Dual Battery To Leisure

[ULRICH]

Coming to the Gritty bits of my conversion. I have a dual battery system as standard, but with a shortage of hookups on some remote sites up here I need to have a 12v system as well. I have the hookup installed and the 12v power supply to hand. I would like to remove the second battery (wired in parallel) and replace it with a hook up charged leisure battery on split charge alternator driving/charger on hookup. Has anyone done this and can offer advice, have searched the forum but possibly missed something.

[daveblueozzie]

why don't you connect your leisure battery up to the split charge relay, for the 12v and have a small battery charger as well that you can hook up to the mains to keep your lb charged when on a camp site.

[Aethelric]

A proper leisure battery is probably better than the second battery you have, but unless you have a use for it, its probably better to use it as a leisure battery until its clapped. It will probably be fine for a couple of years.

[Dabs]

I always thought a leisure battery had to be a "deep cyle" battery that should not be a bigger battery than the main vehicle battery.
A vehicle battery is designed to give a large current for a short period of time for starting the engine,a deep cycle leisure battery is designed to be run down and still recover via charging through a split charge relay.
Dabs

[daveblueozzie]

the leisure battery can be bigger than the main starting battery, i have a bosch 110 amp leisure battery and a 85 amp (i think) main starter battery.

[ULRICH]

Intention is to remove second battery and replace with a deep cycle. Keep second battery as a spare vehicle unit. Trouble is I will have to change wiring, obviously keep the same earth and run the +ve to internal appliances via a split charge and hook up charger, but where does the original +ve lead go and do I need to remove it and will a standard leisure unit fit existing tray? Thanks guys.

[madmile]

Most people just insulate the end of the +ive terminal and cable tie it out of harms way. The standard battery tray will take most 85 amp leisure batteries no problem, but 110's are usually too big. There are some nice 105A batteries out there with twin terminals that will fit, but they tend to be the better quality items and as such a bit pricey.

[Aethelric]

I always thought a leisure battery had to be a "deep cyle" battery that should not be a bigger battery than the main vehicle battery.
A vehicle battery is designed to give a large current for a short period of time for starting the engine,a deep cycle leisure battery is designed to be run down and still recover via charging through a split charge relay.
Dabs

Weeell, all you say is true Dabs, apart from the "had to be" and the bit about the size. A vehicle battery will operate as a leisure battery, maybe not as long as the real thing, but it will probably give perfectly satisfactory performance as a leisure battery for a few years. I used a vehicle battery for years on a caravan with no issues, and I'll use the other battery on my bongo as leisure battery until its clapped out. Then I'll maybe put in a leisure battery (unless I come across a cheap vehicle battery -maybe a bongo owner with one to spare )

Dave

[ULRICH]

Thanks Madmile, that seems the easy solution. An 85ah will be fine, I would rather store the spare battery as a spare for the vehicle as they are expensive and being connected in parallel will probably be okay for years (could always rotate them). I know that the car battery will serve for a while, but was let down once by one going duff on holiday, cost me two evening meals out to replace, well, on the road next week, at last.

[moo n' mad]

I have followed this with interest and hope to end up with a leasure battery some day. In the meantime can anyone (Aethelric?) explain how you use your dual battery to power stuff without running down both batteries or point me to somewhere else on the site where it is explained. I understand one of the 2 needs to be isolated

[daveblueozzie]

basically ma-hale you just do as above put a split charge relay in between the battery's, then you can use one for your ciggy lighter ,internal lights, blinds. and the relay will charge it up when your engine is running, and it wont deplete your starting battery.

[haydn callow]

Easy solution ....Fit one of these to each battery....on site you can then isolate one battery for starting the next morning....also you can remove the green bit as a anti theft measure.
e bay item 360014875966

[Aethelric]

Hi Madmike
The batteries are connected together by a relay. This is an electrically operated switch. It needs to be able to take around 100Amps as the charging current can be very high. The relay can be closed, connecting the batteries together, via
a. a manual switch,
b. the ignition switch,
c. the charge line from the alternator, or
d. a special circuit which senses the voltage on the main battery.

a. is fine but not fool proof, if you forget you can end up with one or two flat batteries. I don't know of anyone doing this.
b. works if the leisure battery does not get too flat. If it does then when the ignition is switched on it may pull the main battrery voltage too low to turn the starter. This is quite a common system.
c. seems to give peculiar problems with bongos
d. works well, and its the system that I have, but when the secondary battery has discharged somewhat, the relay clicks in and out as it pulls the main batteries voltage below the threshold voltage.

When the batteries are seperated, you can then transfer the wiring for things like the internal lights, radio, blinds etc to the leisure battery. Member corblimey has an excellent method of doing this and its what I used. A search should find the details.

Or you can, at a pinch use the way mentioned here
http://www.igmaynard.co.uk/bongo/forum/ ... 47&t=21556

Or Haydns solution should be fine too. Mind you if you disconnect bothe batteries at once you may have to retune your radio as the memory may lose power.

Hope this helps.

Dave

[haydn callow]

You can get round the problem of loseing the radio's memory with one of these.
e bay item...250245948769

[moo n' mad]

Not sure what to make of so many detailed replies from you all I didn't expect all those alternatives!

Just to say thanks very much all - I'll sift through them carefully and try and work out exactly what to do.