Weird electrical stuff - help!

[jage]

Originally Posted by daveb

I think you have a diode isolator not a separator...

Yes, I agree:
In the engine compartment, looks like a brick more or less: isolator. Also correct equipment for your year.

1/2 brown can shape in the house area somewhere, separator. This has the green wire I was talking about, so your wouldn't. Sorry for the goose chase!

Good opportunity to upgrade to a separator. I'm pretty sure you could move all the wires to the house post of the isolater, leaving it in place and turning it into a connection block (house s.t. the other two posts aren't energized) and then install a separator closer to your house batteries on the same wire.

Haven't really thought it through though...

[ANZAC]

This still sounds like a classic bad connection. The radio runs because it doesn't draw much current. You try and do anything else, poof, no voltage. If the puff of smoke was from near the battery, that is where the bad connection could be. Remember when you measure the battery voltage you are usually on the clamps on the outside of the posts, when you use your voltmeter, press the probe right into the center of the post, and see if the voltage is different.

Ironically this happened to me today on my e350. I went to start and kathunk, no lights, nothing.
Fault was a broken battery connector, which meant it wasn't quite tight on the post. As soon as you loaded it, it became high resistance, poof.

[jage]

Originally Posted by ANZAC

This still sounds like a classic bad connection.

Ground, hot or either?

If it's a loose connection (not cracked/broken) you could accidentally fix it while monkeying around... easily miss that you solved your problem.

[Scalf77]

Found a link to a Surepower Isolator Install. In general I believe SMB used Surepower isolators before moving to their Separators. This should help you going backwards if you need to. In general the cable that normally would go from your alternator to your battery is routed to the main input of the isolator (A) . A battery cable the goes from (1) to your van starting batteries and from (2) to your house. After that it depends on your alternator if you would have any other wires. To reverse you could probably just put the wires from (A) and (1) back together on post (A) as I believe Jage said. You would then need to tape off and isolate the cable to (2) house. I believe I would just bolt, (A) and (2) together, leaving the isolator out of the picture. I think you probably have a wire going from the run circuit to terminal E of the isolator. Tape it off also, and then you should have the two systems really isolated and go from there. Good luck

[jage]

I think I meant tie all three, from A/1/2 on post 2 s.t. A and 1 are not energized.

[ANZAC]

Originally Posted by jage

Ground, hot or either?

If it's a loose connection (not cracked/broken) you could accidentally fix it while monkeying around... easily miss that you solved your problem.

You can't tell without measuring a voltage drop across the connections or inspecting each connection.

In my case it was positive. I didn't have to measure it because I found the clamp loose and then saw it. What you do is, is get it in the state where it will power the radio, but at what looks like a reduced voltage across a headlight/radio whatever. So if you see 9v at the radio when using little current, you should be able to measure 3v across one of the connections. (assuming your battery is at 12v when measured at the center of the posts, not at the clamps.)

Shorts blow fuses and melt fusible links. When you see behavior change as the op describes, it sounds more like a bad connection.

As you draw more current, more voltage is dropped across the bad connection, and less voltage is available to the load. This can cause arcing and the puff of smoke at the bad joint.

[Scalf77]

Originally Posted by jage

I think I meant tie all three, from A/1/2 on post 2 s.t. A and 1 are not energized.

Sorry, if you are trying to join them together, that would work. I was going with separating the two battery systems.

[Aldercrest]

Okay, who said, "Did you check your grounds?" Apparently I did not.

Zeta, yes I properly reinstalled the ground cable on the lower bolt of the starter motor, so that was not the problem. However, I decided that before I traced down every inch of large gauge cable to find my short, I'd go ahead and reset the battery cables, complete with a little wire brushing and some conductive goo. Ten minutes later, I thought I'd maybe cycle the ignition again, just to see what happened. Glow plugs went fine, plenty of battery voltage. Hmmm, maybe I'll just try to start it...

Fired right up like nothing was ever wrong. So, the answer is, no, I did not thoroughly check my grounds. Note to self: Check your grounds. I even have my 2-1/2 year old daughter saying it.

Of course, after fixing it, this happened: viewtopic.php?f=8&t=7180 Maybe I should have let it just sit there...