Yes, tested 4 elements, none even close to their sellers quoted rating, all those quoted at 120W (ideal rating for us on circa 12v) are really 70-90w (6-8 amps roughly) and a couple of 200W, more like 110W~9amps.
I have a controller with 0-100% potentiometer with LED capable of driving 300W so comfortable range for 130W (my ideal mid point for getting close to 10amps). I Will look to try and balance up one of the units close to 10amps, to give a range of 0.1amp to 10amps load.
Clearly testing a car with engine on and a running alternator generating 14+v verse an Engine off with mid charged battery of 12.5v will have a small offset (about +/- 5% from target) but that's not an issue, this is meant only as a in the field bit of kit not a laboratory machine!
But hopeful that once all the bits are assembled and tested it gets close to the projections! Need to test the controller and find a box to put it in, along with a box for the element to hold some fluid to keep it all safe!
The Teslite pro
Yes a friend has one, though not seen it in the flesh. Sadly it works on a roughly 0.5amp test, which will not tax an alternator! indeed it will not really help test fuel pumps wiring (or other 5-15amp circuits), as often it is only after some running and heat that faults occur (lifting tracks/Bi-metallic type heating/cooling faults).
For what they are (and the price) they make a great tool, along with a PowerProbe3 (or a Hook when it finally comes along to market - did see one in the flesh, cool tool!) though even the hook does not have a Testlite style load feature (shame). A testlite is easy to make too, just a resistor (even a bulb or re-use an old light up style test probe - probably what I'll do when I have a few minutes to spare!).
The goal is to make a bigger load, say up to 60amps, for alternators testing under load (shows lots of failures normal testing misses) ...
but for other circuits really 90% are only 0-10amps, 8% 10-15amps and 1% 15-20 and less than 1% 20-30amps. I'd just like to have the full range of testing available!
The reason for the artificial load is when the device are impossible to run safely (F1 pump, fuel pumps etc) during testing, or where the device is dead and the wiring needs to be tested before a NEW unit is connected.
Just remember before trying this at home, the ability to blow ECU's and burn wiring harnesses/Fuseboards by improper use is very high! If you DON'T understand a circuit FULLY, don't load it with AMPS!
Will take some pictures of the prototypes and finished unit as it is built.
I guess this whole idea/project is pretty niche, but having had over a dozen occasions needing something, it was time to do it. It's been a learning process too which has helped in many other ways, so it's been fun and beneficial too