Mazda BT 50, Ford Ranger electrical set up

Mazda will tell you that connecting extras to a BT50 will inter fear with the computers.

I had an auto sparky install the duel battery system, electric brakes and a wire from the ignition,which activates a relay to turn the fridge in the van [ three way]
on only when the motor is operating.

Mazda told me that the latter could not be done. The auto sparky said it could.

All are operating OK.

I don't know about the bt 50 but when I had electrcal stuff done by my auto sparkie , who has outfitted all my 4x4 before, came to the pathfinder and the work he did was to blow, the fuses at a later date, I had to take it back to Nissan and get it redone. now days you can't just plug into the fuse boxes without upsetting the computer settings, so to me I would go and talk to Mazda first to find out the lay of the electrical system
Broodie H3

spotties should not be a problem as high beam i dont think is linked to the bus system
be very careful where other accessories have power scourced , most ign and accessory power will have to be tapped into directly behind the fuse box
make sure of adequate fused and relay protection

The BT50's aren't any worse then any other modern vehicle but there are a few things you need to follow.

The dual battery isolator has to have a switching ignition feed wire to control the on and off function and it would pay to use one of the DC-DC chargers as the battery charge rates on them are very low and lower then most...... as low as 12.5v

The positive and earth feeds down to the second battery has to come of the starter battery terminals them selves and no where else.

As for Can-Bus.... the Can-Bus is made up of low, medium and high speed communications and the faster the communications the more critical it is, there are about 15 different types of Can-Bus and protocols used in a modern vehicle, a body control module will run at high speed as it needs big bandwidth and speed.... a fan control will run at a lower speed as the communications is very basic is not as important.

Not every thing in vehicles run on the Can-Bus, Can-Bus is used to communicate between nodes, ecu's and bcm's..... the main light feed to the lights are still done conventionally but the communications to the light control module that controls the lights may be on the Can-Bus.

The best place for accessory power is from the cigarette feed.

Always check power and earth with a multimeter and not a test light and try to obtain a wiring diagram.

When using relays make sure they are a low resistance (140 ohm coil vs 340 ohm coil) one as to not overload a circuit.

Wow. Thanks everyone for their reply. Im guessing there is no problem taking power directly from the battery though? I have heard that if you take power from here the car doesn't 'know' about it and therefore doesn't charge the battery correctly.
Is there any truth to this?
Thanks