95 amp alternator conversion

[spider2081]

If I recall correctly, an original alternator is rated at 65 amps, so I would be very surprised if the original wiring from the alternator to the battery was only rated for 40 amps.
Regardless whether you have the original alternator or you install a 95 amp model, it is probably prudent to check your wiring to ensure it is in decent shape.

I am no authority on what Spiders were originally delivered with for a generator/alternator. I have seen some posts mentioning changing the generator to a alternator. If they are correct it is safe to assume the generator was rated at 30 amps or less. Most reference to alternators is a 55 amp alternator. Often a safety factor of 80% is used with generating systems. So in that case a 55 amp alternator would be required to operate at a load of 44 amps.

I am not trying to be "right or correct". I am trying to have folks operate their cars in a safe and thoughtful way.

Again the terminals and connectors on the ends of the wires are the most suspect areas to fail.

[70spider]

It seems I may in the market for a new alternator sooner than anticipated, it is making a fair amount of noise (bearings) and not putting out enough (the turn signals slow down when braking). My concern is not the amps (wether it be a 55,65 or 95) but the swap from an external voltage regulator to an internal one, what is involved? Also of note, the alternator in the 1970 Spider is on the passenger side. What year did Fiat start putting them on the driver side?

[vandor]

The swap to an internally regulated one is very easy, you just disable the charge light relay. Fiat started putting the alternators on the driver's side in mid-77, at the same time they went to the internally regulated ones.

[vandor]

>I am no authority on what Spiders were originally delivered with for a generator/alternator. I have seen some posts mentioning changing the generator to a alternator

No US-model Spider ever had a generator. Some early Euro ones yes, but never in the US.

[spider2081]

Thanks Casba, was the 55 amp alternator the lowest rating also?

[vandor]

The early Spiders were rated a 42 Amp steady, 53 Amp maximum output.

[spider2081]

Thanks again Casba.

[DieselSpider]

If you do go with one just make sure to verify your wiring for correct gauge and condition coming from the alternator all the way to the fuses and for any creative modifications done by prior owners.

I just had a near miss with mine when the lighter plug came apart this past Friday on may way to work before sunrise which started arching inside the center console and did not blow any fuses making it appear that a previous owner had wired it direct bypassing the fuse box. It was shutting down the lights and even the fuel valve on the mechanical diesel injector pump which requires very minimal power to keep open. I had to pull over and flip the master disconnect in the trunk which I am grateful for having and thankfully I had no fire but just a bit of smoke to clear out and a lighter circuit to chase down and get fused like it should be. I did a quick repair and got to work on time but will vet this out more fully over the coming weekend. Didn't need a second cup of morning coffee after that.

Creative wiring can get you.

[So Cal Mark]

the ONLY wire you need to be concerned about with an alternator upgrade is the wire from the alternator BATTERY post to the BATTERY post on the starter solenoid. That is the only wire that carries charging amperage besides the battery cable.

[4uall]

Hey Mark, curious to know what gauge of wire would that be? anyone have pics?

I found this (min #8 gauge ?)however, I like clarification

http://www.fiatspider.com/f08/viewtopic.php?f=6&t=13451

[70spider]

I have a 42 amp alternator in my '70 and the wire is 8awg. I found this amp/wire gauge chart online, I hope it helps.
http://www.usawire-cable.com/pdfs/nec%20ampacities.pdf

[4uall]

So based on that chart having a new 95Amp myself I should be using a #2 AWG

[majicwrench]

Just threw open the hood of a 99 Dodge pu w a 132 amp alternator, comparing it w what I have on a spool, looks like #2 coming from the alternator.
A 2007 Subaru in shop, no idea alternator amperage (probably 100ish), has 2 wires coming from terminal, both #8. I'll keep checking some cars for giggles.

[So Cal Mark]

10 gauge will carry that load. If you have concerns, merely add another wire from the alternator Battery post to the starter solenoid Battery post.
Just remember, rarely if ever will the alternator actually have to put out that amperage. Add up all of the amperage demands in your car and it will be far below 95a. One advantage is you're not maxing out the alternator constantly like you can with the 55a stock unit. Running anything at max output results in a shorter life

[spider2081]

I spent a little time searching "collector car/hot Rod" wiring and "Marine" wiring regarding alternators and alternator upgrades to higher output more modern alternators.

Here is one link I found interesting

http://alternatorparts.com/wire-size-chart.html

One of my questions is why upgrade to a bigger alternator and leave the alternators output wire as the weakest link in the system?

A few of the "Hot Rod/collector car" vendors market wire kits that replace the alternator output wire to a larger diameter with new terminals the proper lengths to make their alternators a complete upgrade. Nice marketing in my opinion.

A point noted on a few sights is that many new alternators have a ground wire terminal that is often overlooked. This ground wire should be the same size as the alternators output wire . This ground connects the alternator to the cars chassis/body. The higher current alternators should not simply be dependent on their mounting to the engine for a good chassis ground. I found this interesting because there are so many failures of the engine to chassis ground on our Fiats.