Background
Ok for those who haven’t seen my other posts on this subject I need a bike to commute 10 reasonably hilly miles to a station, fold small enough to then go on a busy London commuter train and then take me another 3-4 miles at the other end to get to work. I want an electric bike to do this because I can’t stand the thought of a 10 mile ride home after a 12+ hour night shift! Money constraints are not really a factor in this project (within reason) but I do not want to waste money on anything I don’t need. I am planning on downgrading and possibly getting rid of the car completely if this works.
The ideal package (for me) is impossible with the technology available to me – i.e. a bike which is very light, folds as small as a Brompton and has as much power as the top end full size electric bikes on the market – maximum legal power; I do not want a light assist bike....what I want is a small, foldable electric bike which will fly up hills at the legal maximum speed and get me home with no fuss....it needs to do this reliably, several times a week and with a range of 15 miles (assuming a recharge at work).
So I quickly realised the sacrifice I had to make was in relation to the weight. I cannot go for a larger bike due to the constraints on the train so my project is based on a Brompton M3L folding bike. None of the kits or conversions available quite suits the bill for me. The Electric Wheel Company Nano Brompton does not have enough power for what I want; neither does the CH White bafang based conversion which I have ridden. I started to look for a supplier of the Bafang 8fun SWXK high RPM (300+) but failed miserably to find one; I had intended to run it with a higher power controller to spice it up but had to give up on this idea.
So...I turned to Crystalyte who have a kit for the Brompton on their website which is showing with the now discontinued 209 motor (this is the motor used in the US NYCE Wheels Brompton). However, I didn’t like the look of the fact that it is supplied with a 12A controller and 9Ah battery which is just going to be far too weak and dreary and in fact worse than the Nano Brompton as it’s so much heavier.
So; the Crystalyte G209 is the replacement for the old 209 and fits the Brompton forks without modification; I decided this is to be my motor but I will drive it significantly harder than 12A and with a battery to suit this. As its brand new there is nothing on the internet about this motor so this is a bit of a leap of faith to say the least. On the plus side, it is being delivered to me already built into an official Brompton rim by Crystalyte which makes things a whole lot easier.
I have gone for a Lyen Mini Monster programmable 30A controller with 3 stage power switch, throttle, cruise control module, PAS and Cycle Analyst (which I already have). This is to be set initially at 12, 16 and 20A on the 3 stage switch. The G209 motor should be able to handle high current easily as it is direct drive; at 30A it would theoretically be over 1Kw.
So, this setup will eat batteries when going up hill; I considered 48V with a speed limiter but ruled this out (with advice from others on this site) on the grounds of inefficiency. I have settled on Lifepo4 technology and have ordered an A123 Lifepo4 14Ah battery from Cellman (Emissions-Free) which weighs a hefty 6kg but has a nominal 39.6V which should give plenty of oomph. I have deliberated for a long time over this choice of battery but I am happy that it makes sense for what I am trying to achieve. It will have to withstand 2 charges per day, high current draw, possible deep discharging (depending on how efficient the G209 is!) and I want it to last as long as possible as it is of course expensive. I ruled out Lipo as I think it will just not last as long as I need...I seriously considered the Ezee 14Ah with 2 year warranty. However this warranty is for 60% capacity after 2 years...now 60% of 14Ah will just not be enough for what I need and 2 years is not really long enough for me to spend nearly £700 (as I need 2 chargers) on batteries.
I have also bought a Magicshine 808 bike light head and a DC-DC converter from Ed Lyen; I will have a nice 900 lumen light running from the main battery.
So...the build is soon to begin and I will post some pictures of how I intend to put all this together on the bike; it’s going to be quite heavy but still tiny...fingers crossed it works out how I want; watch this space if you’re interested.
Ben.
Ok for those who haven’t seen my other posts on this subject I need a bike to commute 10 reasonably hilly miles to a station, fold small enough to then go on a busy London commuter train and then take me another 3-4 miles at the other end to get to work. I want an electric bike to do this because I can’t stand the thought of a 10 mile ride home after a 12+ hour night shift! Money constraints are not really a factor in this project (within reason) but I do not want to waste money on anything I don’t need. I am planning on downgrading and possibly getting rid of the car completely if this works.
The ideal package (for me) is impossible with the technology available to me – i.e. a bike which is very light, folds as small as a Brompton and has as much power as the top end full size electric bikes on the market – maximum legal power; I do not want a light assist bike....what I want is a small, foldable electric bike which will fly up hills at the legal maximum speed and get me home with no fuss....it needs to do this reliably, several times a week and with a range of 15 miles (assuming a recharge at work).
So I quickly realised the sacrifice I had to make was in relation to the weight. I cannot go for a larger bike due to the constraints on the train so my project is based on a Brompton M3L folding bike. None of the kits or conversions available quite suits the bill for me. The Electric Wheel Company Nano Brompton does not have enough power for what I want; neither does the CH White bafang based conversion which I have ridden. I started to look for a supplier of the Bafang 8fun SWXK high RPM (300+) but failed miserably to find one; I had intended to run it with a higher power controller to spice it up but had to give up on this idea.
So...I turned to Crystalyte who have a kit for the Brompton on their website which is showing with the now discontinued 209 motor (this is the motor used in the US NYCE Wheels Brompton). However, I didn’t like the look of the fact that it is supplied with a 12A controller and 9Ah battery which is just going to be far too weak and dreary and in fact worse than the Nano Brompton as it’s so much heavier.
So; the Crystalyte G209 is the replacement for the old 209 and fits the Brompton forks without modification; I decided this is to be my motor but I will drive it significantly harder than 12A and with a battery to suit this. As its brand new there is nothing on the internet about this motor so this is a bit of a leap of faith to say the least. On the plus side, it is being delivered to me already built into an official Brompton rim by Crystalyte which makes things a whole lot easier.
I have gone for a Lyen Mini Monster programmable 30A controller with 3 stage power switch, throttle, cruise control module, PAS and Cycle Analyst (which I already have). This is to be set initially at 12, 16 and 20A on the 3 stage switch. The G209 motor should be able to handle high current easily as it is direct drive; at 30A it would theoretically be over 1Kw.
So, this setup will eat batteries when going up hill; I considered 48V with a speed limiter but ruled this out (with advice from others on this site) on the grounds of inefficiency. I have settled on Lifepo4 technology and have ordered an A123 Lifepo4 14Ah battery from Cellman (Emissions-Free) which weighs a hefty 6kg but has a nominal 39.6V which should give plenty of oomph. I have deliberated for a long time over this choice of battery but I am happy that it makes sense for what I am trying to achieve. It will have to withstand 2 charges per day, high current draw, possible deep discharging (depending on how efficient the G209 is!) and I want it to last as long as possible as it is of course expensive. I ruled out Lipo as I think it will just not last as long as I need...I seriously considered the Ezee 14Ah with 2 year warranty. However this warranty is for 60% capacity after 2 years...now 60% of 14Ah will just not be enough for what I need and 2 years is not really long enough for me to spend nearly £700 (as I need 2 chargers) on batteries.
I have also bought a Magicshine 808 bike light head and a DC-DC converter from Ed Lyen; I will have a nice 900 lumen light running from the main battery.
So...the build is soon to begin and I will post some pictures of how I intend to put all this together on the bike; it’s going to be quite heavy but still tiny...fingers crossed it works out how I want; watch this space if you’re interested.
Ben.
