Thread: Holes in the battery box OK?

I've just spent a day playing in this battery box fitting the starter battery from the D2 as a 2nd battery.


In front of the battery tray in the bottom is a hole.
Mine has a grommet in it with a vent tube that plugs into the original start battery to vent it.
I also noticed all the grommets with cables in them aren't exactly tight.
there are 3 small(8mm?) holes on the inner wall of the box about 1/2 way up, 2 had tape over them and one didn't.


Where the rear wall and floor meet there is also a hole.
I figured this was a 3 way thing.
1- Air movement/vent hole
2- Bilge hole, allows water to enter and fill the box on water crossings to stop the Defender from floating.
3- It allows any water etc. to escape from the box.


I'm going to use grommets for all wiring and leave the rear 3 way hole open.




Cheers, Kyle.

That's interesting. Getting two batteries in that box must be a squeeze. Mine also has the jack in there. I think the jack would have to come out to allow a second battery.
I was thinking of fitting a second battery under the driver's seat and linking the two with a dual battery controller. Then I thought I'd run a cable from the second battery to the rear with a plug so I can plug in an Ark battery box and effectively have a three battery setup, with the Ark box still able to be removed for other uses. Then when I'm camping with power I can just plug the Ark box into the power and it should flow back through the whole system, I think. What do you think?
As for the holes, I don't want water and dust coming in the side holes. I must have another look to see if mine has a battery vent. If it does then there's no reason not to block the holes with grommets, is there? I actually bought some grommets yesterday and then when I got home discovered they are too small, even though I measured them, so back to replace them today.
By the time the water got up to the battery holes it would have already come in under the doors, since the sealing seems rather poor, particularly under the front corner of the front passenger door, where I can see daylight. Gotta figure out how to plug that.

Originally Posted by alien

I've just spent a day playing in this battery box fitting the starter battery from the D2 as a 2nd battery.


In front of the battery tray in the bottom is a hole.
Mine has a grommet in it with a vent tube that plugs into the original start battery to vent it.
I also noticed all the grommets with cables in them aren't exactly tight.
there are 3 small(8mm?) holes on the inner wall of the box about 1/2 way up, 2 had tape over them and one didn't.


Where the rear wall and floor meet there is also a hole.
I figured this was a 3 way thing.
1- Air movement/vent hole
2- Bilge hole, allows water to enter and fill the box on water crossings to stop the Defender from floating.
3- It allows any water etc. to escape from the box.


I'm going to use grommets for all wiring and leave the rear 3 way hole open.




Cheers, Kyle.

Mick. Regardless of battery type they all vent, even optima's. The venting into your cabin in not a problem. The only problem is if you seal up your battery box so that can't vent you can trap the fumes to a dangerous(explosive)level.

The fumes are lighter than air so will rise to the top, so a vent near the top on battery containment and one below the the top of the battery is what Traxide recommends.

This was discussed in a thread of mine a while ago. Have a read of this from about page five.

Aux Battery Cabling

Edit. If you happen to read the whole thread and some posts don't make sense it is because there were a few disagreements between some one and it did get a bit heated.

I have now just noticed that all of one particular person's posts have been deleted.

As stated, the battery compartment needs to be ventilated, which is what the holes are for. But they do let a lot of dust in. I suggest that if you want to make the compartment dust tight, you could fit the battery in an airtight case often sold for boats, with a vent hose from it out one of the holes, and seal the rest.

Personally, I have not bothered with this, and have put up with the dust for the last twenty years. My jumper leads live in there as well as the battery.

John

Originally Posted by DiscoMick

That's interesting. Getting two batteries in that box must be a squeeze. Mine also has the jack in there. I think the jack would have to come out to allow a second battery.
I was thinking of fitting a second battery under the driver's seat and linking the two with a dual battery controller. Then I thought I'd run a cable from the second battery to the rear with a plug so I can plug in an Ark battery box and effectively have a three battery setup, with the Ark box still able to be removed for other uses. Then when I'm camping with power I can just plug the Ark box into the power and it should flow back through the whole system, I think. What do you think?
As for the holes, I don't want water and dust coming in the side holes. I must have another look to see if mine has a battery vent. If it does then there's no reason not to block the holes with grommets, is there?
By the time the water got up to the battery holes it would have already come in under the doors, since the sealing seems rather poor, particularly under the front corner of the front passenger door, where I can see daylight. Gotta figure out how to plug that.

As long as the battery can breath I'd grommet what you can.
I'm only leaving the drain hole as the 2nd battery needs to vent.

It was tight getting the 2 batteries in there but I'm not the first to do it.
Most of the build threads have pictures of this setup.
Most don't show how they are bolted down though and that is the hard bit.
I'm doing the Ex-box conversion when the next batch are made at Mulgo.
This will free up the drivers box but it wasn't deep enough for the battery I had.
It will become a storage bin for the jack and back up parts.
I'm not sure if I'll mount the air compressor in there or not, time will tell.


My plan is for the 2 batteries to be linked by a yet to be fitted Traxide USI-160.
I'll be running a fridge, lights and inverter from the 2nd battery in the rig.
I'm running an Anderson plug on the rear off the 2nd battery to go to the Tvan.
The van has a deep cycle house battery and 50watt solar panel.
The USI-160 has the brains to allow the solar panel to charge the tow rig batteries from the panel when it's connected.
I can also link these batteries with the USI-160 for winching if the need arises.

So, I've confirmed what you said below that my battery also has a tube plugged into the end and running to a hole at the front of the battery box, so I assume that is the battery vent outlet, so that's good.
After much poking around in Autobarn I found a grommet that does fit the large round holes on the side of the battery box, although its maybe a little small, but won't fall out. I measured the diameter of the hole but then discovered that was meaningless compared with the numbers on the grommet packets. After three goes I found this one does fit:
Champion Handy Pack 2x Wire Grommet 29/32" No. BH012.
It was the biggest one they had.
So I fitted one to the hole with the sheathed wires exiting through it and that fits well, although it should still allow some air to exit. I fitted another one to the open hole the same size and it was loose, but probably wouldn't have fallen out. However I could only get open grommets, not closed, so I had to put some insulation tape over the hole. Hopefully that will keep the dust and water out for a while.
Incidentally, my battery actually says Land Rover on it. The vehicle is five years old but has only done 54,000 kms. Could that really be the original battery? I checked the levels and they seem fine and it starts immediately so, if its the original battery, its a good one to still be going strong after five years.
I've also figured out why I have daylight showing through the front of the passengers door at the bottom - it is missing a square rubber block which is fitted to the driver's door. So, I'll have to find something similar or bodgy up a bit of door rubber to replace it. Can't have The Navigator getting dust or water on her precious toes! I need to keep her enthusiastic about the Defender.

Re charging, our camper trailer has an inbuilt in DC charger to boost the current from the vehicle, so I'm unsure if I need a dual battery system which can sense the trailer battery or if I can get away with just using a simple one to link batteries 1 and 2.

Sent from my GT-P5210 using AULRO mobile app

What about the risk of inadvertently flattening your cranking battery.

Originally Posted by alien

I'm only leaving the drain hole as the 2nd battery needs to vent.

Kyle. Why is it that your 2nd battery needs to vent and not your first as well?