Coach batteries draining despite being connected to shore power

[Thibby1]

Hello all,
We have a 2020 Winnebago View and have issue with our coach batteries draining despite being connected to shore power. In fact, once the batteries have drained, we have no power even though we are connected to shore power. Any suggestions?

[Eagle5]

Hi Thibby1,
It sounds like the house/coach battery disconnect switch is in the <Off> position. Barring something like that, I would remove the batteries and have them tested.
Eagle5

[Bones2003]

You say that once the batteries drain you have no power even when connected to shore power. Does that mean that even your 120V AC appliances like the microwave and air conditioners do not have power? Or does it mean only your 12V DC items and some of your 120V AC items do not have power? We really need some more specific information to try and give you good answers. What works and doesn't work under various situations? Does it matter if you run on generator power or not? There are a variety of fuses, circuit breakers, Ground Fault Circuit Interrupters, transfer switches, and other interlocks that may or may not be involved.

I think you have an inverter/charger in your RV. When you are connected to shore power, it provides 12V DC to things like the interior lights and it charges the batteries while on shore power. It also provides 120V AC to certain items like maybe the TV. On shore power, it will just pass the shore power through to the 120V AC items (like the TV). With no shore power, it will invert the 12V DC from your batteries into 120V AC for the items connected to it. If that unit has died or the fuses/circuit breaker associated with it have blown then you will not get 12V DC and your batteries will not charge. If your batteries are bad, then some of your 120V AC circuits may not work when not on shore power.

If you have severely drained the batteries, they may now be bad.

[Morich]

Step one to solving electrical problems on RV is to make sure you do have good batteries and they are charged.
One reason this is critical is that the relay that turns coach power on/off (battery disconnect relay) is a type which latches on the last position, off or on, and will not move if it doesn't have good battery power!
So we can get into a situation where we hit the disconnect switch and power is thought to be cut off. But that is tricky as only SOME of the power drains are cut off. Safety items like CO and propane detectors are still using power which can lead to dead batteries. And then when we "think" we have turned power back on, we really have not because there was no battery power to move the relay off it's last position which is "OFF"!

So we plug it in and the charging doesn't happen because all that stuff is still cut off??
Happens a lot around here!

Try starting the RV engine and that tries to connect the engine start battery and the alternator together with the coach batteries and that may let them get enough charge to move the disconnect relay but it may take some time like 15 minutes, etc. to get enough charge.
See if that clears some troubles!