Battery Fuse

Discussion in 'Capri Chit Chat' started by BigJ, 21 March 2015.

  1. BigJ

    BigJ Registered Capri Power Member

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    I've run my battery lead through the car as the battery's now in the boot. I want to fit a safety fuse to cut the battery if the cable was to short out but I'm struggling to find something suitable. Anyone ever fitted anything like this?
     
  2. CMF

    CMF Registered Capri Power Member

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    Ive got my battery there and have been thinking the same.

    I havent seen any manufacturers use a fuse as such, rather a fuseable cable as part of the main battery cable, but its hard to get a rating for them and are usually part of a loom and expencive
     
  3. BigJ

    BigJ Registered Capri Power Member

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    I did see this but not sure how suitable it would be. 100A?


    http://pages.ebay.com/link/?nav=item.view&alt=web&id=311016749602
     
  4. WaxDaddy

    WaxDaddy Registered Capri Power Member

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    The main pos link fuse in a BMW for example is 250 amp, it might be a good idea to nip to a scrap yard and nick some bits out of an old BMW / Merc?
     
  5. WaxDaddy

    WaxDaddy Registered Capri Power Member

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    Just had a quick look and the in line battery fuse box from a BMW e46 looks like a good candidate for this? Scrap yards should have a decent supply of e46's as well.


    Current draw on cranking even on a small-medium 4 cyl engine is going to be anything from 90-110 amps, V6 with good compression could see >150
     
  6. NathanPrince

    NathanPrince Registered Capri Power Member

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    Is that the little black box with a 250amp megafuse built in? Looks like they mount it in the boot and it has 2 terminals for connecting the cables onto.

    Very clean and simple solution, think I'll get myself one of those!

    Cheers Wax Daddy :thumbup1:
     
  7. BigJ

    BigJ Registered Capri Power Member

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    Nice one Matt, cheers :thumbup1:
     
  8. Clockwork Orange

    Clockwork Orange Glasgow Subway- Keeping it simple since 1896 Staff Member Moderator

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    on the Capri as standard ... there is a fusible link wire on the main loom where it bolts onto the battery, I am certain it is 60Amp, designed to protect against the 'systems' overloading the battery
    .. but the direct cable to the starter is not fused..
    me personally fitted a breaker switch into the main cable from the boot to the engine bay with a 10 amp fuse across it to serve the radio, interior light and the central locking ...
    the cable runs internally so is relatively safe short of someone cracking the cable while the car is in use, external damage is most unlikely ...
    I would be inclined not to fit a main fuse in the cable due to not necessarily going to be necessary ... and stick with the standard design albeit altered slightly to support the relocated battery
     
  9. BigJ

    BigJ Registered Capri Power Member

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    Okay here's my motivation for this. Years ago when I was a traffic bobby I attended a fatal accident where a car had gone on fire and burnt the occupant to death because the battery cable was damaged in the impact and shorted out on the bodywork. The guy was alive but trapped when the car caught fire and he couldn't be released before he succumbed to it. If the power had been cut he would have survived. Running the cable internally arguably protects it better but also limits what can be done from the outside so cutting off a potential source of ignition is something that weighs heavily on my mind. No guarantees of course but it evens the odds a bit.
     
  10. WaxDaddy

    WaxDaddy Registered Capri Power Member

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    No problem :thumbup1:


    This is pretty much exactly why it should be fused when running the full length of the car. Obviously BMW thought it was worth while, as did Mercedes, Jaguar, etc etc

    Have a look on eBay for mega fuse or littelfuse, these are the ones BMW use (and you can also get fuse holder boxes for them if you don't want to hunt around a scrappers for bimmer bits). Won't cost you more than £15 - £20 either way and it MIGHT just save your life one day...
     
  11. Vernon240

    Vernon240 Registered Capri Power Member

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    I had the same thought a few years back and put a 'mega' fuse holder in the boot, probably 6 inches or so from the battery. I'll have to check the rating, but rated it below the cable rating. I like the fact that you can crimp on nice big ring terminals for a secure connection, plus the fact past 6 inches, should there be a short, I'm protected. You can draw huge currents from a battery in these circumstances, so better safe than sorry!
     
  12. rossored86

    rossored86 Registered Capri Power Member

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    Based on this tragic story (mut have been bad for you to attend and always the most nobel side of the police constable role).....

    why not fit a heavy cut out switch in the car?

    cp
     
  13. Clockwork Orange

    Clockwork Orange Glasgow Subway- Keeping it simple since 1896 Staff Member Moderator

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    having read the above from BigJ, Wax Daddy & Vernon .. I know what I have got - a breaker between battery and car systems - will protect when I switch it off ...
    but as observed by both, in an accident scenario, I may not be able to manipulate that switch, so am therefore at risk .. I agree that a major fuse situated as per Vernon is a good idea
    as part of my ongoing rebuild I will be fitting a suitable fuse ... at the end of the day I could easily replace a blown fuse, but I don't fancy trying to recover from an accidental fire situation when it could so easily be prevented
     
  14. NathanPrince

    NathanPrince Registered Capri Power Member

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    So you would go with a megafuse just like the BMW e46 setup? Would you keep the circuit breaker or just run the fuse, I have a 200a breaker but if I can get away with just using an E46 setup which I can probably get for ~£10 that suits me down to the ground.
     
  15. Clockwork Orange

    Clockwork Orange Glasgow Subway- Keeping it simple since 1896 Staff Member Moderator

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    I would keep the breaker too .. one of my inline defences ... no point in being all connected up while in the garage ...
     
  16. trevster mk 2

    trevster mk 2 Registered Capri Power Member

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    holy moley , my battery is going in the boot too glad i read this, sorry to hear about your experience Joe, must have been terrible.
    i am not good on all this lecktricky stuff so will pass this on to my main man.
    good info as always from cp,
    stay safe one and all
     
  17. andy

    andy Registered Capri Power Member

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    Hi guys,
    old thread I know but I was doing a search instead of starting a new thread but couldn't find the answer.

    I have moved my battery to the boot and have been looking at a circuit breaker like the one in the link below from car builder solutions.

    https://www.carbuildersolutions.com/uk/200-amp-surface-mount-circuit-breaker

    im unsure what ampage to get though. They do from 200 down to 50. I was thinking 200 or 150. Any thoughts ?
     
  18. mgentry90

    mgentry90 Registered Capri Power Member

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    Depends on cranking amps draw for your engine starter I recon. I've fitted a 150amp fuse on mine (not a ford engine).

    The only thing I will say: make sure you have some ventilation (or a gas vent/drain from the battery to outside?) as now, all the bare metal/screw heads in the boot are furry where the battery has vented over time. Something I now need to sort out..
     
  19. Not_Anumber

    Not_Anumber Registered Capri Power Member

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    Ive always been a bit concerned about the unswitched, unfused red lead between the starter and the battery even when the battery is in its standard position.

    From personal experience many years ago Id agree its wise to fit a fuse or a resetable breaker when the battery has been moved to the boot or passenger compartment. My mate's idea to relocate the battery of his modified Essex V4 powered Morris Minor under the back seat maybe wasnt the best idea in the world especially the day there were 5 of us in the car. We were lucky someone spotted the smoke and we realised why the headlamps had dimmed a bit. Never let it be said that car magazines aren't useful as we used one to put out the fire and then used it as an insulator between the battery and the seat's wire frame.
     
    Clockwork Orange likes this.
  20. caprinerd

    caprinerd Registered Capri Power Member

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    in my strip car i ran a 180 in line
     
  21. andy

    andy Registered Capri Power Member

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    I think im going to go for the 200 amp one. The ones from car builder solutions are 200 or next one down is 150 and I think that 150 maybe a little low. Im running a high compression v8 , and an agm battery so no need to worry about a vent tube.
    I remember my old e30 bmw had the battery in the boot, it had little rubber flaps in each corner behind where the rear bumper sat.

    Thanks guys.
     
  22. Caprick1

    Caprick1 Registered Capri Power Member

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    Used this on mine when I relocated.
    [​IMG]
    From an BMW E30 I Think and this for the fire wall.

    [​IMG]
     
  23. andy

    andy Registered Capri Power Member

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    If it's an E30 one it has a built in fuse near the battery end. I know mine did as I blew it once.
     

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