Big Main Fuse - Gone for Good!
Discussion
I've only ever had one big fuse start to fail, but it is obviously quite a common problem, so I'm in the process of replacing it completely with a 100A 12V DC MCB (circuit breaker). A bit like the type you have in your house, but specifically rated for DC applications, such as boats, cars, etc.
At least this way, if it blows, I can just flick it back on.
Did a bit of searching and can't see anyone else that's done this?
Is there something I should know.........
Cheers FP
At least this way, if it blows, I can just flick it back on.
Did a bit of searching and can't see anyone else that's done this?
Is there something I should know.........
Cheers FP
As above the replacment 125A fuse is a good alternative and as it is not just the plain bit of ali it is more robust, etc. Both that and the 80A replaced were last week as a precautionary measure (after several comments on here about the need to regularly replace them and an impending trip during which I don't really want to have to grovel about) so should be OK now for a while. Must say though the old 100A looked very nice and shiny so maybe the issue is partly about keeping the muck off them by ensuring the box is sealed OK but mine was located under the chassis rather than facing the starter so possibly a better location than some??
Jim
Jim
dvs_dave said:
Is it really that much of an inconvenience to carry a spare fuse? Better still, solve the problem completely by just uprating the standard 100A strip link fuse with a more durable 125A Midi fuse? It's a common modification.
I don't really like the idea of uprating fuses unless wiring etc has also been uprated. My theory, rightly or wrongly, is that TVR made them 100A for a reason. If 125A was that much better they would have just done it at the factory. Let's be honest, the problem has been around for ages so it's not like the factory would have been oblivious to it.And whilst not wishing to state the obvious, the wiring might not be up to the job of carrying a potential 125A load. In which case, the wiring gets hot and
Don't get me wrong, I know the 125A fuse is a hugely popular mod and one that I'm sure many people never have a problem with, but knowing my luck.......
Plus, I suspect that if an insurance company did a proper inspection following a fire and discovered that the fuse was 125A instead of 100A, I'd put money on them not paying out.... especially if the cause was an electrical fault.... which most car fires tend to be.
You need to measure the peak start-up current, once you have this you can then select the correct circuit breaker. You are correct in that just replacing with any old 100A Circuit Breaker might not work - it needs to be a 100A Circuit Breaker that is correctly rated to handle the start-up current without tripping the thing out.
ETA: I must admit, DC systems are not my particular speciality, so plenty of research is going on behing the scenes too.....
ETA: I must admit, DC systems are not my particular speciality, so plenty of research is going on behing the scenes too.....
Edited by FactoryPilot on Tuesday 10th August 00:18
FactoryPilot said:
dvs_dave said:
Is it really that much of an inconvenience to carry a spare fuse? Better still, solve the problem completely by just uprating the standard 100A strip link fuse with a more durable 125A Midi fuse? It's a common modification.
I don't really like the idea of uprating fuses unless wiring etc has also been uprated. My theory, rightly or wrongly, is that TVR made them 100A for a reason. If 125A was that much better they would have just done it at the factory. Let's be honest, the problem has been around for ages so it's not like the factory would have been oblivious to it.And whilst not wishing to state the obvious, the wiring might not be up to the job of carrying a potential 125A load. In which case, the wiring gets hot and
Don't get me wrong, I know the 125A fuse is a hugely popular mod and one that I'm sure many people never have a problem with, but knowing my luck.......
Plus, I suspect that if an insurance company did a proper inspection following a fire and discovered that the fuse was 125A instead of 100A, I'd put money on them not paying out.... especially if the cause was an electrical fault.... which most car fires tend to be.
Whilst the MCB is an alternative, I can't help thinking its an unnessearily complicated solution (and consequently more prone to failure) to what is otherwise a very simple and effective fix. Anyway, let us know how you get on.
FactoryPilot said:
You need to measure the peak start-up current, once you have this you can then select the correct circuit breaker. You are correct in that just replacing with any old 100A Circuit Breaker might not work - it needs to be a 100A Circuit Breaker that is correctly rated to handle the start-up current without tripping the thing out.
ETA: I must admit, DC systems are not my particular speciality, so plenty of research is going on behing the scenes too.....
You will find that the starter isn't fused, its the supply from the alternator and whatever the other one is for (is that battery to fusebox?)ETA: I must admit, DC systems are not my particular speciality, so plenty of research is going on behing the scenes too.....
Edited by FactoryPilot on Tuesday 10th August 00:18
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