Alternative alternators

[jeff jackson]

Hi all,
I have searched the archives for alternators for my 72 +2. I know that the original fitment to our cars is the 17ACR. This Alternator is a 36A type.
Whilst running during the day in dry, warm weather the electrics on the car are OK, but last week I was forced to press the elan into service whilst I fixed the clutch on my wifes car.
Driving in the dark and wet was horrible. The fan was on, the headlights and the heated rear screen. The indicators just didnt flash at all!
I was thinking about upgrading the alternator to a higher current output, say 70A.
Has anyone done this? What are the alternative alternator part numbers I could put on the elan?
I have a new Bosch S5 660 CCA battery fitted, (purists look away now) I cut a section out of the boot floor and re-glassed and painted it to make it fit.
OR am I wasting my time? should I look for voltdrops all over the car?

Kind regards
Jeff 72+2

[garyeanderson]

I believe that galwaylotus upped his to a larger Lucas (higher output) alternator a while back.

elan-f14/alternator-conversion-does-your-car-talk-you-t23099.html

Gary

[rcraven]

If you've got a good battery, I'd suspect poor connections and a bigger alternator isn't the cure for that.

[JJDraper]

I use one from a Montego, with the pulley from the original style alternator (changed over by the local autoelectrician who suggested it). 70 amp max output is enough for me. Fitted with no hassle. Lights, fans, wipers all running and the battery still shows charge at 1000rpm. Slightly chunkier than the original style, but fits the standard brackets. Also has a replaceable diode/rectifier pack.

Picture shows the unit in situ.

Job done.

Jeremy

[ricarbo]

Poor indicators would be low voltage or poor contacts, probably earths, I think. If you tried turning the other loads (like headlights & fan) off and then tried the indicators, were they better?
If you work out what the loads were, did that exceed the alternator's output? I doubt it. I think I would temporarily add a voltmeter, the pocket digital type, to get a better idea.
regards.
Richard

[Robbie693]

I fitted a 45A one from Luke Motorsport.

I'm wondering, would fitting the 70A one need the wiring to be beefed up?

Robbie

[prezoom]

I installed a Denso 55 amp unit from a MetroGeo/Suzuki Swift. Very small and only about 6 lbs. If you get one from a wreckers/breakers yard, remember to take the wiring plug as well.

Rob Walker
26-4889

[stugilmour]

Mine is some sort of Denso unit as well from Dave Bean as they supply the mount. Think they are about 55 amp units; at least the similar RD kit is. I can't find the call-up for Bean's unit in my older catalog. The RD kit with the adjusting turnbuckle looks like it has a better mount than my Bean kit. Might give some ideas.

RD Enterprises

Elan Alternator Conversion
For Elan and Elan Plus 2 LHD

Kit includes a modern 55-amp mini-alternator (only @ 4" diameter, weight 7.5 lb.), turnbuckle style adjuster link and fabricated stainless steel alternator mounting bracket and hardware, instructions and wire.

This alternator is only suitable for use on negative ground cars.

Ref. 50E0501 $275.00


The Denso route is perhaps more important for LHD cars to prevent fouling the steering shaft. I replaced the AC Delco unit installed by the PO due to this issue. The Delco one looked similar to the one Jeremy used. Not sure why Ray lists his kit specifically as LHD; I would think it would fit RHD as well as I assume you guys have more room in this area? On my Federal Plus 2 this area is very tight for space due to dual brake boosters, so the Denso is the way to go.

As I was re-wiring my entire car during a resto I upgraded the main Brown from the alternator with this stuff from http://www.vehicle-wiring-products.eu It was the largest thin wall cable they listed in Brown.

Ref 63. 120/0.30mm, 8.5mm2, 63amp.
?1.88 per metre. ?52.74 per 30 metre reel.
Typical applications. Charging cable for heavy duty alternator and ammeter circuits.

Note that in the Plus 2 WSM they have a section recommending changing from an Ammeter to a Voltmeter or Battery Condition Gauge in conjunction with an alternator upgrade. Perhaps not and issue on an Elan, but something to consider.

Ammeter is wired between alternator output and battery (by-passing the starter load). In stock Plus 2 form the wire runs through the dash loom (next to kindling), so I definitely didn't want it undersized. Believe the Elan runs the wire along the firewall? You can see the basic Ammeter & Voltmeter wiring configurations here. I recall having some confusion with the Bean wiring instructions as they were for an Elan with no stock Ammeter installed. The replacement voltmeter can be very light wire and does not effect the charging circuit; I ran it without a fuse to avoid voltage drop issues at the fuse holder; YMMV.

http://www.lotuselan.net/uploads/smiths ... wiring.jpg

Jeff, I would also think you have issues other than the alternator. I think all the stuff should work just from a charged battery. Although I don't have a rear screen heater, everything on my car including added driving lamps will work without the engine running. Would suggest starting with the rear ground in the boot floor. I moved that one (based on recommendations posted here) to the right rear body to tower bolt as it is a more secure ground attachment point to the frame with a tapped boss rather than a bolt & nut, and doesn't see road crud. Big bubbles, no troubles.

HTH

[Galwaylotus]

I fitted a 45A one from Luke Motorsport.

I'm wondering, would fitting the 70A one need the wiring to be beefed up?

Robbie

Unless you have large electrical loads (lots of electrical accessories) there's no point in going to 70A. While 28A-30A is probably a bit light when all loads are in-circuit, 45A will more than cover the standard Elan configuration. In addition, the Lucas unit requires very little in the way of modifications for installation in an Elan.

[JJDraper]

I fitted a 45A one from Luke Motorsport.

I'm wondering, would fitting the 70A one need the wiring to be beefed up?

Robbie

The maximum output of an alternator is just that. The alternator meets the needs of the system, plus a little more to charge the battery. The power output of an alternator is broadly volts times amps - 12v times 70amps = 840watts (probably higher as the unit will run at around 14v). If the car's systems are not using 840watts, the alternator will not generate 70 amps; only what is needed. A +2 with all the electrical kit running (lights, fans, rear heater etc) is unlikely to need more than 400watts , so a 45-55amp unit should suffice. I only used the 70A one because its cheap, freely available - mine cost around 25GBP including the pulley switchover (that was around 5 years ago). I had concerns over water pump pulley side loading, but this has not shown up. I keep the belt just tight enough for me to turn the alternator pulley by hand with a little effort. If it squeals under load, its too loose. If you can't turn it, its too tight.

It has worked perfectly ever since, no cooked wires, although I do like to make sure all joints are soldered wherever possible (it takes hours to fully solder a loom!). I second all comments about earthing, which is the key to a reliable Lotus Elan, along with regular oil changes.

However, I take your point; if you are using the full 70amps, yes you probably would need to beef up the charging circuit! The rest of the wiring is fine, unless you have fitted super bright (and probably illegal) 100w bulbs. I find the super bright standard wattage ones are pretty good.

In the dark winter conditions we have in these parts, I am still using the car for my daily commute and the battery is kept fully charged by the unit.

To really save weight in the car its probably going to be cheaper to skip Christmas dinner!

Jeremy

[kstrutt11]

On my landrover I used a 90s escort diesel one as a direct replacement for thed 17 acr which is the same as the elan(I have swaped them in the past), only needed to swap the pulleys over, change the vehicle wiring to ring connectors and rotate the front housing to change the hand, it is around 70 amp.

[ricarbo]

I agree with Jeremy. If you want a higher power from the alternator, you need a tighter drive belt, so are increasing the pressure on the water pump, which most people think is a bad idea.
Perhaps the ideal is to use two pulleys on the crankshaft, one driving the water pump, the other the alternator. Perhaps the belts would also ideally be toothed belts rather then Vee, so the can be run slacker.. All this costs money to change.

I can't help thinking your problem is most likely poor earth connections, or less likely a defective alternator.

Have you really checked the earth connections? The easiest way is to put a voltmeter between the alleged earth connection of the item under test, while it is working, and the earth terminal of the battery. Any voltage above 0.5 volts is a fail, and you should be below that. A bit higher if you test the starter motor,perhaps, as it is such a high current.
atb
Richard

[AHM]

Good comments from Jeremy!

An elan will work ok with a 20A dynamo if kept in good condition - suggest your problem is elsewhere.

I'm not trying to say that the dynamo is great, but its output is at best nearly half of the 17ACR, and in traffic is ZERO!

[mark030358]

I fitted a DynoLite to my Sprint, looks like the old dynamo but is an alternator... much lighter and more ziggies...

Mark

[jeff jackson]

Thanks for all the comments chaps.... it is much appreciated. My wifes car is now fixed, so no need to take the elan out in this miserable weather.
First thing to do is to measure and renew all the earth connections. This is the cheapest way forward before buying another alternator.
I would not be surprised if the alternator is on it's way out, it's been on the car for 20 years. It was one of the first things I replaced, and that was optained from a scrap yard.
Have a great Christmas and a happy motoring new year.

Jeff