Let me start buy saying this is a hot rod with a 1 wire alternator. So can't look up any info.
So it could be 70-300A+ likely 100-150A range.
I'm increasing the load a fair amount so trying to work out the specs. Higher specked thermo fan, EFI and 2 fuel pumps to go with EFI.
Can I measure the resistance of the winding or anything like that.
Using a clamp meter will only tell me what it's out putting out not it's capacity.
Cheers.
tell me what it's outti g
what does that mean?
putting
bread and butter putting?
Too many carbs, that’s probably why OP is going efi…
ammount
Ammonia ?
Look up the model number.
no model or anything on it, it s a simply a chrome alt with zero markings
Google lens it then
Then it's probably some crappy cheap 70amp or so thing. Put an amp clamp on it, load it right up and bring the rpm up.
Then it's probably some crappy cheap 70amp or so thing
Yep. There are alternators that are manufactured chromed. They would have a label with a model number attached after they are chromed. You can get them in decent outputs. If it has no label its been 3rd-party chromed, and they took the label off to do that, because it didn't matter what its output was, it was just for show.
That leaves you looking at images on the internet to see if you can identify it. Or going and buying one that you know the output of.
@GordonD: I don't want to load it up beyond its capabilities and cook it. Nor do I have a ~200A load. Its a hot rod with exposed alt so likely label was removed during installation. Google lens wont be much help as they all pretty much look the same. Seems most of the "hot rod" alts are 100 or 140A units but when car was put together it beats me what was commonly available.
I don't see the point of buying another if its not needed. Plus due to Gilmer drive its not quite that simple.
100A may be a struggle 140A should do me.
@Gros21: I am surprised you can cook an alternator. The accessories drain the battery. The alternator tries to refill it as much as it is needed, and as much as its able. You can flatten the battery if the alternator can't keep up with the drain on the battery, but the alternator should just supply up to its maximum rating, and no more.
There's these places called auto electricians….
or maybe insert the following into the ever price prohibitive window thing (google etc)
auto electrician test alternator amperage
auto lecky cant do much except check if its holding the volts stable at its current load or measure current load of alt
If my volts get low im going to loose my efi system or thermos will die and ill cook engine. Thats the worst case but at best case car will not start at next start up its a 7.4L V8 and not the easyest thing to turn over
You're preferred sparky or all auto sparkies?
( I just watched a vid that showed an on car test with a clamp on meter,from idle to 2500RPM, loaded up)
Maybe they can bench test yours, if it's a non runner car?
If the amps on this project are crucial buy a fit for purpose non bling alternator.
auto lecky cant do much except check if its holding the volts stable at its current load or measure current load of alt
Unless you have documentation of the unit itself, or the components within it, that's the only test anyone can do to determine its capacity. Load it up with a dummy load and see when it fails. Not every shop will necessarily have the tools, but the average auto electrician or a dedicated alternator shop should have a suitable variable load.
If my volts get low im going to loose my efi system or thermos will die and ill cook engine
There is a guideline in designing reliable IT systems that says "Monitor what you care about".
I'm not saying you shouldn't check that the alternator is up to the task, but if the real problem you are worried about is voltage drop causing reliability issues or overheating, then maybe the best fix is to set something up to monitor the voltage and temperature. That way you catch it if your alternator is overloaded, but also if your regulator fails, your battery fails, your water pump belt breaks, the fan motor burns out, etc.
No, measuring resistance won't tell you the rating. Even if you did find the exact model you wouldn't know whether it has been rewound with a higher or lower rating (I'm not sure why anyone would rewind it with a lower spec but it's technically possible). The only reliable measure is a load test.
That said, surely the regulator must have a part number, and you wouldn't expect them to over-spec the regulator if they don't have too, so find what the current rating on the regulator is and your alternator is probably within 50A of that.
Internal reg on the 1 wire so thats a no go
Pulling it apart is cheaper than buying a dummy load.
You could try somewhere like Battery World, they do free electrical load tests but I'm not sure whether they would be set up to do a full "lets see what this thing can do" style test, or whether it's just a single fixed load with pass/fail results.
Have you got a photo of it? Also show us your car! Sounds awesome
Sounds like something for a true car forum
*Alternator