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Hi Rangieman and unfortunately, this belief that a battery, labelled “sealed” means it won’t gas is really a problem the battery manufacturers themselves, have created.
There is also no set mandatory standards for the RV industry but there is for industrial use of lead acid batteries.
http://www.traxide.com.au/Caravan/AS_2676.2.jpg
Well thanks for the valuable heads up on this issue, there is a 5 mm space between lid and box which I haven't seal taped yet and the conduit plugs have space around them so it looks like that will be left open, thanks again fot the valuable information, nothing like a bit of knowledge to keep one safe
cheers Ken
Finally finished camper, tows really well, towball weight about 60 kgs, now to get out camping and try it out
Nice job. Are you running some type of stone guard or rock tamer to save your back window/trailer form chipping?
thanks Worane, I am still undecided how or what to build, any ideas or piccy's welcome
cheers
ken
Hi there. Great build. Not sure why I'd not spotted it until now. I too had not realised that gel batteries were not 'sealed'. I thought one of the main selling points of a gel battery was that it could be mounted in any position as it is 'sealed'... Obviously not, (this is the first thing I've learned in 2014, and means that I can spend the rest of the day asleep under a tree somewhere!! :D).. Useful info. Looking at stone guards I've seen a lot of trailers with the mesh system (pictured) across the front of the trailer. Can't help but feel that these then deflect the stones back into the car..? Had nothing to do with them tho so also interested to hear from people who have used them. I would thing a mud guard in front of the trailer wheel would help along with a full with rear mud flap on the rear of the vehicle... Cheers for now! Simon.
Plenty of discussion on van stone guards in other threads. The one pictured could be improved by tipping the top forward to get the angle such that stones will bounce down and out towards the sides.
Sealed lead acid batteries like AGM do not breathe but can vent if an over pressure situation occurs inside the battery. I don't know how often they vent but they can.
Hi Sitec and while many batteries are labelled as being “SEALED”, the labelling is not only misleading ( unintentionally ), it is now being changed.
Many of the battery manufacturers are now labelling these batteries as being “SPILL PROOF”, not as being sealed.
All lead acid batteries can be caused to gas and it can be done very easily.
It is not high current situations that causes gassing ( as many people think ), it is high voltage that is the most common cause of gassing.
If a battery is fully charged in the first place, you only need a voltage a little above what the battery can safely tolerate, and a battery will start to gas.
To get a high voltage you only need a battery charger to fail and continue to raise the voltage being applied to the battery after the battery is fully charged or, something that is now not so common but use to be, and that is a runaway alternator regulator.
This can have an alternator producing constant voltages of 18+v, for as long as you drive.
There is also a new cause of over voltage charging and that is DC/DC devices.
Most DC/DC devices have a TIMED boost charge they apply to a battery at the end of a charging cycle, and this is not a problem in most RECHARGE situations, like when you have been camping and your battery is down a bit, or even in a low state.
Your battery will probably not even get to the boost cycle while you are driving.
Where the problem is now occurring, is when you leave home with a fully charged battery, that not only has a DC/DC devices connected to it but it also has a fridge connected to the battery.
What is happening is that the fridge cycles on, pulls the battery voltage down, the DC/DC device cuts in thing the battery is in need of a charge.
The DC/DC device will apply a higher charging current current to the battery than the current the fridge is drawing and the battery voltage will quickly rise back above the fully charged level and the not so smart DC/DC device thinks this is the battery's first cycle and then gives the battery a TIMED boost cycle.
Doing this once is fine but unfortunately, these "SMART" DC/DC devices continually go into the boost cycle every time the fridge cycles on.
So you have a situation where you leave home with a fully charged battery and arrive at your destination with a gassing and stuffed battery.
This problem is now so prevalent that a number of DC/DC device installation manuals specifically state “Do not connect a fridge to any battery being charged by this DC/DC device”
So as you can see, gassing is a very potential and dangerous problem.