My Raleigh E-bike

[Russell]

FIRST RIDE

I bought a little 36V/250W Bafang kit off of eBay back in the middle of November (see my initial review here; http://www.endless-sphere.com/forums/viewtopic.php?f=3&t=8001 )and while the little customizing I did to it took a bit of time it’s been essentially done for over a month with the final touch, a matching rear wheel, installed just last week.

We had a VERY snowy and cold December followed by an equally cold January so there was little chance to get out on the road. Normally I put my bikes away some time in November and get them back out in March but I have on occasion ridden in January or February. I’ve been chompin’ at the bit to ride my ebike and I finally got the chance today. The snow is still piled high and does extend out into some roads yet but I couldn’t resist the sunshine and 35 degree temperature (that’s 2 Celsius), even the wind was ok at 12 mph (23 kmh) out of the SSE.


I have three bikes and this circa 1992 Raleigh was going to be retired since I recently purchased a new 2009 Kona Smoke 2-9 but I figured if I was going to possibly goober something up it might as well be this bike. The bike itself was a touring model I purchased off of eBay a few years ago then stripped it down, tossed some parts and sold a few others leaving just the frame, fork and seat post clamp to be reused. I had the headset replaced at that time and then built it up as a flat bar hybrid type bike. I’ve ridden it thousands of miles since then and while it’s not the fastest, it ain’t terribly slow either.

Here’s the bike and some of the specs;

1992 Raleigh R-300
Sun CR18 Rims w/700x35 tires and self-sealing tubes
8 speed shifter on right for 12-32 cassette
Downtube shifter for front derailleur
Road triple crankset with bashguard, 42T and 30T chainrings
Cantilever brakes

Bafang 36V 250W front motor laced with Wheelsmith DH13 spokes 2 cross
Controller is rated at 7A (that’s where they get the 250W) /15A peak
Controller is mounted on handlebars with Watt’s-Up meter on top
36V/9AH SLA battery pack in rear bag
Modified scooter trigger throttle (see details here: http://www.endless-sphere.com/forums/viewtopic.php?f=2&t=8026 )

Weight: 59 lbs (27kg) + 2.5 lbs for tools, spare tube and mini-pump. (me: 200 lbs)

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This is today with the snow piles in the background.

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Cockpit

Raleigh3.jpg (87.75 KiB) Viewed 6395 times

OK so how did it perform you ask. Well compared to other bikes folks have on this board this one is indeed slow coming in right where I had predicted at about 16.5 mph (26kph) right off the charger on level ground. I did just want a little assist so in that respect it’s a pretty good match for me and the bike. It did disappoint me with its hill climbing ability which is rather anemic. With the battery still close to full I hit the first hill which is about a 4% grade and the motor struggled to get me up it at 10mph (16kph). I was expecting better. I pedaled all of the 23.6 miles (37.8km) and for the trip averaged 15.6mph (25kmh). That isn’t bad seeing I hadn’t ridden outdoors since early November. Also my average speed on this bike before the conversion for the last 31 rides was 15.1mph. I was still quite damp when I got back and my tootsies were frozen but I noticed then I hadn’t touched the water bottle. I was working all of the way but the motor really took the edge off especially traveling into the wind. On the way back I had a tailwind so the motor could only provide a very minimal amount of assistance at 17 mph and was all done at 18. I now very much want a lithium battery since the working voltage on them is higher than with an SLA. A “36V” LiFePO4 with a nominal voltage of 38.4V would provide a nice little boost I think. Hmmm…do I hear that little 36V/8AH Ping calling to me?

Trip results:

Distance: 23.6 miles (37.8km)
Average speed: 15.6 mph (25kph)

Amp-Hours used: 4.810
Watt-Hours used: 168.1
Peak Watts: 550
Min Volts: 31.62

WH/mile: 7.12
WH/km: 4.45



-R

[dogman]

A 36v ping will have a resting voltage of 44v, and not sag much under load. I bet it's really calling you now.

[Russell]

Yep I could use more capacity and a few more working volts would be nice. The SLA's sag too much right away.

-R

[GASSTINKS]

Nice clean build. We seem to be on the same page with regard to using the motor for just a bit of a boost. I just finished installing a Bafang kit on my hybrid (no suspension, flat bars). I have the same motor, but my kit came with a 25 amp controller and rack mounted 37v 10ah Phylion battery. I've been reading and re-reading your initial posting of this bike, since there aren't many people in the States using this motor in kit form. With bike, motor, battery, rack, and 700x25c Schwalbe tires, mine weighs in at 45 lbs. The fact that it's raining outside right now is killing me. I live in Southern California where it *almost* never rains. As luck would have it, I pick the weekend when the sky finally opens up and dumps a ton of rain. You must have been going crazy for the few months that this bike sat in the garage.

I hope to post a full report by next weekend, including range testing on my hilly 19 mile commute. I'm curious to compare notes on performance.

Enjoy your bike,

Al

[cargo]

.

[Russell]

Nice clean build. We seem to be on the same page with regard to using the motor for just a bit of a boost. I just finished installing a Bafang kit on my hybrid (no suspension, flat bars). I have the same motor, but my kit came with a 25 amp controller and rack mounted 37v 10ah Phylion battery. I've been reading and re-reading your initial posting of this bike, since there aren't many people in the States using this motor in kit form. With bike, motor, battery, rack, and 700x25c Schwalbe tires, mine weighs in at 45 lbs. The fact that it's raining outside right now is killing me. I live in Southern California where it *almost* never rains. As luck would have it, I pick the weekend when the sky finally opens up and dumps a ton of rain. You must have been going crazy for the few months that this bike sat in the garage.

I hope to post a full report by next weekend, including range testing on my hilly 19 mile commute. I'm curious to compare notes on performance.

Enjoy your bike,

Al

Thanks.

Where did you get your kit? 45 pounds is light for an ebike. Mine is heavier than I'd prefer but that'll be remedied to a large degree when I eventually switch to a lithium battery. I look forward to your review since you're running the same battery that tops my short list of batteries to buy. I'm also curious to see how much difference your higher current controller will make on hills.

While I did buy a kit I spent a lot of time on details such as re-lacing the motor to a new rim, relocating the controller, changing many of the connectors, selecting and ordering new parts like the throttle, torque arm and new rear wheel plus buying all kinds of stuff I never used. When I did finish it I “rode” it on my indoor trainer for about a month until I finally got the chance to go outside with it, about a month ahead of schedule I might add.

Well today looks like another nice one with sunshine and a predicted high of 40 so while I’m feeling the last two days of riding I think I’m gonna have to get going and take advantage of the weather before it changes back to winter

-R

[GASSTINKS]

I bought my kit from Cycle9.

I did the first leg of my commute this morning of 18.75 miles of rolling hills. The top speed on level ground seems to max out at around 18 mph. Acceleration at low speeds and hill climbing are where this motor/battery combo excel, plus riding on flat ground without power is easy due to the freewheel capability. I was climbing most of the moderately steep grades at 15 mph, but that consisted of pedaling hard to assist the motor. I have no way of measuring the amount of power I used, since I rely on the throttle lights, but I never saw the green light change. I'm guessing I used only half of the battery.

*Edit: The 1.8 amp charger just clicked off after an hour-and-a-half. Next time I'll be less conservative with the throttle and not worry about hitting the LVC along the way.

[Russell]

Ok so it’s not a big deal with knuckles runnin’ ‘em at 72V but the bike was just sitting there, winter weather had returned and the 6V battery was 10 bucks delivered so I figured what the heck. Today with the temperature rising to 42F I got the chance to try it out. Oh boy the speed was intoxicating. OK I’m exaggerating it was kinda neat though and at times with pedaling at 20-21 mph with no suspension even a little too much for some of the crummy roads around here.

The controller I’m using has 50V caps therefore I didn’t want to add another 12V SLA so the 3.5lb 6V/9AH battery was a good compromise. I only wanted a little more speed anyway (for now ). With 3-12V/9AH batteries I got about a 16.5 mph top speed with all of the assist gone by about 18 mph. The additional battery gave me 46V fully charged and a no-load speed topping out at 23.5 mph Vs a hair over 20 mph previously. On the road the speed peaked out around 19 mph but there was decent assist available yet at 20 mph even on the return leg of my trip. Unfortunately while the 6V battery is the same stated capacity as the 12V’s it died early after only about 4.3AH as evidenced by the voltage sagging under 32V on the last hill when it should have stayed at 36V at that point in the ride. In the end however I still recorded my fastest ride yet, an average of 17.0 mph over 24.2 miles, compared to an average of 15.6 mph at the nominal 36V I used for the last 5 rides. Watt-Hours were up though to 8.0/mile since as they say “power corrupts”

Trip stats:

24.16 miles
17.0 mph average speed
29.4 mph maximum speed
4.782 AH used
193.9 WH used
8.0 WH/mile
31.75V minimum
15.15A maximum
622.0 Peak Watts


I have been eyeing this 48V/15A Ecrazyman controller for just $45 delivered on eBay which would be a perfect match for the Bafang...but what would I do with all of that speed.

48V15Acontroller.jpg (136.15 KiB) Viewed 5788 times

-R

[Kurt]

SLA battery's are effected by temperature and become very sluggish in cold weather. In the same way that your cars battery doesn't have the same kick when its cold. Expect some improvement from your battery when its warmer weather.

That said Lithium is the way to go. Also I found the e crazyman controllers to be very good value for money and he is a reliable dealer.

Kurt.

[docnjoj]

Hey Russell. I have the 28 amp version of that controller on my Bafang with a Ping 48 volt 20 ah battery and I have to back off the throttle on a 5% grade in order to be able to get some exercise in. On level ground it accelerates up to about 20 mph and this is with 300# of trike and me! Super combo and even with 1 steel gear it is still very quiet! Go for it!
otherDoc

[Russell]

Yeah I read somewhere that SLA's are rated for 25C (77F) and that their capacity falls to 85% at 0C (32F).

The most I've gotten on the road so far has been 5.42AH at 48F over a 1.5 hour ride. The most I got from the the 36V/9AH pack is 5.7Ah at room temp during an indoor constant current test on my trainer that lasted about 1.25 hours.

I want to get lithium but I figure I'll use up the SLA pack that came with the kit first.


-R

[Russell]

Hey Russell. I have the 28 amp version of that controller on my Bafang with a Ping 48 volt 20 ah battery and I have to back off the throttle on a 5% grade in order to be able to get some exercise in. On level ground it accelerates up to about 20 mph and this is with 300# of trike and me! Super combo and even with 1 steel gear it is still very quiet! Go for it!
otherDoc

Sounds like a nice set-up.

Today's experiment with 42V was in part to see if I want a higher speed or if 36V would be sufficient. I'm thinkin' now a 36V LiFePO4 with its higher than SLA working voltage would probably be enough. I also think I want to keep capacity on the low end so I do feel the need to conserve battery power, otherwise there's too much temptation to just "gun it" all of the time.

-R

[docnjoj]

When you are as old as me if you "gun it" all the time I have a 3 wheel very fast wheelchair! I manage to feather the throttle a lot so as to get some aerobics in.
otherDoc

[Russell]

trip5.jpg (84.81 KiB) Viewed 5504 times

OK now that I got your attention it was going down hill but not a really steep one, about a 4% grade, but it's long enough and smooth enough to get a decent head of steam...and best of all there's rarely a car in sight. I just mention it because it shows how well the Bafang does freewheel. Normally I only get up to 32 or even 30 if there's a headwind on this stretch of road but today there was a tailwind too. When I get my 9C kit installed the coasting speed on this hill is one thing I want to test for comparison (dang I missed the UPS guy delivering it today).

This is also a chance for a general update. I've ridden the bike 14 times so far since I put it into service in February for a total of 332 miles (531km) or an average of 23.7 mi/trip (37.9km). The only motor related issue is that the Bafang vibrates under heavy load. I tightened the spokes a quarter turn a couple of rides ago but that didn't really help. It's not a big problem but I will look into it further. The only real problem I've had with the bike has nothing to do with the bike per se but rather the problem of riding it in sloppy weather. There is a lot of winter crud on the roads and a number of times metal particles have lodged themselves in the brake pads which has then scoured my nice new rims, front and back. In fact both rims now show more wear on them after a few hundred miles than rims I've had for years and ridden thousands of miles. It's a good argument for disc brakes I suppose though they aren't really an option on any of my bikes as they lack mounts. Otherwise the bike hasn't skipped a beat (knock wood ).

As mentioned previously on this thread I installed an additional 6V SLA booster in-line with the 36V pack for 42V. I removed it after just two rides because while it did raise my average speed from around 15.7 mph to 16.9 mph it did not make a significant difference in the "fun factor" for me. I ride for exercise and fun and all it did was get me home sooner. There were other reasons too; the battery added 3.5 lbs, which I could feel, plus I had to charge the 6V battery separately making it less convenient than just using the 36V pack, and finally the 6V battery would die well before the 36V pack. I'm not totally against using higher voltage, and I still might, but I certainly don't need it. The other day I really humped it and managed to average 16.5 mph on 36V over 24 miles with a LOT of effort on my part. You gotta remember that the best the motor can do hauling a combined 265 lbs is 16.5 mph fully charged on level ground with all assist gone by 18 mph so quite often I'm on my own pedaling a 60+ lb bike.

Today I rode the bike the longest distance yet, just over 32 miles (51km), using 5.3Ah and 191Wh (~6Wh/mi) in the process with an average speed of 15.8 mph (25.3 kmh). The 36V/9Ah SLA pack was just about empty though I didn't quite hit the 31.5V LVC. Theoretically I could continue to extend my range further and further by simply pedaling more but for this trip I did make use of the motor much of the way, I just limited myself to part throttle most of the time. I'm still torn between which battery to get next, LiPo, LiMn or LiFe but I will be buying one of them fairly soon

Oh yeah one more thing, the trigger throttle works great, I highly recommend it

(see thread here; http://www.endless-sphere.com/forums/viewtopic.php?f=2&t=8026 )


-R

[Russell]

Yes I took the plunge and have moved up to Lithium! However since I blew my battery budget on another motor kit, a 9C from E-Bikekit, funds were limited so I chose the most economical solution I could find; Bosch BAT836 36V “Fatpacks”. For a total price of $119 delivered ($135 less 12% MS Live Cashback) I got my mitts on three of these bad boys.

3 little fatpacks, 3 little fatpacks, let's see how they run...

Bosch 002.jpg (91.06 KiB) Viewed 5262 times

Why three? Well one is obviously not going to hack it, though some have tried it, and two…well ya still not enough even with my 250W Bafang w/15A controller. My goal was to equal or exceed the capacity of the current 36V/9Ah SLA pack and fit in the same or smaller space so three Fatpacks it would be. If you’d like to see more details on how I got from the picture above to the one below see this thread: http://www.endless-sphere.com/forums/viewtopic.php?f=14&t=7569&start=60#p145791

Assembled pack

Bosch 029.jpg (86.85 KiB) Viewed 5245 times

Besides the cost factor the other reason for choosing the Bosch battery tool packs was not having to deal with a BMS. Apparently the Lithium Manganese “konion” cells used in these packs discharge and charge so much alike they don’t easily get out of balance.

I have a lithium charger on its way from China but for now I use a 36V SLA charger. I do however monitor the charging process with my Watts-Up meter and stop it when it reaches the target voltage of 41.5V. If I didn’t do this the charger would run the pack all the way up to 44.0V-not a good thing While my SLA’s would show nearly the same starting voltage hot off the charger that is something of an illusion. An SLA charger will maintain up to 41.4V in float mode (I set mine to 41.0) but this is just to make up for the inherent self-discharge of lead-acid batteries. When removed from the charger they will quickly fall to their real fully charged voltage of roughly 13.2V for a 12V battery or 39.6V for a 36V pack. Lithium on the other hand just stays where it’s parked therefore I started out with almost 2 more volts using the Fatpacks compared to the SLA’s.

I completed the pack two days ago and today the weather was good enough for an extended ride to test the pack…but only just; cloudy and cold (low 40’s) but with a very light wind. I was not feeling great but this was to be a ride heavy on the motor assist side to run the pack as long as I could to check the capacity.

The extra voltage from the fatpacks meant the unassisted speed rose from a max of 16.5 mph to something in the low 17's. I didn’t have much perfectly flat ground but this appeared to be on target with the 0.9 mph increase I had observed in the no load speed before starting out. At the start there was also a minor amount of assist available at 20 mph, also a significant boost from ~18 mph on lead. In fact the lithium pack almost felt as strong as the 36V + 6V SLA configuration I tried previously. LiFePO4 with its even higher starting voltage of about 43.8V for a 12 cell 38.4V pack would be even stronger but prices are much higher than these tool packs. Some day…

Usually when I ride I use the throttle conservatively. I generally find a gear I’m comfortable pedaling in and bring in part throttle to ease the pressure a bit and maintain a bit more speed up grades and into headwinds. For this ride after the first couple volts burned off I used full throttle most of the time and matched my pedaling to the speed. With this more throttle heavy approach I used 3.0Ah after 12.75 miles when I normally would use 2.0 to 2.5Ah. The idea for this test was to ride until I hit the LVC of the controller, 31.5V, and see how much capacity I used. With the 36V/9Ah SLA pack the best number was 5.4Ah. I was getting pretty cold when I arrived home after about 23 miles and I still hadn’t reached the test end point so I motored around for a couple more miles (which reduced my avg speed) and finally called it quits when I felt a few rain drops. In the end I had used 6.085Ah / 224Wh with a minimum voltage of 31.61V and traveled 25.50 miles at an average speed of 17.4 mph.

I am very pleased with the outcome of the test. The lithium pack made up of Bosch Fatpacks felt stronger than the SLA pack, delivered greater capacity while using the throttle more aggressively and resulted in a higher average speed even though I wasn’t feeling 100%. The best part is this comes at only a little cost premium to lead-acid batteries AND it reduced the battery weight by 60% (7.0 lbs for LiMn Vs 17.7 lbs for lead).

Bottom line is if you are looking for a low cost lithium alternative to SLA’s then Bosch Fatpacks could be for you. One thing I would change if I did this again would be to forgo the disassembly work and simply take the tops off the individual packs, bring the wires out and strap them together. It would be a much simpler technique that would only increase the length and weight marginally.

And so the lead batteries are retired after only 19 cycles. Ah and they were so young.

-R

[kefa]

nice.

are you charging all the cells in parallel? what kind of charger are you getting from china?

those bosch packs look good, too bad we can't get them cheap in australia though.

[Russell]

nice.

are you charging all the cells in parallel? what kind of charger are you getting from china?

those bosch packs look good, too bad they we can't get them cheap in australia though.

Yes the 3 packs are wired in parallel and that's the way I'm charging them. I'm charging them right now and after 3.5 hours roughly 5.5 Ah has been put back in using my SLA charger. The Li-Ion charger that's coming from China is a cheap-o I purchased on eBay that cost $24 delivered. I was surprised for that price the seller emailed to ask the application and if I wanted any special connectors on it! He said he'll even preset the charger to 41.5V for me, ya can't beat that...if it works of course.


-R

[pwbset]

The Li-Ion charger that's coming from China is a cheap-o I purchased on eBay that cost $24 delivered. I was surprised for that price the seller emailed to ask the application and if I wanted any special connectors on it! He said he'll even preset the charger to 41.5V for me, ya can't beat that...if it works of course.

Which ebay vendor?

[Russell]

The Li-Ion charger that's coming from China is a cheap-o I purchased on eBay that cost $24 delivered. I was surprised for that price the seller emailed to ask the application and if I wanted any special connectors on it! He said he'll even preset the charger to 41.5V for me, ya can't beat that...if it works of course.

Which ebay vendor?

http://shop.ebay.com/merchant/ecitypower


They have one up for sale but the price is up from what I got mine for, and I had no competing bids.


I'm sure they will sell you one quite inexpensively if you contact them directly at ecitypower@gmail.com. The person who wrote me was Mr. Jack Xie. I believe Doctorbass has been in communication with these people about his own charger needs.


They also maintain these websites:


http://www.ecitypower.com/

http://www.bmsbattery.com/




-R

[pwbset]

Thanks Russell.... I've been following that ecitypower thread also. Jack quoted me $25 shipping to US for the 200 watt charger. Was thinking of getting two of them, but I'm going to wait now until you get yours and hear a report on them.

[Russell]

Bottom line is if you are looking for a low cost lithium alternative to SLA’s then Bosch Fatpacks could be for you. One thing I would change if I did this again would be to forgo the disassembly work and simply take the tops off the individual packs, bring the wires out and strap them together. It would be a much simpler technique that would only increase the length and weight marginally.

-R

I can never leave well enough alone so of course after assembling the battery pack and going on one ride I just had to take the pack apart and rebuild it. I broke it down (the RTV came off easily) and then installed the heavy rubber end panels. I removed the in-line 60A fuses since now they were in the way and I still had the 25A fuse for the entire 3-pack. Then I went crazy with the hot glue gun and the finishing touch was a top cover cut from a Lean Cuisine tray. The end blocks are RTV’d together and the whole pack is taped with electrical tape though that will be replaced with something stronger. The end result is the pack grew in size to 7.4”L x 6.2”W x 3.9”H and the weight increased by 11 ounces to 7 lb 6 oz (as shown below) or 7 lb 11 oz in the cardboard box, which is no longer needed for protection, but which I still used just because it fits so nice and snug in the rear trunk bag.

Rebuilt Fatpack 3-pack

Bosch 040.jpg (84.61 KiB) Viewed 1762 times

Today I went on another ride to test the ultimate capacity I could expect from the Fatpacks. For this trip range was to be more important than speed so I reverted back to using the throttle more conservatively. That was until 15 miles into the ride when in my rearview mirror appeared another rider gaining on me. I was averaging just over 16 mph at the time which isn’t a bad pace. With the battery still fairly fresh I was able to up that to 17-18 mph with some real effort from me too. The fact that we were heading into the wind and mostly up a slight grade for the next two miles was actually in my favor. You see while the switch to lithium does give me a hair more speed the fact is at this point by 19 mph ALL assist is gone so after that I’m essentially an overweight 50 year old guy pedaling a heavy 52 pound hybrid bike. Needless to say I’m not gonna win any races with Roadies. Anyway I was able to drop’em this time.

At 20 miles into the ride I had used an even 4.0 Ah of capacity which is more than I wanted to use but no doubt that couple of miles at full throttle to shake the challenger didn’t help. I was close to turning back on the final leg when the wind would be more favorable so I thought I might just have enough power. At 22 miles I noted all assistance was gone by 18 mph. At 27 miles the little Bafang was feeling fairly lackluster (ok no eye-rolls from the peanut gallery). The voltage was down to 34.0V under a 6.5A load (about 1C). At around 30 miles I noticed my rear wheel was wobbling…out of true or did I break a spoke; too close to home to worry about it now. A couple of hills to go and there was still some juice (mental reminder: I’m gonna have to try these hills on a full charge once). Oh almost hit the LVC on that last one .

Trip results:

Distance: 32.2 miles (51.5km)
Average speed: 16.6 mph (26.6kph)

Amp-Hours used: 6.216
Watt-Hours used: 229.8
Peak Watts: 553
Min Volts: 31.63

WH/mile: 7.14
WH/km: 4.46


Compared to the longest ride with the 36V/9Ah SLA pack the Fatpacks delivered 14.8% more Amp-hours, 18.6% more Watt-hours and did it with a 58% reduction in weight though volume is comparable (the fatpacks are fatties ).


Oh yeah...I popped a rear spoke and the brake was dragging. So now I know how you direct drive guys feel


-R

[dnmun]

he has a 500W charger for $76 too i think.

somebody should buy that one and do a report, his charger case looked solid and fan well placed, no nonsense. 48V10-12A would be perfect.

[Russell]

37 miles on 3 Fatpacks

No this wasn’t an exercise in hypermiling just a normal Saturday afternoon ride; more on that later but first an update.

Since putting the ebike into service at the beginning of February I have been on 28 rides and logged 723 miles. Early this month I switched from using 3-12V/9Ah SLA batteries to a LiMn battery pack made up of three Bosch Fatpack 36V tool batteries. After constructing the pack sans all of extra parts I tore it apart and rebuilt it with the heavy rubber endcaps. I did this for added protection even though it added 11 ounces to the overall weight of the pack. Here it is in the SLA tote bag;

Bosch 054.jpg (88.22 KiB) Viewed 1677 times

I have ridden 10 times with this battery pack and really like it. The most capacity is about 6.4Ah which I recorded one day when I ran the voltage all the way down to the LVC of the controller (31.5V) several miles from home. The voltage didn’t just sag to that level as on previous rides, oh no I had drained it completely, well maybe 95% complete since the LVC is a bit high for lithium. Still when the voltage gets this low there is precious little left to give even if the controller’s LVC were marginally lower. I had no power whatsoever for the last few miles of a 33 mile ride which wouldn’t have been so bad, the bike pedals fine with no assist, except I had bonked the same time as the battery. Apparently I hadn’t filled up my battery after the previous day’s ride. Oh well at least I found the battery’s limits.

I bought a LiPo charger on eBay, for $24 delivered, as soon as I constructed the Bosch battery pack but while waiting for that to arrive (from China) I used my SLA charger for the first half-dozen recharges. I monitored the charging process with a Watts-Up meter and pulled power when the battery got to where I wanted it. I charged it to 41.5V the first few times but then noticed that precious little juice was actually being put into the battery after 41.0V. I’ve heard the standard Bosch charger charges to around 40.5V and this is probably the reason why, as is I suppose the desire for longevity which according to Doctorbass is greatly extended by not trying to get that last bit of energy into the cells. For standard LiPo that means 41.5V is better than 42.0V but apparently the cells in these Fatpacks like even a lower voltage. I ended up settling on 41.15V. I finally got the charger and here is a picture of it side by side with my SLA charger;

SLA on the left, Li-Ion on the right

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They not only look the same on the outside they have the same circuit board on the inside. One problem with the LiPo charger was that it came with a 250V Euro style ac plug. The seller sent me several emails asking about how I planned to use the charger and if I had any special connector requirements. I told him to leave the output leads bare, which he did, so I could install Anderson connectors but I never thought to tell him I wanted a 120vac North American style power plug on the thing. Luckily the rating plate states the charger works on 100-240vac, 50-60Hz so I found an old power cable and spliced it in. I then opened the unit and adjusted the output to my preferred setting. I monitored the first couple of charges to make sure it worked properly. The front LED goes from red to green at 41.09V at 0.16A and if I leave it connected for an hour or two it’ll finally settle out at essentially zero current and 41.16V.

As for the Bafang motor itself I have had no problems. It still vibrates under load and no amount of spoke tightening seems to fix that so I’m going to have to live with it.

I broke one spoke at 500 miles on the new pre-built rear wheel I bought to match the rim I used for the front motor/wheel. I found when replacing the spoke that the elbow length of the spokes they used were too long so the spokes didn’t seat in the flange and this probably accounted for the early failure. I replaced not only the broken spoke but 8 others which exhibited the poor spoke head seating.

The 6.4Ah lithium battery and the little Bafang are a great combination that’s well suited for rides of 20 miles. Over this length if you want you can use full throttle and get some assist at 19+ mph due to the higher working voltage of the LiMn battery compared to the old SLA’s which offered nothing at 18 mph. As stated earlier in this thread the top speed of the motor on the battery only went from 16.5mph on fresh SLA’s to low 17’s with the Bosch pack.

Ok back to today’s ride. It’s been quite a chilly April this year in Wisconsin with temps rising only into the 40’s on most days. Today that (briefly) changed with temps in the mid 60’s as I left to ride. The wind was brisk out of the southeast at 14mph and as I got near Lake Michigan I could definitely feel the cooling effect from the big lake. This was the first day I rode in shorts and a t-shirt, well two t-shirts actually, and it got pretty nippy with the lake breeze so I headed west. Just a few miles in it warmed up nicely. I continued on to the rolling countryside.

I got to one particularly rough road, I knew it was rough because they kindly posted a sign “rough road”, though so many of the roads around here are crappy this one would have to get in line for the rough road title. It was narrow however and on the left side of this crummy road I spied a brand spankin’ new bike path (why are they always on the other side of the road?). Let me say right off I don’t like most bike paths. I think many bike paths are less safe than riding on a roadway. I only wish they could build roads with at least a 3 foot paved shoulder on both sides and forget about many of these silly paths. Not all are bad mind you but most are poorly designed and just when you get on them they stop. Take the one I encountered yesterday; I’m rolling along this country road and once again on my left I spot this new subdivision and this brand new bike path. The problem was as I rode along wondering if I should zip across to the path I noticed all of the streets the path crossed and at each one a little stop sign. I must have seen a half-dozen of these crossings and while I was also passing cross streets I was doing so on the main road with the right-of-way. To me each time a bike path crosses a road at a point a motorist is not expecting cross traffic the likelihood of an accident rises. Okay enough ragging on bike paths. Today the smooth goodness of the path beckoned to me just like the sound of the ice cream truck tune does to a youngster on a hot summer day. I found a driveway and hopped on her. Oh how lovely fresh asphalt feels I thought to myself. The curving path combined with a tailwind made the next mile cycling nirvana, but as with all good things it ended far too soon. Back to reality and time to head for home as the power was starting to get low.

The last hills before home made quick work of what was left in the Fatpacks and I was getting a little tired myself. In the end I had ridden 37.1 miles (59.4km), used 6.13Ah/225Wh with an average speed of 16.6 mph (26.6kmh). The 6.1Wh/mi (3.8Wh/km) used was lower than normal for me and speed slightly higher than normal for this distance but that has more to do with the weather than anything else. I ride better when I’m not freezing my butt off and I imagine my aerodynamics are improved without a jacket and sweat pants flapping in the breeze. I estimate I used the throttle at least 80% of the time though it’s almost always partial throttle. For recreational riding the combination of a low-power hub motor and lightweight battery on a decent riding bike can’t be beat.

Oh yeah, when I got home I checked the weather from two websites and one reported 56F and the other 70F. I guess one must be near that ice cube of a lake

-R

[Rassy]

Russel, nice review. Your distance caught my eye, since I just got home from a 37.5 mile ride. I'm getting my 69 year old body ready for a Metric Century in three weeks. I currently have a Bafang in the 20" front wheel of the recumbent, with a 48V 20AH LiFePO4 on the rack. Suprised to find the total weight is now about 80# (plus 220 for me with shoes, etc).

Anyway, I used just under 10AH for my ride. I also pedal the whole time, but not very hard, always in the highest gear. In the 20" wheel the Bafang tops out at about 15 MPH. This was set up to ride with pedal only buds.

[Russell]

Russel, nice review. Your distance caught my eye, since I just got home from a 37.5 mile ride. I'm getting my 69 year old body ready for a Metric Century in three weeks. I currently have a Bafang in the 20" front wheel of the recumbent, with a 48V 20AH LiFePO4 on the rack. Suprised to find the total weight is now about 80# (plus 220 for me with shoes, etc).

Anyway, I used just under 10AH for my ride. I also pedal the whole time, but not very hard, always in the highest gear. In the 20" wheel the Bafang tops out at about 15 MPH. This was set up to ride with pedal only buds.

So you use a motor while your buds pedal? (do they know? )

My bike with everything on it that I ride with, except full water bottle, is 52 lbs and I'm 200 lbs and 50yrs. I'm hoping I can ride a few more decades and with a motor I just might...though I don't think my old(er) bones could handle the rough roads around here so I guess I'll have to head for Florida some day

I originally wanted an assisted range of 50-60 miles, and I suppose with nursing the throttle a lot I could obtain that but at some point it would be better to ride one of my regular bikes that weighs half as much...or I could get a bigger battery

-R