Battery charging

[Apache]

Serious Question

I don't really like the idea of an electronic system.

Could I just fit a mechanical isolator to the leisure battery, then when the truck is started switch in the leisure battery which would charge with the truck running?

I guess the danger would be if the leisure battery was flat, it could draw all the power from the starter battery if the truck was only driven for a short time maybe?

Yes and probably. It would Be OK as long as you didn't deep-dishcharge the leisure battery.

What's wrong with an electronic system?

<edit> Hehe, I mean discharge, too much thinking about Pizzas?

[MattF]

Serious Question

I don't really like the idea of an electronic system.

Could I just fit a mechanical isolator to the leisure battery, then when the truck is started switch in the leisure battery which would charge with the truck running?

I guess the danger would be if the leisure battery was flat, it could draw all the power from the starter battery if the truck was only driven for a short time maybe?

Yup. Mechanical or electrical makes no difference. One of those heavy duty battery isolator switches will do the job. If it is flat as a fart, it'd obviously need a decent charge putting back in.

[MattF]

Yes and probably. It would Be OK as long as you didn't deep-dishcharge the leisure battery.

What's wrong with an electronic system?

<edit> Hehe, I mean discharge, too much thinking about Pizzas?

[24Seven]

What's wrong with an electronic system?

First the cost just for the sake of lifting the bonnet and second and most importantly, peace of mind, with a mechanical system you know for sure the starter battery is isolated . This is my thoughts on a 4x4, simple is best

[MattF]

First the cost just for the sake of lifting the bonnet and second and most importantly, peace of mind, with a mechanical system you know for sure the starter battery is isolated . This is my thoughts on a 4x4, simple is best

Electronic control systems are by default O/C. It's only when the alternator is outputting that they will connect the second battery.

[Apache]

Electronic control systems are by default O/C. It's only when the alternator is outputting that they will connect the second battery.

Plus proper leisure batteries dont respond well to being charged 'rough and ready' like a normal car battery (and car type charging systems). A proper split charger designed for this sort of thing will likely make your expensive leisure battery last somewhat longer.

Once those plates are buckled, game over!

[MattF]

Plus proper leisure batteries dont respond well to being charged 'rough and ready' like a normal car battery (and car type charging systems). A proper split charger designed for this sort of thing will likely make your expensive leisure battery last somewhat longer.

Once those plates are buckled, game over!

Aye, their nominal charging voltage is fairly tight, ain't it. About 0.4V variation allowed, isn't it?

[Apache]

Aye, their nominal charging voltage is fairly tight, ain't it. About 0.4V variation allowed, isn't it?

Cant remember, but the technology is geared up to high energy density, so there's bound to be some drawbacks. A lot of them are gel cells rather than wet cells aren't they.

[MattF]

Cant remember, but the technology is geared up to high energy density, so there's bound to be some drawbacks. A lot of them are gel cells rather than wet cells aren't they.

I think most SLA's are gel type, (excepting car batteries), these days. I've got a cabinet out in the workshop that I started for housing and charging a deep discharge battery, and it's still waiting on the regulator/charging circuit being built. If I remember rightly, off the top of my head, nominal is 13.4V to 13.8V. Below leads to plate sulphation, above leads to burnout.

[24Seven]

So...........what you are saying is that it would be a bad idea to have one leisure battery and one starter battery connected all the time, I guess the leisure battery would hate the huge amps draw of starting a car??

Can you point me to a link of a split charging system please?

[BUSHWHACKER]

So...........what you are saying is that it would be a bad idea to have one leisure battery and one starter battery connected all the time, I guess the leisure battery would hate the huge amps draw of starting a car??

Can you point me to a link of a split charging system please?

http://www.showmesome.info/hilux/workshop/battery.htm

[Les Brock]

Theres a load of stuff on batteries here....

http://www.btinternet.com/~les.brock...batteries.html

on my site....not sure if it will help or make it worse

[24Seven]

Good links guys, thank you

[Tallyman]

As long as you use a split charge relay and only connect the positive side of the leisure battery to "leisure orientated" circuits then it should not cause any problems with your normal car battery. This is exactly how it works when you are charging a caravan battery whilst it's being towed to site.

[MattF]

Theres a load of stuff on batteries here....

http://www.btinternet.com/~les.brock...batteries.html

on my site....not sure if it will help or make it worse

Just had a quick peek at your site. That looks like a nice write-up on the batteries. Glad to see I'd remembered the correct charging voltage.