12 volt system mistery to me

[TimeFlies]

2023 Caravel 19 CB

Battery fully charged. at 13.6

I'm Connected to shore power 30 amp - microwave working - power jack working - inverter working allowing me to charge my phone BUT I don't have any of the following working:
Lights
Refrigerator
water pump
Battery Power Switch by the door will not stay on when depressed.

clues to help me would be welcomed.

tks

[Ginophiles]

First, having made this mistake myself, check the battery with the shore power UNPLUGED. I unknowingly had bad batteries, but as I was plugged into shore power, the converter was sending 13.6 volts to the dead battery, so it read 13.6 volts.

The lights and water pump usually run off the battery. I assume the refer is a 12volt one? So, if you're not hitting the disconnect switch properly, your battery may be disconnected, leaving something like the microwave working from the shore power. The power jack is often wired right to the battery and may not be affected by the disconnect switch, so if it works you likely have a charged battery of some sort.

But you said the Inverter is working and that runs off the battery. Check that disconnect switch again. I find mine somewhat confusing and nearly bought 2 new batteries the night before heading out on a trip. I mixed myself up with the switch and then panicked thinking I needed new batteries. Again.

[TitusNW]

Are you hearing the Battery Guard relay trying to latch when you press the switch? Do you know where the Battery Guard relay is located in your trailer? I'd check for loose wires on the lugs as well as the wires that lead to the switch.

Steve

[DKB_SATX]

Check the breaker panel and see if the breaker that supplies power to your converter/charger is tripped. That would be the easiest fix for the problem you're describing... because even if the batteries are toast, unless one or both batteries is close to a dead short through the battery, when you're on shore power the converter should power the lights, vent fans, fridge and water pump.

Does your electric tongue jack work?

If your converter tripped the breaker and has been offline for a while, your batteries may simply be competely discharged and the things that need 12v have no power source at the moment.

If the breakers are all fully closed (I'd recommend turning them off and then back on one at a time if there's not one that's obviously tripped) then troubleshooting gets more complex. There are fuses on the converter-charger and possibly inline between there and the batteries. You need to determine first if 120V AC power is reaching the converter at all. If it is, then check the fuses on the output side and see if 12V power is leaving the converter and later arriving at the fuse block.

If that last paragraph sounds like gibberish, after checking the breakers you might want to find someone who's done this sort of thing to help you. Familiarity with (and ownership of) a multimeter help a lot here...

[uncle_bob]

Hi

Inverter working *and* plugged into shore power is not a good idea. Turn off that inverter.

The inverter is there to create 120V off of the 12V battery when you do *not* have shore power. In some trailers, there are dedicated "inverter only" AC outlets. When you are on shore power, you plug into a different outlet than when you are on inverter.

If you have lead acid batteries, 12.6V at rest is "fully charged". Anything over that means you are actually looking at the converter charger in action. Working out state of charge while the converter is running is difficult.

If you have lithium batteries, 13.6V is a reasonable number for an "at rest" fully charged battery. Anything above 13.4 probably means you are right up there charge wise.

Working out any of this from voltage readings gets into all sorts of issues so these are all *very* rough approximations.

What to do:

1) Grab your multimeter (buy one if you don't have one ....).

2) Unplug from shore power

3) Check the voltage at the battery posts. It might be well above 13V.

4) Wait about 30 minutes. Check it again. If temperatures are reasonable and it's a lead acid, it should be around 12.6V

5) Plug back into shore power.

6) The battery voltage should go up above 13V pretty quickly.

At this point you know your converter / charger is running and the battery is hooked up. If something doesn't add up as you do this, dive into the batteries, the converter, or the fuses / wires between them.

Fun

Bob

[Escape21]

Check the battery cutoff switch relay. It is likely on the back of the power center. Unplug 120, leave the 12v cutoff switch off. Pull out the converter, usually four screws after the door trim is removed. Look in the back. There is a relay with wires attached and a nut holding them. Sometimes a yellow label as well. Make sure the nut is tight. Several people have found it loose and causes issues with the battery cutoff working. Us included 2023 FC 23. Good luck.

[TimeFlies]

You are absolutely correct, a wire was not properly attached to the relay/solenoid behind the panel. Thank you for your rapid reply.

tks

Norton

[TimeFlies]

Thank you all for reaching out to help for your guidance.
The reason of my "mystery problem" was a loose wire at he relay/solenoid.

[Pat Pierce]

I’ll chime in and maybe knowledge for others to keep in mind. Last year in our front twin Serenity while dry camping and using our generator, something happened and it took a few minutes to realize our 12v system was not working. Turn off the generator, no lights, the refer light status, etc not working. Dead. Hmm. The battery shutoff switch light looked weird and I think I could hear a clunk when trying it.

When back in town, I researched how the battery switch worked, and found the large relay under the right side twin. The relay has two auto spade fuses, and both tested ok. I found online, the manufacturer’s info on the battery switch circuit board, and looked at how to test the circuit board to determine if it is working or not.

Using a VOM, I checked the voltages between I think it was 4 different contact points to see how they compared to the listed voltages. One set was off meaning the circuit board was at fault. I ordered a new circuit board, and all is working fine.

[derouik]

Great to hear that you got your issue sorted out Norton! I had a similar issue with our 2023 Flying Cloud that had me completely stumped were it not for this group I'm not sure what I would have done as our the dealership is 4 hours away and we'd only spent a grand total of 1 night in our Airstream. The issue was a loose ground behind the Battery Guard relay. This and other issues have kind of shaken my faith in our Airstream...

[Prairiedog48]

Pursuant to Time-flies I checked my batteries (AGM). It read 13.5. I then unplugged shore power and tried again. It read 13.4, with everything OFF. One hour later I checked again and it was 12.5. Again, everything was off but I turned on lites and water pump. Everything worked properly. Any ideas as to what’s going on here? Halloween is over with! 🎃

[Wazbro]

Originally Posted by Prairiedog48

Pursuant to Time-flies I checked my batteries (AGM). It read 13.5. I then unplugged shore power and tried again. It read 13.4, with everything OFF. One hour later I checked again and it was 12.5. Again, everything was off but I turned on lites and water pump. Everything worked properly. Any ideas as to what’s going on here? Halloween is over with! ��

13.5 reading is charging voltage, 13.4 surface charge (artificially high reading due to just being on charge), 12.5 actual battery voltage after surface charge dissipated. 12.6 is about full charge for AGM batteries, temperature dependent and some volt meters can be off by .2 volts.

In summery it is completely normal and should be expected.

[mcjohn]

Originally Posted by TimeFlies

You are absolutely correct, a wire was not properly attached to the relay/solenoid behind the panel. Thank you for your rapid reply.

tks

Norton

Hey Norton, I’m having similar issues with my 19cb. I was wondering if you could share where you found the relay? Thanks!

John