Seneca house batteries charging issue - help!

[loki805]

2018.5 Seneca 37TS
Batteries are charging with generator running and when plugged in to shore power but don’t charge when just running engine of motorhome....are they supposed to? They’ve already went completely dead once and have all been recently replaced. Thanks!

[RVermont]

Sounds like a problem with the isolation solenoid/module. The solenoid requires an input signal from the ignition to close the contacts and provide power to the house batteries when the unit is running. I will see if I can locate the drawing and post it.

[loki805]

Originally Posted by RVermont

Sounds like a problem with the isolation solenoid/module. The solenoid requires an input signal from the ignition to close the contacts and provide power to the house batteries when the unit is running. I will see if I can locate the drawing and post it.

Awesome thank you

[RogerR]

A quick test using a multimeter (under $15 at Harbor Freight, lowes, home, menards).

With the engine off you should have at least 12 volts. Under that and battery life is severely effected.

With the motor on you should be in the 13 14 range, battery is charging.

If your battery is not charging than it could be the system problem shown above. Also, make sure posts are clean and the clamps are tight. If you can move them they are way to loose. Even a little corrosion will stop the 12 volts from getting through to the battery.

[SloPoke]

Originally Posted by RVermont

Sounds like a problem with the isolation solenoid/module. The solenoid requires an input signal from the ignition to close the contacts and provide power to the house batteries when the unit is running. I will see if I can locate the drawing and post it.

This is an older wiring diagram... but mostly still applies....

[ChuckW]

As was mentioned the problem is with the battery isolation module. But that is not 100% accurate. You should have 12+ volts on each positive terminal. On my 17 Seneca on the M2 there is a resetable circuit breaker on top of the chassis batteries. If it is tripped the house is out of the chassis charging system.

[RVermont]

Correct to check the fuse first. However if your steps or level jack's work the 120 amp fuse is okay as these both operate off the chassis batteries. The drawing slowpoke provided is the best overall drawing hopefully similar on the new models. Here is the information on the module so you can see what you are looking for.

[loki805]

Thanks for all the help guys. It seems to have cured its self.

[JimD]

The charging solenoid failed in my 2017 Greyhawk - no charging the house battery from the alternator. I was able to diagnose the problem pretty easily. The original one from Jayco was somewhat high-priced and hard to find.

I swapped out the relay, or in this case it is more of a solenoid like a starter solenoid, for a type I have use in the past. Bought on Amazon (I buy everything there). In any case, your relay is probably in the engine compartment. The two small terminals will be the control signal. One is ground and the other will have 12 volts on it when the ignition is on.

When energized, the relay simply connects the two large lugs together. One will run to the alternator or engine battery and the other will run to the coach battery. If you measure to chassis ground, you will measure the voltage going to each battery.

Take a reading on each large lug with the engine off. Then start the engine and you will see at least one terminal jump to the high 13 or low 14 volt range. If the solenoid is good you will read the same voltage on each lug. If not, either the solenoid is bad or it is not getting the signal to turn on.

In my coach there is a button where I can force the solenoid to energize to connect the batteries together. This is used if you engine battery is low and allows you to start the engine using the coach battery. It can also be used to allow the generator to start if the coach battery is too low.

I got fancy with my set up by connecting a wireless relay to the control line of the solenoid that will let me connect the two batteries together whenever I want. I have a cigarette lighter voltage monitor to keep tabs on my engine battery. If I see it getting low while I am camping, which it does now and then because I charge all USB devices from it, I will hit the wireless relay if I am connected to shore power or running the generator. Main engine battery will then charge.

[Crossingover]

Originally Posted by ChuckW

On my 17 Seneca on the M2 there is a resetable circuit breaker on top of the chassis batteries. If it is tripped the house is out of the chassis charging system.

Good to know. So you have to remove the side cover by the driver's step to access this breaker? Or is it under the driver's seat? Or in the house battery bay?

[SloPoke]

Originally Posted by Crossingover

Good to know. So you have to remove the side cover by the driver's step to access this breaker? Or is it under the driver's seat? Or in the house battery bay?

remove the side cover by the driver's step, on top of the batteries.