Looking for a continuous duty solenoid/relay/contactor

[ISPKI]

Heya guys,

I am searching for a continuous duty solenoid/relay/contactor to handle turning off power to my batteries.

I had an electrical issue a while back in my truck and ever since then, something will continually draw power in my cab. I cannot seem to figure out where the draw is coming from but it behaves as though my ignition key is turned partially on at all times and I cannot seem to find the source of the problem.

I have wired in a high amperage relay right next to my batteries that I use to cut power to the system when I shut the truck off. I have burned out 3 relays so far, each time moving up to a larger, higher rated relay. The last one that I cooked was rated for 300amps continuous at 24v dc, so 150A. It lasted almost 1 year but just died on me.

 

[BeastMaster]

What fails...the contacts or the coil?

DC Continuous duty coils are more expensive to make than intermittent duty coils.

Thermal considerations.

 

[ISPKI]

What fails...the contacts or the coil?

DC Continuous duty coils are more expensive to make than intermittent duty coils.

Thermal considerations.

I cant actually tell what fails, they look fine internally, the contacts seem to warp just enough to no longer contact one side.

 

[BeastMaster]

Hmmph...did not leave you much evidence. I was expecting failed coil.

A coil designed for intermittent duty run continuously should have heated up, eventually charred, the winding insulation fail, massive internal winding short, then excessive coil current, glowing windings, until oxidation and melt opens the winding permanently. It would have left evidence.

Are you channeling glow plugs and starter motor current through the contacts?

 

[ISPKI]

GPs yes, but not the starter. It was supposedly rated for 150A continuous which, to my knowledge should handle the Glowplugs fairly easily. I did put about 4k miles on it before it died.

I am looking at one of these:

Contactor Solenoid

It is a contactor rather than a relay. I spent about an hour trying to troubleshoot my issue but couldnt find the source of my problem, may have to tear apart the entire cab as I believe there may be a short in the harness behind the pedal frame.

 

[saburai]

You might want to Google "battery isolator". If not to purchase, just to get some diy ideas...

 

[ISPKI]

You might want to Google "battery isolator". If not to purchase, just to get some diy ideas...

I had actually looked at battery isolators but I did not think those functioned in a way that would work for this.

I ended up installing a 500A contactor that I picked up from ebay. We will see how long that lasts.