Outer Limits 4x4 Board

Ok, I am kicking it over here in London. My house mates have decided to fit out an old bus and tour around europe for a while. They have the old battery and a 300w inverter that they have salvaged and they both work.

There is a live "constantly ON" connection with a sutible sized cable for the 30amps required to run the invertor at the back of the bus.

I want to isolate this battery when the bus is off to stop the cranking battery being discharged. IS there any cheap way to do this without buying an isolator. I was just going to put a manual removable switch, but being girls they don't understand what happens if they forget to remove the switch.

Thanks

Just use a big enough relay that can handle the amps you have and a find a trigger off the igniton or acc that can turn the relay when the bus is started

Poss use the wiper motor or a supply in the engine bay or igntion switch to trigger the relay


What kinda bus

switch is the cheapest way

but if i was you i would just wire in a relay or as the larger ones are caleld a "solinoid"

larger meaning to handle higher current,

you can pick them up from a auto parts shop for around 20 odd over here

anyways all u do it wire it in with the ignition, so reds on bat connected,
reds off bat is free

i think this is the easyest way,

cheers

You'll have to go with them as sex slave and battery switcher?

Seriously speaking, LandRover use a voltage sensing relay (VSR - thanks (again) to the Chimp) in some of their 4wds (will you find any over there? ) which is perfect for this application. Sense from main battery, use it to connect second battery when main battery is high enough, which will basically only be when the engine is running. Stop the engine, main battery voltage drops, VSR separates the two batteries. It's almost girl-proof.

For cheap cheap I'd also wire in a constant duty solinoid which is switched from the ignition (pick up something from the fuse box that turns on when the ignition is on).

Thanks Everyone, don't know why I forgot about the relay option I have done something similar before. It will be perfect, as I am installing a new stereo at the same time so can use the acc off that.

Of course if the girls were "my type" I would be running the Van and probarly getting a free trip, but alas they are not . I am just helping out cause there isnt much 4bies in the middle of London for me to work on.

Sorry I have no idea of the bus brand. It is a short bus with 3 axles, a chippie is fitting out with 6 beds.

...whack in a little 20ma blue LED and mount it on the dash somewhere just to show you when the relay/solenoid is kicked in or not. Adds bling and prettiness to the dash at the same time.

Mud_Muncher wrote:Thanks Everyone, don't know why I forgot about the relay option I have done something similar before. It will be perfect, as I am installing a new stereo at the same time so can use the acc off that.

If you do that it'll end up with a flat battery if they leave the stereo on.

pics of the bus and the girls might provide more technical feedback