Friday, Jul 20, 2012 at 10:20
Firstly, I am not just a theorist, I am a qualified technician that has been working with batteries in some sort for all my working life.
I have been working with sealed batteries sincle when GELL tecnology was new and the term AGM was not yet in general use.
We used to call them "starved electrolite batteries".
I have seen first hand the failures and damage that occurs when people take sealed battery technology at face value and fail to read all the documentation and cautions.
The vast majority of the
population would not have seen a catastrohic failures in a normal wett cell screw top batteries, that does not mean they do not happen.
Sealed batteries are far safer, so even less people will have seen failures in these batteries, but let me assure you they do occur.
As far as the manufaturers installing sealed batteries in unsuitable
places, many of the same companies are installing gas bottles in in sealed compartments and other unsuitable
places.
BTW there is no licencing system or any meaningfull regulation at all regarding DC battery installations in caravans or motor vehicles.
Likewise there is no regulatory body that, sets standards, inspects or prosecutes bad work practices in this area.
Most trailers (including caravans) are manufacturerd by relativly small companies and many of the design decisions are made by people with little or no electrical knoweledge or background.
While we are on the matter of common sence......commonsence dictates that we should be following the clear and easily understood advice of battery manufacturers.
"Never install batteries in an airtight or sealed enclosure and make sure installation is adequately ventilated."
That sounds pretty clear and easily understood and sensible.
As for vehicles with batteries under the
seat......yes ther are many, landrovers, mitsubishi vans and others....for the most part those batteries are accessed via the pasenger compartment, but the battery is actually mounted in open air under the floor.
Yes in the past, many cars has petrol tanks either mounted in the pasenger compartment or seperated only by the rear
seat......you wont find this in any recent vehicles.......
How many battery explosions in caravans....there where graffic pictures posted in this very
forum not long ago of a caravan that that the whole front blown out.
We live in time where "good time engineering" is popular, by that I mean designs where things are all fine and beaut if something does not fail or continues to work to expectation.
Sorry I come from a time and from a background where safety and minimal damage was expected in cases of failure.
Yeh the AGM battery will remain sealed, if it remans in good repair, the voltage continues to be properly regulated and the temperature remains with in the design limits.
Not long ago one of the AGM brands was having a problem with corrosion of the positive battery post, in the long term this resulted in failure, but in the short tem the battery was no longer sealed.
Regulators in car alternators often fail and overcharge the battery, a common cause of battery failure and something auto electricians
check for when replacing batteries......under overcharge situations all sealed batteries will vent explosive gasses and often acid mist.......IF YOU RE LUCKY....if the battery is old or has be subject to sustained heat, the seals stick and fail to open.
Result, the battery blosw up like a balloon intill the seams split.
This I have seen several times.....I have an example on my dead battery pile at the moment.
The normal service temperature of many AGM batteries is below that experienced as the daily maximum air temperature in some
places we wishs to go to.
Under normal charging many sealed batteries will vent explosive gasses and possibly acid mist under these circumstances.
So often we are hearing of "freak accidents"......I have yet to hear of one that was not entirely to be expected and was a result of some sort of follishness.
cheers
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