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MG TD TF 1500 - FIrst time hooking up battery

I am near the point in my restoration where I will be putting the battery in. While I double/triple checked each wiring connection on the dash and regulator for correct position and tightness of the fastener, I obviously have concerns about hooking up the power for the first time. (New wiring harness)

I have new Lucas smoke and don't want any to leak.

Any recommendations on a good procedure for hooking up the battery for the first time?

Or is it just cross your fingers?
Bruce Cunha

Connect the hot side first. Remove both fuses. Touch the ground cable to the battery post. Should be a spark so tiny you are unlikley to see it as the only key off draw is the clock. If no big jumping spark then install the fuses. If nothing blows turn the ignition key on. Turn the lights on and if still no smoke, turn on the park lights, then the head lights. Turn them off and try the turn signals. Try the brakes. Check the horn. Last step is to turn the engine over.

I don't follow any of that that but I don't tighten down the ground cable until I'm convinced I do not have any issues so it is a quick cable removal to avoid smoke release.
L E D LaVerne

You can use a multi-meter set to dc load and connect that between the batt terminal and the cable first to note if there is an unusual load.
Those meter devices that sense load are often fused to 15 amps max.
Might prevent a surprise...
J Stone

Bruce, Instead of the battery, connect a circuit breaker protected battery charger. This will trip if you have an inadvertent short somewhere. The only things that won't work on the charger are the starter motor and horn. But those are usually not likely to be a problem.
Lew Palmer

Great advise. Things I would not have thought of.
Bruce Cunha

I have re-wired several cars and I always use the same procedure. Put an in-line fuse (15 amp is fine) between the battery terminal and the main power lead. Positive or negative ground doesn't matter. Then just go about checking the operation of everything electrical - lights, heater blower, fuel pump, ignition, radio? -- everythng except the starter. If there is a problem anywhere the only Lucas smoke released is from the fuse.
Bruns

I would suggest to use an Ohmmeter rather than a battery. If everything is off, the meter should read several megoohms.Maybe the clock will draw a few miliamps with 12 V but zero with an ohmmeter.

If you don't have an ohmmeter, you can install a 1.5 V battery and measure the current this should be less than 1 mA when everything's off

Third solution connect the powerfull 12V battery but through a 10 kohm resistor on the negative terminal (positive ground I suppose). Measure the voltage drop accros the resistor there should be less than 1 mV when everything's off.

Fourth and best solution is to connect an electronic 12 V power supply featuring an overcurrent protection. But I doubt every mechanic has such equipment.

Laurent.




LC Laurent31

This thread was discussed between 19/03/2023 and 20/03/2023

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