Wiring Diagrams

19 02 2011

I’ve spent a lot of time pondering the wiring of the bike.  Originally, i was thinking about how the main traction pack wiring was going to work (how each of the sets of cells would hook up to each other), and came up with this:

First wiring diagram

However, once i started down this path, i started trying to figure out where more and more of the parts would go.  Mainly, i wanted to do this because although I’ve tinkered with some electrical appliances and whatnot, i’ve never worked with this much electricity in terms of voltage nor amperage.  So, i’ve got a healthy amount of fear (hopefully enough) about working with this stuff.  As i keep telling myself as i’m working around the batteries “this crap can kill you…so be careful”.


In any case, I drew some diagrams on paper, but it wasn’t working out very well.  So, around september, i started laying out all of the pieces of the project as best as i could in a drawing program.  The first “real” diagram is shown here:

v1.1: The first version of the "real" wiring diagram.

Every time i figured out a bit more, i’d update the diagram… Here’s version 1.2, which has separate DC/DC converters:

v1.2: separate DC/DC converters

I sent these diagrams off to Dimitri from MiniBMS, Mark from EnerTrac, and Kelly Controllers.  Each of them had some input that caused some things to change, so i kept updating the diagrams.

V1.3 was after Dimitri told me that running the MiniBMS control board off of 24V would kill it, and also that I didn’t need to run it off the 24V circuit since everything is isolated.


V1.4 is from another set of comments from Dimitri where he pointed out that the tyco contactor doesn’t need a diode and that the 12V/24V relay was wired wrong.


V1.7: I learned about the “main contactor driver” on the controller, so decided to try to have all of the switches that drive the contactor run off of that.  Also added some information about using Anderson Powerpoles to control the charger/BMS interaction.


v1.11: figured out that I can use the handlebar run switch to turn the entire 24V system on and off.  Also learned that the “main contactor driver” (Pin J1-3) on the controller is not a powered pin…it’s actually a GND pin that’s closed when the controller is running properly, but open when there is a controller fault.


v1.13: figured out new way to wire the charger.  In this version, instead of trying to break open and split the hot wire on the charger’s power cable, i’ve got the charger plugged into a normal looking inlet that’s mounted on the bike.  Next to that inlet is a male plug also mounted to the bike that is connected to the house power via an extension cord.  The relay is wired between those two plugs.  The benefit of this design is that i didn’t have to crack open the AC power cord on the charger.  The down side is that it seems odd to be running so much stuff into the bike when trying to charge.

i also had an issue with having all of the emergency disconnects attached to the contactor, because even when the contactor is disengaged, there is still that 1KOhm resistor that spans the contactor poles…that allows some current to flow to the controller.  If you disengage the contactor and wait a few seconds and then twist the throttle, the wheel will spin a bit (less than 1/4 of a turn).  This can be disconcerting and also dangerous.  i moved the inertia switch to the 12V/24V relay so when tripped, it will shut off everything so turning the throttle will not make the wheel spin.


While i was actually wiring up the charger plug box (the male and female power next to one another), i noticed that  i could make it even simpler by moving the BMS AC high current relay off of the bike.  Then the only wires that need to go into and out of the bike are the relay control wires and the actual charge wires.  This became v1.14.


Now, the only problem is that the charger isn’t working properly.  Whenever i plug it in, it always says (via the diagnostic LED, that the battery is not connected).

After doing a bit of research on this tonight, i found someone on the DIYElectricCar forums who is having the same problem.  There have been some suggestions, and i’m going to try some of them.  Looks like my charger may actually be the same as an ElCon (i bought it as a no-name charger), so i may have to do some wiring.  If this works, it will mean i don’t have to use the relay at all.

I’m sure there will be more wiring adventures, and i’ll post more pics about how it actually is wired.  Stay tuned!

Thanks for reading. 🙂




8 responses

6 06 2012
Jonathan francis

I cannot see the diagram at all can you please email them to me asap.I am trying to build an electric motorcycle from just a sashy with the manual engine intact can you assist me by providing some step by step info and diagrams thank you

6 06 2012
Jonathan francis
6 10 2012

Hello. Which app. did you use for wiring diagrams? Thanks.

7 10 2012

Murat, I used OmniGraffle for Mac. It’s not an electronics diagramming program, but does have the ability to specify anchors on objects, which was useful.

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