2013 Zero XU Rebuild: DIY Edition

Hello ESers,

I come seeking advice for what I hope to be my new project.

Summary

I have a '13 Zero XU whose batteries both died suddenly and unexpectedly. One of my frustrations in troubleshooting this issue is that the proprietary Zero systems (MBB, CCU, dash display, BMS) make it incredibly difficult to debug. While perhaps not intended this way, they are a de facto DRM that requires a great deal of reverse engineering in order to troubleshoot and work around. For example, I built a makeshift 112V battery pack, but I cannot use it with the bike because I don't have the ability to send the "all cells are good" BMS signal to the MBB to allow it to turn on.

If I am going to invest the time and money to get this bike working, I would like to be able to work on it without any dependency on Zero. This means either isolating or ripping out completely any proprietary systems within it. By "isolating", I mean that using a proprietary system for a single purpose is fine but it should be replaceable without affecting all the other systems. For instance, I'm fine using Zero's proprietary BMS to monitor the battery, but I am not fine with it being a requirement to digitally unlock the bike.

Getting My Bearings

Before I commit to the largest financial investment of this project (a new battery), I have a few questions:

1. Has anybody done this before?
2. If not, does anybody know Zero bikes well enough to tell me what this would require? I assume reprogramming the sevcon at minimum. Not sure what else.
3. Has anybody published a schematic of their DIY electric motorcycle, that I could work backwards from?
4. What compromises, if any, should I expect from the resulting bike? Obviously I won't have the dashboard (though that would be a very fun future Raspberry Pi project). Anything else?
5. Any other general advice is appreciated. I'm a software guy. Know enough about EE and ME to ask the right questions. Very little experience relative to what others here have so hugely appreciate any guidance you all can provide.

Thanks,
Robby

robby said:

I assume reprogramming the sevcon at minimum.

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It's possible the sevcon will work without change, if you can find the wire(s) that enable or disable it and send those to a regular keyswitch or whatever (or send it the right canbus data to enable it, if it's not a simple on/off). There are some threads about sevcons, and programming, that might have this info.

Not sure what else.

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If it's all linked together via canbus (or other serial network), you might have to replace the dashboard/etc. There's a lot of electronic or electromechanical speedos, "fuel" gauges, etc., that are made for this purpose; some of them are in other motorcycle, scooter, or other larger-than-bicycle EV conversion threads around ES. Might take some poking around to find them, but most are probably in the Motorcycle section adn the other Large EV sections.

3. Has anybody published a schematic of their DIY electric motorcycle, that I could work backwards from?

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I dont' recall any complete schematics here on ES, unfortunately. There is a custom trike build going on right now that you could post to, in the MC section, to see if he's got one drawn up, if it's not in the thread.

4. What compromises, if any, should I expect from the resulting bike? Obviously I won't have the dashboard (though that would be a very fun future Raspberry Pi project). Anything else?

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As long as you don't have to change the sevcon, performance would be the same, I'd expect. However, if the console or brain box talks to the sevcon to limit performance for the various modes, then it may be "stuck" in whatever mode it was last in. (unless you find out what commands need to be sent to change that, and make something to do that).

Presumably you'd end up using a new BMS, unless you can "talk" to the original to reset it / etc as needed. So whatever that BMS does or is capable of might limit things.

Anything else that has to be replaced or worked around might affect performance.

5. Any other general advice is appreciated. I'm a software guy. Know enough about EE and ME to ask the right questions. Very little experience relative to what others here have so hugely appreciate any guidance you all can provide.

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Since the bike is already electric, and working (other than power), it shouldn't be that big a deal to re-convert it, depending on the path you choose. If you work with someone else that has a working zero of the same type, you could sniff teh BMS data lines and then just emulate that signal whenever the bike is powered up or whenever it is that it would normally be sent.

Similarly, you could do teh same thing with the various other signals to/from various parts if you can't go the above route, depending on what you have to replace.

The less you have to replace, the more like the original it will operate, feature-wise. But also, the more you're dependent on those original parts to do their jobs, and if they fail then you're stuck with replacing them with originals, or doing the workaround again with those.

Were the thermal sensors and balance wires correctly connected to the BMS?

Skimmed

I used to work at Zero Motorcycles and was bound by their NDA's around this subject.

I went out and ground my face against the ground
Starting from scratch
To understand (from a non-insider perspective) what they did and why

I came to Zero Motorcycles an "Expert" in CAN enabled EV's
(Reference two proofs - validation testers for the Tesla Model S BMS)


Here is how I figured out how it works

1) The Sevcon is programmed in a way that requires CAN interaction*

2) The Sevcon programming CAN BE PULLED OFF SUPER EASY and its file format is *.DCF

3) You go and read the ENTIRE (end to frocking end buddy) Gen4 programming manual

4) From those readings you will understand some basic CAN Open concepts

5) In layman terms... the Sevcon Broadcasts some things (no changes needed here)

6) In laymans terms... the Sevcon is *dependent* on some things (changes needed here)

7) Should your Zero attempt to fire up *without* the messages it expects... NO WORKY


You can:

1) Wire up the Zero BMS to your new cells and stay locked within the Zero Paradim

2) Modify your DCF to not require CAN messages - AND VERY CAREFULLY - work around those
2.1) Ensure your have proper interlocks
2.2) Ensure you have proper and safe control

Basically...

Read the Sevcon Manual
Look at what is sold on Thunderstruck EV
Strip out all that black box shit

Replace the black box with a CA and a good quality current sensor adapter (converts hall to 0-5V or whateva)

About like that.

I would NOT try to stay within the Zero Confines for the following reason:

1) They do not support legacy equipment. They simply wont sell it to you or it is too expensive
2) The early stuff ... quite simply... was not all that great anyway!
3) The Ingress Protection scheme on that setup is about as lame as it gets
4) The throttle safety scheme is - not radical
5) The Paralleling of balance taps leaves undetectable single point failures
6) You would have to master the BMS and MBB - which can only be done with "insider information" - no thanks

I have steered completely off the Zero Path
Even tho I love the product and love a few guys who worked or still work there

Because

It is not a LiGo compliant design*

Its a lock-in design

Thats not how we win as a community
Glad to explain it ad nausium

-methods

Great post, methods!

Trying to understand. When you say makeshift 112v you mean a battery in a configuration different from oem so the bms can't see the cells that are supposed to be there?

It is looking for 28 cells individually via 28 pairs of wires into the bms?

It sounds like you are giving the right answer to the test question but are failing to show your work and therefore not receiving credit.

it wants 28x4=112 and you just wrote 112?

Hello,

I am looking to buy a BMS and/or a dead battery so that I can use it to rebuild my bike. Would you be willing to part with one of the two batteries/BMS you have?

pitzmans said:

Hello,

I am looking to buy a BMS and/or a dead battery so that I can use it to rebuild my bike. Would you be willing to part with one of the two batteries/BMS you have?

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you can check here http://litechpower.com/BMS, they are the distributor of BesTech BMS, they dont have minimum order qty. limit.

I can get new farasis 28Ah cells for 40USD per each. Just replace old and you will get 2017 battery.