Fisher Fury - Battery Problem - Advice needed

[Northern Rockape]

I recently fitted a new battery on my Fury and after a weekend watching the racing at Cadwell I parked up in my garage to discover that the battery had boiled over. I have had the Fury a couple of years and this problem has never happened before.

I have had the alternator checked by professionals and it operates correctly. The regulator was replaced as a precaution and so was the plug that fits onto the alternator. The output to the battery has also been checked as well as any obvious wiring issues and nothing was found to be wrong.

Despite doing all the above I decided to check all was well with a replacement battery. I took a short test drive of 15 miles and drove the Fury as I would normally do. After the test drive the battery was fairly warm but could still to be handled without any discomfort.

The negative post on the battery was hot and probably getting to a point where if I had driven further it may have got too hot to touch. I checked around the battery box area to see if anything else was hot and everything was ok so I have ruled out the possibility of the battery box being overheated by engine heat.

I have rechecked the battery cables for continuity then checked and cleaned the earth points including the engine earth strap. There is nothing visibly wrong with any cables, straps or wiring.

Has anyone had a similar problem and how did you deal with it?

[AdiT]

What engine?

[Northern Rockape]

Pinto bored out to 2.1l

[ruaricoles]

If it was an issue with the first battery itself, is it possible that the second battery is from the same batch and has the same issue? Just a thought, as it sounds like you've checked everything else....

Ruari

[AdiT]

Assuming the alternator tests were correct (and it's not overcharging) then it could be the starter sticking in drive. Thats normally pretty noisey and you'd be lucky if the starter survived and worked again. A hot terminal could be a poor contact but that wouldn't account for the boiling.
My money would still be on a charging fault. It could be intermittent and not doing it at the time of the tests.

[Northern Rockape]

Thanks for the responses. I will recheck the alternator outputs and have another test drive .

[Mojocvh]

"and it operates correctly. The regulator was replaced as a precaution and so was the plug that fits onto the alternator"

Don't really like this kind of "throw bits at it" if there isn't a fault, they could be fitting duff components.

hmm what is the output voltage of the alternator measured at the battery terminals.?

Edited by Mojocvh on Tuesday 26th July 15:44

[dozracing]

It's not an issue with alternator pully size is it? Possibly over charging at higher revs? I've seen that before on some installations.

[Northern Rockape]

The voltage was measured by an electrician and if I recall right the reading was approx 13.6 volts.

[Mr2Mike]

Northern Rockape said:

The voltage was measured by an electrician and if I recall right the reading was approx 13.6 volts.

At anything above idle that is rather low.

[Northern Rockape]

The reading was taken while the engine was idling.

[Northern Rockape]

The reading was taken while the engine was idling.

[AdiT]

But did they also check the output at higher revs as well?

[Northern Rockape]

Yes they did and they were clear that there was no problem with the output.

My feeling is that with the negative post getting hot that there is a poor or intermittent earth. Alternatively that somewhere a short is feeding back through the chassis to the negative. I have checked the wiring as far as I can but still have not found anything.

[Steve_D]

Northern Rockape said:

....My feeling is that with the negative post getting hot that there is a poor or intermittent earth. Alternatively that somewhere a short is feeding back through the chassis to the negative. I have checked the wiring as far as I can but still have not found anything.

A poor connection will cause heat at that joint. It will not cause the battery terminal to get hot however a poor connection at the terminal will.

Steve

[Mojocvh]

Northern Rockape said:

Yes they did and they were clear that there was no problem with the output.

My feeling is that with the negative post getting hot that there is a poor or intermittent earth. Alternatively that somewhere a short is feeding back through the chassis to the negative. I have checked the wiring as far as I can but still have not found anything.

Well the obvious question is about fuses, but, as you probably have checked them it gets back to that hot post. Is the alternator bracket joint corroded? something in the charging earth loop hi resistance? how thick are the cables/braids?? [had this problem originally on the Mojo with a "racing" harness installed....]

[Northern Rockape]

I have checked and cleaned up the the earth lead from the battery then refitted it and if I get the chance this weekend I will have another drive and see if this has made any difference.

[Northern Rockape]

After a check up and clean of the earth cable the negative post is back to normal so probably resistance in a poor connection caused the heat. The battery still is spitting some acid while out on the road so at higher revs may be when the trouble starts. I've booked the car in for an electrician to have another look.