Print

Please login or register.
1 Hour 1 Day 1 Week 1 Month Forever
Login with username, password and session length

[Spoonman]

Howdy all,

I'm an electronic engineer in Trinity College, Dublin, Ireland for the last 10 years and I've been interested in EV's for the last 4-5.

There's a Revai in the family since 2009 and I purchased a Nissan Leaf in May of last year and have clocked up ~32000 miles since then. Love the car to bits and couldn't go back to ICE for the commute. We've a pretty good charging infrastructure here (relatively speaking) but nevertheless, I've also built my own EVSE which will autoselect between L1 and L2 charging based on cable detection, and instruct the car to charge as appropriate. I've been using that in work about 3 days a week for quite a while now and I'm pleased to say that it works incredibly well.

In any case, I'm also a major motorcycle head and have in the stable an '87 NC24 which is currently broken down for restoration, and a '98 TL1000S which is more mods and custom parts that it is original at this stage (and I'm not done yet).

My reason for joining this forum is that I'm considering a TLS/TLR ( or some other big twin sportsbike - basically whichever chassis can handle the reduction in torsional stiffness better) EV conversion and so when I happened upon this place I figured it might be a good spot to make some aquaintance and pick some brains for the common speedbumps in drivetrain specification and performance.

The outline of the system is an AC15/20 motor, Curtis 1238-7601 controller (..is there a higher revving 'r' version of that too?), and either an LFP or an NCA pack to the tune of 10kWh (likely stacking to ~114Vnom in series and then parallels of that)- I'll be building this over the course of the next 2-3 years I reckon so I'll be spreading the costs as much as I can that way (I don't smoke and drink sod all so I have the funds to redirect  ). Cells will of course be purchased last although I do intend to get my hands on a few early on for performance testing and fitment purposes.

So far I have 4 of the A123 systems 20Ah pouches (their performance is quite impressive), and a handful of the Panasonic 18650 NCA cells, with a few of the LG versions on the way and some of the cheaper Ultrafire ones ordered as well just for comparison.

Initially the plan was to direct drive the rear at an appropriate reduction, but having crunched the numbers, that's just not gonna work in any way effectively for real world riding - so now the plan is to mate the motor to an appropriate gearbox and I think I've a good notion of how I'm gonna go about doing that. Just gotta check all the measurements work.

I'm pretty much gonna head on over to the tech help section now to post up my most immediate quandry - so I'll hopefully be chatting to a few of you on there. 

[NoiseBoy]

I think plenty of people, like Zero, have shown direct drive is a good option.  a TLS frame is seriously heavy, I would be looking at something like an RS125/250 frame or at least something a bit more modern.  a 1000cc chassis seems like overkill to me.

If you want to build something serious you should be looking at higher voltages.  All depends on the budget.  endless sphere is the place to be for serious technical advice.

[frodus]

TL1000S may seem heavy with engine, but It looks like a nice shape for a conversion. It's about as heavy as that NC24 (I used to own an RC24 which was even heavier). Anything under 450lbs is just fine IMHO.... since most of that comes out with the engine. I like the TL1000S because it has a nice and boxy with good support from the headstock down to swingarm. It doesn't really use the engine as a stressed member, which is great! RS125/250 are tiny frames and you will have a hard time putting an AC20 into that with any useable amount of lithium batteries. Shouldn't be a problem with a TL1000S.

Go direct drive, no reason to do a gearbox. Just do a 5:1 or so reduction and you'll be just fine. Ought to be able to get up to ~100mph.

The AC20 goes to about 7500RPM, so I don't think you'll have trouble there. It's a good motor. I used one in my conversion which I sold (To fund an Empulse R). LiFePo4 would be my choice for a first build, but there's some NMC out there if you look. 10KWH of anything is going to be difficult to fit, but it's possible. Purchase a couple cells first, test them and you'll be able to use them for fitment. But yeah, buy the batteries last. A123 is no longer producing cells at the moment, but that may change.... only time will tell.

I sell HPEVS stuff, so let me know if you do want to move forward, I can beat anyone's prices, although shipping out to you is going to be spendy.

[Spoonman]

Howdy Frodus - yeah, I've spotted you about the place alright and I'd say we'll definitely be getting to know each other a lot better over the next few years. 

Your analysis of the TLS frame is pretty much in line with my own - I reckon the ladder construction will work better against torsional forces than the spar frame of the TLR, but the TLR has the advantage of not having suspension components within the engine bay. I'll likely still have to throw in some bracing but hopefully not too much.

As to using an RS frame, you must be joking - not only would that make for a painful riding position but it would never have the room for the batteries, controller, motor (which would have to be VERY offset to begin with), but even beyond that you're talking about a chassis that was never built to handle that sort of weight or torque. It'd tie itself in knots!

The motor, controller, pack combination, by my maths rings in at around 90-95kg (call it 100kg [~220lbs]) for 11kWh in NCA - and that's before the charger.

The TL motor tips the scales at about 80kg (~160lbs), couple in the exhaust system, tank (wet), and other related ancilliaries and you're actually looking at being pretty close to the same numbers out as in, and no major shift in the CoG.

I had been considering the NC24 as the foundation for the work but you simply couldn't fit the batteries.

Regarding the performance - I dunno, the numbers on the 5:1 ratio are exactly what I was running and whilst it'll move alright, I'd like to be able to shift the peak around depending on my needs. Having it sit fixed at 60mph or so isn't really a runner - but I might be persuaded yet.

[NoiseBoy]

The RS250 isnt that small but I didn't realise the AC20 was so big, I was thinking more in Agni terms.  I measured one up and you would be surprised how much will fit when using the subframe for the controller.  Have you considered building your own frame?

I don't really get why would want the weight and hassle of a clutch and gearbox on an electric bike, it defeats the point imo.  What about some way of switching between a high and low range quite easily so that if you are pootling around town you could run a higher ratio and then change to a high range if you are cruising.

[Spoonman]

I've started a thread here on the reasoning - clicky

There are a few significant merits.