Electrical issue

JDSquared · 11-29-2019, 11:38 PM

Background first: I got my walls off and 11 of 13 ceiling panels off. There was a speaker in each panel that I took off and disconnected, and a light in each panel that's still hanging from the ceiling. Lights are a rectangular metal box and plastic cover. The lights have one wire coming in. I wondered the other day about ground but didn't think much about it. I was tired from pulling down ceiling panels.

Been gone all week and finally came by the bus tonight. The battery was completely dead. First time it's gone out completely. I plugged up a charger and after a bit tested my ceiling lights. Only half came on. There's two switches for front and rear but it was the right side out and the left side working. Then I touched the metal box to the metal ceiling and the light came on. The right side was hanging free and the left was sitting against the metal frame and working.

So I figured out the ground to chassis lol. But would that have drained my battery this week while I wasn't around? If not the lights I also have the alarm box from the rear door unattached to any metal. Bus started fine with no buzzer so I was guessing everything was fine. When you touch that to metal with the door open it buzzes like it should.

I guess long story short I'm wondering if that back door lock is draining the battery when it's disconnected like that. I was planning soon to pull useless wires and keeping that disconnected.

Thanks for the help. At some point I will eventually be able to share knowledge for others but I'm not there yet!

JDSquared · 11-29-2019, 11:43 PM

To clarify a little bit I've already left the keys in the ignition. Twice. Both times after about 24 hours I still have battery power just not enough start the engine.

Tonight, everything was completely dead even though the keys were nowhere near the ignition. And all the switches turned off.

john61ct · 11-30-2019, 12:04 AM

I put a high-amp DC master isolation switch right at the battery.

A DMM should tell the story of parasitic drains.

Personally I don't use chassis for negative returns much.

TheHubbardBus · 11-30-2019, 12:14 AM

The internal lights couldn't drain your battery unless the ignition key was in the accessory position, and/or a switch on the dash activated (assuming the circuit can be energized w/o the ignition key). Same with the rear door buzzer. It can't drain anything disconnected. Its just an open circuit.

If any of the hot wires from the disconnected lights (or buzzer) were to short to ground while energized, they'd blow fuses, not drain the battery.

JDSquared · 11-30-2019, 01:12 AM

Quote:

Originally Posted by john61ct

Personally I don't use chassis for negative returns much.

As I was pulling the ceiling I thought about leaving the wires and switching the bulbs for led. Attaching to my battery bank when I get that in. I don't know if I like the idea of one wire.

I like the look of the original bus lights. And I already have two switches for them too.

JDSquared · 11-30-2019, 01:15 AM

Quote:

Originally Posted by TheHubbardBus

The internal lights couldn't drain your battery unless the ignition key was in the accessory position, and/or a switch on the dash activated (assuming the circuit can be energized w/o the ignition key). Same with the rear door buzzer. It can't drain anything disconnected. Its just an open circuit.

If any of the hot wires from the disconnected lights (or buzzer) were to short to ground while energized, they'd blow fuses, not drain the battery.

That's what I was thinking. Have the battery on a charger now for overnight at least. Probably all day tomorrow too. I don't know how old it is.

But I got my plates in the mail. Get insurance soon and start driving around town. I'll test the battery and keep an eye out.

Thanks.

Brad_SwiftFur · 11-30-2019, 02:58 AM

I'm guessing you'll have two batteries (very common in these buses). One may be weaker than the other and one bad battery will kill multiple good ones - they discharge trying to constantly bring the low one up to the same level. Get your batteries tested, I'm betting one is toast. Replace as a set, otherwise you'll end up with the same situation, the new battery trying to top off the old one.

JDSquared · 11-30-2019, 07:40 AM

Quote:

Originally Posted by Brad_SwiftFur

I'm guessing you'll have two batteries (very common in these buses). One may be weaker than the other and one bad battery will kill multiple good ones - they discharge trying to constantly bring the low one up to the same level. Get your batteries tested, I'm betting one is toast. Replace as a set, otherwise you'll end up with the same situation, the new battery trying to top off the old one.

It's actually just the one battery. Interstate 8D group. It wasn't giving me any trouble. But I wire it down twice leaving my key in. Both times I still had power but not enough to crank. But I haven't driven it anywhere to charge it through the alternator.

TheHubbardBus · 11-30-2019, 09:53 AM

Without knowing the age of the batteries, in addition to the two times you deep cycled it (& who knows how many times previous owners did), it very well could be just the battery. But I'd still check for parasitic draws as John mentioned. If nothing else it's a valuable skill to have in your tool-belt. There are considerations with computer control modules when doing such tests (speaking in generalities, not bus or your-bus specific), so if that applies, do your homework.

I'm a really big believer in trickle chargers like Battery Tenders, particularly for vehicles that by their nature aren't driven daily. It will likely pay for itself in extended lifespan of the first battery you hook it up to, and can reverse - to a small extent - sulfation that decreases capacity. Just wire up the leads using the ring terminals, so it's a semi-permanent installation (as opposed to the alligator clips). Keep it plugged in 24/7 whenever it's parked. Pull the plug & drive off when it's time to play.

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