8 replies to this topic

[Dalla]

Hi Guys

In have recently bought a 1995 Mini Cabriolet SPI. I have had an issue with it not charging the battery. I found that the large 40 Amp fuse between the Alternator and the starter motor was blown. I suspect this is the cause for it not charging. But then my question is, what will cause this fuse to blow?

[68+86auto]

A 40A fuse is probably too small so that would be what has caused it to blow. What size is the alternator?

[Dalla]

A 40A fuse is probably too small so that would be what has caused it to blow. What size is the alternator?

Not sure how Big the alternator is. I am sure it is original. I am also quite sure that the fuse is original.

[68+86auto]

I am used to older minis which are unfused so until I searched I didn't know later minis were fused.

Based on this post I found, I don't think 40a is at all correct or original. https://www.theminif...ernator-wiring/

Edited by 68+86auto, 23 May 2023 - 09:24 AM.

[Dalla]

I am used to older minis which are unfused so until I searched I didn't know later minis were fused.

Based on this post I found, I don't think 40a is at all correct or original. https://www.theminif...ernator-wiring/

Thanks mate. That was exactly what i was after.

[Dalla]

Anyone with an idea how I determine the size of my alternator. Cannot see if it is a 45A or 70A? Would like to know what size of fuse to fit. Would you just go ahead and fit a 80A fuse no matter the size of the alternator?

@kernowcooper can you help?

[Steam]

Fit the correct size cable and forget the fuse, Worked for 40 plus years from the factory.

[Spider]

To me it seems an odd thing to fuse an Alternator Circuit, but keep in mind here, fuses are for short circuit protection, not over loads. If it was me and I wanted to fuse the alternator charge wire, I'd be fitting at least a 100 amp fuse.

[viz139]

The original fuse would have been a Hypalon fusible cable so if you are looking at a large 40A fuse unit it has been replaced previously and you have an ongoing problem. First thing I would check is the battery cable under the car for damage where it may be earthing against the body.The standard alternator is 45Amp and will very seldom see that unless you are running many spotlights. The fuse is there to protect cable and equipment and may already have saved you an alternator or car fire so replace with same size and find the fault.