McElectric Yamaha FZR

Hello all,
I've been working on a bike for a couple of years. I've used ex-laptop batteries (840 in total) with a Headway buddy pack to absorb some of the biggest current draws.

I've documented it all on the UK based BVS http://www.batteryvehiclesociety.org.uk/forums/viewtopic.php?f=34&t=3550&start=120

I'm getting to 66kmh, and I think with a longer road and more air int he tyres 70kmh is on the cards. A gearing change could get me my goal of 80kmh

Here's the latest short video, enjoy https://www.youtube.com/watch?v=LdhxEzJ7owk

Happy to answer any questions, the cell testing and battery construction is covered in a separate video here https://www.youtube.com/watch?v=KLNaoNWTz8o

Thanks
Chris

I've acquired an ignition lock and barrel with key so have now got some security and the ability to switch all electronics off.

I have avoided putting pack voltage through the ignition switch by introducing a 12V supply. At first i was putting a hefty 12V lead acid battery in circuit, but then realised that I only need a battery which is strong enough to activate a 12V relay(with 40A rated contacts switching the 80V supply on) and hold it on until a 12V supply powers up when the relay makes contact. Then the output from the 12V supply holds the relay on and also recharges the 12V battery.

For the 12V battery I now have 3 ex-laptop cells in series, whcih are recharged through a diode and 33Ohm resistor from a non-isolated supply. I had to use a non-isolated supply because it is required for hte voltmeter/ammeter.

I have also collected a couple of 80V to 12V power converters by Powersolve, rated at 12V, 6.5A output. The circuit board which I removed the isolated supplies from also had a good quality line filter in circuit, designed for 100V input voltage so I've also cut that from the board and added it in circuit. Now all low voltage supplies receive filtered 80Vdc.

I've made up the brackets for the onboard charger too. I need to add isolation shields (plastic sheets) above the main terminals and below the charger (just in case) and add various other terminal shields.

The only mechanical thing needed now is the cladding for the main battery pack. Once that's in place I can consider running the bike down for an MOT test which I know it will fail, but which will give me an indication of what few things are needed (I know I need some fork oil seals and lighting but the rest is almost up to spec)


Photos at the bottom of the page, here http://www.batteryvehiclesociety.org.uk/forums/viewtopic.php?f=34&t=3550&start=120

Not bad. Big job putting those battery modules together. Nice work characterizing each cell. Hopefully the use of mixed-SOH cells won't result in a regular need to replace cells. Serviceability is good (big weakness in A123's current prismatic module design), but it's not something you want to have to utilize very often. I have to say that used metal-oxide cells would make me nervous, personally. Soldering to them would make me more nervous. Do you have any kind of fusing in the big pack? How are you monitoring cell voltages/health?

For monitoring I'll be installing my own design of pack monitor, which I already have a Yahoogroup for https://groups.yahoo.com/neo/groups/CellMonitor/photos/photostream

I'll be able to trip low voltage and high voltage alarms and use them for the respective purposes of cutting down the current, or ending the charge cycle. Adding logging is going to be easy so I will be able to identify any modules with a wayward trend over time.

There is no individual fusing per cell. Each submodule of 21 cells has 'robust' inter-cell tinned strip, but an accident in handling where one pack's terminals rested against my belt buckle caused a bit of a fright (!) and in that case the steel strip burst between a couple of modules. The load is then transferred to other modules and in a short time they would all blow. Each battery has it's own 200A Bussman fuse too. All low current feeds from the batteries have inline blade fuses and the 12V key circuit is fused too.

Would I use individual fusing per cell ? I think it is not unwise to do so. Then again every single pack of 6,8 or 10 cells which I dismantled all had failed cells and yet there was no sign of any fire risk, only in a couple of instances did a cell's plastic sheath seem to have melted, or deteriorated due to corrosion as a result of an electrolyte leak.

It is my understanding that Tesla use fusing at cell level, but then again i believe they use the very latest technology very high level discharge rate cells and so there may be a case there where fusing is much more important.

I plan to install temperature monitoring too and integrate that with the main safety circuit, which will consist of a charge protection relay (physically installed now but not wired in), a throttle inhibit and a warning panel or LCD information display.

The maximum pack voltage is theoretically 84V, but I don't intend to charge above 82V (4.1V /cell) and the onboard charger only brings the pack up to 80V (4.0V /cell ) charging to a 'cautious' level like this I believe can increase the life expectancy of the cells and reduce cell stress in return for a very slight reduction in range.

The next job is to clad the main battery pack and add some weatherproofing, and also add splash shields around the motor. (not forgetting the battery monitoring electronics required). The front forks need new seals but that's trivial.

From the test runs which I've already made, running the bike backwards and forwards at full throttle on the test road I use, the sag of the battery voltage is quite acceptable and if I use a maximum of only 80% throttle the sag is very small and the current stays below 150Amps. At cruising speed the current drops away nicely. I'll need to gather more accurate information, but the volt/ammeter died a couple of weeks ago and the replacement hasn't arrived. The last time I tested the bike I started with a voltage of 82V and took it for about ten full power runs over a few hundred metres each time, and ten minutes after returning home the voltage was still above 80V, representing a drop from 4.1V to 4.0V per cell.

Sounds like you're in very good shape. Individual cell fusing is just a final layer of safety which is a must in OEM automotive. A123's modules have cell level fusing as well. This cannot protect against internal cell failures (no fuse can), but is more for service workers who may drop a wrench across a couple busbars while working--that kind of thing.

I still have yet to monitor current on my bike. I have some shunts and a logging DMM...just need to install the rig on the bike.Not the highest priority at the moment, but it's on the short list.

Have fun!

I'm all done with measuring current, and ready to remove the shunt.

Voltage monitoring though, IMHO , is crucial at cell level. I had a combined volts/amps digital meter from China, which failed so they sent a replacement. That failed too. I checked it out and think the onboard voltage regulator is running out of spec and the meter isn't deisgned to run at such high voltages originally.

Anyway, it tells me nothing about what is happening at cell level, under load, and knowing the current is pretty meaningless to me, I know that setting off gently uses less current, so when the voltage is low or when I need to travel a long distance I'll be as careful as I can be to maximise range.....but you need to use *some* current.

I know that under maximum load the motor draws a peak of 250A and it puts me well within the safety margin for my battery packs.


I've finished writing the code for the cell monitors now and am about to build up an array of them to read cell level voltages, to be displayed on a master LCD display built into the tank.

The bad news is that it looks like winter is coming in fast so I doubt I'll be riding this within a few months now....my garage can get incredibly cold and the ice on the road takes all the fun out of it. My new realistic target for putting the bike in for inspection is the spring of 2015. This gives me enough time to build in battery warmers and to do a full strip down and get everything which requires it sent to the powder coaters for treatment

Wow...it's taken me a year to get my battery monitoring system done ! I've just had a scan through some of the more recent posts and there's some amazing work being done by other guys

Anyhow I've built a battery monitoring master unit, which provides low voltage cutout, high voltage cutout (non-resetting for unaccompanied charging ) and is safe enough to let me refit the battery pack and work on a few last features, such as pack voltage display - that's always nice to have . I can then start cladding the pack and rewiring with a colour coded scheme.

I'll get some more pics up soon