Small capacity (4-5AH) high quality batteries

Alex W

10 W
Joined
Feb 8, 2015
Messages
68
Location
Seattle, WA
I built my first e-bike a couple of months ago. It is an assist only system (no throttle) basically modeled after the Faraday and using the same front hub (8Fun SYXD01F), a Thun BB, CycleAnalyst V3, and a small motor controller. I sourced my parts through G&O Cycles in Seattle and they were very helpful in understanding what I wanted to build.

I really like the setup because it added very little weight (about 4lbs without the battery) and no drag to the bare bike and so I still often ride the bike with minimal or no assist. In a typical ride the assist helps to accelerate to 21mph where the motor maxes out at 36 volts. I do use the assist on steep hills to maintain a 16-18mph climbing speed where doing the work myself would have me going about 10 mph (Golden Gardens Drive in Seattle is an example of such a hill).

I'm using a AllCell Naked 36V 10AH battery and it is overkill for this bike. Based on my last month's worth of testing my nominal range is 60-70 miles. I'd like to find a 4-5AH battery to have a range of 30 miles. Ideally it would weigh around 3lbs and I'd just store it under my saddle.

I'm aware of the RC Hobby Li-Ion batteries which are quite cheap but not as safe to use and charge as the AllCell Naked. I'm not interested in any batteries which are recommended to be charged in a fireproof box. Who else supplies low capacity high voltage lightweight packs?
 
You could build it custom with round cells, or have it built to your spec to the shape that fits best.
 
Is it possible to buy the phase change casing that AllCell uses in their battery packs for DIY builds?

This is a photo of the bike (I should have included that in the first post). I made the frame:
19385_10152783490860780_7709455535785854888_n.jpg
 
You can maybe make your own battery out of 30 18650 cells, which would give 8.7ah if you use Panasonic ones. It would weigh about 3 pounds and with a BMS, it would be safe and convenient to charge.

I have seen 30 cell 36v batteries on Aliexpress, but they're not easy to find by searching.
 
Can cell pack would be great but whatever you do why not mount it in that nice large triangle?

Relatively big battery packs seem to lose a lot of weight when they’re stashed in the triangle. By comparison, front/rear mounting always tend to intensify the effects of battery pack weight.
 
I have a mixed modal commute and use the bus as part of my commute. I remove the battery when getting on the bus (to reduce bike weight), and that is easiest if the battery lives in my handlebar bag or other easily removed bag. A large battery is just extra dead weight and expense. I don't need a 100 mile range on this bike.

This bike has a low trail geometry that handles quite well with large front loads. The battery weight doesn't affect handling much with it's current location. The size is a big annoying.

Is there a good reason that 20 18650 cells wouldn't be enough? My motor controller is only 15 amps (and at my normal speeds it is running at 1-2 amps, while climbing or accelerating it goes up to ~6 amps), this is not a high power bike.
 
10 25r cells would provide plenty of power for a 15A controller. They're rated for 20A continuous discharge. 10s2p would give you the range you want at 5ah. Personally, I'd use 5ah of 20C rc lipo for $80, but that's just what I prefer.
 
Nice looking bike. I also live in Seattle and I'm researching electric bike options. Your solution seems like it could be a good way to go. I don't need an electric motorcycle, I'd like to be able to keep riding the bike without the motor on, putting my bike on the bus, etc., but it would be great to flatten out some of the hills (I live on top of Beacon Hill). I rode the Faraday recently and liked the user experience: simple but effective. That being said, while it's a very cool looking bike, the cost is beyond my current budget.

So I'm trying to figure out whether I could retrofit a similar drive system onto my existing bike.

If you don't mind me asking, I'm curious how much did the ebike components set you back. Just trying to get a sense of what it would cost for me to get those same parts to put them on my current bike.

TIA,

KS
 
kingsinger said:
Nice looking bike. I also live in Seattle and I'm researching electric bike options. Your solution seems like it could be a good way to go. I don't need an electric motorcycle, I'd like to be able to keep riding the bike without the motor on, putting my bike on the bus, etc., but it would be great to flatten out some of the hills (I live on top of Beacon Hill). I rode the Faraday recently and liked the user experience: simple but effective. That being said, while it's a very cool looking bike, the cost is beyond my current budget.

So I'm trying to figure out whether I could retrofit a similar drive system onto my existing bike.

If you don't mind me asking, I'm curious how much did the ebike components set you back. Just trying to get a sense of what it would cost for me to get those same parts to put them on my current bike.

TIA,

KS

Check my sig (pg 2 on) for a couple mild eBikes running around NYC. Between $400-$600 for all the gear used to convert. But I do RC Lipo so those numbers probably not comparable if buying RTR (ready to ride) battery pack. But it's a great way to tackle dense urban areas.
 
Alex W said:
I'd like to find a 4-5AH battery to have a range of 30 miles. Ideally it would weigh around 3lbs and I'd just store it under my saddle.

I was looking for something similar and contacted Paul at http://www.EM3ev.com.
He can build a 36 volt 4.9 Ah battery using SDI INR18650-25R in a 10S2P configuration.
Weight would be less than 2 KG (4.4 pounds).
see this message for more information:
http://endless-sphere.com/forums/viewtopic.php?f=3&t=70586&start=25#p1067805
 
2 kg is not 2.2lbs, it's 4.4 lbs. 1kg=2.2lbs.
 
Check my sig (pg 2 on) for a couple mild eBikes running around NYC. Between $400-$600 for all the gear used to convert. But I do RC Lipo so those numbers probably not comparable if buying RTR (ready to ride) battery pack. But it's a great way to tackle dense urban areas.

Thanks. I'll give those a look. Definitely still curious about the cost of the gear used in Alex W's build as well, since his goal was to recreate the functionality of the Faraday. I liked the way the torque sensor worked on the Faraday. Not a lot of options, but more options that something like the Clean Republic Hill Topper, which just has an on/off switch.

Although I know the reviews here seem to be mixed on the Hill Topper, I'm still tempted by it, because of the cost, but also because their store/headquarters is 5-10 minutes from my house, so it seems like if there are problems, I can physically go down there for support.

That being said, I also want to make sure that if I get something it's sufficient for my needs. Speed is not my highest priority. 15 mph is fine for me. My goal is more about flattening some hills.

It's always easy leaving my house to go anywhere, because we're on top of a hill. But to get from Beacon Hill, where I live, to Capitol Hill (a couple of neighborhoods north), there's a pretty good uphill stretch. It's doable without assistance. But it's enough effort that it can create a disincentive for me to want to ride my bike up there. So I end up driving instead, even though it's gotten to be much easier to bike into that neighborhood than drive, because the parking has gotten so bad. The same thing is true of a couple of other nearby neighborhoods (Columbia City and Georgetown). Easy to ride to, because it's all downhill. Just hard enough coming back that it's a disincentive to bike there (or that I put my bike on the train or bus to come home, even though it's not that far away).

Yes, I'm a bit lazy. But that's the reality of how my psychology seems to work around this stuff.

KS
 
I just came across this post and funnily enough I'm in the midst of a similar build using a Soma Wolverine converted to 26" x 55mm tires with an outrider geared front hub, torque sensor bottom bracket and Alfine 11 belt drive. This is for my 70+ year old dad in Australia but I'm building the bike in Seattle.

My plan was to put a battery in a front rando bag (Swift Industries Ozette, probably with a foam cut out) and I'm researching smaller battery options. What did you end up going with? My leading contender at the moment is the em3ev option.
 
Also, is anyone using two battery packs (say 36V 4.5AH) and rotating through them each ride with the ability to connect them in parallel when needed for longer range? I'm considering this also to allow one to travel with them - a 36V 4.5AH battery is right around the 160WH limit for airline travel.
 
I have used the Kobalt 40v (37v nominal) yard tool battery (the 4 ahr version) on some small geared hub motors and have been very satisfied. It is marked 144WHrs right on the case for air travel. It is fairly easy to take the case off to connect a power output lead...I use 4mm bullets. It's easy to find for $50 to $80 on ebay and the chargers go at a 2 amp rate and are silent. The chargers can also be found on ebay for about $25. The 2AHr versions are way more popular so make sure you go for the 4 AHr version if you get one. I just checked mine and it is 2.6 lbs.
 
Thanks for the Kobalt battery idea. While on ebay I also found a bunch of these for sale by various sellers (using Samsung 22p cells):

http://www.ebay.com/itm/Replacement-36V-4-4Ah-158W-Battery-For-2-wheels-Self-Balancing-Unicycle-Scooter-/361383652280

Anyone have any experience with the battery and/or a specific seller? Any safety issues I should consider?
 
http://lygte-info.dk/review/batteries2012/Samsung ICR18650-22P 2200mAh (Blue) UK.html
If you don't understand why most packs made with 18650 cells are crap for any controller over 18A max, you need to do more research. The 22P is a 3C cell at best, and imo, shouldn't be used in ebike battery packs at all with more than a 1C discharge, which would be an 8.8A max controller for that pack. Some of the newer 18650 like the 25R rated at 8C max can be used if the ah is high enough, but even it wouldn't be very good in a 10s2p configuration like that pack is.
 
Grin is making my dream battery. 56 minutes into this video they show them:
https://www.youtube.com/watch?v=IxB2j-egWcQ&feature=youtu.be

You can order them here:
http://www.ebikes.ca/shop/experimental/b362-5lim-r.html

I can't find any discussion on them here (I searched for the part number). I ordered two to play with. They look perfect for my needs: 480 grams each, 5 amp hour for two, compact enough to fit under my saddle.
 
Alex W said:
Grin is making my dream battery. 56 minutes into this video they show them:
https://www.youtube.com/watch?v=IxB2j-egWcQ&feature=youtu.be

You can order them here:
http://www.ebikes.ca/shop/experimental/b362-5lim-r.html

I can't find any discussion on them here (I searched for the part number). I ordered two to play with. They look perfect for my needs: 480 grams each, 5 amp for two, compact enough to fit under my saddle.

Nice find, 'hadn't seen that yet!
 
Those do look nice. I love the idea of all bike batteries being more modular.

But right now, during the Christmas sales, look for 48v 4 ah lawnmower batteries and chargers for a nice micro battery.
 
You can get about 300 cycles from a echo 58 volt 4 ah battery. I ran one two to three cycles a day for about five months on a 36 volt controller. They have a rugged case. Weigh about three pounds and have a battery gauge. You can pick one up at home depot for about 180 bucks. You would probably get more cycles with a fifteen amp controller.
 
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