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The last 2 defenders I looked at had dual batteries under the passenger seat that never looked vented to outside the vehicle. Think the box was meant to be sealed, certainly looked that way.
I guess its just the passenger so if it goes bang the driver should still be ok.:wasntme:
Cheers Ean
Yes it is and so is daves thats why I mentioned it☺
Speaking of VW beetles and their battery locations,
I well remember the back seat starting to smoke one cold night doing the Rally fan thing.
May possibly had something to do with the 4 Super Oscars on a roof bar & the somewhat dodgy cabling done to the battery. :p
What?
Groan...
:wallbash::wallbash::wallbash:
Yep was and is still a problem with the old Beetles.Quote:
Originally Posted by AndyG
They came from the factory with a cover positioned over the battery, but the cover itself was not fixed to anything, so people would service or change the battery and forget to put the cover back and the next time they had a passenger in the back!!!!
Ok. Having another look/think after reading the above I have more questions.Quote:
Originally Posted by drivesafe
If I vent to outside my plan was to run some hoses down the side and out towards the back to prevent dust getting in.
Now knowing that the gas is lighter than air I am assuming if the top vent had a hose going down that the gas would just get trapped there.
Now looking at the pic below. If I cut a hole at "a" the gas could then vent into the space "b"
It could the travel upwards behind the trim "c" and get trapped in the top cavity and if it exploded could blow my roof off.:(
Would this be ok to vent here?
https://www.aulro.com/afvb/images/im...14/11/1038.jpg
Dave, you are over thinking the problem but that’s because I have not given you all the info you need to know.Quote:
Originally Posted by d2dave
Here is a bit of a deviation. Some science for you to ponder.
Hydrogen needs to reach at least a ratio of 4.1% to atmosphere, before it can ignite or explode, but hydrogen will not pool in an open area and will simply mix with the surrounding atmosphere.
As I posted above, the IEEE ( Institute of Electrical and Electronics Engineers ) sets the maximum safe ratio level of Hydrogen to atmosphere at 2%.
A lead acid battery has a given amount of water in it and this means there is a specific total amount of hydrogen that any give battery can produce.
In other words, there is a limit to the amount of hydrogen any battery can produce. If you cause a battery to gas, it doesn’t just produce hydrogen for ever, only some much gas will be produced.
Next, the IEEE also has a calculation you can use to work out just how much hydrogen a given battery size will produce, and the minimum area you need surrounding that battery so that if the battery completely gasses out, the ratio of hydrogen to atmosphere can not reach 2%.
Using their calculations, I worked out I could fit 3 x 100Ah batteries in the rear of my Range Rover, and if all 3 batteries totally gassed out, the hydrogen content of the air in my cab could not reach 2%, let alone the ignition point of 4.1%
Now back to your setup Dave.
If your battery gasses and you have no venting, then because of the VERY small volume of air in your battery box, the ratio of hydrogen will very quickly reach the ignition point.
But with suitable venting into the cab, the hydrogen will instantly mix with the air passing through your battery box and into your cab and it will NEVER reach the ignition ratio.
So don’t worry about all that tubing, just make sure the air can circulate freely through your battery box, job done.
A different point of view.
During the operation of a lead acid battery, hydrogen and oxygen are produced and reabsorbed.
The gasses a battery may vent are hydrogen and oxygen and perhaps a little vapour that may be corrosive. If the battery is in an enclosed space (i.e. a sealed plastic container with no ventilation), it can build up and reach levels of a potentially explosive mixture. A small spark could start an exothermic reaction converting this hydrogen/oxygen mixture into water vapour. Generally in an explosive way.
This is why we vent the gasses to a well ventilated area. (I'll leave it to the reader to work out what a well ventilated area is.
I have been involved in the design of UPS installations that take up cabinets and rooms. Generally speaking these cabinets or rooms are vented outside. In any case, they are vented to a ventilated area where the concentration of hydrogen can be dispersed to a safe level (for more information on safe level refer to the Mythbusters episode on the exploding portaloo).
If I was installing a second battery, I'd make it simple and ventilated. I leave it to the reader to define what that is. Don't over complicate the design.
Edit:
Gee, it took me well over twenty minutes to type that.
drivesafe explained it better than me.