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Discussion Starter · #1 ·
have done a search but havent found the answers im looking for.

the casing on my 2nd battery seems to be warping, bubbling up. Took the car to an auto electrician and he explained that the auxiliary battery on the 3.0ltr turbo diesels are too close to the turbo. because the turbo generates so much heat it is effecting the battery case. This is why he recommends a battery that i can maintain, ie put water in not a sealed battery. i do put more water in this battery than the starting one when i do check on them

He also recommended to put some sort of heat shield or cover around the battery to help with heat soak.

My question to all the more experienced patrol owners out there is does this sound right or is this bloke spinning me ****. Or if you have had this problem how did you rectify it. I replaced this battery only 18 months ago and it looks like it wont last much longer. i was hoping to get at least double the life out of it.
I had a look on the net and found this battery cover, bottom of page

Battery Trays & Clamps

it doesnt look like it would do much but maybe better than nothing
 

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Autos are Superior
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heat will kill a battery
heat shield is a good idea.. i got some matting off ebay to make one.. Lovely Vince is gettin me some sheet from work to make the rest with
 

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Old XJ6 Jags had a shroud around the battery with a fan to force cool air around the battery. Probably a few others have done the same.

Lots of heat under the bonnet. Glad my auxiliary batteries are in the back...
 

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I have one of those wrapped around my second battery, and also have cut up a plastic battery box and have heat matt wraped around it for extra protection. Seems to work ok.
 

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At last, a smart Auto Electrician

Hi salzo and it’s nice to hear of an auto electrician who actually knows his business.

The problem you have is quite common and your auto elec got it in one. most AGMs are NOT designed for automotive use and putting them under the bonnet just shortens their life.

It’s not just the heat.

Your problem has been caused by a combination of factors.

Ordinary AGMs must not be charged with anything higher than 14.4v, and most are not designed to take charge currents of more than 20 to 30% of their total Ah rating, in other words, if your battery is a 100 Ah AGM, then the maximum charge current it can safely take is somewhere between 20 and 30 amps, depending on the brand of AGM.

And with the battery so close to the alternator, cable wise, your battery is going to be getting too high a voltage which in turn increases the charge current your battery will pull when in a low state and then just to make things worse, the heat generated by the motor means that both the voltage and charge current must be even lower, which is the revers of what is happening in your case.

Burra Boy has the right idea. Putting AGMs in the back of a vehicle not only removes the heat factor but the long cable run acts as a quasi voltage/current regulator, which further protects your AGMs.

The alternative is exactly what your auto elec told you. Fit a flooded wet cell battery instead of an AGM, because flooded wet cell batteries are specifically designed to by used under the bonnet. They tolerate higher voltages than an AGM and flooded wet cell batteries are literally charge current self regulating, so they are not effected anywhere near as much by the operating environments found under a bonnet.

The heat shield is also a good move and a thin sheet of stainless steel placed between the battery and the motor, so air can still flow around the battery, will dramatically increase the battery’s potential life span.
 

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Discussion Starter · #6 ·
thanks for the response guys. since my battery is already set up under the bonnet i will look into putting some sort of heat shield around it. if i can get a longer life span out of the battery it will be worth doing
 
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