View Full Version : Contactor gets pretty hot??

24 October 2010, 2050
Sooo, I connected my batteries to controller etc today, and motor for a no load test.
It came to 77kmh, which I'm pretty happy with.
Only sorta problem is, if it is one, is that my contactor got really or pretty warm afterwards, I left it off for a while and it was still pretty hot, so I just disconnected the batteries,
Also the BMS has stopped working, what a bitch. One of the boards has given up I think, might have to send the boards over to them, to get fixed, which would be another 2-3 weeks and more money... UGH

25 October 2010, 0808
are you sure you're using the right voltage for the contactor coil? If its too much voltage its going to get really warm.

Also, if you're pulling too many amps for what the contacts are rated, then you will have connection loss and it could heat things up too.

a part number and more details would help.

25 October 2010, 1220
I'm not sure on part number, but it is a 200A 48v rated coil. So I'm not too sure why its getting warm, was pulling less than that in amps. And it was at 53v. Maybe too much, but it should be able to cope with that.
I bought it off the kellycontrollers website.

25 October 2010, 1403
have them verify that its the right part number. It sounds like you're using a 12V coil at 48V.....

is it the coil that is hot or the contacts?

25 October 2010, 1744
Frodus is definitely on the right track. One other quick test is to turn on the bike and just leave it be for a few minutes (no motor spinning, just on with the contactor closed). Then check the contactor for heat. Compare this result with your load test.

If there is a coil issue, the contactor will always be warm whenever it is on, no matter what test. If there is a corrosion/contact issue, the contactor will only be warm during your load tests.

Happy Hunting!

25 October 2010, 2224
Ok, The contactor gets warm anyhow, so it's coil is not rated for 48v. Gets warm with motor on or off.

ALTHOUGH, the contactor has a label on it saying 200A 48V DC.

Looks like I'll need to get a new one.

25 October 2010, 2329
Hey Jake, the contactor in one of the pictures on your blog looks like the Albright sw200, although if it doesn't have an Albright sticker on it then it could well be one of the oooh so many Chinese copies. Anyway, the point is that depending on whether the device is either 'Intermittent' or 'Continuous' rated, then the coil power consumption (as per the datasheet) can be as much as 60W and 20W respectively, and probably would feel warm / hot!

Stick your ammeter in and see what you're drawing.


26 October 2010, 0033
I'll get onto it as soon as I can, tomorrow sometime.

Whatever happens I think I'm going to need a new one. It just gets hotter and hotter, LOOL

Thanks for the feedback Y'all