Building an EV motorcycle. Need opinions.
 

I was on another forum (endless sphere) asking this, but I wanted some more unbiased opinions. I'm building an electric motorcycle (well, it's built). Motor is Mars ME0913 72v and the controller is an Alltrax 7245 (450 Amp)

My goals: 45 miles while maintaining an average speed of 45-55 MPH. I'd like to be able to do a few mile bursts of 65-70 MPH should I need to take it on the freeway.

I'm down to 3 battery choices: Lead-acid, LiFePO4, and LiPo.

On endless sphere everyone (literally EVERYONE) pointed me away from lead acid. It seems Lipo, with all of its dangers, was still a better option than lead acid. It seems everyone had their own views on which battery was better. LiFePO4 fans were against LiPo. Lipo fans were against LiFePO4 (because of size and cost). But it seems all were against lead acid, though I couldn't get a better reason other than "they're heavy". Which it's hard to argue against.

So lead acid: readily available, reasonably priced...but heavy. Is it worth it? The bike is a 1996 Honda CBR 600 and I can fit about 6 yellow optima batteries.

I have also heard that lithium has far more recharge cycles, which if you keep the bike, more than make up for the extra cost after replacing a few lead packs.

I do plan on keeping the bike, but at the same time I plan on upgrading it in the future. So I could save for better batteries and hopefully in a few years battery technology will improve.

I'm entertaining building my own lithium pack from a large box of used computer batteries fyi. It involves things like building a battery tab welder out of a microwave transformer and sorting out an appropriate and affordable BMS and charger and dissecting the packs and matching the cells, ditching the bad ones. Lotta work, not sure I'm up for it, but the batteries themselves will be like $100 (or free if you are really good)

Life would be what I would go with. I don't know what kind of cycle life you get out of lipo but life is great. I've heard that most lipo also has a shelf life which isn't what you want if you are planning to keep it for a long time. I would also recommend just building it the way you want the first time around. It is very costly to redo things like a bms and charger.

I would definitely avoid lead. Its heavy, cycle life is horrible compared to lithium and it requires different charging profiles at the very least.

Grrr. I'm still captivated by lead acid. With lead acid there's no BMS required I thought. And I could get some good deep cycle batteries for $120 each and it'd only be about $720. if I go with Life, it's $1200 for the batteries plus another extra chunk for the BMS and chargers.

which life and lipo batteries are you looking at and how many?

One other consideration is efficiency, higher loads affect lead far more than lithium due to the pukert effect. So weight, lifespan, efficiency, cost per mile, performance, how many reasons would you like? :)

Yes the charger/bms does add to the cost, but just so you know, you can trade convenience/time for cost there as well. If you have a suitable 3.7v charger (i.e. for one battery or collection in parallel) you can balance charge the whole pack by simply charging each battery one at a time. When you make/build a second one, it will take half as long, and could be controlled by a relatively simple box of chinese relays and a microcontroller.

Continuing to add 3.7v chargers gets inefficient though, as you take 120v down to 4ish volts several times, each at the same current that you could apply 72+ volts across the entire pack. Though you still have to monitor the individual voltages to prevent overcharging one of them.

The best ev battery deal right now by far are the Chinese refurb AMP20 cells for $25.

Where do we find those? I might order 36v worth and upgrade to 72v in a few months.

Yeah I got about 0.6KwH worth for about $250 shipped.

Where did you order them from?

Ebay seller in china.
I tried to contact A123 battery systems in the US but they are stupid, useless and bankrupt now.
There is pretty much only one place for a battery maker to go when they build batteries, throw most of them away and refuse to sell them to any one.

Darn. I'm sure there's a website that sells them. I don't have an eBay account. Lately things on eBay are more expensive than Amazon.

The website is useless.
That website was A123 battery systems customer inquery web page.
Lots of people sent them emails and none were replied to.
Its like they just didn't care.

Only idiots ignore customer inqueries.
Then we laugh at them when they go under.

OSN Power sells them.
.
Endless-sphere.com • View topic - PROMOTING OSN A123 20ah packs
.
You will want to chose your voltage and stay with it. Any motor you buy for 72v will only top out at half the speed when running 36v. Read more theory at endless-sphere.

I was pricing out Optima batteries and noticed that they cost about the same as my GBS brand lithium batteries for the same labeled capacity, the Optima batteries of course are heavy, rated for 300-500 cycles and can not handle as strong of discharge without seeing their capacity drop, my lithium batteries are tested to 2000 cycles with 70% capacity left at that time, that's discharging it fully every day for over 5 years and if you don't discharge as fully their capacity stays higher for more cycles.

All batteries need to be balanced, a pack that is never balanced will end up being a short lived pack, if you want to make a pack of lead acid batteries last as long as possible and perform at it's peek then put a battery management system on there! the other option of course with lead acid batteries is to manually balance the pack from time to time with a small charger over night, but without a good battery gauge that connects to each battery in the pack you have no idea what is going on with your pack or if anything is going wrong until you've caused damage.

I spent $1,800 on my 48v 100 amp hour lithium battery pack, it weighs 112 pounds, I then spent another $1,000 or so on the battery management system, LCD display and charger, all of the parts talk to each other so it can charge at a faster rate until a single cell starts to get full then it throttles back until the rest catch up, this feature cost a few $100 extra but it's well worth it.
If I wanted the same capacity with lead acid batteries the pack would weigh 520 pounds, take up 3 times as much space and last 500 cycles or less, I built my motorcycle up with 400 pounds of lead acid batteries and it was unsafe to ride, I have lithium batteries in it now and it's FUN and lighter then stock.

You really shouldn't skimp on batteries. Lead acid is viable, but lithium will be cheaper (in the long run) and lighter and more fun, and and and. There is a reason there haven't been many lead acid EVs over the years, but there are now a good handful of lithium EVs around. If you can't afford it, wait until you can.

Also, I was just checking out your motor and controller selection... I don't think your controller is going to work with you motor. That is a 3 phase AC motor, and your controller is a DC motor controller.

The mars ME0913 is a DC permanent magnet motor. Where did you get that it was AC?

What is the eBay seller name for the batteries? Have any of you had any bad cells or negative experiences?

I don't know the name of the seller. I bought them a long time ago and they are still in use and work perfectly fine.

Endless-sphere is charging $380 for an 8cell pack.
I built my 8 cell pack for $250.

ME0913 PMAC Motor
3 phase motor with hall sensors.... good catch Daox.

So because it's a 3 phase motor it's not going to work at all? Shouldn't a DC motor work with a DC controller?

Its not a DC motor, its an AC motor. Permanent magnet just means it uses magnets instead of electro-magnets. Permanent magent motors can be DC or AC. You're going to need to go with a DC motor, or get a controller that is compatable with that motor.

Fudge. I already have both sitting in the garage. I was told by numerous people they'd be a good pair. This really sucks. Now I have to get rid of either the controller or motor.

With that alltrax 7245, which 73v motor would you guys recommend? Maybe I can trade it or return it to the place I got it from.

DC motor and controller will be more affordable, I would try to ebay the PMAC motor (or see if your supplier can exchange it).

Which DC motor would you recommend in the 72v range? I'm going to see if I can exchange it. Even though I got it about 6 months ago :-/

I see the ME1003 bundled with your controller, they are like $700 shipped on ebay, reasonably similiar power ratings.

A suitable kelly controller for your PMAC is about $1000.

I see your PMAC motor sold (new) for like $820 on fleabay.

oops, I lied, this *should* work with your PMAC and is $700, but you should be doing more homework and googling for opinions on part nubmbers and motor/controller (and battery) combinations. The cost between DC and AC might not be as bad as I thought these days.

High Efficiency Brushless Motor Controller

So the me0913 will work? That's why I'm so confused. I've done research and gotten lots of opinions and everyone says it'll work.

Specs say it works on DC

Needs more homework if the me0913 will work with the bldc controller I just linked to (bldc is the square wave version of PMAC, so they do often work just fine, not always).

Which spec are you referring to?

*3-Phase Permanent Magnet Brushless Motor
*24 - 96 Volts
*Efficiency of 92%
*12 KW (180 amps DC) continuous @ 96 Volts
*23 KW for 1 minute (600 amps DC) Peak @ 96 Volts
*Peak Stall Torque of 90 Nm (66 ft)
*Designed for long life. No brush maintenance.
*8" OD, 7.17" long (w/o shaft)
*7/8"x 1-5/8", 3/16" key shaft
*35 Lbs

And when I was looking at motors, I specifically browsed DC versus AC categories. But I've been researching this project for a while and settled on the motor first and then found what controllers would work with it. But I guess the phases were just overlooked. And I guess this link confirms it: http://www.thunderstruck-ev.com/moto...ity-chart.html

But I'll just sell the motor and go with the ME1003. I'm already getting a box to pack it up to get it sold. Man, this thing is heavy.

I would avoid a Kelly controller, I've seen them cause way to much damage and have yet to talk to anyone who has had good luck with them, at best they fail off and just don't work, worst case they start on fire or fail full on.

I'm kind of sad. So theres no electrical converters I can get to make it work? I really like this motor and this controller

Get an NiMH pack out of a ford escalp hybrid or chevy tahoo hybrid or whatever. For $350 you get 300v of 6ahr NiMH batteries, which is enough to run a motorcycle.

Yes they weigh more but they are more durable and easier to charge and less dangerous to overdischarge.

Good Luck

That is pre assembled and with a BMS. Loose amp20 cells are around $25 each shipped.

I guess I'm still confused how it's still advertised as DC motor and even the specs say it takes DC ("The motor is 92% efficient at voltages between 24 to 96 VDC. Continuous current of 125 amps AC (180 Amps DC into the motor control)") But it's still an AC motor? Can someone explain how that works so I have a better understanding of where I went wrong?

-edit-
I decided to keep the motor and go with a new controller. My original goals were to get more than 72v (faster speeds) and I'd like to stick with that. Looks like I'll be getting a different controller. You say the kelly KBL72501E is compatible? What about the KBL96351E? The KBL96351E seems to be closer to what I need (higher voltage.)

I'm kind of facepalming because the Kelly is what I was looking at originally. I got caught up in the hype of the Alltrax being the most popular (for other motors. I didn't consider that) and the fact that the Alltrax cost less.

Do you really know what motor you have?
Does your motor have 2 cable lugs or 3 cable lugs plus small hail sensor wires???

Alltrax controllers have a lot of hype because they don't tend to fail, Kelly controllers fail, I was talking to someone on Sunday who gave up on the kelly controller after paying to mail it back and getting a 2nd dud, friend of mine got a great deal on a near complete electric car after a Kelly controller burned up as the car sat over night and destroyed a $3,000 Netgain motor, look at EVAlbums.com and search kelly controllers and see how many people have had them be a costly mistake.

It's definitely an ME0913 with 3 cable lugs and the sensor wiring. 100% sure of that.

I'm second guessing my choice of the kelly controller since I've been researching them more. I don't like to google "[product] problems" because all I'll find are problematic posts. I can do this with any brand. I'm sure I can find people who hate Alltrax. But Kelly seems to be problematic with a lot more than I care to deal with. So I think I'll stick with the Alltrax and sell the motor. I'll be limited on speed, but I can upgrade the motor to something else compatible in the future.

I haven't searched for issues with Alltrax controllers but when I read about EV's I see that there are people who have 1000's of miles on them with Alltrax, then I have people walk up to me and start going off on how their Kelly controller failed and meet people who's Kelly controller looks like someone took a cutting torch to it and see the other damage it caused and I look around for people who are HAPPY with the Kelly controller and I fail to find the happy EV builders other then a few people who have way over sized Kelly controllers on E-bikes... way over sized on a bicycle, not hard to do.

But that is why EValbums is nice, you sort by part brand and you see everyone who has it and you see how it performs and you see their notes about issues.