Help - Dead house batteries

Hello and thanks in advance for your help.

We forgot to disconnect the house batteries while the MH is in storage. It's probably been about a month since we visited the MH.
DH went today to drive it and charge the batteries. The MH started, so we're good there, but the house batteries are dead. They are
about a year old, so it's not an age issue. I'm sure it's a sitting issue. ;D

Is there a way to charge them without having to take them out and take them somewhere to get them charged?

Thanks again.

You can either plug into shore power and let your converter charge them, start the generator and let your converter charge them, or use an automotive charger to charge them.

Thanks. Unfortunately, can't plug into shore power as the jacks won't retract, so can't drive it anywhere, and there's no shore power where we are. We'll get an automotive charger and see how that works. If we could get the generator on, we'd be good to go. Thanks again.

Since you can start the engine, and since most motorhomes have a special momentary switch that connects the two sets of batteries together (aux start, start aid, or some such label), if you can identify that switch you should be able to use it to start the generator.

Yep, start the generator with the e-start switch while the chassis engine is running.

I'll add...unfortunately there's a good chance that your batteries will hold some charge, but they won't hold nearly the full capacity of a new battery.  I've found that running a battery dead will cause harm.  Sometimes I've had batteries run cold dead once that would not take a charge...but usually in my experience with a good battery after 2-3 times they will be dead and not take a charge again.  Each time down their capacity takes a noticeable hit

Three answers: two apply
First: if they are STARTING batteries.. Toast
Second: If they are MARINE/deep cycle or MARINE/rv.. THey MIGHT recover.  having put SOME charge in 'em by driving.. Plug her in or run Generator for about 6-8 hours.

Finally if they are TRUE Deep cycle. good chance they will recover. but you may have lost a year of battery life.. See "Second" for what to do.

He tried the aux start earlier today, but no go. Maybe the batteries are toast, as mentioned, so the aux start won't help.

Thanks for all the replies. He'll go back tomorrow and see if he can figure it out. As mentioned, we can't plug to shore power, and the gen won't start without some battery. If we have to spring for new batteries, well, I guess that's what we'll have to do.

We just moved to another town. We had covered storage with metered electric and now are storing outside with no electric. We had a great set up where we were. This new set up is taking a lot more effort and thought.

May very well be  a mile off base (cuz I don't own a big ol' DP) but would it be feasible to jump the house battery bank with your car/or pickup via jumper cables and try to (a) start the generator or (b) at least raise the jacks so you can get mobile? 

Just a thought ...............  ed s

Nice thought, Ed, but that's what the AUX START switch effectively does, so I'd be surprised if it would help.

If your battery bank get down to about 9 volts, your charger will not engage.  You will have to employ an external charger of some sort (stand alone charger, car battery charger, or even a jump from your own car). Once the batteries get some life, the on board charger will kick in. Still, an external stand alone charger will charge them faster, but the on board charger will do the trick, just take longer. 

Put a volt meter on the batteries to find out what your starting point is.

I mention that DEEP CYCLE  batteries can recover from a OH ***! level discharge better than Starting or Marine/deep cycle.

one of those OH S**! cases the isolator failed to isolate when I left headlights on..

I used a JUMP START battery (Small portable battery) to crank 'er up.  I am now on my Second Jump Start battery. the first one, which I got years before I got my RV, jump started many cars, it was a 1000 amp peak curent job. finally the case started falling apart so when the battery died I recycled it.

With the RV of course I have a built in jump... but not with my car which cost me liek 50 bucks or more for a jump from a tow when the battery in it died of old age (The car is a 2001, it was 2013, I don't know if it was the original or not).

Last summer I needed a portable battery so I got another Jumper. I think it's 900 peak amps, about 100 bucks at Auto Zone or several other auto places.

IN between.. I had a couple of smaller 12 volt batteries I used for multiple uses. one of them jump started the generator.

For that start I hooked DIRECTLY to the generator. there is a big bolt with a big wire labled _+ covered in a red cover on my Generator.. that got the positive lead

Negative went to teh chassis

Pushed the button and varoom

Waited for the clunk and change of engine noise before I disconnected (Converter engagement)

I do like having that fully charged jump pack about. Re-charge it every 3 months  even if I dont' use it. Which reminds me. Time to plug it in.

Larry N. said:

Nice thought, Ed, but that's what the AUX START switch effectively does, so I'd be surprised if it would help.

Click to expand...

Yes, that's what the switch does alright but.... Using  jumper cables from a known good external battery to the disconnected cables of the house batteries will allow starting the generator, just like installing a new battery would. You could do the same with a chassis battery, if that was the bad one, and start the engine. (Assuming the battery is the actual problem!!)

If a battery is really "DEAD" It will do little good by jumping it with a good battery. It should be disconnected beforehand to avoid the good source being absorbed by trying to charge up the bad one . It will thus effectively be replacing the dead one.

it could be that the e-start switch just isn't working.

Last year I found that my relay was dead and had to replace it.

blw2 said:

it could be that the e-start switch just isn't working.

Last year I found that my relay was dead and had to replace it.

Click to expand...

Had the same thing happen on my ERA.  I only discovered it when I found my start battery wasn't being charged while plugged in (have since added a Trik-L-Start).  I opened up the old solenoid to see what happened (it was still being thrown when energized).  The contacts has burned and were not making contact.

The E-Start NORMALLY is used to jump start the CHASSIS from teh house. Now there are two ways to wire that puppy.

Cheap method.. It is hooked to the HOUSE batteries.. This saves perhaps a dollar

Better (Intelletec BCC method) A pair of diodes, one to the house, one to the chassis

That way it works both ways.

DH went to MH again. Couldn't get the E-start to work. Probably as Sarge noted above. He brought 2 home and is trying to charge with a stand alone charger to no avail. Will take them to be tested. Did find out they are deep cell and are 2 1/2 yrs. old. He talked to someone at Interstate Batteries who said they could possibly recharge, but not a given. What a PITA.