Lotus Elan and Lotus Elan Plus 2 Forums

stugilmour wrote:I believe the large Brown that comes from the alternator goes through the ammeter and then to the solenoid terminal. The large black cable takes the charging current from the solenoid terminal on to the battery positive terminal.

Stu,
I decided to do away with the Ammeter connection and left the gauge in for appearances. I took the browns from my new alternator to the solenoid connection on my Wosp starter (same connection as the main black from the battery) and the other brown as the main feed for the new 6 way fuse box. Is this still okay, or am I running my whole loom on about 14 volts? Does it matter? I have also removed the old control box.
Kev.

That sounds the same as the way I did it Kev.

Basically, if the ammeter is not in the circuit, the loom mains can be attached in the control box side of the car or the solenoid side of the car as they are electrically equivalent; i.e. The two points are simply connected by a heavy gauge wire. As we have removed the control box, the wire just goes straight from the alternator output lug to the solenoid terminal with the battery main.

In my case I removed the remote solenoid as well and replaced it with a small electrical bus and a fusable link to protect the entire loom, but Allan has indicated he wants to retain the remote solenoid feature.

Allan, if you opt to do similar to Kev and simply by-pass the ammeter to get the car going (or plan to replace with a voltmeter in the future), you can just run the main wire from the alternator output to the solenoid along the firewall. I think that is how I did it. The brown is properly shielded with loom tube; I figured this was a safer location for the unfused brown than next to the wooden dash, and makes future dash removal easier. Make sure you have the ammeter fully isolated and any 'extra' Brown wires removed or at least disconnected at both ends. Nothing scarier to me in a Lotus than unfused Browns or Whites dangling around.

I replaced the ammeter with an eBay sourced voltmeter as per the WSM write up on retrofitting an alternator. The bezel for the voltmeter was a bit different, so I swapped with the ammeter bezel so all the gauges match. Here is an example of the gauge I bought with the curved bezel similar to the WSM illustrations:

http://www.ebay.co.uk/itm/SMITHS-BATTER ... SwimdXoy7D

Here is one with the matching squarish bezel. I didn't know these were available when I bought mine.

http://www.ebay.co.uk/itm/SMITHS-CLASSI ... SwawpXrMkD

Not sure about the chrome beauty ring on these two examples as I think those are a bit different for various Plus 2 models. Both these ones look the same as my Federal car.

A stupid admission with the ammeter. When I first bought my car, we merrily drove for over an hour, dutifully checking the gauges, etc. After the car sputtered to a halt we realized the ammeter reads 'backwards' to what I intuitively thought; if the needle is to the right the system is discharging!. Our alternator was not working at all and we drained the battery. Can't believe that was eight years ago now....

free-parking-f45/half-way-across-canada-lotus-plus-t16492.html

Stu

Stu, thanks for walking me through the circuit logic, I think I understand the philosophy. I'm hoping that this harness was already configured for an alternator so most of the wires should be there, and the heavy brown already leads to the solenoid, so that is done already. But the volt/amp meter swap might be simpler just to get the car running and buttoned up for now. I haven't even started to look at the dash wires yet but have to figure out the brown yellow to the tach (which is still removed from the car) and how to power the fuse box and go from there. Will start rebuilding the 18 ACR I found in the trunk today and setting up a mount. I think I recall doing this decades ago using the same generator mounts, but with spacers, but I'll figure it out. I'm sure I'll have more questions as I go and very grateful for the help. Thanks again Allan

Rohan, never knew that the "R" means a built in regulator. Good to know. Now to rebuild the 18 ACR that I found in the trunk, thank you Allan

Yes, great topic with lots of good info. Jeff might move to the electrical section at some point.

Stu

As per Rohan, 18 for 18 amp output (pretty decent output; use LED lightbulbs and you'll have more than enough juice for a rainy night ), AC for alternating current, R for regulator inside. My 17ACR has the regulator inside; I've replaced it once during rebuild. These ACRs are quite simple to rebuild. Don't forget bearings.

Randy

Way ahead of you lol, rebuilt the 18 ACR last night and spent the day fussing with the mount. Used the existing generator mount with a couple of tubing spacers and it lines up fine. I had to mill down one of the mounting bosses to clear the bracket, but it was only 0.125" at most. Have still to fabricate a top brace if I am to use the original belt, but at the correct belt tension (way loose) it will only have to be 2 inches long and have some real tight bends. But with a real feel temperature of 106 degrees today, I'll work on something else inside like restoring the rest of the gauges. BTW, I thought the 18 ACR alternators put out 45 AMPs at 3,000 RPM. Thanks Allan

Oh, a quick question. I assume the two lower 3/8" blade connectors (Brown Arrows) is the heavy brown wires that go to the battery via the solenoid and that the 1/4" blade connector on top (Yellow Arrow) is for the ignition light in the Tach, or is it the 1/4" connector at 3 O'Clock? Thanks Allan PS if so, what is the 3 O'Clock connector for?

gearbox wrote:BTW, I thought the 18 ACR alternators put out 45 AMPs at 3,000 RPM.

Oops. Sorry about that; got carried away with myself. It appears the number is simply a naming sequence, as one model supercedes another. Looks like each number-incremented model produces about 5 more amps: 16 is 35 amps, 17 is 40 amps, 18 is 45.

Good job getting that gen bracket to work with the alternator. As Stu said, much nicer to have an alt in the car when you're actually driving and using the car.

Allan, I absolutely don't know the specific terminals for sure, but found these pages that migh help you ID the exact type of alternator and the connections. Short answer is the extra terminal looks to be for an obsolete wiring setup.

http://www.mgb-stuff.org.uk/altplug.htm

http://1.bp.blogspot.com/-6DSQglK3HfI/U ... ltconn.png

http://www.mossmotors.com/graphics/prod ... 30-100.pdf

After scanning the pages, I take it the 3 o'clock terminal may be a second IND terminal? i.e. IND means Indicator, and is the Brown / Yellow to the dash light. The two large ones are either two + terminals or a + and a B terminal for the output and Battery Sensing respectively. Can you see in your alternator that the two large spades are in fact tied together? I take it the Battery Sensing is obsolete, and if the two big terminals are together the sensing in internal to the machine?

HTH

Stu

I'm not sure that you want that black spacer on the rear end of the alternator.

As far as I am aware the rear alloy frame of the alternator is supposed to be able to slide along its mount a small amount to cater for expansion of the alternator when hot.

Stu, yes the two large connectors are tied together at the diode pack. On some literature I have found, it was recommended to run two 10 ga. wires from the alternator to the Battery. Not sure if I had ever seen that set up, but it can't hurt. As long as the top blade is for the Brown Yellow wire, I think I'm good. Thanks Allan

Bill, Good to know and it does make sense. I read lots of threads saying that the alternator bracket would crack on race cars and the bracket they use are these heavy triangulated plates or heavy cast iron ones that are of course NLA and impossible to find. So I was concerned with just letting the back mount hang loose. But I don't expect to be driving the car at a constant 8,000 RPM, so I guess I will be ok, I hope. Thanks Allan

The rear mount would not actually be hanging loose as it would still be on that Rod you have fitted, preventing it moving away from the bracket.


Mine has a standard type bolt at the front, not a long rod. At the rear of the alternator it is a long ish bolt with a sleeve over it so the nut clamps the sleeve to the bracket. The outside diameter of the sleeve is a smideon less than the inner diameter of the rear alloy casting of the alternator, so that it is held firmly but can expand along the sleeve.

Ok, understood. The alternator I have had a tube pressed into the rear mount, but it didn't look like it moves, rather pressed in. Would this be the tube you are referring to and should the alternator move freely on it? Thanks Allan

Yes that is probably the sleeve I am speaking of. I suspect that the forces involved in the alternator expanding are similar to tht of pressing in that sleeve, However I think I would prefer a slightly looser fit.

The difference is that your bracket is much longer. In my case the rear casting of the alternator is very near the rearmost arm of the bracket.

I think you could get the effect by leaving the black spacer tube off; letting your existing (arrowed) small piece of tube free to expand along your long shaft. If it is an easy fit on the long shaft, the pressed-in tube is unlikely to move relative to the alloy casting.