I want to install a couple of new 12v leisure batteries into the mothership to ensure we have sufficient power for our opulent lifestyle throughout winter weekends. Although all lighting is now LED, we have diesel blown-air heating which eats amps, as well as a 15″ 12v TV.

I’m thinking of replacing the 92Ah battery that came as standard with 2 110Ah batteries to more than double the current (no pun intended) capacity.

I was reading this article yesterday which has left me a little confused. Is the author basically saying that ANY automotive 12v battery should be fine providing it is properly maintained?

There are ebay deals on cheaper non-branded batteries, but I don’t know whether to avoid them.

If anyone in central Scotland is looking for a 6 month old 92Ah battery, let me know…

I think what he’s saying is that a normal automotive battery might not last as long as a lesuire battery if used for that purpose, but given they’re a lot cheaper you might not care.

I thought about upgrading our motorhome to have more lesuire battery capacity but it was going to mean relocating them from under the passenger seat (although I think there might just about be enough room for 2 75AH ones in there) and also probably upgrading the charging system. In the end I decided against it and bought one of the 2Kw Honda suitcase generators instead!

TW – your diesel heater (eberspacher?) is better served by a normal cranking battery rather than a deep discharge leisure battery. They are originally designed for fitting to trucks and cars without leisure batteries.

It may make sense for you to keep your 92Ah but also get an inexpensive 70-80Ah cranking battery just for the heater glowpin. The fan on the heater doesnt take much juice. That leaves the deep discharge battery for the lights/fridge etc which dont draw large currents but are on for long periods.

Yeah, it is an Eberspacher. Pumps out some heat on full blast…

According to my measurements I should be able to fit two 110Ah or 120Ah batteries under the passenger seat. The vehicle is a Mk7 Transit. The current battery is 354 x 175 x 190mm. I have found 120Ah batteries (sold as leisure batteries) at 353 x 175 x 190mm – so a perfect replacement. They have a 4 year guarantee so shouldn’t be too much of a gamble.

Are those batteries you mention elecsol by any chance trout? If so don’t. Customer service on failed ones (which is common) is very poor and the capacity is never what they claim. My local battery shop refuses to ever deal with them again.

Is the Mk7 the current Transit? If so then I think that’s what mine is on as well. The space under the passenger seat is a fair size but I’d have thought 2 x 110ah would be pretty tight, but it could be the ones I’ve seen in the shops were bigger than the ones you’ve found.

Mk7 is the current Transit. Those dimensions should fit… I’ll be measuring again before ordering though.

Thought about Elecsol, but a quick Google of “Elecsol Warranty” makes your blood run cold.

I’ve been looking at these on Ebay, but they look very cheap. They also do a 120Ah with the same dimensions.

A leisure battery will be fine powering the eber, yes they take a fair amount of power during the startup but it does not require the huge cranking capacity of a starter battery. A leisure would probably be better suited as it will cope with being (only slightly) more deeply discharged. As the article says, leisure batts are often just relabelled starter batteries, otherwise they just have slightly thicker plates to offset the erosion caused when they are abused and discharged too much. They are a completely different animal to a proper deep cycle traction battery.

I too have heard bad things about Elecsol. Varta do a good range of quality batteries, the better ones are designed for sleeper cabs where the trucker will be running an eber and microwave overnight, tail-lifts and other hungry equipment.

The Mk.7 transit can come with an optional ‘dual battery’ option. There is space for two batteries under the drivers seat, with the dual option, when the engine is stopped all power is drawn from one battery, if you leave your headlights/radio/interior lights/laptop charger plugged in, it can go flat as a pancake, radio loses its code and the central locking won’t work, but it will still start off the other battery. Its the ideal set up and well worth speaking to a ford dealer to see if they can retrofit the dual battery option. It includes a split charge system so don’t expect it to just be the price of an extra battery though!

P.S the eber takes most of the current during the start up stages for the glowplug, so try to avoid it cycling on and off from a thermostat.

(I drive a mk.7 transit with dual batteries and an eber for work. 🙂 A colleague has just phoned to tell me I left the interior light on…can I be bothered to go and turn it off to save the faff of re-entering the radio code, or shall I just let it start off the spare battery tomorrow?!)

TroutWrestler – Member
I want to install a couple of new 12v leisure batteries into the mothership

so that’s what they’re called these days…

Spooky, my conversion is based on the chassis-cab and has 2 batteries already. The ‘vehicle’ one is under the driver’s seat, and takes care of all the vehicle based systems. The ‘habitation’ or ‘leisure’ battery is under the passenger seat and runs everything that the motorhome conversion has added – lighting, water pump, tv, heater fan, current to the water heater (though this runs on LPG).

What I want to do is double up the leisure battery so I can go for longer without hook-up to the mains, or driving a distance so the alternator re-charges.

the personwho wrote that knows their stuff
As a general rule a liesure is designed for cyclical discharge – to cycle to low charge and be charged back up a starter battery is designed for large cranking amps – dropping all its current in one go-starting.
IME – I live of 12 V all liesure batteries are much of a muchness unless you have deep pockets and want to purchase traction batteries which are superb but very expensive. Get whatever battery fits the space with the largest amp hr.A battery is classed as flat at 50% so you get half of what it says. For two days 220 should be sufficient for your needs.
e-mail me if you want geeky info on this

I wonder if the single battery option comes with one large battery, and the dual comes with two smaller ones in the same space. Might be worth a look under the drivers seat, could be a space in the tray for another battery 🙂

My camper has two 85ahr batts for the leisure side, would have gone for 110’s but the 85s fit under the bonnet saving space inside 🙂

I bought two leisures in the end, but only as they were the same price as standard halfords batteries and I didn’t want the hassle of batteries coming by courier. I wanted Varta but the extra height of their batteries and the price premium meant I went for normal ones in the end.

To add to Jumkyards post, a battery is at 50% (flat as you should go) when the voltage drops to 12v. 12.4v is fully charged. 10.5v or below is when most appliances such as heaters/fridges will start to show fault lights and if you get anywhere near this you are killing your battery…it won’t last long.