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I've been having problems with my battery staying charged. I've had the alternator tested and I've cleaned all the connections between the alternator and the battery. I'm thinking I have another bad battery. This is my third battery within 6 months. Do you think I might have a bad voltage regulator?

Ok, well buy or borrow a battery tester from a neighbor and test each battery cell. If there is a dead cell, it's usually one of the end ones, that will save some time to test the end ones first. A battery tester looks almost exactly like an anti-freeze tester and will cost somewhere between $3.99 and $10. OR remove the battery and take it to one of the many parts stores that will charge up and then test your battery for you. They can tell you if the battery is bad. (Got a local Autozone?)

If the battery is good, then it is possible that there is an internal problem with the alternator, even if it still charges OK. The current could be draining back from the battery overnight THROUGH the alternator. That is usually fixable if you have a local place that fixes alternators. If you don't, then it would have to be replaced IF the short is indeed, inside the alternator! Another typical place for shorts is if someone installed an aftermarket stereo and a wire shorted or came loose under the dash. Check these things in the order I gave them to you, and tell us how if worked out. Good luck!

mine would be good for a few days but if it sat over 2 or 3 days it would be dead, ended up to be my regulator. was rusted inside... replaced and has been fine since

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My old but now gone Luv...

If you have a bad regulator, it will either undercharge, and not give enough current to charge the battery up, or overcharge, and fry your battery. But be sure to get a decent battery, if you are buying Wal-Mart brand batteries, go a step or two UP in quality and price, I took 3 cheepos back to Wal-Mart and finally upgraded to something that lasted more than 30-60 days, and there was nothing wrong with my charging ystem, just a poor quality battery.

Thanks, I'll try it

I absolutely agree on the quality battery comment. I had a Saab with 430,000 miles on it, and upgraded to a red top gel battery the first winter I had it. Never had a single electrical problem with it, and I put roughly 24K a year on that car.

You can see here some of the electrical troubles I had with my '78, a lot of the same symptoms you've described. After a new voltage regulator and alternator, the problem seemed to resolve itself with a new Die Hard battery. Along the way I also found the hot wire for the fuel pump had been spliced under the truck, the heater wiring was landed on the wrong fuse, etc., etc...

These trucks are pushing 30+ years old, so there are lots of places the wiring could be shorted. Just becuase it starts and runs, and seems to charge, doesn't mean you don't still have a short somewhere. It can be a real pain to find out where, but by baselining the system with known good parts, it will help determine if the problem is inherent to the wiring harness or if in fact it's a charging system issue. If you decide to replace the VR, I'd recommend spending the extra $5 for a solid state unit...

Good luck.

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"If we did the things we are capable of, we would astound ourselves" - Thomas Edison

Where do I get a solid state voltage regulator?

I like NAPA, they run about $24-28 new. Here's a useful thread w/some part numbers...

http://forums.luvtruck.com/viewtopic.ph ... lator+napa

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"If we did the things we are capable of, we would astound ourselves" - Thomas Edison

Careful, as far as I can tell, the parts specified in that thread were for an '80 LUV, and starting with '81, they're probably different (same as a P'up). I thought the VR was integrated into the alternator on mine.

Jack

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'83 Isuzu P'up Diesel LS - Original Owner
JoeIsuzu@IsuzuPup.com
IsuzuPup.com