gemellocattivo.com

I had no idea what it was, thanks for the info!

A 10a device should be fine, it should draw a lot less current when PWM holding. I probably wouldn't worry about it, or reduce the spring load a bit.

Most devices are rated at worst-case temperature, e.g. I know the designer of a motor controller and he would start with 120a rated FETs and rate his final product for 100a peak/40a continuous. In ECUs, a 2a driver can probably become a 3a driver, and a 5a driver can probably become an 8a driver without too many issues, as long as the entire ECU isn't loaded this way.

You could also jumper-wire between the two H bridge inputs on the board so they are in sync, then just drive one of them in software (the other micro pins need to be high-impedance/output driver turned off or disconnected)

With external drivers, you have to worry about what happens with the ECU off (all driver outputs go high probably, since they are low-side), how fast the SSRs can switch (so you don't have overlap between the high and low side of a half bridge which would short-circuit), and make sure the software won't switch them on at the wrong time. To be safe, you could build a half-bridge on each side (equivalent to a relay with C connected to motor, NC to ground and NO to batt). Then, you can switch one as a discrete change direction and PWM the other. Setting both off turns the motor off entirely. This is called 'sign magnitude' rectification, and doesn't require you to synchronize 4 outputs from the ECU.

more info:
Sign Magnitude: http://modularcircuits.tantosonline.com/blog/articles/h-bridge-secrets/sign-magnitude-drive/
Locked Anti-Phase (the other option): http://www.modularcircuits.com/blog/articles/h-bridge-secrets/lock-anti-phase-drive/

_________________
"Sometimes, the elegant implementation is a function. Not a method. Not a class. Not a framework. Just a function." ~ John Carmack

"Any sufficiently advanced technology is indistinguishable from magic" ~Arthur C. Clarke

Yes, I was thinking just lock ground relay and PWM the power side

I'm thinking maybe something like this is easier and cheaper:
https://www.pololu.com/product/758

25A for $50, so 1/2 the price the relays and no worry about watching the logic order, it just needs a box.

This looks like a newer version
https://www.pololu.com/product/2991

17A replacing the 15A of the one I was thinking of, but this has current sensing and limiting as well as reverse voltage protection so less power than the 25A one, but more features and feedback and 25A will fry the actuator anyway I think.

Another VW engine failure today, this time the jetta. Loud banging and grinding sounds follwed by an oil light

It turned out the banging/grinding was the harmonic damper fell apart but the engines wedged in so tight it couldn't fall off so it banged and grounsd on the frame. The engine leaks/burns oil so the level was low and when I pulled onto the shoulder what oil there was moved to the side...light light which had nothing to do with the banging/grinding failure. I thought it threw a rod or something but I think the tow truck cost about double what the repair will but I think I'm about done driving this thing.


In real news I ordered all the fuel fittings and lines today and finished up the fuel rail. Now I need to make the injector wiring harness and the intakes/TBs are ready to install.

You can't just give up on the Jetta. Get a new engine rebuild thread going man!!

A rebuild the VW engine/trans thread would interfere with the finish the V12 thread and we can't have that

Ever thought of a Bentley engine in the Jetta?

I thought about mid mounting a W12.....and then I remembered I don't even like the car and I have a V12 to finish

i spent a little time...ok, a couple hours playing around getting the TBs to return properly with less spring. They now snap back with just 1 spring per bank but I installed 2, one on each end just for good measure for a total of 4 springs down from 12 which should be 1/3 the current to open them.

Then on to some wires. I mostly made up the fuel harnesses but didn't have the proper heat shrink for the connector end. I'll get that ordered Monday, but the TBs can now be installed for keeps as is I think.