# Battery Box for the son's ute



## malmac (Sep 3, 2020)

Well spent another day working on a custom battery box for my son's new ute.

Gave me a chance to clear the dust off the small pan brake. It worked really well for this job.

I opted to build a sort of chassis for the battery to be secured to, as the 2mm aluminium box has no strength to deal with a heavy battery.
Still got some more work to do on that with some tie down rods and wing nuts.

anyway there you have it.

Mal


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## markba633csi (Sep 3, 2020)

Hi Mal, If this is going to hold a wet lead-acid battery I would coat the inside of the box with something.  Sulfuric acid is hard on aluminum I think
-Mark


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## malmac (Sep 3, 2020)

markba633csi said:


> Hi Mal, If this is going to hold a wet lead-acid battery I would coat the inside of the box with something.  Sulfuric acid is hard on aluminum I think
> -Mark



Mark

The battery is a sealed AGM battery. However all of that aside you do make a good point.
Thanks for the suggestion.

Mal


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## aliva (Sep 3, 2020)

Since its a sealed battery don't worry about a coating.


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## Flyinfool (Sep 3, 2020)

Sealed AGM batteries leak too. I have cleaned up after a few of them.
They are still vented and acid can still get out the vent.


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## malmac (Sep 4, 2020)

Flyinfool said:


> Sealed AGM batteries leak too. I have cleaned up after a few of them.
> They are still vented and acid can still get out the vent.



Sort of makes the word "sealed" seem a bit questionable. However it is something to pay attention to.
Thanks for your input. I am planning to have breather/ventilation holes in the case, but I was just thinking heat rather than nasty fumes.

Mal


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## Bi11Hudson (Sep 4, 2020)

Not being familiar with "AGM" batteries, I can't be unequivical, but. . . Any battery, even dry cell flashlight cells, will be vented. It may not be obvious, maybe even a soft plug, but there must be some way to relieve internal pressure. And despite what the marketing gurus have to say, *any* wet or "gel" cell will have a vent. Of course, I trust the marketing types about as far as I can spit in a headwind. The vent may be concealed, but there *will* be one, somewhere.

A while back, I built an electric (tri)bicycle, using 4X4 winch motors and an automotive starting battery. I am familiar, intimately, with wet cells so opted to use one even though they were not the most effective efficient. If there is a visible vent tube of any sort, a plastic tube from that to a point below the base of the case will serve you well. Sort of like the vent tube on a motorcycle.

Further, a lining will pay off in the long term. I used a sheet of 1/16" rubber gasket material. A bit of "over engineering" but what I had on hand. There should be some sort of insulation between the battery case and the enclosure. I used contact cement to affix the rubber. A spray on type should work just  as well.

Also, the application may not involve such, but if there are multiple batteries, each one should be insulated from the others. Only a sliver of milk jug plastic will serve. Acid proof is better, but use what you got.

..


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## tq60 (Sep 4, 2020)

AGM batteries are in our wheelhouse so we will share...

First, they are acid starved meaning they have a sponge like material that holds the acid and there is no liquid so most can be mounted in any position 

We have some that are very high performance that cannot be so always check.

They also are called VRLA or Valve Regulated Lead Acid.

They are sealed and contain the gasses produced when the chemical magic happens during charge and discharge.

The "VALVE" is a pressure relief valve that vents excessive pressure 

If over charged excess pressure builds up and valve opens.

Once gas exits it cannot be put back so very important to correctly charge them 

Float charge current cannot exceed 0.1 % of labeled 8 hour rated capacity so a 100 amp hour battery only needs .1 amp float.

Smaller ones less.

Easier to set charge voltage to spec, read manufacturer sheet as generic term is 2.25volts per cell meaning 13.5 for a 12 volt unit.


PROPER charging and ventineng should not occur.

Current Dodge chargers have AGM battery in trunk with vent hose going out.

Also charge above 14 volts so proper battery selection a must.
I always look for the valves or vent port on the battery to check for residue.

This indicates a vent event.


Sent from my SAMSUNG-SM-G930A using Tapatalk


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## malmac (Sep 4, 2020)

Bi11Hudson said:


> Not being familiar with "AGM" batteries, I can't be unequivical, but. . . Any battery, even dry cell flashlight cells, will be vented. It may not be obvious, maybe even a soft plug, but there must be some way to relieve internal pressure. And despite what the marketing gurus have to say, *any* wet or "gel" cell will have a vent. Of course, I trust the marketing types about as far as I can spit in a headwind. The vent may be concealed, but there *will* be one, somewhere.
> 
> A while back, I built an electric (tri)bicycle, using 4X4 winch motors and an automotive starting battery. I am familiar, intimately, with wet cells so opted to use one even though they were not the most effective efficient. If there is a visible vent tube of any sort, a plastic tube from that to a point below the base of the case will serve you well. Sort of like the vent tube on a motorcycle.
> 
> ...



Thank you for sharing your experience. I actually have a camper which slides on to my ute/truck and I want to improve the mounting system for that battery in the near future, so I appreciate your experience.

In this current case I am putting a 6mm heavy duty rubber under the battery case and a 6mm rubber pad between the battery top and the plate to hold the battery in place.

The battery has an inch clearance in all directions from the actual aluminium case. I am giving consideration to how to provide a suitable surface inside the case.

Mal


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## malmac (Sep 4, 2020)

tq60 said:


> AGM batteries are in our wheelhouse so we will share...
> 
> First, they are acid starved meaning they have a sponge like material that holds the acid and there is no liquid so most can be mounted in any position
> 
> ...



Thank you for your inside knowledge.
I will discuss this with my son.

Cheers


Mal


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## tq60 (Sep 4, 2020)

Also of note...the sometimes get pregnant so consider room for expansion.

Square D made a UPS back in the day that had charge voltage set too high and would eat batteries once a year.

The batteries "just fit" the housing and they would expand and form fit, very difficult to remove.

Once we figured out proper adjustment they lasted many years 

Sent from my SAMSUNG-SM-G930A using Tapatalk


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## malmac (Sep 5, 2020)

tq60 said:


> Also of note...the sometimes get pregnant so consider room for expansion.
> 
> Square D made a UPS back in the day that had charge voltage set too high and would eat batteries once a year.
> 
> ...



Yes you are right and I am not to quibble.

My son thinks he will never need a larger battery - this one is 100 amps.
Well he will want a bigger one later or maybe even two. Maybe I will be called on to make another box at that time, maybe not.
I have given him an inch clearance all round, so even if this battery distorts its walls it will be unlikely to fill that void without destroying the box.

I do appreciate your input....... as you would also know, not much use arguing with the young until they get old enough that you both agree without argument.



Mal


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## malmac (Sep 5, 2020)

When I am interested in other's projects I like to see the updates as the project progresses.

So here is a couple of photos from today.

I certainly found small holes in the top of battery which I suspect are the vent holes if needed.
So I cut a hole in the metal tie down strap so none of the holes are covered.

Mal


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## brino (Sep 6, 2020)

malmac said:


> I am giving consideration to how to provide a suitable surface inside the case.



If you are looking for custom fit, you could wrap the battery in a garbage bag, and then add just a little expanding poly-urethane foam to the sides. It will fill and expand. Just do a little dot on each side before adding any more.

You can use the low-expanding foam (for around windows) to be sure it's not deforming the battery.

You could also cover both sides with plastic to have a custom fit but only a little painful to remove custom "margin" of foam.
A temporary spacer would give a little play in the final liner.

Experiment before committing!
-brino


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## malmac (Sep 7, 2020)

In regard to a custom fit, I have machined up some plastic spacers.
These fit near the base of the battery and should restrain it from sliding.
While the battery box does not accommodate a battery of any significantly larger size, a smaller battery could have over sized spacers made to facilitate fit.

Mal


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## malmac (Sep 8, 2020)

OK, there you have it. Project completed.

Thanks for your comments and suggestions. I hope you can see where I listened.

Your help is much appreciated.


Mal


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