Can't start generator

[PhrogPhlyer]

I recently purchased a used 1997 Holiday Rambler Vacationeer from a private owner. About 5 weeks ago I stored the motorhome at a storage facility that does not offer a plugin. The RV sat for about 25 days. When I went out to exercise the generator I was unable to start it without the coach engine running. I drove the RV home and plugged it in for a week to get the batteries charged up; however, I still cannot start the generator from the house batteries. I get a very weak start sound and that's it. The meters show that the house batteries are 100% charged at about 12.6V, but there's just not enough "umph" to get the generator to turn over. The house DC circuits all appear to work, but no generator start-up unless the coach engine is running.

[tenbear]

You don't know if it is your battery or the connections to it. Load testing would give you the answer, so would measuring the battery voltage, right on the battery posts, under load, assuming the battery is fully charged.

[ksg5000]

No offense intended but you std onboard battery monitor is almost worthless - almost anyplace that sells batteries will load test your batteries for free.

[PhrogPhlyer]

Since I can start the generator with the coach engine running I'm not that concerned at the moment about replacing the batteries. I did try to start the generator this morning with the engine off. It appears, if I can trust the onboard battery status monitor, that the voltage drops to near zero when I try to start the generator. It bounces back to the original value - 12.6V - when I release the starter button. Another indication, if I'm not wrong, that the batteries have "gone south".

[ksg5000]

When that happens to me the first thing I do is clean/polish/tighten the battery connections - then do the same with the chassis ground and generator ground. You should also note that some people just get in the habit of starting the rig before starting the generator - no big deal.

[westend]

I have had exactly one battery that lasted 10 years. That is out of a total of 100 or so different vehicles and other equipment.

If you remove the batteries and take them to one of the auto parts houses, they can confirm the demise of your batteries by doing a load test.

[PhrogPhlyer]

Actually, I have the receipt from the original owner showing he purchased the batteries and charger in 2003.

Also, I suspected that although the battery shows that it's charged, it wasn't pushing out enough amps to crank the generator. That's probably why it starts with the coach engine running - the alternator is pushing the amps into the system to crank the generator.

Going to check out a couple of more things today, but I think you all have confirmed my thinking that the house batteries have "gone south".

[Gjac]

You can also have corroded connections from the battery terminals or back at the genset.

[german57]

batteries need amps for starting that is why they say how many amps a battery has I imagine you don't have enough starting amps

[german57]

Even though your batteries show charged they don't have enough amps to turn over starter have run into this alot

[Dakota98]

There is a manufacturers date code on the battery. Usually on top somewhere. Depending on where you obtained the 2003 as being the batteries age. The battery / s may be 2013, & not 2003.

[PhrogPhlyer]

Would need another person in order to do that. Batteries are on the opposite side of the RV from the generator.

[tenbear]

Have you checked the battery voltage when the generator is cranking?

[MrWizard]

you probably need new batteries
but when you store it, use the disconnect and disconnect the house batteries from all loads
there are parasitic loads like smoke detectors, inverter idle, LP / CO monitor that will drain batteries

[Mandalay_Parr]

Most auto parts stores can check your batteries.