Ezip Troubleshoot- Battery or Motor?

[cleansteve]

Ok, so I recently got my son's Ezip Trailz working again, after blindly going through a few controllers, turned out to be a bad brake switch. Disconnected that, and it worked fine....for about 2 days! On a fully charged battery (26+ volts), when you give it throttle, you get the green battery light, moves maybe 10 feet, then when you try to give more throttle all you get's a little "burp" of movement, like the motor wants to turn but is shut off, and you hear the click from the controller, then no action from the motor, if you then hit throttle again you just get the same..and the throttle lights up on yellow or red at this point. Motor will turn if you lift rear wheel and carefully give it 1/2 throttle, but go to full and it dies. I checked the battery voltage at full charge (26-27 volts at battery), when I turn the power on this drops to 24v or so. I dissconnected motor wires at controller, and at no throttle I have 23 volts, at 1/2 throttle I have 23.7 volts, and at full it drops 2 volts to about 21 or so. What I've done so far is to check all wires, battery terminals, etc, for tightness and continuity, all good, opened up motor to check brushes and wiring, all good, I've been through this routine before. I'm not sure what the parameters are for the voltage needed and/or if I'm within them. Throttle is brand new. Batteries are about 8 months old, I replaced original Currie cells with no name ebay batteries. Bike's used 3-4 days week for maybe 8 miles/day.
Bike itself is about 4 years old (2008 model), and rest of components are original......I guess it's down to the motor or battery, and I'm betting on the battery, but if it's the battery I'll be a little upset as it's not that old and the original (Currie) battery lasted 3 years! I hate to just start blindly replacing components as they're expensive!
Help and Thanks!!!
-James

 

[Ykick]

Sounds like a bad battery situation to me, the best way to qualify battery is to attach volt meter under load and/or get a power meter or CA. Really running blind without...

 

[d8veh]

SLA batteries can last a long time as long as you don't let them go flat. If you left them for about a month or more in a discharged state, then they will be scrap. Is that what happened to yours because your symptoms show knackered batteries.

 

[wineboyrider]

I vote batteries as fault. Time to upgrade to lifepo4 or lipo.
8) 8)

 

[TylerDurden]

If you have a couple of 12V car batteries, you can hook em in series (24V) and test the bike with the wheel off the ground. Use the brake to provide a load on the motor.

If the bike seems fine, you have a battery problem.

If the bike still fails, you can test the motor by directly connecting the wires to the batteries and bypass the controller. Again, use the brake as a load. That should show you what's failing.

 

[cleansteve]

Thanks for the responses, I found a SLA battery pack on craigslist fairly cheap, so I went ahead and replaced the battery....got a block away, everything's working fine, then the throttle lights (battery) go out totally!! Noticed one brake was dragging pretty bad, fixed that and got it home, opened it up and controller was warm, but not hot, and I did smell that acrid smell a little...opened up the controller, and sure enough, blown mosfet. Here's my questions, did the new battery pack cause this (it appeared to be new and totally unblemished, putting out 26.5volts) and how would that be possible, I used the motor up a moderate hill for a block with the dragging brake, should this be enough to fry a controller (the controller was brand new), and should I risk putting a new controller in it (I do have a spare), and if I do I'd like to add a fuse to the main power line in to the controller, what'd be ideal for a 24v 35a controller to protect it, can it be anything I'm missing, i.e. the motor(I've already checked the rest of the wiring for shorts, etc.).

 

[dogman dan]

Holy crap. I would have expected too much load, like the brake and the hill to fry a motor not the controller.

So maybe just the random failure of components we've all had with china stuff. Not really the battery volts or the power you used IMO. I bought a brushed controller for a think bike, and it lasted all of a month. It was really cheap, and lasted like it.