Using an automotive battery charger when onboard fails

Kaliforniastan banned everything but battery sulfators a few years ago. Does any state allow manual control battery chargers? Thanks to ----can grade chargers with no shutoff switch, the central committee diverted enough time away from being a political attack dog and insane asylum to effectively doom 10,100,000 batteries over the next decade.

Never let a politician think. The only math they understand is how to pad billing hours.

When my Converter failed a couple years back I got a Deltran Battery Tender. Now you are used to the little ones. This one is not so little. it has 3 modes

TENDER (like the little ones)
Boost (20 amps) auto switch to tender
Jump (70 amps brief period wants to see almost no voltage to kick it in useful for, as the name implies. starting car with dead battery worked too)

Took it 24 hours to charge my battery bank. and then I hit the road... Next stop was abou 15 miles from Progressive Dynamics. Next Stop, as you might guess WAS Progressive Dynamics.. (I know the area).

opnspaces wrote:
My question is, can any newer, automatic battery charger be used for to keep the coach 12 volt running? Or does a person need to look for a cheaper (possibly something from Harbor Freight) charger?

Yes any newer automatic will work fine.
Your choice to shop at HF but low price is not a necessity.

I recommend 5 amps minimum with 10+ being much better for a portable. Ignor the 'start' or 'boost' rating for general battery charging.
If you have a WFCO converter, do not replace with same when you get around to fixing it.

We did just what you describe a couple years ago when our friends' converter failed. My charger had a 12A setting and didn't cut out all weekend and managed to keep up acceptably. The biggest issue was protecting the charger from the rain.

Lots of chargers get confused and shut off in constant voltage absorption when the load on battery changes like a fridge cycling off. I have a schumacher which would stay running but voltage would spike to 15.5v+ when compressor shut off and drop to 12.8v when it cycled back . This happenen on 12 amp setting. On two or 25 amp setting it would shut off.

opnspaces wrote:
can any newer, automatic battery charger be used for to keep the coach 12 volt running? Or does a person need to look for a cheaper (possibly something from Harbor Freight) charger?

Not sure I understand. Why would you 'need' a cheaper charger?

If the converter fails, you are on battery until it dies. Idea is to have spare charger that will recharge the battery. Amps size of that should be within generator's VA and high enough to keep gen time low.

If on shore power, still on 120v but on battery for 12v, same thing but now question is can the charger act like a power supply same as the converter does, or does it shut down when the battery is charged up? Most of them are like that so you still need the battery for between recharges.

If the scenario is shore power but no battery and converter dead, you need a charger that will stay on like a converter does. It will need to be about 40 amps to run the RV 12v stuff.