battery shorting out

[blackpoolsparks]

suggestion:
get another battery out of your/ someone elses car (dont matter the size) and try it with that.
If it starts = your battery
if same problem = your truck

[mud skipper]

have you put a multimeter on the terminals to prove positive is positive and neg is neg. i have seen a battery that has reversed itself.

[getsome]

as much as it pains me to say i think i have done a bad job like albannach said, so tommorrow ill replace the terminals with better ones cheers for the help guys. if this doesnt work then out comes the hammer

[wishbone]

Try running a jump lead from the neg terminal to one of the bellhousing bolts. If it starts fine you have bad earthing.

[adpsimpson]

Had exactly this problem while off roading last week. Everything was fine till I went to start it, then a loud click and nothing for a couple of minutes (although it wasn't cooking the battery). Turns out the stock terminals are crappy hollow pressed sheet metal things, and it had worn so that it couldn't be tightened to the terminal well enough to get a good connection. Very confusing symptoms, very easy fix.

Cooking the battery could be caused by large spikes in the circuit, caused by arcing at the battery terminal. In our case it simply disconnected completely, then as it settled over the next couple of minutes it reconnected again.

[malxwal]

Pretty much he type of thing I was describing earlier...very confusing.

[sparkyaj]

ok, a few questions - if you disconnect the new bat - does it start and run ok with the other bat?

If so imo i would think that old bat cons were so poor that the second bat connections would be high resistance and cause the charge to fail into the bat. then, less voltage = more amps resulting in one hot smokin bat.

remove the bat leads, test voltage with engine off and again with it started. check you have a charge supply on the secondary leads.

good luck

[getsome]

after all that the battery was just knackered!! ordered a brand new one for £70, when that arrives will get the alternator checked! again thanks for all your help people.

[sparkyaj]

after all that the battery was just knackered!! ordered a brand new one for £70, when that arrives will get the alternator checked! again thanks for all your help people.

Glad you sorted it.

You can check your alternator with one bat. Test the voltage b4 you start it. start it up and re test. you should find its kicking out about 13V DC

that will tell you that it is charging. If the voltage stays the same both times, you know it is not chargin. That being said, your bats will go flat after about 2/3 turns at starting with no recharge.

SO I would say it is working fine :-)

[getsome]

thanks sparky ill do that.

[blackpoolsparks]

14.8 Volts - Sparky

[Apache]

Actually, optimum charge for a 6 cell battery is 14.4V. 2.4V per cell, though most modern batteries will withstand a little overcharge without much reduction in capacity.

Military Vehicle EMC / Power Systems Specialist.

Also, there's no reason a battery would gas due to poor connections. That would lead to lower current flow (through poor terminals / high resistance) so would tend to heat the terminals rather than cause the battery to gas.

[blackpoolsparks]

I was allowing for 0.06666667 volt per cell voltage drop from the battery terminals to the instrument as most testers don't allow for the drop in the leads


NICEIC Approved Contractor

[wishbone]

In the real world I've never seen more than 14.1 volts at the battery terminals of my 2.4.(cold mornings seem to produce that) I have a digital voltmeter in my dash. I've checked it against my fluke multimeter and its only .02 out.

[Apache]

I was allowing for 0.06666667 volt per cell voltage drop from the battery terminals to the instrument as most testers don't allow for the drop in the leads


NICEIC Approved Contractor

Ah of course! I'd forgotten about that...

As wishbone says, the real world is usually less than optimum too. I've seen all sorts during vehicle testing, from around 23v (and they wondered why their batteries were flat all the time) to 38v (!!!) which was due to a regulator on its last legs. Customer told me it was normal. I disagreed. He came round to my way of thinking - after spending a day changing the very inaccessible regulator.


*24v power systems on most military vehicles.