You guys got anywhere I should start at when I grab the multimeter and try to find this ign-off draw? The stereo was installed correctly, so that's a couple mA draw to hold the station memory etc. No dome lights on, nothing I could find, and it's raining tonight so I just threw it on the charger and closed the hood most of the way on the charger and connections. AFAIK, there's no aftermarket electrical work except the stereo, and the fuse box looks looks unfuxed with. Ideas? I should be able to find it with the multimeter and dry weather, but it's supposed to rain for a week! <img src="/forums/images/graemlins/scared.gif" alt="" /> Last time this happened, I got the dual batteries checked at a battery shop, and he said they were older, but fine. So I chalked it up as a mystery gremlin, and I guess I've driven it every day since then so it's never popped up until now.
Thanks,
Duncan

One battery shorted internally?

I'm a bit of an electrical rube unfortunately, limited to the basics. I did go out and try to check current across the battery, and I got a spark when I touched the pos. probe to the battery terminal. So I'll hold off until I can check it without frying my meter (it was on 10a too). The batteries are charged, and I ran it for 5 minutes after I got her started, 13.9v out of the charging system the whole time.... odd.

One shorting battery,...that was my problem..took me a month to figure out which battery it was. Happened out of the blue too. Would take a charge, but if you left it hooked up overnight it would effectively discharge both batteries. Funny thing was if you took off the cables..it wouldn't. Replaced it in July, no worries since. What a PITA

Hmm, I wonder if that could be it.... I thought dual batteries had to be replaced in pairs? That would be great if I could get away with buying one battery!

Umm..... ya you don't want to hook your ammeter across the battery terminals. The meter has a very low resistance so you are basically shorting the battery, allowing potentially 500-1000 amps to flow through your ammeter (not good). It will spark every time, and destroy your meter.

What you want is to disconnect one battery (rear) and then disconnect the negative terminal from your other battery (front) and put the ammeter BETWEEN the negative wire and the battery terminal. This will measure the current flowing from the battery to the vehicle.

A normal deep cycle battery holds around 100 amp/hrs. So a starting battery will have the same or less (they usually aren't rated). So if you have a 1 amp draw, it will last for 100 hours before it's flat. So basically you want your draw while off to be a lot less than even 1 amp. A few milliamps for your clock is max... anything else and you have a short somewhere.

I'm not sure what I was thinking when I checked my battery across the terminals... I took Electronics 9 way back in 1989 so I should know better! LOL.
I've since found out how I should have checked it, but I'm trying to figure out a budget way to preserve my stereo settings since it takes me 5-10 minutes to put everything back every time I disconnect the battery for something. arghh. <img src="/forums/images/graemlins/angry.gif" alt="" /> I love my head unit, but the setup menu is so convoluted it needs a Sherpa guide as an accessory.

Can you pull all the fuses (except the stereo <img src="/forums/images/graemlins/scared.gif" alt="" />) and see if the problem goes away? If it does, you've narrowed it down to something on one of the fused legs. If it doesn't, you've narrowed it down to something in the charging, battery or stereo system.