Leisure Battery Rethink

[CovKid]

Having found my 'so called' leisure battery has reached the end of its useful life and in common with these batteries, they are often sealed, I thought I'd rethink the whole split charging thing.

Firstly I use a straight relay, an 80amp one, and heavy gauge cable in my setup and although I have run (a few times) with just two car batteries, I never really found this particularly successful with the second battery being ok for maybe an evening but soon down to 11 volts. The plus side of normal lead acid types is that they charge up fairly quickly compared to those marketed as leisure batteries - plus you can actually top up the electrolyte if needed but their physical size limits what is available from them. Much can be found on the net regarding the different types of battery and clearly traction batteries are about the best but I'm not convinced that what most of us know as leisure batteries are really a wise choice, particularly as you need quite a run to recharge them. I'm not even convinced that there IS such a thing as a leisure battery - just sealed lead acid ones.



Anyway at the moment I'm now running with a good starter battery and a big lorry battery, around 180ah, for the leisure (joined up for test purposes with jump leads) and it seems to be working well. Whilst lorries actually use 24v, this is achieved by strapping two large 12v ones (as pictured) in series. Arguably the size of the thing may put some off but I have a feeling this has more going for it and probably worth making permanent space for it when I do my refit this year. You can buy a brand new truck battery for under £100 and it can at least be maintained. It seems to deliver over a much longer period (without complaining) than the previous leisure battery and substantially more than just a straight car battery, the only downside of course being the space needed and the extra weight.

Food for thought anyway.

[ghost123uk]

For similar reasons, only yesterday I re-wired our new Lesuirdrive's leisure wiring to now go to the big cupboard under the front of the bed on the o/s. I already have an almost new and fairly big (though not truck sized) dual purpose starter AND leisure battery (I know, a non too common article) that would not fit behind the seat, and this seemed the best way forward. I connected the earth to the small reinforcing web at the rear bottom of the sliding door frame using a nut, bolt and (~45A) wire with eyelet on it, fused (for now) at 30A right next to the battery terminal.

When I figure out the layout of the Propex and pipework that is also going in that cupboard, I will figure out how to secure the battery properly (wedged in place at present with bit of timber).

[CovKid]

Yep, more or less what I'll do. These big batteries are long, about the width of the large bulkhead which the front seat runners are welded to so they could either be sat behind the seat on the floor and held securely with suitable brackets, inside a wide purpose made buddy seat, or inside kichen cupboards. A good fixing important though to stop them moving around and thought given to ease of removal if it actually needs to come out. They generally have rope handles so not to bad to move around to be honest.

I should clarify though, I have a 90amp alternator.

[ghost123uk]

I wonder what is the biggest "leisure" battery you could get in the rear quarter (where a Diesel has it's battery) ?

[Mocki]

The diesel has its battery on a welded in holder where the petrol air filter box is.

Physically not much bigger than the seat box .
Although less of a height restriction .

Just what are you people running leisure wise?

I only have a 85ah proper leisure battery and it easily lasts even running the ebber constantly for a long weekend without starting the van at all, and I can't say as I have ever sat still for longer than that without moving!

[ghost123uk]

The diesel has its battery on a welded in holder where the petrol air filter box is.

Ah yes, I was thinking of the other side

I might stick mine there eventually...

Physically not much bigger than the seat box .
Although less of a height restriction

Just what are you people running leisure wise?

I only have a 85ah proper leisure battery

Same here (now) I was using a 65 ah car battery until this (rather decent, almost new) 85ah one came my way (in lieu of money owed )

[trentjim]

This sounds like a good idea to me...
it would be really useful if you could connect a known fixed load to the fully charged battery and measure the achieved Ah to 50% discharge - have you got a hydrometer?...
also any time you suspect you may have needed to deep discharge, check how low it went.
then in 6 or 12 months check the Ah to 50% discharge again.

the data on number of deep discharge cycles and useful capacity after 12 months would be a good baseline that other setups could then be compared to.

my understanding of the difference between cranking and leisure batteries is that cranking batteries have a larger number of thinner plates than leisure which have fewer, thicker plates - thereby making them more discharge resistant
hypothesis... since a truck battery is effectively two batteries does it retain thicker plates and utilise the x2 multiplier to provide the larger number?

[CovKid]

More thoughts here:

http://www.sterling-power.com/support-faq-2.htm" onclick="window.open(this.href);return false;

[Mocki]

my main battery is in the taillight void on the ns . my leisure battery is in the drivers seat box with a heightened lid

[trentjim]

http://www.sterling-power.com/support-faq-2.htmMore thoughts here:

http://www.sterling-power.com/support-faq-2.htm" onclick="window.open(this.href);return false;

Yep its 90% a good article but i dont really like this bit

"As you can see from the above 2 battery types, the plate configuration cannot be blended. If for starting, you have a large surface area of thin plates, for traction you have a small surface area of thicker plates. One is black and one is white, there is no grey area"

well I see no reason in principle that one cannot have a medium surface area of medium thickness plates, or to have a high surface area of thick plates at the cost of a larger/heavier battery. There is no theoretical reason that a "grey area" battery like this cannot exist. If his assertion was backed up with plate count/ thickness data for a variety of manufacturers that says that none are made in this configuration then I would accept it. I suppose what I am thinking here is that a lorry battery might in fact have a design that puts it in this "grey area", or to put it another way "sweet spot" but that there is unfortunately no evidence (yet)that one could point to to back this up.