HJ61 Battery problems - melting terminals

[Nasr Qaisar]

Hi Guys
Absolute newbie to posting on Ih8mud but have been leeching off of your excellent forums for the past few years now. Six months ago, I finally bought a 89 Sahara FJ62G converted to a HJ with a 12HT diesel swap(previous owner's handiwork). The problem I am having is that the negative to ground terminal on the first of two 12V batteries keeps melting/sparking, it happened once with the previous owner and now with me. There is a loose connection on the wire itself so I am guessing that is the only culprit as these batteries are only 3 weeks old. Question is, how can I check if there is any internal power contact with the body(detect voltage on ground) just to be sure. None of the gauges are misbehaving however the console light of the AC button/panel randomly goes out, and my 12v stereo (using an insulated 24v-12v step down converter) also randomly shuts off and then turns back on, especially in bumpy driving.

Any advice would be greatly appreciated.

 

[Mr Tibbs]

Lets see a pic of your set up. Also, what other wires are coming off of the batt terminals?

 

[brownbear]

So this is the battery on the bottom of the 24 volts? Meaning it's ground goes to the chassis? Then it's positive goes to the negative of the upper battery? (Series connection).

With any of these batteries it is utmost important that the terminal clamps are extremely tight. Tight means solid contact and cannot arc/spark. My welder does't melt metal with the electrode is touch (stuck) to the surface. So if you have a good contact it should not melt or spark

Often times we think we have a good connection but don't. I spent days on my boat trying to fix an issue and it turned out to be my battery posts. I replaced the clamps with new. And used a post cutter to clean the post. But I thought it was good and tight, but really it needed to be taken apart and super scraped with one of those tools for posts and clamps.

Your radio turning off is an indication of the battery connection. A radio will react to a tiny surge or blip in the power and show itself as a bad connection.

 

[Nasr Qaisar]

Lets see a pic of your set up. Also, what other wires are coming off of the batt terminals?

I will get you a picture tomorrow after work, this battery only has the negative to ground and to the block, and the positive to the serial battery negative.

 

[Nasr Qaisar]

So this is the battery on the bottom of the 24 volts? Meaning it's ground goes to the chassis? Then it's positive goes to the negative of the upper battery? (Series connection).

With any of these batteries it is utmost important that the terminal clamps are extremely tight. Tight means solid contact and cannot arc/spark. My welder does't melt metal with the electrode is touch (stuck) to the surface. So if you have a good contact it should not melt or spark

Often times we think we have a good connection but don't. I spent days on my boat trying to fix an issue and it turned out to be my battery posts. I replaced the clamps with new. And used a post cutter to clean the post. But I thought it was good and tight, but really it needed to be taken apart and super scraped with one of those tools for posts and clamps.

Your radio turning off is an indication of the battery connection. A radio will react to a tiny surge or blip in the power and show itself as a bad connection.

Thanks for the advice brownbear. You're right, the negative connection was basically loose and had a lot of carbon build up on it, it seems the last time it was removed a couple of weeks ago, it wasn't properly placed back. I had the terminal replaced and re-tightened last night and now the truck itself is working fine. The radio however is still shutting off randomly. The 24v-12v step down converter isn't fasted down properly and I think some of the connection wires are getting pulled when the car hits a bumpy road. I might have it opened up after work at which time I will post pictures here.

 

[60Works]

Interesting. My HJ has had the same problem. I attributed it to the same cause. New terminals which hadn't been tightened enough to fully conform around the battery post.

 

[Nasr Qaisar]

Hi Guys, Sorry for not getting back to you with the pictures, the 24v-12v issue was isolated to a bad step down converter. I had bought a second unit as a backup but that failed as well, seems something is wrong with this series(20A) from DROK as the other ones I imported(3A) are working fine. I'll be uploading the pics soon.