48V frame ground on conversion... Ghost Ground!

[khoff99]

Ok guys, I need some help! I have a 48V frame ground that I can't track down. Here's what i've done so far. I realize this isn't complicated but it's like it's a ghost! I have lots of accessories hooked up so I started there. I have a 48V to 12V convertor hooked up that goes into a fuse panel then out to my, radio, winch, lights, 12V 30amp plugin. So I unhooked all the accessories and no frame ground. So then I hook them back up one by one and see which one has the short. So, as I hook them back up I find what I think is the one, leave it unhooked and walk away. When I come back, the ground is back? WTF? So, I repeat. It goes away, same ole story. But when I leave them all off, no matter how long it doesn't come back. I'm open to options here...... What else can cause a frame ground? I realize that battery acid on the frame can cause a few Volts, but not 48? Any Ideas?

[gornoman]

It's not uncommon for pack voltage to show on the frame on a sparky. I have yet to see the definitive reason for it, too many variables as you have experienced yourself. Unless there is an actual DRAW, don't worry about it. To determine if you have a draw wire a single tail light bulb from the main pack positive to the frame. If the light shines you have an issue. If it stays dark, you have stray voltage potential only.

[scottyb]

Your short may be somewhere in the converter mount or the accessory fuse panelmaount ???

[khoff99]

Scotty, That's just it. During my search, i've unbolted the convertor and fuse panel and let them float off the frame. It's nuts! So, based on the response above about the draw. What will that ground do to the controller? The cart has stoped moving when going up hill. I have ALL new components, including new batteries. There is NOTHING, including charger that is more than 6 months old. I have over 3k in upgrades and now it won't move.

[gornoman]

So, now the cart is dead in the water? Please describe the cart so we know what we are dealing with.

[khoff99]

The cart is a 92 ez-go modified with an EMP motor that started it's life as the biggest D&D motor I could get for my rear end configuration. It has a Controller Test Services (Curtis 1204 700Amp Controller) Which by the way, NO ONE SHOULD EVER BUY FROM CONTROLLER TEST SERVICES. Horrible experience and now I think a junk controller. New Selonoid, new heavy duty F/R switch, New 0-5k pot switch, lifted, 22's winch, radio, lights, 12V outlet, 48V convertor, 2/0 welding cable on ALL CONNECTIONS. New Trojan 6V batteries, 48V, New 48V charger.... NOTHING IS ORIGINAL!! The cart starts out full power then when coming up the hill, the battery meter drops from full charge to 0 and flashing.

[bioniccartsandcustoms]

Hook a digital volt meter to the main pos. and main neg. on your battery pack. Drive the cart and see what happens when you try a hill and it stops. Also, you can check for a short to ground on the motor. Go from each one of the motor lugs to the rearend housing. You will need to have the motor wires unhooked for this. If you get continuity theres your short. You can do the same with the controller. Unhook the main cables going to the controller and check from the controller lugs to the frame. Keep us posted.

[GarageBuilt]

Originally Posted by khoff99

Ok guys, I need some help! I have a 48V frame ground that I can't track down. Here's what i've done so far. I realize this isn't complicated but it's like it's a ghost! I have lots of accessories hooked up so I started there. I have a 48V to 12V convertor hooked up that goes into a fuse panel then out to my, radio, winch, lights, 12V 30amp plugin. So I unhooked all the accessories and no frame ground. So then I hook them back up one by one and see which one has the short. So, as I hook them back up I find what I think is the one, leave it unhooked and walk away. When I come back, the ground is back? WTF? So, I repeat. It goes away, same ole story. But when I leave them all off, no matter how long it doesn't come back. I'm open to options here...... What else can cause a frame ground? I realize that battery acid on the frame can cause a few Volts, but not 48? Any Ideas?

I have seen this a few times on some older EZ-GO frames. And yes 0ver 48 -volts from the frame. I have been told this is from Corbin deposits from the motor.

[dougjones31]

90% of the time......when looking for this type of short to the frame.....it turns out to be the motor windings shorted to the case and onto the frame from there. Undo your leads to the motor and if it disappears.... A can of brake cleaner and an air gun will fix it....maybe.

You said "So, as I hook them back up I find what I think is the one, leave it unhooked and walk away. When I come back, the ground is back? WTF? So, I repeat. It goes away, same ole story. But when I leave them all off, no matter how long it doesn't come back."............

by what you said there...I have to believe the short is in your 48-12v converter. Which might account for your problem pinpointing the short. the capacitors are discharging when mess with it and it takes a while for them to charge and allow the path to frame. If you have nothing hooked to the converter the path is not there so never comes back.

Oh...I bet the voltage to frame also is current.....and has shot out a cell or two and causing you to loose power under a load.

PS...I see now how old this thread is....geeeze!