100amp fuse with 120amp alternator ??

[chris52]

Hi guys my alternator was going a bit dodgy so I have got another wich is an new original landrover one but is 120amp not 100amp as the previous one. If I fit it will i need to upgrade the fuse?
Cheers Chris

[Alistair H.]

You can get a better quality fuse which is rated at 125amp.

http://www.tvrpower.co.uk/store/slug/125-amp-fuse/

Jobs a good un.

[Marty V8]

Alistair H. said:

You can get a better quality fuse which is rated at 125amp.

http://www.tvrpower.co.uk/store/slug/125-amp-fuse/

Jobs a good un.

If you havent done so already, I would also get a new fuse holder as well, which is what I fitted to my ex-Griff along with the 125 amp fuse replacement. They are cheap and easy to fit and due to being located under one of the engine mounts, are subjected to the weather.

[chris52]

Cheers for the info will get one ordered.

Chris

[steve-V8s]

chris52 said:

Hi guys my alternator was going a bit dodgy so I have got another wich is an new original landrover one but is 120amp not 100amp as the previous one. If I fit it will i need to upgrade the fuse?
Cheers Chris

Your new alternator will not blow the 100A fuse. It may say 125A on it but it is unlikley that you will get that amout of current unless there is a fault in which case you want it to blow anyway.

[Motik]

Never use a fuse rated higher than specified. The fuse is there to protect you, you want it to blow as soon as the current gets higher than normal. If the fuse doesn't blow, then the weakest part of the circuit, probably the wiring, will overheat and eventually catch fire. Then your car will burn. Then your house if your car was in the garage. Get the idea ?

A 120 Amp rating on an alternator does not mean that it will produce 120 Amp. It means that it is able to produce that much current. The actual current at a given time is only determined by how much power is needed by the car's electrical devices (ignition, lights, fans, battery charging...)

If TVR specified a 100 Amp fuse it is because they knew that the total electrical current needed at any given time would be less than that. So you don't need to worry about using a 120 Amp alternator with your 100 Amp fuse.

HTH

Motik

[chris52]

Ok thanks I certainly don't want to have a fire, I will buy a spare 100a fuse and see how it goes. I have noticed a difference since changing the alternator firstly the gauge is showing higher and I now don't see a dip in revs when the fans come on etc.
Chris