Miles' Project 1 [eMoulton]

[es2150]

What size wire is in that coil? i figured out what size wire to do for hub motor and 50amp controller and came out to an 8 for 5ft tether. have since gone back for commute just because I wanted to loose the heavy backpack. I was carrying 48v 15ah lifepo4 about 15lbs plus 5lbs kit = 20lbs backpack. It was great for offroad but too much for commuting. Anyway, I had similar coil wire but thought size was way to small, am I mistaken. By the way, your rig is literal a work of engineering art. I am assuming you are using lipo right. Do you ever have any concerns about discharge rate and having in backpack?

[Miles]

Hi es

I'm still using 36 5Ah high power density NiMH cells... The lead is from an electric kettle - 15 amp rating, I think. I'll check the gauge.

Maybe doubling up conductors is the way, for a ready-made coil?
http://www.cablescience.com/retractile_cords.html

Backpacks work better for a stretched-out riding position - I forget mine's there after a few seconds - mind you, that's only 5lbs weight of batteries... say 7lbs total weight .

[Green Machine]

Really sweet build...

Too bad you cant mount rack your batteries to finish it off...

I really love this battery for my downtube folding bike build:

http://ebikessf.com/50v10ah-lipo

I have 3 of these and swear by them..really a tight package...i think would fit stealthily on rear rack.

[liveforphysics]

Hi es

I'm still using 36 5Ah high power density NiMH cells... The lead is from an electric kettle - 15 amp rating, I think. I'll check the gauge.

Maybe doubling up conductors is the way, for a ready-made coil?
http://www.cablescience.com/retractile_cords.html

Backpacks work better for a stretched-out riding position - I forget mine's there after a few seconds - mind you, that's only 5lbs weight of batteries... say 7lbs total weight .

Have you felt the extremely supple ultra-fine-strange silicone 8awg wire Miles? I think you may find a cable made from twisting a pair of 8awg silicone wires together, and fixing a fine elastic bungee to some point of the cable which you don't expect to be needing to drawn from the backpack, so it keeps the slack all tucked away when not needed, but if you change positions or dismount or whatever to require additional slack, you've got an extra few foot loop that the be drawn out from the backpack by stretching the bungee.

I think you may find something similar to that to be an even less intrusive backpack-bike cabling approach, gaining high-current capability.

[Miles]

Really sweet build...

Too bad you cant mount rack your batteries to finish it off...

Thanks. I may fix the batteries to the frame on the next build. There are real advantages to having them in a backpack, though. IMO, on a rack over the rear wheel is the worst place for them....

[liveforphysics]

Really sweet build...

Too bad you cant mount rack your batteries to finish it off...

Thanks. I may fix the batteries to the frame on the next build. There are real advantages to having them in a backpack, though. IMO, on a rack over the rear wheel is the worst place for them....

I agree. For smallish sized packs, backpack makes a lot of sense. Backpack with a compact, quiet, high current opertunity charger and a few Nano-tech packs able to be charged in 6mins makes boatloads of sense. Even if you only have a couple hundred watt-hours, you can really leverage them well with a setup like that.

[Miles]

Have you felt the extremely supple ultra-fine-strange silicone 8awg wire Miles? I think you may find a cable made from twisting a pair of 8awg silicone wires together, and fixing a fine elastic bungee to some point of the cable which you don't expect to be needing to drawn from the backpack, so it keeps the slack all tucked away when not needed, but if you change positions or dismount or whatever to require additional slack, you've got an extra few foot loop that the be drawn out from the backpack by stretching the bungee.

I think you may find something similar to that to be an even less intrusive backpack-bike cabling approach, gaining high-current capability.

Good idea... That would be a lot neater.... Thanks for the prompt, Luke.

[liveforphysics]

I don't know if the quality of this wire matches the suppleness of the HK stuff, but it's local to you evidently.

http://cgi.ebay.com/8-AWG-Silicone-Batt ... 1403wt_905

I figure you would want both wires black.


Then something like this:

http://cgi.ebay.com/20-Ft-1-16-ID-Tiny- ... 116wt_1139


Then a premium connector that would never disconnect unintentionally, but could disconnect from a firm tug in the event of a wreck or forgetting to disconnect. I'm thinking EC3 would be a good match for your needs, while having ample current overhead.




And then of course no BMS or balancer in your pack, as you're responsible, and neither savage nor fool. Batch charging from something like this 755w 48v compact server power supply would likely tuck nicely into the backpack and enable very useful opertunity charges.

http://www.serversupply.com/products/pa ... ?pid=86912

[liveforphysics]

BTW- I only posted those links for Miles because of the irony of linking something I found online to Miles, the king of all human/machine search engines.

[Miles]

Good stuff...

Thanks Luke.

[Green Machine]

Really sweet build...

Too bad you cant mount rack your batteries to finish it off...

Thanks. I may fix the batteries to the frame on the next build. There are real advantages to having them in a backpack, though. IMO, on a rack over the rear wheel is the worst place for them....

Hi Miles,

Its interesting you say this..and i am not knocking the idea of backpack at all since i havent tried it, but am contemplating a new build and a back pack battery could be a consideration although a distant one.

I love your bike and is one of the nicest aesthetic e-bikes i have seen in picture...i know you probably spent a bundle...again well done.

SO i have 4 high end bike builds, and it turns out my cheapest one...a downtube 20 inch wheeled folder is my favorite...i put 1300 miles on it so far in 4 months. I call it my beater...of all my bikes its the one i can lock outside and not worry cuz its low key looking. I love it and cant put my finger on just why. It had thin tires like yours and i went with schwab fat apples and disc brakes and that made a big difference. I hated those thin racing bike tires on a ebike especially since mine is front wheel drive. When i put the fat apple tires on it (amazingly they fit) my love affair started with this bike. I also ended up loving the front wheel drive (it spins out on start up but is fine all other times) and internal hub shifter on the back. I just love the 20 inch wheels on a road electric bike, and because of the fat tires i am able to ride off road on fire trails. Mostly i love the low center of gravity that having the battery mounted above the rear wheel has compared to full sized bikes with the same configuration i own. Because i never have to lean the bike over because of the low downtube i never feel the extra weight of the battery on the back, and because of motor on front it is well balanced. It just doesnt feel like an electric bike like my large frame bikes do. I use the topeak small dxp bag which is pretty aesthetically nice because it is so small (fits 10ah pack perfectly) and i like having the side panniers for extra stuff on my rides. I dont like to have anything on my body when i ride including in my pockets...i got spoiled always having rear topeak bags on all my bikes.

Anyway i think a 20 inch wheeled bike is a nearly ideal electric bike build...and i rarely see one...and yours is sweeter than sweet.

For a while i was thinking of spending the money on a quality 20 inch wheeled frame and moultons were one of the bikes i look at.I have never had my bike folded and dont need the folding function...so a moulton would be perfect except for the price point (1700 is as cheap as i can find a starting bike here in california).

So why do you not like a rear mounted battery? Is it asthetics? Or functionality? Is it a balance thing? Like always...just gathering info...

[HAL9000v2.0]

Miles, do you need 498 pcs? I'll take two...
http://www.diytrade.com/china/4/product ... _cord.html
http://www.alibaba.com/product-gs/31085 ... cable.html

I googled this before for some time but never find anything bigger then 3 x 1,5mm2. I'll be happy with 4 x 1,5mm2.

For now I am using guitar coaxial cable. it is good up to 40A.

http://www.amazon.com/dp/B003NE5WO4/ref ... B003NE5WO4

[Miles]

SO i have 4 high end bike builds, and it turns out my cheapest one...a downtube 20 inch wheeled folder is my favorite...i put 1300 miles on it so far in 4 months. I call it my beater...of all my bikes its the one i can lock outside and not worry cuz its low key looking. I love it and cant put my finger on just why. It had thin tires like yours and i went with schwab fat apples and disc brakes and that made a big difference. I hated those thin racing bike tires on a ebike especially since mine is front wheel drive. When i put the fat apple tires on it (amazingly they fit) my love affair started with this bike.

I'd prefer it if I could fit sturdier tyres on mine but using the Stelvios was the only way to create enough space for the motor

So why do you not like a rear mounted battery? Is it asthetics? Or functionality? Is it a balance thing? Like always...just gathering info...

Mostly balance. On the Moulton, the best place to mount them would probably be under the tie rod for the cruciform.

I have to carry my bike up and down steps whenever I use it. Having the batteries in a backpack makes the bike itself an easy lift.

[Miles]

Miles, do you need 498 pcs? I'll take two...

I'm leaning towards Luke's idea at the moment, perhaps with a sprung cable reel, even

[Miles]

On the Moulton, the best place to mount them would probably be under the tie rod for the cruciform.

Something like this...

[liveforphysics]

That isn't just 2 x 6s packs I'm seeing is it?

[Miles]

That isn't just 2 x 6s packs I'm seeing is it?

Yes, a whopping 6 Ah...

Plus the same in a backpack...

[liveforphysics]

That isn't just 2 x 6s packs I'm seeing is it?

Yes, a whopping 6 Ah...

tisk tisk It's a good thing you're an extremely responsible guy who can handle not over discharging anything.

Despite the tiny capacity, if I'm not mistaken, you will be enjoying the battery power potential of ~13kw on command if you needed it. If you're going to make a pint-sized pack, you did make the right choices.

[Green Machine]

Miles,

What kind of top speed do you get with that rig?

What is your average range per pack?

[Miles]

At the moment, it's set up for a top speed of 22mph in 3rd gear. Street legal in 2nd gear (direct drive)...

As for range, I normally just use the motor on hills, so it's highly dependant on route. Around 15 miles of continuous use, I guess.

[jag]

For smallish sized packs, backpack makes a lot of sense. Backpack with a compact, quiet, high current opertunity charger and a few Nano-tech packs able to be charged in 6mins makes boatloads of sense. Even if you only have a couple hundred watt-hours, you can really leverage them well with a setup like that.

Quick "opportunity charge" sounds like a good idea. Problem is, where to find a powerful (around a kW) yet compact and quiet charger. The Meanwells many of us use are 350W/kg. The Flatpack2 I just bought is 800W/kg. However this is nothing compared to the power density of some of the DC-DC converters that are around 2000W/kg. Problem is the DC-DC are typically max 70V in (48V nominal). They are small beacuse Switching frequency is in the 100kHz to MHz range. (Most 110V mains PSUs seem to be 10's to 100kHz range)

So is there some source of compact 110V to 48V PSU/chargers I've not found?

[magic carpet]

dirty_d - I didn't make the bike itself, I just did the conversion to an ebike.
That's an understatement! Beautiful job on a beautiful bike!

[crossbreak]

congratulations for your build miles, it is a very harmonious concept, keep making it prefect for your all day use before you buy components for your second build I did not do so. Now I have some parts lying around worth a hundred bucks which I maybe wont use any time because I learned from experience in between

Quick "opportunity charge" sounds like a good idea. Problem is, where to find a powerful (around a kW) yet compact and quiet charger. The Meanwells many of us use are 350W/kg. The Flatpack2 I just bought is 800W/kg. However this is nothing compared to the power density of some of the DC-DC converters that are around 2000W/kg. Problem is the DC-DC are typically max 70V in (48V nominal). They are small beacuse Switching frequency is in the 100kHz to MHz range. (Most 110V mains PSUs seem to be 10's to 100kHz range)

I was once told that the power supplies for large CPU (the ones on the mainboard which switch down the 12V DC to 1.2V for the CPU, about 100Watts and more) are supplied by step-down converters that use "some khz". But they use 7-10 phases. Does the phase count affect power density? I write power electronics on monday. maybe i should know this

EDIT: ok I got the answer myself: the more phases u switch the smaller the smoothing coil will be. That way it effects power density.

I also use meanwells and they are quite heavy if you try to take them with you. I also use bmsbattery charger 400W, which definitely plays in a different class

[sk8norcal]

[Miles]

Crikey... I had completely forgotten about that! Gives a good impression of the noise level, if nothing else....