12 volt stuff only works with generator sometimes

[Bugman114]

Hello all. I'm having an issue with my 85 Pace arrow. When i have the generator on, all my 12 volt stuff works fine. But when I shut the generator off, normally the lights would shut off or only like halfway shut off, and then come back on immediately (run off the batteries). But now they just shut off, and nothing 12 volt works with out the generator. But sometimes it the 12 stuff will come on by itself over night. So i guess the main question I have is what's the part that's responsible for switching over the 12 volt stuff from the generator to the batteries? Does the converter switch back and forth, or maybe the isolator? Some other part? Thanks in advance 😄

[Carrie_S]

My problem ended up being a battery cutoff switch relay if that helps at all...It looks like a capacitor. See my post dated 8/9/14.

[wa8yxm]

As some have said, On some Motor homes and trailers the converter contains a change over system.. Newer ones do not.. What is the make and model of your converter.

NOTE: if you open a single door or panel and there are both FUSES and Circuit breakers behind it... What is the make and model of that panel.. It may well be your converter... NOTE: there is an easy fix, improves battery life too, cost around 150 bucks as I recall (But I never did it cause... Well, came already done)

[Bugman114]

Well my dash A/C doesn't work and neither does the blower motor. That's a task for another day lol. So i just keep the generator running the roof A/C while I drive.

I can't remember exactly, but i know I have one of those relays is hooked to a button on the dash, to allow self-jumpstarting, but i don't recall anymore of them, but i don't remember exactly. I know my 90 Fleetwood has like 5 of them for various stuff. But if I do have them, and they weren't working, would that have anything to do with the batteries getting charged? Because they are all being charged via the alternator.

I'll check on the relays and the converter today, and let yall know. Thanks so much for the help guys, I really appreciate it 😄

[Carrie_S]

I had an issue recently where I would lose power sporadically, then eventually not at all. The batteries were charging from shore power but the only power I got was to the outlets. No lights, no toilets! Nothing, even when running the generator. Ended up being the battery cutoff relay or solenoid. Good luck!

[MrWizard]

It will but not continuously
After it warms up max is about 70 amps total
And all power loads come out of that, leaving the rest for charging
So lights, a/C, ignition, stereo.. etc come off that 70, leaving the rest for charging
A/C is a big hog compressor clutch and blower motor

[Bugman114]

I had just replaced the two house batteries, and checked them. They are at about 13.2 volts with everything off (it has an on board battery charger), and they both load tested fine (disconnected them and tested individually) with an actual load tester (the one with the heating element inside).

I'll check out the converter, and let yall know what I have. Thanks for the info! 🙂

I should also mention that I have been driving my MH to work everyday, because both my cars broke down at the same time, lol. I have installed a 100 amp alternator which charges both the house, and starting batteries (i assume that's what the isolator is for, but now that I mention it, I wonder if it's capable of handling 100 amps).

[MrWizard]

your RV is old enough to have an old magtec converter for charging
and depending on the which model number converter
they had a 6 amp charging circuit and a 30amp power circuit and a reed leaf relay
that switched out the battery and the converter supplied the battery and house separately
that relay is inside the magtec, behind the fuse panel

I think it is failing and sticks (this is why it doesn't switch back to battery immediately) , and the 6 amp charge is way too low, for charging from generator, your batteries are possibly in bad shape from not getting charged and then being dragged down again
it will take about a week on shore power to completely charge the batteries using the magtec

you need a new high rate smart 3 stage converter OR an external high rate battery charger

[wildmanbaker]

Your house batteries are apparently not being charged, or it would be seamlessly to transfer from shore/generator power to battery power. Check your house battery voltage, if anything less that 12 volts place a battery charger on them to charge them at least overnight. Voltage should come up to 12.7 volts when charged, and hold a charge for several days, if they are good. Both shore power and the generator will power the converter, which is suppose to supply 12 volts to the batteries and house loads.

[OnaQuest]

On most modern converters, there is no actual "switch over" from converter 12Volts, to the battery 12Volts, however, if you have a model of the Magnetec converter (a 63xx or 73xx) there is a relay inside the converter that does make this switch. I suspect that this is your problem.

You would be well advised to replace this converter with a much newer and improved model in any case.