Fitting a leisure battery

[therealpigdog]

Where to put this? Let's try TC&M ...

I want to install a leisure battery in the back of a pick up truck with a split charger so that it charges as I drive. Reason being that we often take our caravan to sites with no hookups, and it's not unusual to run through a 110 battery over the course of 10 days or so. Solution has always been to carry a spare battery, change them over and then get it charged when I get home. Seems to make sense to charge it from the truck instead.

Whilst I'm at it I'm planning on installing a couple of 12v sockets in the back of the truck to plug in a cooler box for day trips away (not strictly necessary, but why not eh?). It probably makes sense to run this fused from the leisure battery to avoid risking draining the main battery, and means it can be left on all day. I'll also fit an inverter in at the same time for charging laptops etc.

So, the question(s):

• For the sake of tidyness it makes sense to put the leisure battery in some sort of enclosure to stop dogs investigating. Will this need to be vented somehow, or can I get away with it for the sake of a fortnight's trip?
• Has anyone done anything similar?
• Any tips and tricks?
• Anything else I should consider whilst I'm at it?

Whilst I'm hopeless with a spanner, electrics don't scare me too much as it's just down to careful planning and taking your time - that said, depending on the level of complexity needed I might just farm it off to an auto-electrician.

[GAjon]

Can't really help with the siting or wiring of an additional battery, with the exception of it should be enclosed and ventilated, but -

You shouldn't fully discharge lesure batteries so a 110AH battery is really only good for 55AH, apparently they degrade pretty quickly and can't get full charge if you constantly fully discharge them.

But just to add to the mix, have you thought about one of these portable solar panels to keep your batteries topped up?

[therealpigdog]

GAjon said:

Can't really help with the siting or wiring of an additional battery, with the exception of it should be enclosed and ventilated, but -

You shouldn't fully discharge lesure batteries so a 110AH battery is really only good for 55AH, apparently they degrade pretty quickly and can't get full charge if you constantly fully discharge them.

But just to add to the mix, have you thought about one of these portable solar panels to keep your batteries topped up?

:nod: We don't fully discharge (or at least try not to) - but it's a good point.

I've looked at various solar panel configurations, but they seem to be pretty expensive for what they actually give you. I'd rather have a spare battery in the truck than rely on the british sunshine! That said, the benefit with solar is that it is constantly maintaining the charge, so useful when a caravan isn't used for a while - fortunately not a problem for us as we are away a fair amount and if it's getting left for a month or so then the battery comes home and is put on charge from the mains.

Putting a split relay into the truck makes sense if I'm going to be running wires into the back for the 12v sockets, and the battery is otherwise just sat in the back witing to be changed over - although if I can't think of a way to sort out venting then I may just carry on as I am.

[Upatdawn]

I fitted a LB with smartcomm relay charger wired for 100A through a relay, the smartcom carried only the trigger vots/amps to operate the large relay


http://www.ebay.co.uk/itm/Ring-Towing-12S-Smartcom...


http://www.ebay.co.uk/itm/12V-100A-Relay-/15101937...


BTW, our compressor fridge would run down to -20 (freezer box) and -10 in the main fridge and run 3 days on a 90A LB

Edited by Upatdawn on Friday 29th March 22:13

[WIJ933]

Hoping not to be rude but not discharging a leisure is wrong.

I own a Motorhome dealership and run my own Bailey Approach which I free camp for a month at a time.

Leisure batteries are deep cycle batteries. This means they can discharge a 12v (well actually down to 11.2v)supply right up until they are flat ( a car/ truck/ tractor battery is a shallow cycle design. This means its voltage output will drop as it discharges. This is why with a car battery you find the systems on your caravan fail after a shorter period than a leisure battery coz its output has dropped below 10.5v.

You should fully discharge and recharge a leisure battery to get the best from it for longer.
As far as ventilation goes it should be ventilated. Maybe drill holes low down in the box to do the job for now.

Hope this helps guys

[GAjon]

All these say don't fully discharge????

http://www.leisurebatteries.net/


http://www.campingandcaravanningclub.co.uk/helpand...

http://www.solaratlas.com/Related_Information_Page...

http://www.batteriesuk.uk.com/news/1

http://www.thomson-caravans.co.uk/advice/caravanad...

[WIJ933]

GAjon said:

All these say don't fully discharge????

http://www.leisurebatteries.net/


http://www.campingandcaravanningclub.co.uk/helpand...

http://www.solaratlas.com/Related_Information_Page...

http://www.batteriesuk.uk.com/news/1

http://www.thomson-caravans.co.uk/advice/caravanad...

Hmmmm
I can only guess they mean not on a regular basis. We deal a lot with leisure batteries and they told out shop guys 2/3 single full discharges per year. I do agree with them about not leaving them discharged though.
I will call them to check things haven't changed.

[GAjon]

WIJ933 said:

Hmmmm
I can only guess they mean not on a regular basis. We deal a lot with leisure batteries and they told out shop guys 2/3 single full discharges per year. I do agree with them about not leaving them discharged though.
I will call them to check things haven't changed.

That would be handy, I've spoken to others who advocate fully discharging liesure batteries, but what I've read contradicts that.
But things change and I wouldn't mind some up to date advice.

[therealpigdog]

Thanks - would certainly be interesting to hear what the manufacturer's recommend.

In terms of ventilation - would vents from the battery box/enclosure into the main truck bed (with hard top, but not exactly air-tight) suffice, or presumably it would be better to be fully ventilated externally?

[Hybrids]

I spent several years with a major battery company, so hopefully this will be of use without getting too anorakish...

New batteries improve with use, so there is an argument to cycle a battery a few times when new, but not over cycle.
Most traditional wet leisure type batteries should be cycled to no more than 50% DOD (depth of discharge), thats 12.1v. Some AGM & Gel can be upto 80% DOD
Most leisure batteries are not true deep cycle batteries, they are more of a half way between an engine starter battery and a deep cycle, this is usually down to price rather than suitability.
A lightly cycled battery will last much longer than a battery that has gone to its full DOD each time.
Batteries gas when being charged, the gassing threshold begins at 14.4v
When charging through a generic split charge relay you will loose around .6v at the diode, plus whatever you may loose in the cable, DC does not travel well.

[GAjon]

Thanks for that very informative and more or less the regime I use for the type of batteries I am using.

[Upatdawn]

it is good practice to fully discharge any wet cell battery and trickle charge back up

[Upatdawn]

the gas produced by a charging lead acid battery is hydrogen and very flammable

[Upatdawn]

BTW, a 12v laptop charger would be better to avoid the drain of an inverter

i have one that has a variable output upto 21v

[anonymous-user]

I used an old boat battery in my camper. It was big and bloody heavy but it was a great power source.