Batteries are dead after sitting for few months

[HeislerP454]

1999 fleetwood discovery 36T. I have new batteries and new alternator but when it sits for a few months the batteries always are dead so won't start. What is draining them when sitting or what don't I have on to preserve the batteries when stored????

[Sweetbriar]

There could be any number of small electrical loads, such as the engine computer, dash radio and such, that will slowly deplete a battery. If you do not have access to power to maintain a charge the best course of action would be to disconnect the negative terminal of the battery bank.

[Crasher]

If you have a trickle charger for the chassis batteries that is plugged into an outlet near the chassis batteries, it can drain them in a matter of several days if you are not plugged into shore power. Either remove the fuse for it of remove it and install an Amp-L-Start that can transfer power from the house batteries to the chassis, but only when plugged into shore power. It will not drain either battery when not on Shore power.

[pcurt23]

My batteries need recharging at least once per month even with the disconnect. If you leave the inverter turned on in storage it will deplete the batteries in a few days.

So inverter off, batteries disconnected by switch or removing a lead and you still need to service them monthly or plug in.

[Mudfrog]

What is a "few" months? An isolated battery will lose some of its charge after a month. Go three months and it probably won't have enough voltage to turn the engine over.

If a battery is left connected to the coach/chassis, then it will probably end up dead in a short time because of parasitic draw. Disconnecting the batteries will help, especially if you aren't planning on maintaining them properly.

[marjoa]

Well, I think everyone's pretty much covered it.

Summary...
• Can't let batteries sit for months and expect them to stay charged
• Turn off Chassis battery switch of disconnect neg battery cable
• You still have to maintain them properly (read up on this) & maintaining them more in the summer. Heat is a batteries enemy.
• Plugin to shore power or hook up a trickle charger once a month to keep charged
• Turn off inverter

[mtknight]

A 100 watt solar panel does a nice job of keeping your batteries charged.

[vsheetz]

Yup, solar if the couch is not where you can plug it in and some sun is available.

[Bigd9]

Originally Posted by HeislerP454

1999 fleetwood discovery 36T. I have new batteries and new alternator but when it sits for a few months the batteries always are dead so won't start. What is draining them when sitting or what don't I have on to preserve the batteries when stored????

Are the house batteries also dead or just the starting batteries?

Can you check to see how many amps are being withdrawn from the battery bank?

Since you mentioned they go bad in "a few months" it sounds like a really small current draw. Check for a luggage compartment light especially check the engine bay compartment light. If they are left on that small current draw will kill your batteries.

How old are the starting batteries?

[70ChevelleSS]

A fully charged GOOD battery with NO LOADS will retain a charge for months. If you don't have a chassis battery disconnect then it's most likely the ECM. Our previous MH, 1994 Bounder, had a chassis battery disconnect and could sit for months and retain a charge. Our current MH does not have a chassis battery disconnect and the ECM will drain the battery. We have a small solar panel, factory installed, that charges the coach batteries. I jumper the coach to chassis battery if it's going to sit for a few months. The solar panel is enough to keep both sets charged.

I also have a 1970 Chevelle. It can sit for months and the battery can still fire up the 454 engine.

[Superslif]

I noticed on my "new" RV trailer, the radio/CD player has a back light that stays on 24/7. While boondock I got tired of conserving power when off the cord, but having the radio / CD play lite up. So our Yellowstone trip this year I took the 4 screws off the radio and unplugged all the wires. I think is has made a big difference, both boondocking and while sitting in the driveway between trips.

Get yourself a digital volt meter that plugs into a 12 volt outlet. But two months unplugged even a small draw on the battery will drain them.

[Triker56]

Are you using the both "Battery Disconnect" on top of the House monitor to the off before leaving the D?

The chassis batteries provide power to the LPG monitor(near the floor), bedroom CO monitor, steps, dash radio(make sure you don't have the bedroom radio switch on) and any vehicle thief monitor if you have one of those. Plus maybe a few other things.

[Triker56]

Are you exercising the generator once a month for at least an hour like you should?
That will help the both bank of batteries.
Turn both disconnects on before starting it and then off when done.

Not exercising the generator could cost you big $$$$ later on. Especially if you are in a humid area.