Advice needed on split charging.

[60041]

I found this today, it is expensive but does not require bringing a cable all the way from the alternator so fitting it should be a doddle. I have dealt with autosparks before and they are a highly professional outfit.
http://www.xtremevan.co.uk/product_i...oducts_id=5026

[skye740]

Thanks, I'm sure it is very good but extremely expensive and out of my price range. So I wont be persueing your suggestion any further.

Cheers

[DC850]

Hi Skye740,
I know mikealder linked to a split charge system, but what I think this will give you what http://www.towsure.com/product/SelfS...bination_Relay
which will need some wire with it but a little cheaper than the other solution. These drive Caravan's fridge and charge the battery with a basic direct feed via 30amp fuse from Car's Battery Pos terminal and a good earth. The two wires to battery you wish to charge. A switch to isolate the battery connections when not attached would help to make the free ends safe.

DC850

[skye740]

Originally Posted by DC850

Hi Skye740,
I know mikealder linked to a split charge system, but what I think this will give you what http://www.towsure.com/product/SelfS...bination_Relay
which will need some wire with it but a little cheaper than the other solution. These drive Caravan's fridge and charge the battery with a basic direct feed via 30amp fuse from Car's Battery Pos terminal and a good earth. The two wires to battery you wish to charge. A switch to isolate the battery connections when not attached would help to make the free ends safe.

DC850

Now that looks good, although I wouldn't know where to start with the wiring and what size the wire would have to be. And originally I was told that it must be a solid state relay and this model does not specify.

Cheers

[mikealder]

Its only rated at 32A so its going to have a hard time when it clicks in if the second battery is very depleted, repeat this a few times and the contacts in the relay will weld closed.

As for cable you really want the larger the better otherwise you will suffer from voltage droop where the voltage drops as a product of the current flowing, the higher the current the more volt drop.

Thicker cable will overcome some of the voltage droop, I would be looking at something around 25MM squared for the POS cable, I would also use a short length of 25MM Squared cable to connect the Neg of the second battery to the cars chassis/ metal work, I doubt you will get substantial diameter cable such as this to fit the relay terminals in the last link - Mike

[DC850]

Lets just recap,
The battery is to be used for camping, well this unit is for Caravans also used for camping. I have a simular device fitted to my 850 for the past 6 years. I camp most weekend without mains hook up, using TV, Laptop, water pump, lights and motor mover supplied by a 110amp battery. So at the end of the weekend, a well used battery. When I am connected to the car the fridge and battery are then supplied via a 30amp fuse though the unit. The fridge and battery are then charged via the unit when the car is running.
As I have said I have used this system along with may other caravanner for many years without issue.
True if you try to start the car with the charging battey it will not last long. But when the car is not running the charging battery is isolated.
You could damage things if the battery was a total short, but then this would also damage a soild state device, that is why the 30 amp fuse is fitted.
Yes the other system is a great system and the price shows it. but I think is over kill for what you are after.
DC850

[outnumbered]

http://www.caravanningnow.co.uk/cara...faqbattery.htm

[skye740]

Trouble with that method you need a 12s socket which I do not have.