Lotus Elan

Unfused Circuits

PostPost by: William2 » Wed Sep 16, 2015 12:16 pm

Out of interest, am I correct in saying that the electric windows, sidelights and headlights are unfused circuits on small Elans?
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PostPost by: RogerFrench » Thu Sep 17, 2015 2:24 am

Well they are on mine!
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PostPost by: denicholls2 » Thu Sep 17, 2015 1:10 pm

William2 wrote:Out of interest, am I correct in saying that the electric windows, sidelights and headlights are unfused circuits on small Elans?


No. All of these are fused via remarkable devices known as Lucas Bullet Connectors. If those fail to break the circuit, the switches will generally oblige. Final fail-safe is offered via the undersized wiring leading to these devices. :)
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PostPost by: William2 » Thu Sep 17, 2015 3:48 pm

You're right about the undersize wire gauge. I have totally rewired my car with new cable assemblies and was very surprised at how thin some of the main feed wires are. I am thinking of fitting extra fuses to the lighting and window motor circuits which is an easy job.
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PostPost by: Grizzly » Fri Sep 18, 2015 10:14 am

When i saw the wiring in my Elan the first thing i did was fit a Fire extinguisher and the second thing was fit a Battery Cut off switch.

I know Lotus got better with the wiring with the +2's but i'm not sure how there was many more fires on the 2 seaters :shock:
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PostPost by: TroonSprint » Fri Sep 18, 2015 6:35 pm

My Elan now has 12 fuses covering almost all circuits, and multiple relays taking the load off those precious switches. Since an electrical fire is an absolute disaster in a glassfibre car, it only seemed sensible to me. I'm not a great one for originality, especially when safety is the issue.

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PostPost by: William2 » Sat Sep 19, 2015 11:10 am

Hi Mike, I am interested to know how you went about installing additional fuses. Did you fit the fuses in one new fuse box in the engine bay or separate in-line fuse holders around the car? Regards, William
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PostPost by: TroonSprint » Sat Sep 19, 2015 2:51 pm

Hi William. I have redesigned the wiring for my car starting from scratch, not from an existing wiring harness. You can see the twelve fuses in two boxes of six down at the bottom of my photo. Since I have fitted an alternator, the voltage control box is no longer needed so that gave me space for the fuses. I have also included a diagram I made explaining which fuse does what. The relays are mostly mounted in a twelve relay block on the side wall of the passenger's footwell.

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PostPost by: RogerFrench » Sat Sep 19, 2015 7:37 pm

The reason headlights were not fused was to eliminate the risk of instant darkness in the event of a fuse blowing. Self-immolation as a result of overheated wiring was deemed an acceptable risk!
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PostPost by: TroonSprint » Sat Sep 19, 2015 8:57 pm

That's right Roger, and the debate still goes on in classic car circles about whether the headlights should be fused or not. I came down on the fused side, after all they are fused on any modern car and how many reports do you hear of the fuse blowing and the lights going out?

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PostPost by: elanner » Sat Sep 19, 2015 11:19 pm

For a trivial way to fuse the headlamps there are neat fused relays available from Hella. I purchased mine from Amazon.
Hella.jpg
Hella.jpg (22.02 KiB) Viewed 603 times

These can simply replace the regular relays - all done in a few minutes, for Main, Dip & Flash.

I think the greatest risk of instant darkness comes from the headlamp microswitches & wiring failing. I wired mine in parallel, so one can fail without causing a problem. Others, I know, prefer to disconnect them altogether.

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PostPost by: Lyn7 » Sun Sep 20, 2015 6:46 am

Hi guys, these discussions always makes me wonder how my car ever got to be 43 years old? :lol:
I like the Hella relay though, v neat. Lyn.. :)
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PostPost by: bob_rich » Sun Sep 20, 2015 8:41 am

Hi All

My 1973 +2S 130 had two thermal cut outs one for the whole side / main light circuit and a second for the side lights. It also had 4 fuses for the bulk of the electrical circuits fans, heaters, wipers etc. The window motors, ignition coil feed, and the alternator were not fused.

I was always concerned that the wiring to the dashboard mounted fuse bank ( 4 fuses) was a bit risky as the fuses were around the 30A rating and some of the individual wires were not (imo) rated for 30A. With fuses the fuse should protect the wiring first and foremost. Modern blade fuses have predictable breaking characteristics whereas the glass fuse links in the original fuse box looked a bit iffy and I could not find sound info on the type and value they should be.

I rewired my car fitting a bank of 10 blade fuse for the accessories and did fuse the window motors. I fitted resetable circuit breakers for the lights instead of the thermal breakers. All of these accessible through the original dash board fuse cover I also added a battery cutoff switch and fitted a 50A fuse in series with the alternator.

For the clock I fitted a 1A fuse directly from the battery so that when the battery safety switch is off the clock is still powered up

Hope this helps

regards

Bob
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