Lotus Europa Community

Having just finished re-wiring, I have few comments.
If you want a historically correct restoration ignore the rest of this post and just repair what you have.

I wanted to take advantage of modern technology in any way that did not change the character and general look of the car.

On my 70 S2 some wire was internally damaged and over 50% of the connections were corroded or failed. I removed the amp meter (not really necessary if you sort out the electrical system, I replaced it with an air / fuel meter and added an idiot light). Also remove the high current coil wire that runs through the tach (there are several posts, on this site, on how to do this. It dramatically reduces the electrical noise in the car allowing a radio to work properly).

I sized my wire by using the length and resistance of the wire (many tables on line) to find the wire gauge that results in .5V of voltage drop at max current.  Voltage drop = Max Current X Total Resistance. Total resistance includes the wire to the battery, wire to ground, and any switches or connections on the way. A good clean flat connector or switch will be less than .05 ohms. Good solder connections are 0 ohms.

If you remove the ammeter the only high current connections / lines go to the radiator fan, cabin fan, headlights and starter. I added relays to front area so the cabin switches just turn on the relays.

I replaced the alternator with a mini-denso 70A ( https://www.ebay.com/itm/151571437369. ) .Smaller, lighter, more current, internally regulated. Some fab for the mounting is needed. Link to dimensions  https://www.amazon.com/DENSO-EXCITING-ALTERNATOR-MOUNT-1-WIRE/dp/B00DMS4YIG.   

But ..... I have heard you can simply buy a new wiring harness and move on.

Ron

That's something I've wondered about.
I don't know the gauge or amps rating of the 'big' brown wire, but is it much different to normal cars running a 70 amp alternator?
At a glance, it doesn't seem so but I'm no expert.
Enquiring minds and all that...

When I fitted the A127 it comes in several ratings (55/65/70/?? IIRC), the higher ones don't use the spade terminal plug but are stud connections with, from the photos I saw, fairly chunky wiring. There are plenty of cable guides on the internet but most of them stopped at 50amps. I did find one supplier that gave a 70amp rating and that was massive, almost 8mm and I don't think I've ever seen that in a car before.

https://www.autoelectricsupplies.co.uk/p/standard-cable

To be honest it's mostly above my head. I could never grasp electronics, if I can't see it, touch it or hit it, then it's black magic.  After reading about wire lengths/diameters/voltage drops I guessed the big problems were voltage drops or the wire getting overheated.  With the ammeter in the dash and what's probably a longer cable run than most cars I figured Lotus had probably sized their cable  on a 30amp rating (5mm on that chart).  But as I'd never seen anywhere near 30amps before I just put the A127 in and watched the ammeter.  It works and after running for what's now several years  (2016)  there's no visible problems on the brown wires, so technically correct or not, it seems to work ok.

Gee, I guess I have to modify my image of RD Enterprises being a big box store with acres of shelves of Lotus parts and greeters in Lotus shirts meeting you at the door like Walmart. Hmmm.
Tom

Quote from: SilverBeast on Saturday,April 27, 2024, 02:47:23 AM

Quote from: 4129R on Friday,April 26, 2024, 06:32:35 AM

...........

But the car started easily and ran well today. The "to do" list has no major items on it.

  Dang, I'm JEALOUS,  I chickened out on driving mine today, because as you just stated I also have no major items .
  Best of luck with her.
Dman
   

If anyone in the So. Cal area wants these and can wait until Hot August Nights for delivery I have an offer of free transport.