New eBike Project Iron Horse Maverick

[SHARKBITEATTACK]

Here's a pic of my Iron Horse Maverick SE I plan on converting. It's a 21.5" frame with disks front and rear and a 9 speed cassette. I plan on using the 9C 2806 hub motor kit from ebikes.ca with a 48v 14ah SLA battery pack. I have a surplus of SLA batteries laying around from scooters and UPS systems that are still good and I only plan on using them to get the project up and running and then switching to Lipos or LifePO4s. YES I'm already familiar with the many disadvantages of SLA's :wink:

Half of the batteries and hopefully the controller can be mounted within the frames main triangle and the other half on a rear mounted seat post. I'm tempted to upgrade the stock 25amp controller to the 35a unit for future upgrades. Would short bursts of 35 amps be ok with my battery pack? I always thought that the one benefit of lead batteries was that they could withstand the highest rapid current draw, but lately I've been reading about the peukert effect and how it drastically reduces efficiency. Could a Cycle Analyst computer limit the current draw to protect the batteries? Would this also limit my top speed? The full 27mph sounds nice for quick bursts but I plan on doing the majority of my riding at a 20mph cruising speed while pedaling.

The bike isn't meant to be a serious commuter just more of a hobby. I enjoy going on 30+ mile bike rides and exploring the unknown. I also enjoy tracking where I've been via GPS, shooting photo's of nature and searching for geocaches. Hopefully with the addition of electric power I'll be able to venture out past my 15 mile radius comfort zone.

Couple other questions while I'm at it. Any input on choosing a throttle? I've always preferred an index finger throttle over a motorcycle twist grip throttle but have never used a thumb throttle. I feel like an index finger or thumb throttle may get in the way with rapid fire gear shifters. Also, I'd like to retain all 27 speeds by using a 9 speed freewheel. Ebikes.ca mentions I would a spacer or two to accommodate the larger freewheel. Would this offset the disk rotor? Anyone use clipless pedals with their ebike? This bike has campus pedals and I've toyed around with the idea of buying some cycling shoes

Thanks ES community for all the help and knowledge shared.

 

[RallySTX]

Hello, and welcome to the Sphere. Looks like you have a good start on things. That bike looks like it would make a good ebike. The Cycle Analyst measures and displays detailed information about your battery pack, acts as a general purpose trip computer, records and calculates numerous statistics on the vehicle performance, and can limit the speed or current draw through a throttle feedback loop. That is from their page. Your pack will show a voltage drop when you exceed its capabilities. If it gets low enough, it will either trip the controllers LVC, or the CA's LVC. You can avoid trouble by rideing conservatively. Read below, and ask us if you have questions.
http://www.ebikes.ca/drainbrain.shtml
Voltage has more effect on top speed than amps. SLA's are Safe, Low power, boat Anchors. I would use the stock controller, and save the bigger one, for the better batteries. You might get a bit more out of the SLA's with it, but the potential early ruin of your batteries isn't worth the risk, unless you can get accurate controll from the CA. Always check your harness after a ride for hot spots. Those represent resistance, and a loss in power. You may need to file down the Caliper mounting bracket to realign the rotor, or use washers on the rotor. I am unfamilliar with Campus Pedals, or clips. Back in my day, we had a choice. Use pedals with straps and regular shoes, or buy special pedals and shoes that lock into them. I would use the straps method, if you want to walk after you ride. Don't forget to lock it up. I ran across something about Rapid Fire Shifter issues, but I don't remember what it was about. Search the site, mabye someone else with more experience here will chime in. Best of luck, and keep us posted!
Brian L.

 

[oldpiper]

Half of the batteries and hopefully the controller can be mounted within the frames main triangle and the other half on a rear mounted seat post. I'm tempted to upgrade the stock 25amp controller to the 35a unit for future upgrades. Would short bursts of 35 amps be ok with my battery pack? I always thought that the one benefit of lead batteries was that they could withstand the highest rapid current draw, but lately I've been reading about the peukert effect and how it drastically reduces efficiency. Could a Cycle Analyst computer limit the current draw to protect the batteries? Would this also limit my top speed? The full 27mph sounds nice for quick bursts but I plan on doing the majority of my riding at a 20mph cruising speed while pedaling.

...

Couple other questions while I'm at it. Any input on choosing a throttle? I've always preferred an index finger throttle over a motorcycle twist grip throttle but have never used a thumb throttle. I feel like an index finger or thumb throttle may get in the way with rapid fire gear shifters. Also, I'd like to retain all 27 speeds by using a 9 speed freewheel. Ebikes.ca mentions I would a spacer or two to accommodate the larger freewheel. Would this offset the disk rotor? Anyone use clipless pedals with their ebike? This bike has campus pedals and I've toyed around with the idea of buying some cycling shoes

Thanks ES community for all the help and knowledge shared.

SLA's? You can't draw any substantial current from them at all - that's why car batteries are so huge, compared to the lithium-whatever or even NiMH kind for the same current capacity. IIRC, the capacity in Amp-hours for an SLA is at a C/20 draw (using up the battery over 20 hours) whereas the capacity for the others you'll find used here is for a 1C - 20C draw (using up the capacity in 1 hour down to 3 minutes [but you're only talking for really short spurts here]) or better, and that's why your controller limits your current draw to something less than the thrust of the Space Shuttle main engines. You can fine-tune your current limit with a Cycle Analyst, also. Oh, and the Peukert effect works out that at the draw you'll usually be using on your ebike, a 14Ah battery will pretty much poop out after 7Ah or so. THE ONLY advantage of SLAs is that you don't have to worry about hazardous materials shipping, just with hazardous waste when they're dead.

It looks like you've got a pretty darn big triangle in which to put your batteries - you should be able to get your 48V14Ah in there without any trouble. If you think you need to place them in a particular way to fit, just make yourself a simple box out of wood, aluminum, steel, fiberglass, carbon fiber, marble, Corian, mother-of-pearl, titanium-gold alloy (indestructable, didn't you watch Ironman?), Plexiglass, old circuit boards, etc. to fit and fasten them to it. And the controller, generally they're puny, just a bit larger than a decent sized paperback book. I'd just strap it to your downtube, making sure that it has clearance around it for air cooling.

As for the 27 speeds, I'll bet when you get on your finished creation, you'll use at most 2. The highest to keep up with the motor when you're cruising along, and the lowest to drive the bike when something goes wrong and you're working on "manual" (especially with 30+ lb of batteries). IMHO, the derailleur looks pretty cool, but in practice on an ebike it's often just a dirt-catcher. IIWY, I'd use a single-speed on the rear and just use your front three for the above situations, but YMMV. Cycling shoes? Many, many moons ago I toyed with them, and unless they're made different now, they're just not made for walking when you get off. Real pain in the nether-regions. Again, IMHO, if you want to get the most efficiency out of your "human-assist" (don't fool yourself about who's assisting who), just get yourself a pair of muzzles for your pedals so you can pull a little power out of the upstroke.

Cameron

 

[torker]

IF you have to start with lead then limit the power for sure. Looks like it will all fit in the triangle for sure. You might check out my Giant Rincon thread. I had my lead on its side. Not sure if that was good or not but it worked for awhile, till I got Lipo Much better. I never had a voltmeter on it before going to the Lipo so not sure how much voltage sag I had but it was a lot with lead. Ditto on the gears. You won't need many. Plus what I have run into is the rear drops are usually only 135 mm which doesn't leave any room for extra washers. I only ran a 7 spd. on mine and still had to spread the drops a few mm to fit the hub. You may get lucky and that Ironhorse will have more room.

Ok Just looked and realized most pics from back when I posted about that build are gone. I reposted a couple but I will put one here and you can check out my weblink to photobucket if you want.

 

[SHARKBITEATTACK]

So here I am 2+ years later and I've finally made some progress. I ditched the idea of SLA batteries (although I still believe in them for a budget and short range neighborhood ebike) and decided to use NiMH batteries. I've got over 800 used Tenergy Sub C cells that were donated to me and I'm trying to put them to use.

Here's what I got so far.



36v 10Ah NiMH pack, 2808 9C, infineon 40A controller. I'm eventually going to bump the voltage up to 72v but I want to add more batteries in parallel first because the current draw would be too much for the batteries. What I really want is BIG range and a bike that's fun and comfortable to cruise around and get excersise using pedal assist at about 25mph. I also would like this bike to do be capable of some moderate offroading. Being able to venture off into the woods and into unexplored territory on dirt trails at<10mph. I may eventually swap to a 2810 Motor since I think a 40mph top speed is a little too much for liking and too demanding on my battery pack.

I'm trying to stuff ALOT more of these batteries within the bikes main triangle and then build a nice battery enclosure to hide it all. If anyone has any advice on using NiMH batteries please see my thread here.

 

[SHARKBITEATTACK]

So I hooked up the Cycle Analyst and went on a test run. I got my NiMH specific battery charged the batteries to 100%.

The results were a bit disappointing but I think it's because I have a couple bad cells inside my 60 cell pack. I went 7.7 miles with an average speed of 11mph, used 91 Wh and averaged 12 Wh/mi. This was all unassisted btw. I was being very conservative and avoided any "hot rodding" since this was just a test to see how what my batteries were capable of. I started out at 41.5V and ended at 36V. The battery voltage was sagging down to 31-32V during the last mile under a minimal load 3-4 amps and the performance really sucked. First thing I did after I finished was check the voltage of each of the 6 batteries. 4 were still in the 12.5-12.8 range but 2 of them were around 11.5. I know I coulda kept going and gotten more range but the bike just didnt feel right anymore and I didn't want to do any or anymore damage to the batteries.

So my 36V 10Ah pack only gave me 91Wh instead of 360Wh which means I only used about a 1/4 of its rated capacity. I'm gonna trickle charge the batteries for a while and then go out and repeat the test. If I get the same results then I think the next step is to dissect the battery, try and identify the weak cells and try and solder in some new ones...

 

[wollysf]

Hi,
I am working on a 15hp electric motor boat project. I am looking for some inexpensive NIMH cells to augment the recycled/rewired hybrid EV NIMH cells I am using. Any chance you want to sell 60-70 of your single cells?
The bike looks cool - that's my next project! Thanks