I've had various Optima & other gel batteries in my Landy with a split charge system, and now I'm back to a conventional 'wet' battery system - the gel batteries all self-destructed after a while, by comparison I have a little 'leisure' battery which I have used in an assortment of vehicles for years (8 years at least) and totally abused, and it still works perfectly - it's now in it's 2nd Defender as a main starting battery - it's outlived the first car!

I don't know why the gel batteries die - they all claim to be 'deep discharge' but after they have been run down and left for a bit (I"m away a lot so the car gets left standing for 3 months at a time and for some reason the gel batteries always seem to discharge while conventional ones don't) the fancy gel batteries are always dead - if they are recharged they liquify the gel and gas out...

At first I was told this was because they have to be used as matched pairs - so I got a pair of Yellow Top Optimas - one of them was dead within a few months, the other lasted 2 years before dying... this is despite conventional batteries lasting for years in the same car. At one point I believed a dealer who told me it must be an alternator fault, so I fitted a new alternator - no difference (at least I have a spare alternator now!) now I just use conventional batteries and have no more problems!

I'd advise you to spend the money on something more useful - get a couple of ordinary good quality batteries as big as you can fit into the space available, and spend the money saved on something more essential for an overland vehicle - a good stereo for example!

Tony