No 12 V juice--battery or converter?

[coolmom42]

My new-to-me 2014 Coachmen C (21QB) has no 12 V juice without the generator running. As in, the lights won't even come on. The battery is a cheapo, previous treatment unknown. When I looked at it prior to buying, the generator was running, because it was a really hot day & I wanted to make sure the AC was working.

It's possible a light was left on inside the first day I got it home, too. That may have flat-lined the battery in a couple of days.


If the 12 V systems work when the generator is running, does that mean the converter is working?

If the 12 V systems work when plugged in to 110 V, does that mean the converter is working?


The generator hour display has a tiny battery icon and as best as I can see it shows a symbol of a battery charging (zigzag in the icon.) Does that mean that the generator is charging the battery?

What battery does the generator use to crank up? It starts just fine.

[mchero]

bikendan wrote:

jaycocamprs wrote:
But be aware that there are likely still a few things (like the propane detector) that draw electricity even with the disconnect switch "OFF". So for long term storage, disconnect the negative battery cable.

Or install a battery disconnect switch right on the battery. I did and my dual batteries were still nearly fully charged after 4 months of storage.

Good idea!

[bikendan]

jaycocamprs wrote:
But be aware that there are likely still a few things (like the propane detector) that draw electricity even with the disconnect switch "OFF". So for long term storage, disconnect the negative battery cable.

Or install a battery disconnect switch right on the battery. I did and my dual batteries were still nearly fully charged after 4 months of storage.

[jaycocamprs]

But be aware that there are likely still a few things (like the propane detector) that draw electricity even with the disconnect switch "OFF". So for long term storage, disconnect the negative battery cable.

[coolmom42]

MrWizard wrote:
Problem solved ... Learning experience acquired

Definitely. It doesn't help that the switch labelling is in microscopic letters in a poorly lit location. But now I know which position is for disconnect.

[enblethen]

Thanks for the update!

[MrWizard]

Problem solved ... Learning experience acquired

[coolmom42]

MrWizard wrote:
The disconnect
Is for disconnecting the house from the batteries when the RV is stored and Not being used and not on Shore power to maintain the batteries
The connection between chassis and house is normally open and connects automatically only when the engine is running,
From your description the house/RV is completely disconnected from the batteries, they are not being charged, you need to put the disconnect switch back in use mode, it should not drain the engine/chassis batteries
The generator or a large inverter are things that would be connected directly to the batteries and not go thru the battery disconnect relay

You were correct. The switch was turned to the OFF position! DUH.

I was previously a partner in a TT that did not have a disconnect switch.

[MrWizard]

The disconnect
Is for disconnecting the house from the batteries when the RV is stored and Not being used and not on Shore power to maintain the batteries
The connection between chassis and house is normally open and connects automatically only when the engine is running,
From your description the house/RV is completely disconnected from the batteries, they are not being charged, you need to put the disconnect switch back in use mode, it should not drain the engine/chassis batteries
The generator or a large inverter are things that would be connected directly to the batteries and not go thru the battery disconnect relay

[coolmom42]

MrWizard wrote:
Sounds like the converter is working
Try this test
With the generator on and you have 12v power
Flip the the battery disconnect switch several times
The latching relay might be stuck
Or if the batteries are discharged the latching disconnect relay might not have enough power to engage
Check to see if the batteries are getting charge voltage

Somebody will post where the relays are located
And any fuses

Generator can be wired chassis or house
The Onan in my RV is wired to the engine battery

Thanks!

More questions:

OK does the battery isolation switch totally disconnect the battery from the RV? For some reason, I thought the disconnect was between the house battery and the chassis battery, so you couldn't run down the chassis battery and be stuck. I googled around and found differing info. Can you clarify this for me?

[coolmom42]

midnightsadie wrote:
find some body close to you that has a rv get them to walk you threw things. better than throwing money at it. then finding out it was a simple fix.

I'm fairly proficient at most things RV. This is my first RV with a built-in generator and an unknown battery.

[mchero]

Double post

[mchero]

Dusty R wrote:
How does a load tester work on a dead battery?

Silly Question......

You fully charge the battery then load test it. If it won't take a charge or fails the load test it's toast.

[enblethen]

Dusty R: It doesn't! Does it? OP must try to charge it first, then attempt a load test. I fop has a battery separate battery charger, he or she could try charging battery.

[Dusty_R]

How does a load tester work on a dead battery?