Wombat wrote:
OK this is all interesting - I would like to hear what Convertible Mini says about hooking up a battery for the first time after installing a new wiring harness - think but not sure if everything is hooked up correctly with a couple of changes like relays to the headlights.
Do you just wack it in with fingers crossed or take out the fuses and check across the fuse terminals with an ammeter?
I use a standard low amp battery charger as a source of 12 volts for initial fire up. The cheap ones are fine for this job.
If there is a dead short in the loom, then the battery charger will drop out on dead short protection. The cheap ones make a audible click-click as they do so. I can mess about with wires, turn things on and off and do everything except start the car without fear of a dead short melting wires in the loom.
Saying all that, Tony and Goodie's lamp tricks across the fuse terminals are a corker.The lamp bulb will only allow a low current to pass. The lower the wattage of the bulb, the better. An LED in line with a 1k resistor would be the ticket.
As for fuses, I would stick with as low as you can as well. I don't need to get home that bad that I am ready to melt a loom. Minis use about five amps to run (60 watts) but this is taken from the battery side of the fuses in stock form, so does not figure in the fuse calculations.
There is 130 watts from a pair of standard 55/60 H3 lights, plus maybe a hundred watts for the horn plus blinkers and electric fuel pump, etc...that adds up to 230 watts which is 19 amps or so. Using 20 amp fuses assumes you will drive all the time with your high beams on and your hand blasting the horn forever, so I figure a 20 amp fuse is fine, with a spare jammed into the lucas cover in the little spare holder they give you.
Fact is, I've used 12 volts as a nominal, but with 13.8 volts figured in then the power consumption is less at 17 amps in the above operating context for worst case. Stereos are another drama with different people looking for different setup with wildly varying loads. I would wire these independently to the battery side of the fuses, with a custom inline fuse to suit.
