keyed battery disconnect hi amp draw switch fails

[Mantac]

$80 dollars at Pegasus maybe 4yrs old seams to fail at 35 amp draw. Low amps seams to not be problem. Opened switch looking for arching .Did not find any, barely found any sign of contact at all ! check with meter Hi resistance at 35 amp pull . Red removable key with alt connects Has any one had similar problems with these switches? Or is there a better one out there?

[E1pix]

Hi, Bob. :-)

[Rick Kirchner]

They all pretty much suck. Best luck I've had was with that $119 Lucas switch. Had a Hella fail at the track, dug the Lucas out of a box of parts for my '72 FSV. Used it for probably eight years.

I've extended their service life by putting a washer under the key to get more contact pressure.

[Mantac]

They all pretty much suck. Best luck I've had was with that $119 Lucas switch. Had a Hella fail at the track, dug the Lucas out of a box of parts for my '72 FSV. Used it for probably eight years.

I've extended their service life by putting a washer under the key to get more contact pressure.

I look at that as a option . Not a great choice for a switch that costs that much .Hoping for a better switch even at twice the price.

[mark elder]

Medina spares in the UK.
Bomb proof switch, I would use nothing else

[Steve Davis]

In my experience, I have found a 'measurable' difference in the keys for that type. You can buy the keys separately and I generally have a couple in the trailer. You can test my theory, by simply PUSHING on the key during your test. If that fixes the 35 amp problem, (it probably will), you know the answer. Rich's solution of gluing a washer to the bottom of the key is a decent fix. The switch should have a good 'snap' when you close it and it should also take 'some' pressure to open the switch.

Steve, FV80

[Dave Welsh]

Check out post # 6 in this thread.

https://www.apexspeed.com/forums/sho...ht=kill+switch

[APEowner]

Yeah, Kill switches are unreliable. I carry a new, tested spare in the trailer. You can lengthen their life by not using them to shut off the car (except when required by a tech inspector to demonstrate that it's functional) and by making sure all the other switches are off when you turn the master on.

[DaveW]

Yeah, Kill switches are unreliable. I carry a new, tested spare in the trailer. You can lengthen their life by not using them to shut off the car (except when required by a tech inspector to demonstrate that it's functional) and by making sure all the other switches are off when you turn the master on.

In my experience, I have found a 'measurable' difference in the keys for that type. You can buy the keys separately and I generally have a couple in the trailer. You can test my theory, by simply PUSHING on the key during your test. If that fixes the 35 amp problem, (it probably will), you know the answer. Rich's solution of gluing a washer to the bottom of the key is a decent fix. The switch should have a good 'snap' when you close it and it should also take 'some' pressure to open the switch.

Steve, FV80

I use mine to shut off the car every time. That has not caused issues for me. What has caused issues is vibration making the contacts microscopically vibrate apart and arc. That kills them in a very short time. Steve Davis' recommendation to make sure the contacts are firmly pressed together will prevent that.

Since I've had varied results with the keyed switches, the last time I had one fail, I un-crimped and rebuilt it to assure it would be a good spare. It's not hard to do - just making sure the contacts are clean and the contact pressure is enough to prevent arcing.

[APEowner]

I use mine to shut off the car every time. That has not caused issues for me. What has caused issues is vibration making the contacts microscopically vibrate apart and arc. That kills them in a very short time. Steve Davis' recommendation to make sure the contacts are firmly pressed together will prevent that.

Since I've had varied results with the keyed switches, the last time I had one fail, I un-crimped and rebuilt it to assure it would be a good spare. It's not hard to do - just making sure the contacts are clean and the contact pressure is enough to prevent arcing.

I'm glad you've got a system that's working for you. Making sure the contacts are firmly pressed together is important but the reason for the recommendation to not use the switch to shut off the car is that opening a switch with current flowing through it causes arcing. The higher the current the bigger the arc. If your car runs a total loss system then it's less of an issue because the current draw is pretty low but switch life will be dramatically shortened on cars that charge through the switch if you use it to shut off the car.

[DaveW]

I'm glad you've got a system that's working for you. Making sure the contacts are firmly pressed together is important but the reason for the recommendation to not use the switch to shut off the car is that opening a switch with current flowing through it causes arcing. The higher the current the bigger the arc. If your car runs a total loss system then it's less of an issue because the current draw is pretty low but switch life will be dramatically shortened on cars that charge through the switch if you use it to shut off the car.

What you say is undoubtedly true for systems with an alternator that provides significant charging current at idle. I use a Kubota dynamo that produces almost nothing at idle RPM. In any case, you are right that repeatedly shutting off with the cutoff switch "could" shorten its life. I just have not had an issue doing that.

Any time I've had an issue with one of these switches, it showed up initially as a high RPM misfire or total ignition failure that progressed to lower and lower RPM's as time went on.