Leisure battery size

[andyb]

I am going to get a camper conversion done to my bongo with a compressor fridge. After looking though the posts on here, its apparent the bigger the battery the better so it can be used for longer periods. I'm guessing that a 100Ah battery should last about 4-5 days while using the fridge, lights and radio.

My problem is, i was told some time ago that you can't have a leisure battery with a greater capacity than you normal engine battery. Is this true? and if so Why?

I have looked through previous posts and found nothing that explains if this is true. Any help would be greatly appreciated.

Many thanks

Andy

[mister munkey]

Can't tell you how or why Andy but the 110ah lb is about the biggest that will fit & a fair few peeps on here have them.

[mikexgough]

I have a Willinton split charge kit and I have a 110 amp hour leisure battery.....and your 4-5 days on a compressor fridge is possible too....might not do that with the radio on as they consume quite a bit, I use a portable radio "on site"..... we recently did 3 nights away from hook up with compressor fridge, tv & satellite receiver and the lights.....no probs

[missfixit70]

Not sure where that came from initially about the lesure battery not being bigger than the existing starter battery, but loads of us have 110ah LB's. With a decent split charge system & sensible use - maybe change some of your bulbs for leds? - you may get 4 to 5 days with the fridge etc, but if there's any doubt just run the engine for a bit to top it up.

[francophile1947]

Not sure where that came from initially about the lesure battery not being bigger than the existing starter battery,

It actually mentions it in the factsheet "When choosing a leisure battery, you must make sure that it is not more powerful than the main vehicle battery" - no idea why though

[missfixit70]

Yep, I know it's in the factsheet, but I don't know where that info came from is what I meant

[andyb]

Cheers guys. I'll just put the biggest one i can in there then

[daveblueozzie]

Yep, I know it's in the factsheet, but I don't know where that info came from is what I meant

Why not edit the fact sheet to correct the error, or is that to easy and simple an idea.

[Ian]

I don't know where it comes from either. I will amend it.

[Simon Jones]

I've been trying to find out more about this, but have been unable to locate the article that I read on the subject. As I recall, when two batteries are connected together in parallel (as occurs when using split charger), the amount of charge you can put it can be no higher then the lower of the two batteries. So, if one were 75Ah & the other were 110Ah, it could only ever reach 75Ah.

I think an analogy would be two water butts with an interconnecting pipe at the bottom. If one water butt was twice as tall as the other one, you could never get a higher level in the tall one as it could only go as high as the top of the lower one.

That could be complete twaddle, but in my head it makes sense

[missfixit70]

Aah but as long as the water butts are sealed at the top, I see the interconnecting pipe at the top, if they are connected to a pump (alternator) & therefore pressurised, the bigger one will still get filled, as long as a one way valve is fitted (split charge relay), it won't empty down into the smaller one. That's my theory, again, that could be twaddle & we could both be twaddling around needlessly in waterbutts.

[Simon Jones]

My butts are open topped (!) so the smaller one overfloweth

[Romney_YW]

This might be a bit too late to be helpful, but ....

I've just fitted an Elecsol carbon fibre 100A leisure battery in my Bongo for about £90. It's physically a bit smaller than the old 110A I took out, so it's much easier to fit in/remove from the battery tray - AND it's not quite so heavy to lift up there! My supplier said that he thought the next larger size (110A, I think) would also probably fit in easily, but I stuck with the 100A.

Elecsol claim some pretty impressive performance figures for their batteries, and back it up with a 5 year guarentee. Only time will tell, though...... Another neat touch is that they seem to supply all their batteries with with positive on right, or alternatively positive on left orientation, so you're pretty much guarenteed to find one that fits your vehicle/wiring. Some other manufacturers appear only to supply one terminal configuration ....

If you need a supplier in the NW (just off the M6 and M62 near Warrington), try http://www.alternativeenergystore.co.uk/

[mikeonb4c]

This might be a bit too late to be helpful, but ....

I've just fitted an Elecsol carbon fibre 100A leisure battery in my Bongo for about £90. It's physically a bit smaller than the old 110A I took out, so it's much easier to fit in/remove from the battery tray - AND it's not quite so heavy to lift up there! My supplier said that he thought the next larger size (110A, I think) would also probably fit in easily, but I stuck with the 100A.

Elecsol claim some pretty impressive performance figures for their batteries, and back it up with a 5 year guarentee. Only time will tell, though...... Another neat touch is that they seem to supply all their batteries with with positive on right, or alternatively positive on left orientation, so you're pretty much guarenteed to find one that fits your vehicle/wiring. Some other manufacturers appear only to supply one terminal configuration ....

If you need a supplier in the NW (just off the M6 and M62 near Warrington), try http://www.alternativeenergystore.co.uk/

Excellent tip and thanks+++ - I suspect my Numax 110Ah will need changing soon and I believe the type you've bought is the best overall for handling higher discharge rates as well as having the LB ability to handle being (fairly, not totally) flattened repeatedly without damage. I believe this is (similar to) the type Ron Miel has fitted in his, and he researches his needs carefully. Not the cheapest, but not a false economy either!

I wonder if gh8de (or whatever his BF name is - Dave? he's v. clued up on electrics!) could comment on mismatched SB/LB charging is it would be good to clear this one up. I don't suppose the split charge relay / VSR thing steers round it, as I guess all that does is allow the LB to 'join in' with the SB charging from the alternator rather than switching charging from SB to LB on an exclusive basis

[Biobongo]

Think you will fined the split charger deals with the different size batteries. Leisure battery is very different from car battery as they have very different job to do.
If you connect two leisure batteries in parallel of different sizes, that is amp hour sizes, the fully charged capacity will only be double that of the smallest.

Here is a very useful link that covers many questions I have seen. It is American so mains voltage is 110v. But all the information is still valid. The wattage required is just the same, just remember :
Volts X Amps = Watts
So at 220v you only need half the Amperage for the same power as 110v.

http://www.ccis.com/home/mnemeth/12volt/12volt.htm

Read parts 1& 2.

This site should be very useful to many like a Fact Sheet. Can you fix it somehow Ian?