No Frame Ground! Electric Golf Carts and such systems

[Industrial Toys]

I can't win for loosing!

Yesterday, my special lighted two pole switch arrived from China. So, I switch the ground as well via a ten or so amp fuse. The frame is now only grounded when the converter is switched on.

Low and behold, I have a lot of interference (birdies) emminating from the computers in the motor drive system! It also affects a portable nearby, which I mistook (this last weekend) as a band opening or temperature inversion. It just sounds like a carrier and I never suspected the vehicle I was riding in!

 

[k0ua]

I can't win for loosing!

Yesterday, my special lighted two pole switch arrived from China. So, I switch the ground as well via a ten or so amp fuse. The frame is now only grounded when the converter is switched on.

Low and behold, I have a lot of interference (birdies) emminating from the computers in the motor drive system! It also affects a portable nearby, which I mistook (this last weekend) as a band opening or temperature inversion. It just sounds like a carrier and I never suspected the vehicle I was riding in!

Yeah, welcome to the wonderful world of switching power supplies and CPU's. I used to have a pontiac that had a birdie on one of the local 2 meter repeater frequencies.. That sucked. Wife wrecked the car with under 10,000 miles(with a careless 16 year old male driver in a pickup trucks help). So that problem went away.

 

[Industrial Toys]

Sometimes accidents have a sliver lining.

I found some Golf Cart threads complaining of RFI on carts with people trying to install stereos. Many suggest rerouting power wires, various antennas and grounding. None of this helps if I am even getting RFI on a portable. And a good (Motorola) one at that. Decent front end. Many of the posters are not even aware of the floating ground issue.

I am surprized that I have not come accross issues with security people having issues.

Maybe I should ask the Dayton Hamvention people if they have run into this. They simply MUST have.

 

[k0ua]

Sometimes accidents have a sliver lining.

I found some Golf Cart threads complaining of RFI on carts with people trying to install stereos. Many suggest rerouting power wires, various antennas and grounding. None of this helps if I am even getting RFI on a portable. And a good (Motorola) one at that. Decent front end. Many of the posters are not even aware of the floating ground issue.

I am surprized that I have not come accross issues with security people having issues.

Maybe I should ask the Dayton Hamvention people if they have run into this. They simply MUST have.

Are you a member of the ARRL?. Maybe they can help with RFI issues. There is a book on this, and one of the sections deals with Hybrid Electric Vehicles. Not exactly what you have, but you might get some tips from it. Wouldnt hurt to give them a call at the Newington HQ and see if anyone will talk with you.

ARRL :: Technical :: The ARRL RFI Book 3rd Edition

 

[Maximum42705]

The reason their is no frame ground for it to rely on is in case the frame ground ever became compromised for whatever reason that you don't become the frame ground and have said current go through you to ground. Its not the voltage that will kill you its the current\amps that will. I have worked in the wireless telecom industry for over 20 years and an average cell site is running at a small 27vdc however that 27 volts has about 400 amps behind it. I've seen people work in the power bay and actually create an accidental short between positive and negative with a ratchet and think they dropped their ratchet and can't find where it went when they dropped it. They can't find it because it doesn't exist anymore. With 400 amps the ratchet literally disappears.