My Bike is the Most Efficient

When I charged the 2 year old (4000 miles) 400wh battery, the LCD showed 554.7 miles on the trip meter. The next time I charged it, it showed 720.0. That's 165.3 miles on one charge - approx 2.4 wh/mile. The meter had just gone down from 2 to 1 bar on the battery display, so I would probably have been good for another 30 miles or so.

I'm 100kg and all my journeys are very hilly. I encounter a 30% incline on most journeys. A couple of the journeys were over 40 miles, but most around 25 miles. Here's the bike:

http://i451.photobucket.com/albums/qq236/d8veh/rocky%202/20141230_141700_zps2746a47d.jpg

must be magic

http://i451.photobucket.com/albums/qq236/d8veh/rocky%202/20141230_141700_zps2746a47d.jpg

You really must remember to switch it on when setting off.

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must be magic

It would need to be with that saddle angle.

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Edited September 27, 20169 yr by EddiePJ

if you could only have one of your bike builds, which would it be and why?

that could be a subject of a new thread.

Out of interest d8, if you could only have one of your bike builds, which would it be and why?

Very good question. I have about 10 ebikes and two roadbikes. I use the roadbikes for exercise and this electric bike for everything else.

Since I build this one, it's the only electric bike I use. It's comfortable, light and efficient, and when required, it can handle very steep hills without pedalling. 30% inclines are a breeze. Since I built it, the only maintenance required, other than a squirt of oil on the chain occasionally, was a broken gear cable. I bought the gears used from Ebay, so that cable could have been very old. In fact every part of it was from Ebay, used, except the cranks, chain, tyres and electrical stuff. Total cost was about £1100 IIRC. It's done 4000 miles so far.

The only problem with it is that since I built it, I can't find anything better, so it's stopped me from building new bikes. I used to build about 4 bikes a year to try out all the new motors and stuff. Now I only build them for other people.

That's a great distance, fabulous conversion as well d8veh.

Time to update us on what's happened with your Bearprint!

Hello d8veh,

I'm pleased to see you are still building amazing bespoke Ebikes.

I've not looked in much on the forum lately.

After completing 26,500 commuting miles on the Bearprint - more than the circumference of the earth - in October 2015 I bought a Xingyue XY150XK Vogue scooter to use travelling to work.

It has a roof and windscreen so is more weather proof.

I figured after 5+ years I have nothing to prove regarding my Ebike usage.

The only trouble is my workplace closed down at the end of March this year and I have been out of work since then.

With the redundancy package I decided to take some time off after working for the last 30+ years.

I replaced the crappy Clarks disk brakes on the Bearprint my bike shop fitted with Avid BB7's which are far superior.

For a generic chinese Ebike the Bearprint overall has done a great job for me and I have thoroughly enjoyed being an Ebiker.

It's nice to post here again.

As usual best wishes to all!

Barry Webber.

Hi Bazwaldo, long time no see. Amazing mileage on your Bearprint, I do wonder if you have the record. You are a beacon of ebiking to which we all should aspire. How many batteries have you got through? I'm currently needing a re-cell on my Eagle. I guess your experience suggests there is plenty of life left in my bike, it's only done 6700 miles, so perhaps I'll do some fettling to bring it back to scratch.

Alternatively, I could ask D8Veh how much he wants to build me a Rocky Mountain Beasty!

in October 2015 I bought a Xingyue XY150XK Vogue scooter to use travelling to work.

It has a roof and windscreen so is more weather proof.

That looks great Barry, and with 150cc much more practical than Honda's earlier very underpowered 50cc equivalent. Though ironically the Xingyue has a Honda engine!

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Today's ride 7.58 Wh... That is 1 Wh better than the other day! Oh and 1259 m elevation gain over 61.54 km...

I would have to come and test on your route d8veh in order to compare bike efficiency. Mine is heavier that yours!

Before this thread drags on too far, and before everybody rushes out to buy a Xiongda motor, I'd like to malke a couple of points:

The 165 miles range is genuine, and was done with the bike switched on all the time. Anyone could do the same as long as you have at least 2 chainrings. Instead of using the motor to power up hills, I used a low gear and low power. That means going a lot slower. I'm fairly fit (legwise) so I'm able to pedal fairly hard. Most of the time, I can travel on level zero because there's no drag from the motor. I sometimes do 30 miles before I leave level zero.

I made this thread to show the ludicrousness of any claims made about range. Range depends on the rider and their rides, not the bike. Obviously, the bigger the battery, the further you go.

I ride with my friend and forum member Saneagle. His bikeweighs about 30kg, It's got a 27Ah battery that weighs 9kg plus a 4 kg Bafang BPM motor. On an average ride of 20 to 40 miles, he uses about 100Wh, which gives him an average range of 291 miles. When his wife uses the bike, the range would be about 50 miles.

I made this thread to show the ludicrousness of any claims made about range. Range depends on the rider and their rides, not the bike. Obviously, the bigger the battery, the further you go.

Exactly.

My average ride stats for riding off road work something like this.

I almost flattened the first 500wh battery on the Bosch CX powered bike in just 9 miles during the following ride, and I hadn't realised just how hot that a battery could get. Changing battery to complete the last 1.4 miles was an annoyance. https://www.strava.com/activities/658404106

Riding locally on my own on say the South downs, I would guesstimate that I get an average of 22 miles from one charge. This is an average taken from both bikes running the CX motor and 500wh batteries.

Riding to and from work off road, or with others who are on pedal only mtb's, I would guess that my average miles from one charge might if lucky hit the late thirties.

I am convinced that CX motor is nowhere as frugal on battery consumption that the Performance Line motor was. With both bikes now running CX motors and 500wh batteries, I sadly can't make any direct comparison.

Edited September 28, 20169 yr by EddiePJ

 

I almost flattened the first 500wh battery on the Bosch CX powered bike in just 9 miles during the following ride, and I hadn't realised just how hot that a battery could get.

That's handy for winter riding. It sort of puts the kibosh on those that say a battery loses performance in the winter.

That's handy for winter riding. It sort of puts the kibosh on those that say a battery loses performance in the winter.

i put a cell in the freezer over night and it did lose a bit from fully charged.

0.02v is all it lost

I average about 4wh/mile on the Gtech, proved it's worth again today riding into a hellish head wind..

Keep practising. Soon you'll be able to use a roadbike like me and do 0 Wh/mile, which saves a lot of messing about. No battery range anxiety either. Wind is also easier to deal with.

i put a cell in the freezer over night and it did lose a bit from fully charged.

 

0.02v is all it lost

Self discharge is not the effect of a cold cell, but it is a good indicator of a problematic cell, regardless of temperature. 0.02V is certainly nothing to worry about though.

When a cell is subjected to low temperatures, it has the effect of raising the internal resistance (IR) of the cell. This higher IR will then cause the voltage to drop further than usual when a load is put on the cell and current is drawn.

This is the reason that car batteries give so many problems in winter. The apparently healthy battery sits outside in the cold and when we ask it to provide hundreds of cranking amps, the voltage collapses and is unable to provide sufficient power to turn the starter motor.

When we ask a cold battery to power our bike motors, the voltage sag causes LVC to trip earlier than usual and therefore has the effect of giving less capacity from a charge, as well as a bit less power.

I'm not sure why d8veh suggests that the idea of capacity loss of a cold battery is spurious as it is a widely understood property of all battery chemistries. I might have misunderstood what his point was though (possibly about the self-heating of cells), so I'm sure he'll be able to expand further if he feels he should or wants to.

Edited September 29, 20169 yr by danielrlee

S

I'm not sure why d8veh suggests that the idea of capacity loss of a cold battery is spurious as it is a widely understood property of all battery chemistries. I might have misunderstood what his point was though (possibly about the self-heating of cells), so I'm sure he'll be able to expand further if he feels he should or wants to.

You answered the question yourself. Batteries have internal resistance. As soon as you start using them, they warm up, so the ambient temperature doesn't make much difference.

Ebike batteries are not the same as car batteries. Car batteries only discharge for a few seconds when using the starter motor, which doesn't give them enough time to heat up. After that, all the electrical power comes from the alternator. Ebike batteries give more or less continuous power until empty. How much they heat up depends on how much current you draw.

The good 18650s have an internal resistance of 50 milliohms. Lets say that an ebike averages about 4 amps (160w). The heat generated would be 0.8 watts per cell, which is 32 watts for a 40 cell battery. That's enough to gradually warm it up. When you go up a hill and use, say 10 amps or more, the heating would be 5w per cell and 200w total, which is substantial. That would be if it stayed cold, but actually, the internal resistance would go down when it warms up, so actual heat would be less.

Therefore, if your bike feels sluggish because you left it out in the cold, just run full power for a couple of minutes and then your battery will come to life.