Under Bonnet AGM Battery

[JME_GU]

I'm looking at getting an AGM as a second battery and mounting it under the bonnet. Some of the info I have read says that they don't like high temperatures. Has anyone got an AGM under bonnet and have you had any problems with it?

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[TimE]

Yep, had an AGM under the bonnet for 8 years, not a problem. Have also read that they don't like the heat, but so far so good for me :)

[threedogs]

what motor do you have??

[Hodge]

I have been also told it's a big no no. Have read many times it's a big no no. But I have also seen other people have it under the hood for ages and no issues...

Have been running one in my other Patrol for 3 years, and no issues as in, no visual problem on the outside and no Voltage differences as the time went on. And the tray sits right next to the turbo. Now have the same setup in this patrol as well as so far so good...

However, this is not to say that the battery is not coping well internally?? I don't know. I haven't had many other options though so this will have to do for now.

My 2 C.

[threedogs]

My battery ppl would sell me the battery but they would not install a sealed battery.
In the end I ended up buying a wet cell 115ah Trojan, Ive also fitted a turbo beanie
to help keep temps down on the Aux battery side, doubt Ill buy a sealed battery
as you get more bang for your buck with a wet cell, had the trojan now for three yeers
and its not messy at all ,and more than big enough for my needs, now I use LEDs

[the evil twin]

I'm looking at getting an AGM as a second battery and mounting it under the bonnet. Some of the info I have read says that they don't like high temperatures. Has anyone got an AGM under bonnet and have you had any problems with it?

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Depends entirely on the Battery Model even from the same Manuf..

Many AGMs are made for useage like UPS or WheelCahirs, etc etc and will not handle heat or even medium current draw.
Others that are manufactured for higher loads and temps will be fine.

Full River, purely as one example, make AGM batteries (damn good ones) for many solutions but one of their DC Series AGMs may not last 6 months under the bonnet wheras a Full River HC Series AGM should last years as a vehicle battery

[BigRAWesty]

This is what I've been told TD aswell.
The AGM sealed batteries are not covered by warrenty when placed under the bonnet..
They don't like high heat..
But as above. Plenty do..
I've seen many more fail from the variable voltage alternaters than heat issues..

[threedogs]

This is what I've been told TD aswell.
The AGM sealed batteries are not covered by warrenty when placed under the bonnet..
They don't like high heat..
But as above. Plenty do..
I've seen many more fail from the variable voltage alternaters than heat issues..

I think they have been told by higher up so they cover their butt

[BigRAWesty]

I think they have been told by higher up so they cover their butt
Totally agree there.
That's probably why your shop declined to install

[Hodge]

Full River, purely as one example, make AGM batteries (damn good ones) for many solutions but one of their DC Series AGMs may not last 6 months under the bonnet wheras a Full River HC Series AGM should last years as a vehicle battery

I've got a full river under my bonnet. Is there a way to tell other than the model number???
Pictured battery has been now sitting for about 4 years under the CRD hood right next to the turbo and hasn't skipped a beat.
Identical one except a 85AH is now under my 4.2 hood.

[Bacho86]

I ran into the same issues / discussions about AGM batteries under the bonnet voiding warranties and such when I was doing my research as well.

I ended my choosing a century marine battery for under $200 which gave me both decent 760 CCA and 100 A/H ratings, and so far so good!


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[JME_GU]

I was looking at getting either an AGM or a marine, can't decide which

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[the evil twin]

I was looking at getting either an AGM or a marine, can't decide which

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Is the battery a second Cranker or a House (Fridge etc etc and not used for winching)?
My setup is the latter IE I use it as a Cranker and parallel it for general Vehicle use such as Winching etc.
I don't use it for deep discharge applications such as camped up running a fridge for days.
If that is the case then any decent Cranker or All Rounder is the go incl Marine.

Having said that there are some very high CCA AGMs about and some are over 1000 CCA but they are quite expensive.
I don't quite see the point of the extra expense

[JME_GU]

what motor do you have??

4.5 litre petrol

[JME_GU]

Is the battery a second Cranker or a House (Fridge etc etc and not used for winching)?
My setup is the latter IE I use it as a Cranker and parallel it for general Vehicle use such as Winching etc.
I don't use it for deep discharge applications such as camped up running a fridge for days.
If that is the case then any decent Cranker or All Rounder is the go incl Marine.

Having said that there are some very high CCA AGMs about and some are over 1000 CCA but they are quite expensive.
I don't quite see the point of the extra expense

The second battery is just for running a fridge and inverter. I have a winch but have never even gone close to needing a second battery for winching.

[JME_GU]

I was thinking about using a plastic battery box as they are really cheap and should keep some heat away from the battery. The only real problem is that they will reduce the available space so I may need a physically smaller battery.

[threedogs]

Run some decent cable to the cargo area and and as
you said have a battery in a dedicated case in the rear.
You can then move it around camp as you see fit

[the evil twin]

The second battery is just for running a fridge and inverter. I have a winch but have never even gone close to needing a second battery for winching.

Then I would do as TD suggested.
Get a Sealed Deep Cycle and put it close to where the fridge will be.
Happy battery and a happy fridge means a happy patroller.
You can use a smaller capacity battery for the same draw down.
You can mount the battery so it easily comes out at camp if needed.
etc etc

[JME_GU]

Run some decent cable to the cargo area and and as
you said have a battery in a dedicated case in the rear.
You can then move it around camp as you see fit

I thought about putting one in the back, and I already have a battery box but I'm a bit nervous about having a battery in the back of the car

[threedogs]

I thought about putting one in the back, and I already have a battery box but I'm a bit nervous about having a battery in the back of the car

Secure it well and you'll have no problems .
Trouble I see in owning a 4.5 petrol is lack of real estate under the bonnet especially if
its dual fuel or ABS equipped.

[JME_GU]

No dual fuel or ABS so there is a spot at the rear passenger side of the engine bay.

[threedogs]

you should be able to buy a battery tray that will fit, you might need to move a few things around.
My second battery runs my Fridge first and maybe a small LED light. If Im not moving I have a 100
watt folding solar panel to top it up if need be,

[lucus30]

I've got a battery tray in mine. I can dig up a picture if you like?

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[threedogs]

If I had a dual battery set up in a petrol Id probably fashion
a heat shield to further protect the battery. Dont forget to use Nyloc
nuts on the battery clamp plate, also big mud guard[penny washers]
for the inner guards again with nyloc nuts

[BigRAWesty]

Just an FYI, the gu st have a vented battery shield on the main and a tube from the drivers side wheel arch..

[threedogs]

It doesnt fit my start battery, still have it but its in the shed

[Bacho86]

Just an FYI, the gu st have a vented battery shield on the main and a tube from the drivers side wheel arch..

You been doing some reading recently mate... You're coming out with all the GU facts and figures now! Hahaha :)


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[BigRAWesty]

You been doing some reading recently mate... You're coming out with all the GU facts and figures now! Hahaha :)


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No so much reading but what I'm finding on my new bus..

[Bacho86]

No so much reading but what I'm finding on my new bus..

Always good fun familiarising yourself with a new vehicle!!


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[BigRAWesty]

Always good fun familiarising yourself with a new vehicle!!


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Absolutely.. I'm loving it