Main fuse installation

[Tonyw]

Hi all,
Has anybody fitted a main fuse in the supply from the battery on their Stag? I am thinking of fitting a fuse or breaker in the main feed on my MK2 and wonderd if it has been done before. Does anyone have any idea of the current draw on starting for the main starter feed? Obviously this is, I would think, going to be in the 150Amp range and the general wiring main cable possibly in the 40Amp range. These are only my estimates and if needed I could measure them unless someone knows already.
Many thanks
Tony

[Stagdad]

What's the reason for fitting it Tony?

[rac]

me too why?

[Tonyw]

Hi,

The reason I wanted to fit fuses is to protect the cable through the engin bay area. If any of the cables in this area, from the battery to the starter or the main brown supply cable short out, melt on anything or get damaged they will just burn. Perhaps it is a little ott but as my trade is an electrician I feel this would be a good way of protecting against the unforseen!!

Tony

[Ian Durrant]

The fuse would need to be hundreds of amps. Starters can draw a heck of a lot of current. Batteries are marked in the range 260 to 600+ CCA (Cold Cranking Amps), I don't think fusing the starter is practical. Certainly I have never seen a fuse in the main starter circuit.

[Tonyw]

Hi Ian,

Thanks for that info, that is what I was wondering as on new cars you do have a main fuse but as you have said I was not sure if it cover the starter. I may just fuse the main loom feed.

Tony

[marshman]

Current draw for the starter on a cold morning on an engine with thick oil could be in the order of 3 or 400 amps. Hence why one of the ratings on a car battery is CCA, cold cranking amps, which depending on what battery you have in your stag will be around 500 amps. The will put out about 45 amps, quite a few owners uprate thiers to 60 or even 80 amps to cope with electric fans and more powerful headlamps.

Personaly I've never seen a fused starter feed. A lot of 1960's or earlier cars had very few fused circuits. I would double check the insulation making sure no cables are chafing on anything and the insulation is sound and hasn't gone hard and brittle, especially behind the engine close to the bulkhead. one main fuse rated high enough for the starter will not protect anything.

Roger

[Tonyw]

Hi Roger,
Thanks for the info I didn't intend to fit a single fuse, I was looking at one for the main loom and one, if practical, for the main starter cable. As this is not really an option I will protect the main starter cable in flexable conduit and fuse the main loom which is better than nothing. I already use a battrey terminal cut out when not in use.
Thanks all for the info.
Tony

[V Mad]

As this is not really an option I will protect the main starter cable in flexable conduit and fuse the main loom which is better than nothing.
Tony

The main loom consists of many wires, most of which are already fused. Those which are not have been kept unfused for perhaps goods reasons, one example being the ignition circuit.

[atc40]

Hi Tony,
I also have the same concern, especially since moving my battery to the hood well.
Recently bought a proper heavy duty Lucas battery isolator, (not one of the cheap isolators that would disintegrate if opened with any current flowing through it). Only problem I have is where to install it that would be easy to access.
Not the same as a fuse but at least it would give me the opportunity to isolate the battery if there were a problem, and hopefully limit any damage. Would also be useful to isolate the battery when carrying out any maintenance on the car especially considering where my battery is located.
If anyone has fitted an isolator to the main supply cable would be interested to know where they located it (the Lucas isolator is big!) really needs to be as close to the battery as possible to limit the length of un-isolatable (?) cable.
Andy.

[jleyton]

If anyone has fitted an isolator to the main supply cable would be interested to know where they located it (the Lucas isolator is big!) really needs to be as close to the battery as possible to limit the length of un-isolatable (?) cable.
Andy.

Perhaps not an ideal solution, but how about fitting a Discarnect to the battery itself and then fixing the back seat with velcro, rather than the two bolts.

That's how my back seat is fitted, for quick access to tools and spares, rather than a battery, and it makes it dead easy to access that space.

Cheers

Julian