Alternative Alternator wiring?

[welshrat]

Hi auto electrics have always confused me so thought I would check this out before setting fire to my car.
Finally decided to retire the dynamo and now have all I need to fit an alternator, however I would like to keep the control box in place and if possible use the existing wiring. if I strip out an old control box and link the terminals up as per picture (inside the box) and if needed extend the wires from the dynamo to reach the alternator will this do the job?[frame][/frame]

[andy.pointeer]

Hi did you buy a conversion kit, as the kit I used had a new wiring loom for the alternator.

The instuction provided below
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[frame][/frame]
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The control box shown below with the disconnected wires taped up, No change was made to the workings of the control box. You can also see the new charge light cable.
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[frame][/frame]
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The photo below show new alternator and the old wires taped up by the coil. It shows the new fed wires connected to the starter solenoid coming from left
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[frame][/frame]
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Hope this helps

[welshrat]

Hi, thank you for the information. No not bought as a kit so no new loom.

[bmcecosse]

Essentially YES - what you propose will work - although you are giving yourself extra work..... Remember the car must be -ve earth.

[IslipMinor]

Unless you have a very low output alternator, the main 'brown' wire that takes all the load will be too small for an alternator. Most alternators available today have at least twice the output of the original dynamo. The main output cable should definitely be changed.

What alternator are you planning to fit?

[welshrat]

OK will stick with the tried and trusted plan. The alternator is a SA402, from a Mini I believe.

[bmcecosse]

The alternator will only supply whatever it is asked to supply - so unlikely to be any more than the presumably deceased dynamo. But indeed no harm in increasing the cable size for the main feed.

[IslipMinor]

The SA402 looks to have 45A output, so the main output cable should be at least 6.00mm2 (84/0.30mm) in size.

Assuming the alternator has the standard Lucar output terminals, there will be 3 x 35A (3/8" wide) terminals - are there?

The original dynamo cable is probably either 2.50mm2 (35/0.30mm) or 3.00mm2 (44/0.30mm), so using this and adding a second cable to the second output terminal on the alternator is a good way to do it. The additional cable should be at least 3.00mm2 (44/0.30mm).

It's easier to run 2 smaller cables than 1 large one around the engine bay.

[welshrat]

Takes this plug also has another male terminal on the back, not quite sure what that one is for.[frame][/frame]

[IslipMinor]

Ideal - use 2 main cables to give the current capacity.

The later Lucas or Lucas 'type' alternators seem to have alternative connections within the same unit. I recently bought an A127 and that has quite a range of rear connections, including the usual 3 Lucar connectors.