Relays that could be used for a hybrid power circuit

[UConnStudent]

Dear NI,

I'm currently working on a hybrid electric vehicle that uses a fuel cell and batteries to provide the power.  I was thinking about using LabView to have the ability to control which power source I wanted to use, and in order to achieve this, I need some relays.  The problem that I am running into is, I need a relay that could handle 36VDC @ 40A (1500W), or something in this ball park.  I was looking through the relays on the site, and saw that the max current that they could handle was 5A.  Are there any products that I've missed that could handle this load?  If not, is it possible to have NI custom build a relay to meet these specs?

Thanks,

Andrew

Department of Mechanical Engineering

University of Connecticut

[AnalogKid2DigitalMan]

By relay- do you intend to have simple ON/OFF control of the motor? (As opposed to PWM switching).

You could use an NI device with a digital output or actual contact style relay output provide a signal or power to a 2nd relay that can handle your voltage and current requirements.

-AK2DM

[UConnStudent]

Just a simple on/off switch was what I had in mind.  Something that allowed the user to switch between power sources, or even charge the batteries via the fuel cell (obviously I will need additional hardware to meet this requirement).

And what you're saying, is to use a relay that is controlled by the user via LabView (low current/voltage), that then will open/close another relay that will be part of the power circuit (high current/voltage).  Am I understanding this correctly?

-Andrew

[AnalogKid2DigitalMan]

Correct.

An alternative approach is if your hardware has a digital TTL output, you could use that to drive a transistor or relay driver chip to control your high power relay. A digital output could also drive a solid-state relay (SSR).

-AK2DM

[UConnStudent]

Excellent, thanks for the suggestion. I've started to do some research on what SSRs I would need in order to complete this.  The coding looks very straight forward, it's just a matter of finding the right relays to do the job...