90's Model Suzuki GSX1100 Shaft Drive

[E-GSX]

I found this forum after reading about electric street bikes such as the Enerjica and Zero. I have a complete GSX1100G along with a parts bike to use for parts fitting, and after viewing a YT video where the owner converted a Honda Sabre to electric, I thought this would be an interesting project. He makes some pretty bold claims such as 145 MPH top speed and a range of 155 (mountain terrain), 175 (highway), & 190 (city) using 36 120AH batteries. So far I've been mostly lurking, but am learning more every day. Any positive commentary is welcome, as I'm brand new to this concept.

My plan is to keep the shaft drive as was done on the Sabre. I don't think I need a motor as powerful as the Netgain Hyper 9 he used, so I'm looking at what all is available. I want to avoid placing batteries where saddle bags would go, I just don't like the look. My goal at this point is to achieve similar performance (74 KW or 100 HP @ 7500, and 99NM or 73 lb-ft @4750) and a highway range of around 100 miles. My daily commute is 70 miles round trip over mostly open roads on a mildly rolling terrain at an average speed of 60-65 MPH. While I could possibly recharge at work, I don't think it will be practical since I have to park far away from buildings.

Here's some initial research:
I found a picture of the shaft drive unit taken apart. It is a splined shaft that goes to the 2.66:1 differential on the 17" rear wheel.
View attachment Shaft drive with driveshaft.webp
I'm not overly concerned at this point as to how to couple the motor to this shaft. It would need some type of cardan or u-joint to allow for rear wheel movement.

Batteries:
Since my complete bike has a fairing, I measured about 16" between the openings. The engine itself is about 18" wide at the top. It's hard to measure with an engine in place, but it looks like the frame opening is about 17" high. Front to rear, it's deeper at the rear, but from the bottom to where the frame curves is about 14". I realize this could be squared off to make room for batteries as some have done, but I'd like to avoid cutting the frame. I found a site that allows Calculation of energy stored, current and voltage for a set of batteries in series and parallel. It's educational to play with and see the various results. My plan is to make an enclosure to keep rain out while making it fairly easy to remove and replace the packs.

One thing I have read about are battery scams on China sites such as Aliexpress. While I have bought stuff from there mostly w/o issue, many battery prices are just too good to be true. Even if I got money back, this would eat up a lot of time & cause needless aggravation.

Motor:
According to a formula I read about, I'd need a 75KW motor to equal 100 HP (HP*745/1000). The one on the Sabre project is 88KW and is certainly overkill. It seems like most motors for this type of project involve sprockets and chains, which I want to avoid. The other alternative I've seen is a hub drive, but even though those come in 17" sizes, I have not seen one past 12KW, so I suspect that would be underpowered.

I'd like some advice here as to what volts this should operate at given my goals, or any sources for motors.

Range:
The range formula I found goes like this:
Miles desired / average MPH= # of hours
# Hours * KW used at speed= KWH needed.

I'm not sure this is a valid method, as the faster you go the less KWH you are using, which seems contrary to what I've read about electric motorcycles.

I put in 150 miles @ 60 MPH, which equals 2.5 hours. I have no idea how many KWs are used @ 60 MPH to move about 800 pounds of rider & bike, but put in 10 (or 14 HP) to get a number. This showed I needed a battery capable of 25 KWH. I know the Enerjicas have a battery around this size, but they don't have that kind of highway range.

Using the calculator above, I put in some 3.2V 300 AH batteries I found on Amazon, and with 26 of them this would give me 24.96 KWH @ 77V.

Putting the known Sabre data (36 3.2V 100AH batteries) into the calculator, this gives 115V and 13.8 KWH. Using his claimed 175 miles on the highway (figuring 60 MPH) and the range formula, he's using < 5KW (or about 7 HP) to cruise @ 60 MPH.

Controller:
Still learning. Will decide on this after motor selection. I'd like to add cruise control "while I'm at it".

Recharging:
Still learning.

DC/DC Converter:
Still learning. My BMW has heated grips, so "while I'm at it", I would like to add this as well for colder weather. I know this will affect range.

 

[amberwolf]

I found this forum after reading about electric street bikes such as the Enerjica and Zero. I have a complete GSX1100G along with a parts bike to use for parts fitting, and after viewing a YT video where the owner converted a Honda Sabre to electric, I thought this would be an interesting project. He makes some pretty bold claims such as 145 MPH top speed and a range of 155 (mountain terrain), 175 (highway), & 190 (city) using 36 120AH batteries.

I don't know whether that's possible or not; but you can verify it if he has test data (wattmeter/etc results for various conditions).

It depends on his specific riding conditions as well as his bike's aerodynamics, and his riding style and position.

One thing I have read about are battery scams on China sites such as Aliexpress. While I have bought stuff from there mostly w/o issue, many battery prices are just too good to be true. Even if I got money back, this would eat up a lot of time & cause needless aggravation.

Most likely your best bet for batteries is recycled large-EV batteries from various second-life sellers similar to BatteryHookup and EV breakers that salvage the packs, etc. They're almost certainly better quality than the stuff you can buy "new" as cells from various places, primarily because the EV makers will likely have gone to some lengths to match all the cells for characteristics, so they all charge and discharge and perform the same, and you already know they worked in the EV up to the point it was scrapped for whatever reason. (which, if it was a battery problem, probably wouldn't end up at these places, but instead would more likely get shipped to China for recycling and instead get diverted to being broken up and resold as "new" cells by the various unscrupulous places there).

Motor:
According to a formula I read about, I'd need a 75KW motor to equal 100 HP (HP*745/1000). The one on the Sabre project is 88KW and is certainly overkill. It seems like most motors for this type of project involve sprockets and chains, which I want to avoid. The other alternative I've seen is a hub drive, but even though those come in 17" sizes, I have not seen one past 12KW, so I suspect that would be underpowered.

Well, ICE HP vs motor watts isn't necessarily a direct correlation with any specific formula, since they have different power curves. If you want to know how much power it will take, put your conditions/etc into something like the ebikes.ca motor simulator using the custom options for things and see what it guesstimates power/etc to be under those conditions. You can also use the manual calculators, but the sim is "faster" to change conditions with and see what's actually going on, once you experiment with it enough to see what it's doing.

If you want a hubmotor, and you have highly varied conditions, you'll have to get one that's big enough for the worst-case conditions that will last long enough to heat it up. If your worst case conditions are very short-term, like startups from a stop, a smaller motor may handle that ok, but if they're long term like a hill, or highspeed highway conditions, a bigger motor would be needed to prevent it from overheating. (or some form of active cooling, or both).

QSMotors is probably your best bet for hubmotors, and a number of MC builds here on ES also use QS mid motors.

I'd like some advice here as to what volts this should operate at given my goals, or any sources for motors.

The system volts depends on the max speed you want vs the size of the wheel vs any gearing between motor and wheel vs kV (RPM per volt) of the motor used. Use a voltage that even when the battery is empty is still well above what's required to get you to that speed, because you still want to accelerate quickly enough regardless of conditions; if the voltage isn't high enough you won't get the current needed to do that. (see the ebikes.ca motor sim; even if you're only using the bicycle stuff there you can still see how it works).

Range:
The range formula I found goes like this:
Miles desired / average MPH= # of hours
# Hours * KW used at speed= KWH needed.

I'm not sure this is a valid method, as the faster you go the less KWH you are using, which seems contrary to what I've read about electric motorcycles.

It's a reasonable enough formula--you must use the actual power at the actual speed to do the calculation, for all speeds at all distances, which makes for a lot of math.

It's easier to use a wattmeter that also measures speed and distance to get an average Wh/mile instead, for an actual ride on the actual conditions, but that's tough to do if you're still working the bike's plan out and haven't got one to test with.

There are also simulators like the trip sim at ebikes.ca . It's designed around bicycle stuff but you can use the custom options to create a motorcycle-level sim for guesstimates.

put in 150 miles @ 60 MPH, which equals 2.5 hours. I have no idea how many KWs are used @ 60 MPH to move about 800 pounds of rider & bike, but put in 10 (or 14 HP) to get a number. This showed I needed a battery capable of 25 KWH. I know the Enerjicas have a battery around this size, but they don't have that kind of highway range.

I'd venture without doing any math that at 60MPH you'd use at least a couple hundred wh/mile. So for 150 miles, x 200wh/mile, is 30kwh.

(wild guesstimate only, of course, would require real numbers from your stuff and conditions and usage to scientifically wild-ass guess. )

DC/DC Converter:
Still learning. My BMW has heated grips, so "while I'm at it", I would like to add this as well for colder weather. I know this will affect range.

13.6v-14.4v output, however many amps all the stuff you want to run off of it times at least two (for all the things you forgot about and add later plus making up for the exaggerations of the sellers). Potted for water- and vibration- proofing if possible. Isolated if you want to keep the systems totally separate (traction and lights/accessories), not needed if you're connecting any grounds between them for any reason.

 

[E-GSX]

Thanks for all that info.

 

[E-GSX]

In another thread, a member provided info on current electric motorcycles and their final drive ratios- all were over 4:1. I've spent a bit of time looking up shaft drive bikes final drive ratios. The only ones out of the box over 4:1 are some older Moto Guzzis, but the drive is on the wrong side and to graft the drive and rear wheel was too problematic. The best I could do with this is the Yamaha FJR1300 that uses a 3.66:1 drive (mine is 2.66). I also looked into having a custom 7 or 8 tooth pinion gear made, but couldn't find anyone to make one.

I don't want a chain drive, so the method I'm looking at now are what are called high torque sprockets. They are available in various widths and tooth counts. For example, using a 20mm wide belt and a 22 tooth front sprocket and 90 tooth rear one, I'd get a 4.09:1 ratio. Looking at my rear wheel, I think I could have a custom rear sprocket made from aluminum with a splined hub on the inside to fit into the wheel, and a recess for an outer bearing and likely use the existing axle. Since the swingarm is single sided due to the shaft drive, it looks like the bracket for the left muffler mount could be used for a spring belt tensioner. If this works out, I can use a mid motor setup and have enough room around it for a significant battery pack. I'll update as I do more research.

 

[E-GSX]

As I've read & learned, I'm narrowing down some choices. First, the motor I like at this point is the new SiA 200-50. It has a 2.5:1 internal reduction whilst not being as large/heavy as the HyPer9 on the Honda nor as small/light as the QS138 H90 V3 that also uses an internal reduction. Cost should be around $1,500 shipped.

The next challenge is the batteries. At this point, it looks like the Chinese 4695 cells are the best bang for the buck. I measured (roughly) my frame with the engine still in place, and I think I'll have enough room to make a 20kwh pack @ 96V.

For a controller, I've read good things about the Fardriver ones, but I'm still researching this item.

I know I'll also need a host of other stuff, such as a contactor, wiring (I usually use TXL automotive grade for chassis wiring and GXL: for power), some fuses & switches, a DCC converter, a charger, and a dashboard. I'll continue to update as I make progress.