Glow Plug Relay Amperage

[rtimgray]

In another thread, I had posted about a glow plug relay failing on my Mahindra 4110. A new part from a dealer was about $90. I tried a $6 relay from Autozone and wired it in, and it seems to work fine.

My concern is that the $6 relay is rated for 12v/40 amps. Does anybody have any idea what type of amperage the glow plugs draw when they are activated? 40 amp was the biggest relay that Autozone had on the shelf, so that was why I picked it. I'm sure I can get a higher amp unit, but thought I would see if anybody had any idea how high I should aim for, or if 40 amps is sufficient.

Thanks for the help.

Good luck and take care.

 

[rtimgray]

Should have searched first - sorry. Looks like this was answered in a thread a couple of years ago, with the answer being somewhere around 10 to 20 amps per plug, depending on what specific tractor/plug. I think I'll upgrade to a higher amp relay.

 

[k0ua]

Should have searched first - sorry. Looks like this was answered in a thread a couple of years ago, with the answer being somewhere around 10 to 20 amps per plug, depending on what specific tractor/plug. I think I'll upgrade to a higher amp relay.

Yeah, about 20 amps per glow plug instantaneous surge current. it drops back in a few seconds as the plugs heat up. Of course the current rating of a relay is reflective of it contact size, surface area and composition of it s contacts. It could be that your relay contacts are underrated, or it could be that your relay is even now pitting and burning its little contacts. On my Kioti the relay is rated 70 amps. Two other relays right beside it are rated 40 amps. They are used for the fuel shutoff solenoid and the start relay.

 

[rtimgray]

I just looked and I can pick up a Kioti 70 amp relay (probably same as yours) that will fit on there, so I will probably use that.

Thanks.

 

[Dave M7040]

If you want to do it on the cheap, wire a second 40 amp relay in parallel with the first one.
In that way they will each handle 1/2 the load.
Dave m7040

 

[rtimgray]

But how with the electricity know which lead to follow when it comes time to split?



I found the 70 amp relay for $15 (a nearby Cub Cadet dealer had it in his new-old stock), so I'm going to swap it out for that one and only use it between now and then if I have to.

Good luck and take care.

 

[JRobyn]

What fuse size is the supply to the plugs? 40A or less?

 

[Dave M7040]

But how with the electricity know which lead to follow when it comes time to split?



The electrical resistance in both relays and the circuits they serve will be the same which will balance the power flow equally between the relays.
Consider the headlights in your car. Both are fed by the same wire from the headlight switch yet they both burn with the same intensity. This happens because each headlight bulb has the same resistance and this balances the power flow to each.
Dave M7040