split charge relay

[96terrano]

what is it?

http://www.ebay.co.uk/itm/12v-DC-Towbar-Split-Charge-Relay-Wiring-Kit-Caravan-/220932866723?pt=UK_Campervan_Caravan_Accessories&hash=item3370a002a3#ht_937wt_699

[Fez_uk]

so you can have 2 batteries with the option of isolating them. you can have your main battery for starting the vehicle and the second for accessories.

When you are not running the engine you can make it so they are both not connected. Thus taking all the power from the 2nd battery without the possibility of draining the main starter battery.

[96terrano]

so you can have 2 batteries with the option of isolating them. you can have your main battery for starting the vehicle and the second for accessories.

When you are not running the engine you can make it so they are both not connected. Thus taking all the power from the 2nd battery without the possibility of draining the main starter battery.

cool, just been looking at caravan stuff on flebay, how hard it it to fit a 2nd battery to a t2?

[Lazy-Ferret]

I am just fitting one at the moment, just waiting for a few more wiring bits to turn up.

The Relay you are looking at is basically to charge the caravan battery while in situ within the caravan, It can also used to power the fridge. Basically it is just a relay that disconnects what ever is connected to it, to stop it discharging back through the vehicle electrics when you try to start the car, as without it, you would burn out wires on your car and caravan, or at the very least blow the fuse every time you started the engine.

The down side is, it is not very high current, and works on the principle of the length of run, along with all the connectors en route limiting the current.

To do a slit charger with the battery in the car, especially in the engine bay, you need something more substantial, like this....

http://www.ebay.co.uk/sch/i.html?_nkw=durite+split+140a&_sacat=0&_odkw=durite+split&_osacat=0

Plus fuses, and heavy cable.

[96terrano]

I am just fitting one at the moment, just waiting for a few more wiring bits to turn up.

The Relay you are looking at is basically to charge the caravan battery while in situ within the caravan, It can also used to power the fridge. Basically it is just a relay that disconnects what ever is connected to it, to stop it discharging back through the vehicle electrics when you try to start the car, as without it, you would burn out wires on your car and caravan, or at the very least blow the fuse every time you started the engine.

The down side is, it is not very high current, and works on the principle of the length of run, along with all the connectors en route limiting the current.

To do a slit charger with the battery in the car, especially in the engine bay, you need something more substantial, like this....

http://www.ebay.co.uk/sch/i.html?_nkw=durite+split+140a&_sacat=0&_odkw=durite+split&_osacat=0

Plus fuses, and heavy cable.

cheers, i was just getting ideas:)

[solarman216]

this is an area that I could talk all night about, so many anomalies and misconceptions, it is all about length of cable run and volt drop, to charge a caravan battery you only need a relay of an amperage that = the maximum output of your alternator (not that it will ever receive that many amps) the more important item (if you want to FULLY CHARGE your battery) is cable size and it will not fit in any standard trailer plug and socket, the sort of cable commonly used is just not capable of producing the max voltage needed for a full charge and you will not get a full charge from a car alternator any way as it only charges to around 14.4 volts, for a full charge you need 15 to 15.2 depending on the lead composition of the leisure battery you have fitted to your van, I will stop here as I have a few other thing to do, but hope you get the general idea, I can suggest a very good way to achieve a full charge if interested, Rick

[jims-terrano]

And all the crud build up on the plug n socket, makes a great resistor don't it Rick.

[solarman216]

And all the crud build up on the plug n socket, makes a great resistor don't it Rick.

yes very low tec stuff, I regularly spray my plug and socket for the car trailer with silicon spray but still gets poor connections and odd lights till I give it what for, Rick

[rustic]

I regularly spray my plug and socket with silicon spray :naughty

some of us use vaseline, but I prefer Waxoyl. :augie

For the second battery, I use a 40 amp relay that is energised when the ignition is on, BUT not during the actual starting cycle.
Usually the power lead to the radio is suitable to tap into.
This way the battery is charged only when the engine is running, but it can't supply current to the starter motor, thus preventing burnt cables and relays etc.

What ever you do, fuse the cable to the second battery at a value less than the cable rating.


In addition, I also fitted a starter solenoid relay, with heavy duty cable, so that I can select the second battery at the press of a switch to boost the main starting battery.

I posted a picture recently showing what I did, so search second battery.

Hope it helps,
Best regards, Rustic

[kitchenman]

Hi, I hooked my relay [coil] up to the wire from the alternator that goes to the charge light on the dash. There are two wires on my Mav, I was advised to use the blue one. I ran a new wire from the alternator output to the relay as the leisure battery is on the other side to the main battery
When the alternater is charging the relay kicks in when the blue wire goes live.
Relay from maplin around a fiver:thumbs

[panelbeater]

i will be fitting a second hd battery to the t2but i wont be using it to power t2 just the van.
when its connected to my van with 800a cable and my solar controller in my van will put up to 15.5v i am sure it will get fully charged.well in theory it should the split charge solar controller in the van will take care of it.