Controller Grounding

After wiring up the controller, we found that the chassis was being grounded somewhere. We weren't sure if this was normal or not or good or not so I researched it.

Kelly User Manuals:

Version 2.3 of the Kelly user manual specifically mentions not connecting B- to GND on pages 10 and 11 (sideways footnote), but in this instance, I believe they are referring to the GND pin on the front and rear panels which is simply a ground connection for input and output sensors. So this doesn't answer my question. However, version 3.1 of the Kelly user manual specifically mentions it being preferable to wire B- to the chassis on page 9.

The Forums:

I signed up for ElMoto.net recently and today I was in the chat room when a couple guys joined: RC and Guff. We got to talking about my bike and I asked about this issue. Each said their bike has neither the low-voltage system (12 volts) nor the high-voltage system (72 volts in my case) grounded to the chassis. When I asked about how to accomplish that with respect to the high-voltage components, at least two solutions were mentioned. I guessed that plastic screws / washers were required, because that's what Lennon did. However, RC mentioned using polycarbonate board, which serves as an insulator. Without using special hardware, a component can be mounted to a sheet of polycarbonate or something like "garolite" and the sheet then mounted to the chassis. This isolates the two, so even if the component isn't internally isolated from its outer casing that won't leak on the bike chassis. For the low-voltage components, I've read posts about running new ground wires to the lights and horn instead of using the chassis.

After chatting with them a while, I searched more and found these threads agreeing with their input

• ElMoto.net, Thread 1039 - Grounding the chassis
• ElMoto.net, Thread 1527 - Main fuses, internal Kelly grounding
  

Additional threads:

• ElMoto.net, Thread 2167 - Main high-voltage components / grounding
  
• DIY Electric Car, Thread 14817 - Kelly KDH14500 wiring / grounding
  
• V is for Voltage, Thread 4066 - Kelly refund & exchange policies / testimonials
  

That last thread mentions something interesting: The author of post #5 in states that High-voltage Kelly controllers are not insulated from the chassis ground while low-voltage controllers are insulated from the chassis ground. That might have been the case in July of 2008, but I'm not sure it is still reliable information, and I don't know which controllers he's considering high or low-voltage.

The issue:
Safety is the main deciding factor here. If the bike chassis is grounded to the pack, then (depending on exactly what you touch) you could complete a circuit with your body or with a tool and damage yourself and your bike. I don't feel great about ignoring what the controller manual says, but I'd rather the bike be safe to work on than dangerous because of what could be a poor translation in the manual.

For the record:

Strangely, while researching, I stumbled upon a thread about using a Kelly controller in some Z20 model scooter, and then a completely separate thread referencing the first, concerning (rather questioning) Kelly, their product and their service.

1. V is for Voltage, Thread 3714 - Moving to a Kelly controller for Z20b
2. DIY Electric Car, Thread 16961 - Kelly controller quality

I guess the guy whom started that thread on DIY was in a hurry or failed to notice the picture was not of a Kelly manufactured model, but of some controller being provided for electric scooters by some dealer. Anyway, for the record, I've had no problem with Kelly, nor with my Kelly controller (it's been in use for one week). While chatting on ElMoto.net, one member mentioned his Kelly controller has been working just fine for 6 months. My only complaint is about the lack of clarity within Kelly's manual and wiin replies to questions via email. I've emailed sales@kellycontroller.com a couple times regarding both sales and technical wiring support and have always received quick responses. If you can be patient and don't mind reading and thinking a bit, I imagine Kelly will do right by you. If you do email them, use direct and very clear language to ask individual questions. That's what has worked for me. I haven't read about any instances of faulty Kelly controllers, though you do have to seriously study the user manual provided. Even in cases where a controller gets cooked because of user error, it seems they often replace the controller or offer to repair it, usually only for the cost of shipping.

On another side note, ElMoto.net has been a great resource so far. The users seem down to earth and willing to help newbies like myself. There's a lot to figure out, and it seems every bike is slightly different. Starting a thread for my project has helped quite a bit already.

-Colby