I purchased a 2000 Winnebago Ultimate Freedom Class A this summer. We plan to use it during the January - April time frame. I live in a Condo complex so have to store it offsite. I have been going down ever couple of weeks to start the coach engine and generator. After a 3 week period I started the coach but found the house batteries dead. I replace the batteries and 3 weeks later they were dead again. I obviously have something depleting the batteries, even though I hit the 12v isolation switch on the dash and verified no 12v power. My question now is, what is the best way to jump start the generator to recharge the house batteries. I have no ability to plug into house current.Apreciate ny help you can offer.J

Start the main engine, and let it run for maybe a minute...then start the generator. Assuming your battery isolator is working decently, this probably would be enough.If you have an emergency start switch for the main engine, it might also let you start the generator as it simply connects the two battery banks together when you press it down. Often it's the same contactor as the battery isolator system to bridge the two together.

If you start the rig then you should be able to start the genny in a few minutes.Engine alternator should charge house batteries

Possibly you have a Battery Boost switch on the dash that ties both battery systems together. Must hold it down while starting generator. That switch may have another name.

OK, I let it run for about an hour this afternoon. I tried the switch you mentioned, but no luck. Perhaps I didn't hold it down long enough. I'll try it again and hold the bypass switch down for a while before attempting to start the generator.

jgmace wrote:OK, I let it run for about an hour this afternoon. I tried the switch you mentioned, but no luck. Perhaps I didn't hold it down long enough. I'll try it again and hold the bypass switch down for a while before attempting to start the generator.Let's back up a bit please.Obviously your house batteries are NOT charging when they should be.THAT is more likely the real problem instead of a parasitic drain (but it could be a combination of both).There is a "battery solenoid" which is responsible for connecting the two batteries together when they should be; while the main engine is running and when you push the "emergency battery" switch.You need a meter to do some voltage tests.......or you need to take it to a shop for testing and repair. IIRC the replacement of my battery solenoid cost me around $100 at a shop.

House Batteries Dead | Good Sam Community

17 Replies

time2roll
Nomad
Dec 15, 2016
You need to tip top 100% charge the battery and then disconnect a cable for storage. Switch is convenient as long as it cuts off everything.

Consider adding 100+ watts of solar to maintain all batteries.

Going over and starting it up and idling is a bit overrated. Take it out and drive 20 minutes if you start it up. Better IMO to just let it sit.
dstock50
Explorer
Dec 15, 2016
I would suspect the inverter is turned on.
Chris_Bryant
Explorer II
Dec 15, 2016
Not certain yours is like this, but Winnebago used to use a double throw switch- one side for emergency starting, the other for charging the battery. It is momentary in the boost position, latches in the charge position. It must be in the latched position to charge the house battery.
Sam_Spade
Explorer
Dec 15, 2016
Effy wrote:
The only way I have found to prevent it is to physically disconnect the terminals.

In some (many?) models, the battery disconnect switch actually DOES disconnect everything.

AND....wet cell batteries "self discharge" even when completely disconnected so they need a refresher charge every 30 days or so.
Effy
Explorer II
Dec 15, 2016
Offsite storage is a PITA. When we stored our rig at our house it was easy to keep it plugged in and keep the batts charged. But if there is no power supply, despite the disconnect turned off, they will still drain. The only way I have found to prevent it is to physically disconnect the terminals. I have no idea why the disconnect still allows for a small drain, but it does. Someone could probably explain it, but it doesn't really matter. Disconnect allows for "most" things not drawing power and will work for short periods like a week or so until they can be replenished. But for long periods, physically disconnecting them is the only way I've found to keep it from happening.
SCVJeff
Explorer
Dec 15, 2016
Obviously you need to fix the problem, but also consider installing solar. That will eliminate parasitic loss issues
CharlesinGA
Explorer
Dec 15, 2016
If the boost solenoid is the same one used on many Class C rigs, they are notorious for failure. They click, and appear to work, just don't pass current because the contact plate is burned up. The solenoid closes every time you start the chassis engine, to allow charging of the house batteries. If you start the engine with weak house batteries, this puts a real heavy load thru a solenoid not designed for that.

I replaced my original boost solenoid with a Cole-Hersee 24213 which is 200 amp rated with silver-tungsten contacts, instead of the <100 amp rated one with its burned up copper contacts.

You really need to be near an electrical outlet to put a regular battery charger directly on the house batteries to recharge them. Then troubleshoot what is killing them.

Charles
STBRetired
Explorer
Dec 15, 2016
On most coaches, the "Battery Boost" switch operates a solenoid. The power for that solenoid comes from the house batteries, because it is assumed that the starting battery is dead, hence the need for the "Battery Boost". If the house batteries are dead, you cannot use the switch to energize the solenoid. Might work if the house batteries are just too weak to crank over the generator but have enough juice left to energize the solenoid. Best to just start the engine and let the alternator put some charge back into the house batteries.

FYI, it takes hours of generator run time to put a decent charge level back into the house batteries.
Kayteg1
Explorer II
Dec 15, 2016
Unless you pull out battery clamp, the current will always find a way to flow.
usersmanual
Explorer
Dec 15, 2016
doxiemom11 wrote:
New batteries are not always fully charged when you get them. Did you make sure they had a full charge? We stored our MH thru a winter in MI with both engine and chassis battery switch to off. 6 mo later we turned switches back on and everything worked and it started right up. Are you sure the new batteries were installed and connected together properly?

you were lucky if you had a big 3000 watt inverter/converter your house batterys would have been dead