Cougar in a Motorcycle
 

Hey folks. I've been gearing up to start a 72v motorcycle conversion. I have been intending to buy an altrax 7234 or 7245, but JohnStan's posts in the AEVA forums have got me thinking about the OpenRevolt. Partly because it is apparently cheaper than an altrax, but also because I like building electronics!

I have a few questions though.

How big is a typical openrevolt controller? Space (and weight) will be limited on my bike. The 7245 is 8.44 x 2.80 x 5.75 inches (the 7234 is smaller of course).

How does the controller handle 72v? I imagine it shouldn't have any trouble. Would it be possible to use lower-spec components for 72v? I'm not sure what the current requirements will be, yet.

And lastly: Being open source, I guess the controller is extremely customisable, but how do you connect to it, and what's the software like to use? I run ubuntu on my laptop, so i'm not too bad with command line and that sort of thing.


Sorry if these questions are obvious. I'm still searching through the hundreds of threads here to find the answers, but I thought I should ask too. Thanks!

Now I'm certainly not one of the experts, but I know the answers to this!... Just wait a while and the experts will come along though...;)

The Cougar is modular, ie a control board and a powerboard... So yes you can spec the powerboard to handle lower voltage, altough I'd probably keep that as a margin for upgrades and just lower the spec a little (say 96V?)... Just enough to save space...

The size of the Cougar is really up to you... The tighter you manage to buch things together the smaller it gets... Using the prefabricated powerboard it will be larger than the Altrax, but if you are swapping those components you could potentially slim it down a lot...

You connect to it using a com-port and software, I'm not sure if that software is windows only, but if so wine should solve that... The largest problem would probably be to find a computer with a laptop today, or a USB com-port adapter that works (they have a tendancy not to follow standards)...

The software is actually able to be modified in both windows and linux. I use Ubuntu and also windows.

The com port adapter works well on everyone's computer that I have talked to. Fran took care in dealing with the timing issues that come up from using an adapter.

Thanks for your help! I don't have a huge amount of experience building circuits from scratch, so i'm not sure i should attempt something that could potentially have me thrown from a moving vehicle at speed if i screw it up! I can solder well, though, and it is very tempting, cost permitting. I'll have to do more research!

The simplest possible power stage can be made from just one 2-pack igbt and a capacitor! Doing that for my own bike project.

Hmmm... You know, with the power requirements of a bike, that might be dang near perfect...

should work fine. i'm using two old 3rd gen fuji 800amp igbts in my car right now. handle 500amp accelerations no probs. A more modern 5th or 6th gen 600amp two pack would work even better.

Would you be able to show me a schematic of how you're doing your power board? I'm looking at the schematic from the wiki, and there are 10 mosfets in the power section, with individual triggers, by the look of it. Is this done so the circuit can handle the sort of power needed, with the mosfets triggered together?

Yeh the fets are paralleled to handle the current. Same with the flyback diodes. Have a look at these videos i made of initial tests:

http://www.youtube.com/watch?v=Y_VMPA-oO3w

http://www.youtube.com/watch?v=5uwVp6l05UE

http://www.youtube.com/watch?v=aL1sItO2HQs

Connection is very simple. You just use 2 resistors and a fast diode. I'm getting into a bike conversion myself (cbr600 with twin motors) so i'll probably be designing a compact version hopefully 500amp capable.

I'll be very interested to see how you do that haha!

I do like electronics, and i'm good with a kit, but going from that to design seems to be a big step - in my mind, at least.