Re: battery change questions

On 8/3/2024 1:00 PM, bfh wrote:

Ted Heise wrote:

On Fri, 2 Aug 2024 23:13:42 -0400,
   bfh <redydog@rye.net> wrote:

  Ted Heise wrote:

On Fri, 2 Aug 2024 14:07:23 -0400,
    bfh <redydog@rye.net> wrote:

>

   Back in a previous life, we did a lot of flatspotting and got
   along fine without a generator, but we didn't have a microwave,
   electric coffee pot, or a toaster.

>
The wife and I are spoiled, what can I say.    :)
>
But how did you charge the trailer battery?

>
  It charged through the 7-pin when driving, and with the
  built-in charger when we had shore power. I don't remember
  having any battery problems when flatspotting, but we rarely
  stayed in one place longer than 2 days/nights. Plus, we weren't
  spoiled back then, and all we used when parked were 1 - maybe 2
  - lights and the water pump.

>
Okay, charging from the 7-pin is what I'd expect, but I haven't
seen any evidence of that happening since I put in the new LiFEPO4
battery.  Admittedly, it's just been one trip of ~5 days.
>
I do wonder if the battery has to reach some lower SOC than I've
seen (85%?) for charging from the 7-pin to kick in.  Operation of
the Dometic battery monitor is still largely a mystery to me...
>
https://www.amazon.com/Go-Power-GP-BMK-25-Battery-Monitor/dp/B09NRXD9G8
>
Is it possible the 7-pin will actually charge the battery if it
gets to a lower SOC?  If yes, do the GP-BMK-25 settings make a
difference in this level?  I can't tell from the "manual" and mre
broadly havn't been able to get a good unserstanding of how it
works.
>

I really don't think it will charge from the 7-pin connection if the battery is low. At least not with the standard size wire you now have. By the way, I may have missed it but did you ever verify if you have voltage coming through the 7-pin connection at the positive battery cable on the trailer battery?

Maybe another relevant point is that the new battery shows its
state in good detail via a nifty bluetooth linked app; the info
from the battery makes sense, but diverges at times from what the
Dometic monitor shows (especially as it relates to SOC).
>

 I don't know. I didn't have a battery monitor, and the battery was a standard old deep-cycle battery. It just charged when I drove or was plugged into shore power.
 

LiFePo batteries are a different breed. My opinion, FWIW, is to go with a small generator.
--
“The Party told you to reject the evidence of your eyes and ears..." George Orwell