to make this system work long term.


Ray Walters
Remote Solar


On 12/13/2025 12:13 PM, pieter offgridenterprises.org via RE-wrenches wrote:
I couldn't agree more with Ray. Those batteries are tough. Assuming there is adequate charging capacity the batteries have a very good chance of recovering. That being said the renter has to be trained! Simply spending more money to replace the Hup batteries wit a set of new LIPO batteries will most likely trade one problem for another. As others have already pointed out: If energy in is less than energy out the batteries will not be able to make up the difference. Even LIPO batteries.
Pieter Huebner
Project Manager
Off Grid Enerprises
------------------------------------------------------------------------
*From:* RE-wrenches <[email protected]> on behalf of Nick Lucchese via RE-wrenches <[email protected]>
*Sent:* Friday, December 12, 2025 11:41 PM
*To:* RE-wrenches <[email protected]>
*Cc:* Nick Lucchese <[email protected]>
*Subject:* Re: [RE-wrenches] FLA battery problelm
Are you able to get near the 75 amp charge rate with the SW's charger and that 7.5 KW generator with a step down transformer maybe? Neither charging combos can push the voltage above 52? All the bus bars and hardware have been cleaned and reassembled recently or not since 2022? Have you made any other observations looking over that 128 day logging menu?

Battery banks prematurely heading to the smelter is the unfortunate reality of our systems of the past. Chasing that mostly unrealistic goal that the bank will do some dramatic turn around to redeem everyone's efforts may likely result in more wasted time and money. Replacing with a lithium pack that offer's it's own onboard SOC capacity meter is almost a necessity with renters. Removing the unknown cloud around understanding what the battery needs results in a much more enjoyable homestead experience and engages the renter to be accountable for recharging. Offerings from both Midnite and Rubix can be had for less than $.28 a watt hour retail these days. Impressive times for folks storing sunshine. The sooner it goes in the sooner the fuel savings and lack of service calls can start paying it off.

I always default to Midnite first for quite a few reasons and especially for `UL9540 but Rubix might be a better solution in this case since that volatile memory Steve mentions might become a concern if a trained individual isn't frequently checking up on the system to make sure all the settings are still in tune with the battery. Besides for LBCO, SW default settings are quite ideal for all of the Rubix series. You also gain the bonus of a digital net power meter on the battery to validate the SW's meter screens along with the Outback logging menu.

Nick



On Fri, Dec 12, 2025 at 10:21 AM David Coale via RE-wrenches <[email protected]> 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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