My new bike (puma 48v nimh mtb)

NickF23

100 W
Joined
Nov 23, 2006
Messages
291
Scarily I've been about six or seven months now without an ebike :shock: not quite sure how that happened but its time to finish my new electric bike.

Here are the specs for the bike


Motor: BMC puma at 48 volts 60 amps peak. An old one that steve had, might be slightly damaged but seems to work ok. Mounted in 24 inch wheel
Controller: 72 volt 60 amp crystalyte 4110 fets
BIke: Cheap Ali Mtb got second hand. Importantly it has suspension - the lack of which killed my last bike.
Battery: 48 volt 13AH nimh - old ones I've had for ages and fortunatly/unfortuneatly they show no signs of deteriation so no lifepo4 for me yet.
Charger: powerstream 2A - with discharge facility
Meter: Old Drainbrain with speedo.

My goals for this build are

All batteries in a hard case in the triangle
The bike must be able to be ok to ride or leave in the rain.
The bike must be reasonbly tamper proof and the batteries can't be visable as some people think they're exposives - i got a bit upset after a security guard pulled out the phase wires - "just in case"
Nice simple wiring and connections, no fiddling around with connectors. simple plug in charger and keyswitch on.
Try to minimise duck tape :D
Lots of torque, 25 mph top speed and around 25 mile range with pedalling.

Some pics so far

bike and bits

104_0623.jpg



4 pieces of wood glued to the frame with gripfill. I was going to use a couple of bolts drilled through the frame but the glue seems so well stuck I don't think I'll need them

104_0624.jpg


Steve's old BMC puma a welded on torque arm and bracket custom made in about 5 minutes by Richard the welder at PHEV. 8)

104_0625.jpg


Controller stuck to the bottom and semi waterproofed. Wires should be covered up when case is fixed on.

104_0626.jpg



More updates soon, i only have 2 weeks to the london to Brighton EV rally :evil:
 
Nice one Nick.
You got a mudguard planned for that? The controller looks like it will get all the runoff... :wink:
 
I really like that torque arm. U just welded it to the end of the axle???? Seems like a good solution, since it really doesnt affect the nuts!
otherDoc
 
hey nick,

nice build so far - definately the best idea to have the cells boxed and in the triangle :)
2 week build ? :shock: lol i've taken nearly two years and im still not done - only safes projects take longer than mine and he has the excuse of building everything himself!! :oops:
hehehe, good luck and keep the piccys coming!!


Cheers

D
 
ot a mudguard planned for that? The controller looks like it will get all the runoff... :wink:

Some of it should be covered by the case. But you've scared me though, hmm constructive fear, I might have to rethink some of the design

I really like that torque arm. U just welded it to the end of the axle???? Seems like a good solution, since it really doesnt affect the nuts!
otherDoc

Credit to Steve for that, yep it just welded to the end of the axel, not a problem as long as I don't have to change the nut


hey nick,

nice build so far - definately the best idea to have the cells boxed and in the triangle :)
2 week build ? :shock: lol i've taken nearly two years and im still not done - only safes projects take longer than mine and he has the excuse of building everything himself!! :oops:
hehehe, good luck and keep the piccys coming!!


Thanks for the encouragement D,

Bikes of real beauty do take lots of time to build. I'm going for rough, ready and more or less functional with the 2 week deadline :D


Been long day today, but I'm 1/4 of the way through soldering the batteries together, more pics soon
 
Gripfill and gaffa tape? THats not Crude! :D
 
Yeah, that's straight ghetto. :p

Throw some latex-based black paint on it. Make it look slick. I plan to do similar on a future build, but in plastic.
 
THose screws arnt really countersunk, they are just a little overtightened I bet :wink:

Nick was a hero today, in spite of 30mph+ headwinds and the UK's version of a monsoon, he set of from the city streets to face the almost 60mile ride to brighton. At the halfway point we admitted defeat and left the bikes on the van...but by then Nick had proven his mettle!

Nice to meet Cedric Lynch and his amazing handbuilt coroplast/lemco motored 2 wheel velomobile. Another legend!

Steve
 
yo,

Half way is a good effort, bravo!!!

any pics from the day Joz???


Cheers


D
 
Hi Deec, afraid I didnt have time to take any...I spent the whole time arranging test rides on the KMX (shame, I would have had the biggest gallery of "EV Grins"!), or chatting with Cedric about how many motors must be put into a CBR :twisted:
 
was thinking about the rally as i did bugger all at the weekend - maybe i should have come down :D
ah well next meet. So the cats outta the bag huh? a cbr :) one motor or two?
How did the meet go ? many ppl there? weather was awful tbh so kudos to all those who did brave it!!!


Cheers


D
 
aye, a good meet. Some 12+ people made it, and the response from the public was great. Optibike was there, toghether with Bob, showing off his tricks, you should have come indeed!

2 motors for a CBR I think, or 1 induction motor...not quite decided! Wanted a Ducati, but seems tricky to convert and has will take a hit on battery pack size:(
 
Nice Job.

I'd recommend flipping the controller over so the heatsink screws face out if possible. This is the side that needs cooling. You'd have to figure out the mounting. You can flip the end plate over on one end of the controller.

Watch out for termites.
 
fechter said:
Nice Job.

I'd recommend flipping the controller over so the heatsink screws face out if possible. This is the side that needs cooling. You'd have to figure out the mounting. You can flip the end plate over on one end of the controller.

Thanks Fechter thats a good tip. I'll do that before it warms up here, (not warm at the moment).

fechter said:
Watch out for termites.

I've always wanted to see termites, sadly we don't have them over here. Amazing engineers http://www.youtube.com/watch?v=0m7odGafpQU and also unusual swarm intelligence (warning don't watch this next vid if you don't like termites!) http://www.youtube.com/watch?v=mY9LNEJNrZs
 
Well.... how does it run?

The bike I'm working on will also be a Puma at 48v.
How is the battery?

PS, I can send you some termites if you want :shock: About a week ago I saw a huge swarm of them on the sidewalk (with wings). I don't like finding piles of wings around my house.
 
Its a really great ride, the puma is a really nice motor, the only problem the case is slighly out of alignment which made fitting a disc brake a headache. A big improvement over early bikes I've had. It tops out at about 25 mph on motor power alone. One slightly annoying problem is the gear range isn't high enough to pedal at anything over 15mph, I've just fitted a racer 2 speed cassette at the cranks with 50 something teeth which is a big improvement over the original mtb 3 speed 42T highest. I'm hoping to be able to pedal her up to 30mph with motor assist.

The other great thing is having suspension, its an an absolute must with fast ebikes, I can't believe I rode around ona 30mph ebike without suspension for so long with out serious injury :shock:

The batteries are doing really well, their 2 years with about 400 cycles at 50%dod, they basically perform like new, I left the controller on the 37.5amps stock limit so the max sag is about 10 volts which is fine, the batts don't seem to heat up aswell which is nice as they don't get much airflow. It seems to top out at about 1500 watts which is good enough to go up any hill where I live at a decent speed, though I do always pedal. I'm not really sure how much heat the puma will take before burnout, its hard to tell as the case doesn't get hot but and Ihave no idea how hot it is inside, should probably fit a thermotstat but it seems ok for now.

Thanks for the offer of the termites, unfortunatly I don't think customs or the rest of the countrywill share my enthusiasm so probably a bad idea :lol:
 
I saw this bike tow a van earlier today!! How cool is that?
 
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