Need Help with Solid State Relay wiring

[cdjnight]

Here's cut sheet on the different relay, I have know idea what they mean in the wiring diagram near the bottom.

[cdjnight]

Originally Posted by motorhead

So you are going to use the relay for PWM to rapidly cycle the pump to try to maintain a certain pressure at a certain boost? Why not use a Boost-A-Pump instead? Just curious. I would call Hella. The spec for that relay doesn't give a rating for an inductive load which is what a fuel pump is.

the set duty cycle will start at a certain "set" boost pressure then ramp up as boost increases till it reaches 100%. Basically I'm making it into a wide band slash water/meth controller slash boost gauge, all in one.

[motorhead]

Originally Posted by cdjnight

Here's cut sheet on the different relay, I have know idea what they mean in the wiring diagram near the bottom.

According to those specs you should use the 40 instead of that one if you are saying your pump drawls 20 amps. Also since you are using it as PWM instead of on/off, the max off times and on times along with the min on voltage would be important for a curate control. You could try it and see. Do you have a very over sized pump for your application that you want to control it in this fashion? Bare with me I know wiring. I'm just not that up on modern boosted motor design. I'm just thinking logically. Why not run the pump at a 100% unless it makes way more than needed at max power? Once again just curious.

[cdjnight]

Originally Posted by motorhead

According to those specs you should use the 40 instead of that one if you are saying your pump drawls 20 amps. Also since you are using it as PWM instead of on/off, the max off times and on times along with the min on voltage would be important for a curate control. You could try it and see. Do you have a very over sized pump for your application that you want to control it in this fashion? Bare with me I know wiring. I'm just not that up on modern boosted motor design. I'm just thinking logically. Why not run the pump at a 100% unless it makes way more than needed at max power? Once again just curious.

ramping it in makes it easier to tune and doesn't flood the motor all at once with a large shot of water/meth.

Min on voltage is good because the gauge fires 12v output on/off/on/off etc...

I'm using an unconventional pump that isn't from a kit or been used for this before that I know of. It is a variable voltage dc pump. which I tested by just manually tapping lead against 12V battery and I was able to cycle it down to 30% manually.

I will have to test the pump at full load (100%) with appropriate restrictions in place to see what it actually draws.

[motorhead]

Originally Posted by cdjnight

ramping it in makes it easier to tune and doesn't flood the motor all at once with a large shot of water/meth.

Min on voltage is good because the gauge fires 12v output on/off/on/off etc...

I'm using an unconventional pump that isn't from a kit or been used for this before that I know of. It is a variable voltage dc pump. which I tested by just manually tapping lead against 12V battery and I was able to cycle it down to 30% manually.

I will have to test the pump at full load (100%) with appropriate restrictions in place to see what it actually draws.

Well, that sceond relay should work then. I would probably go with the higher current one though. You will also need a diode since you are running an inductive load.

[cdjnight]

Originally Posted by motorhead

Well, that sceond relay should work then. I would probably go with the higher current one though. You will also need a diode since you are running an inductive load.

what kind of diode do I use? Never used one so I am clueless on that part

just to make sure I understand the drawing correctly
battery - goes to motor negative
battery + goes to terminal 2
terminal 1 goes to motor +
diode across motor leads