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Re: Output Current Limits
Posted: Tue Jun 27, 2017 7:03 pm
by TimH
(my response was meant to be on another thread lol...but same basics apply!).
Re: Output Current Limits
Posted: Wed Jun 28, 2017 2:21 pm
by T04GTR
at 100hz it sounded like a jack hammer.. and im aware you get alot of loss the higher freq you go. wasn't heatsunk. was just dangling in the air. (as i was testing it)
what is the difference internally between a cheepo one and a good one?
i thought it was isolated, but but it still killed the driver in the ecu..
Re: Output Current Limits
Posted: Wed Jun 28, 2017 5:28 pm
by TimH
I've no idea about the cheap ones, but a decent SSR is opto-isolated so there is no way it should blow up an ECU output.
They are noisy, and do need heatsinking if you're drawing any decent current from them - check the derating curves in the datasheets see
here for example.
Re: Output Current Limits
Posted: Wed Jun 28, 2017 7:20 pm
by stevieturbo
Hmmm..maybe I wont risk the cheap one then, in case I bust something lol
Havent a clue what the differences are, but there must be some. I could cut one of the cheap ones up, but not really sure much would be seen anyway ?
TBH I thought the Crydom one I opened up after I broke it looked cheap crap inside.
Re: Output Current Limits
Posted: Thu Jun 29, 2017 4:21 pm
by Mark_r33
Re: Output Current Limits
Posted: Thu Jun 29, 2017 4:27 pm
by stevieturbo
Google it, I've definitely seen reports online of people using them.
Re: Output Current Limits
Posted: Thu Jun 29, 2017 8:39 pm
by Slowie
I use one of those to control my water injection pump (with Schottky flyback diode across the motor). Nothing to report, works fine. Silent, doesn't get hot even when I had the pump running at 90% duty cycle for 20 minutes, recycling into the reservoir, to test the reliability. I run it from 10-90%.
My actual one looks slightly different, like this:
http://www.lingenfelter.com/PDFdownload ... 773001.pdf
Only downside is you have to use a conventional relay holder, the terminals don't screw on, so you're at the mercy of your relay holder.
Re: Output Current Limits
Posted: Thu Jun 29, 2017 9:08 pm
by stevieturbo
Interesting the wiring on the LPE/Hella is not standard ?
I thought the Hella one is sold as a direct replacement for any normal relay ( with same pin config )
Re: Output Current Limits
Posted: Thu Jun 29, 2017 9:29 pm
by Slowie
Yes, you have to be careful of that. I guess the pinout has to be different because of the different operating principles (no coil).
Re: Output Current Limits
Posted: Thu Jun 29, 2017 10:39 pm
by stevieturbo
Principals are the same....same as a SSR ?
Except that Hella one seems to want a permanent ground, AND a ground trigger, which is a little odd.
Most would want a live, and then a ground trigger, same as any relay ?