Output Current Limits

TimH
JT Innovations
Posts: 661
Joined: Wed Sep 01, 2010 2:51 pm

Re: Output Current Limits

Post by TimH »

(my response was meant to be on another thread lol...but same basics apply!).
T04GTR
Posts: 51
Joined: Mon Jan 14, 2013 7:37 am

Re: Output Current Limits

Post 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..
TimH
JT Innovations
Posts: 661
Joined: Wed Sep 01, 2010 2:51 pm

Re: Output Current Limits

Post 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.
stevieturbo
Posts: 961
Joined: Sun Dec 07, 2008 2:04 pm

Re: Output Current Limits

Post 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.
Mark_r33
Posts: 26
Joined: Sat Jan 18, 2014 7:14 pm

Re: Output Current Limits

Post by Mark_r33 »

Only rated to 20A, but has anybody used these much?

http://www.ebay.co.uk/itm/HELLA-12V-4-T ... SwzaJYBjXi
stevieturbo
Posts: 961
Joined: Sun Dec 07, 2008 2:04 pm

Re: Output Current Limits

Post by stevieturbo »

Google it, I've definitely seen reports online of people using them.
Slowie
Posts: 113
Joined: Thu Jan 17, 2013 7:30 am

Re: Output Current Limits

Post 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.
stevieturbo
Posts: 961
Joined: Sun Dec 07, 2008 2:04 pm

Re: Output Current Limits

Post 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 )
Slowie
Posts: 113
Joined: Thu Jan 17, 2013 7:30 am

Re: Output Current Limits

Post 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).
stevieturbo
Posts: 961
Joined: Sun Dec 07, 2008 2:04 pm

Re: Output Current Limits

Post 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 ?
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