Wading in a Defender - Lessons Learned

**Landyluvver** · 2012/10/20, 11:09 PM

Originally Posted by WernerLouw79

I would guess that the rot is caused by sulphuric acid vapor not hydrogen. Sulphuric acid will be released when the hydrogen boils up in the battery. The hydrogen will escape out the top of the container / cavity even if the bottom is not vented. Hydrogen is the lightest substance on earth and has the highest escape velocity. If there is any hole in the top, it will find it and escape...

AFAIK hydrogen does not readily react with metals... You need an oxidiser like oxygen.

Sorry to have dug up such an old thread...

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directly behind the battery box is a cavity all the way up to the top level of the box. would it not be a good idea to make a hole in the top of the box through to this cavity?
as you drive, the vehicle will naturally create a vacuum behind the box drawing out heat and gasses.
the vehicle will have to be in water to the depth of the top of the box for water to enter. at that point your ECU will be floating around in it box in any event.
the rest of the box can then be waterproofed with a bitumen base material which is resistant to scuffing and acids.
battery clamps mounted to the floor of the box is also a potential spot for water to enter. it is also a soft target for rust to start.
battery brackets mounted from the top would probably be preferable. newspaper stuffed in around the battery works well in absorbing acid reducing damage to the box. this can periodically be replaced for fresh paper.
it will also buffet the batteries preventing damage.

**WernerLouw79** · 2012/10/20, 11:33 PM

Albert,

Your plan seems viable, if i am thinking of a similar spot to you.

I do like your idea with the news paper, quite simple and easy...

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**psc** · 2012/10/21, 06:33 AM

The OP missed the wading plugs (on a 300TDi) - not sure whether they have them on later defenders

**Dave 2000** · 2012/10/21, 07:38 AM

Yes Werner you are right, I meant to say the sulpur would cause rot, and the hydrogen would defintely not be good as it can be ignited by a spark. As mentioned earlier batteries can explode in in the open with disasterous results, imagine it inside your car!

regards

Dave

**WernerLouw79** · 2012/10/21, 10:29 AM

Originally Posted by Dave 2000

Yes Werner you are right, I meant to say the sulpur would cause rot, and the hydrogen would defintely not be good as it can be ignited by a spark. As mentioned earlier batteries can explode in in the open with disasterous results, imagine it inside your car!

regards

Dave

No harm no foul...

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