Battery Charging Problem ***UPDATE***

[whizbang]

While dry camping in freezing weather, the charging system died for the dual type 24 house batteries (2002 Winnebago Mini).

It appears to be a solenoid system. It failed two years ago and the RV shop ran a new replacement wire "to tell it to charge".

I am going to fix it myself this time. (I am a ham radio operator and licensed general contractor, Tinkering are us). However, I have zero expertise in automotive charging systems.

My inclination too, is to remove the solenoid system and run a battery isolator instead. I had an isolator in my F350 twenty years ago and it worked great.

Comments or suggestions? I have no clue where to start, other than doing lots of homework...

[bobndot]

OK, as per the above post, i have a SMART charging system 2018. I was advised that I can bypass it. That's what my rv mechanic told me to do a few months ago when I had a problem with a faulty isolation battery charge manager. He told me to just bypass this garbage and do it the old way which worked just fine. Somebody convinced the rv mfg's to buy this gadget to charge our batteries.

I wasn't sure if this was the right thing to do or not because the system involves the converter charging things when we are plugged in to shore power. I was told bypassing it would not interfere with that converter portion of the system.
The part was a little over $100 to replace, not that expensive. I was torn what to do, in reality, it probably doesn't matter which way its done.



my follow up:
I ended up just replacing the OEM manager to see if it would work. It is working , alternating the charge voltage between my 2 bank coach batteries and my single chassis battery. However if my coach batteries show 12.5v at rest, they will NOT jump up to 13 or 14 volts when I start the rv. The chassis battery will charge off the alternator but not the coach set. Therefore , I'm not able to top off my batteries as I would by the old method. Those coach batteries will only click on via solenoid at a lower voltage of 12.3 or 12.4 volts. Once they reach 12.6v they cut off charging until they drop down again.
I guess this manager is suppose to be a brain like a type of charge wizard to charge our batteries as they drop in voltage and not in a constant float charge rate, that is actually a safe mode as far as I know, the way it was done in the past, as you stated. It appears if they are designed to kick on at a preprogrammed voltage.

I actually like the old way, it seems more simple without these sensitive digital electronic parts to breakdown. KISS is what I prefer and probably what I should have done, but I had to satisfy my curiosity.

[theoldwizard1]

Before you start doing anything, you need to find out if you have a "smart" charging system ! With the house batteries disconnected and the engine NOT running, turn on the headlights and leave them on for 5 minutes. Now start the engine.

Check the voltage at the battery. It should be 14.0V-14.5V. Drive for at least 10 minutes. With the engine still idling, check the voltage at the battery. If the voltage is below 13.8V at the engine starting battery, you have a smart charging system.

A smart charging system WILL NEVER FULLY CHARGE A "HOUSE BATTERY BANK" !

If that is what you have, the best bet is to purchase a DC-DC battery charger. Not only does it does it provide isolation, but it boosts the supplied voltage to properly charge your house battery bank.

Likely your house battery bank is dead. Replace those dual Group 24 batteries (in parallel) with two 6V golf cart batteries (in series). They will provide a lot more power.

[Lwiddis]

Consider a solar system. Hardly ever breaks.