My GSM / Muddy Fox eBike build

davidg

Pedelecer
Jun 13, 2016
26
11
54
France
For the last 5 years or so I've toyed with converting an old Muddy Fox courier mountain bike into an eBike. I used to use the Muddy Fox every day but it had been languishing in the attic for the last 15 years. I'd thought about a simple hub motor but live in a hilly area and everyone seems to use big 1000 watt motors around here. Then the Cyclone came along but it looked just too complicated and funky. Finally the Bafang's caught my eye, a refined mid motor. A neighbour was selling eBikes and I borrowed a 250 watt mid engined Matra which I used to climb Alpe d'Huez and it seemed to have enough power.

However I still wasn't confident about wiring everything up. Finally, after getting a small bonus, I took the plunge and ordered the GSMoon kit from Woosh bikes. This is the latest revision of the motor with the new controller. Here is my build for anyone who is interested, feel free to ask any questions:-

 

davidg

Pedelecer
Jun 13, 2016
26
11
54
France

anotherkiwi

Esteemed Pedelecer
Jan 26, 2015
7,845
5,785
The European Union
You are riding in traffic? I average about 25km/h (at least I did on my hub motor) but it isn't as flat around here. I am going to buy a mount for my GPS (a.k.a. smartphone) so will see how fast I go on my new steed. As it is more comfortable I have the impression that I am going much slower, no more spine jarring vibrations and bumps...
 

davidg

Pedelecer
Jun 13, 2016
26
11
54
France
As it is more comfortable I have the impression that I am going much slower, no more spine jarring vibrations and bumps...
I've just been (re)reading about your build. You are p;robably one of the people Woosh Bikes told me about who'd ordered the external controllered GSM in France. I'd noticed that Lipos are pretty cheap from places like HobbyKing but didn't want to make my life too complicated at first.
 

anotherkiwi

Esteemed Pedelecer
Jan 26, 2015
7,845
5,785
The European Union
There are a couple of good reasons to use LiPos, price is one and lack of sag when climbing the other. They require a bit of discipline but the danger of using them is less on a bicycle than in a toy which is prone to crashing as long as you respect them and don't use them below 3.6 V and charge above 4.15.

I think that having the right charger(s) and good charging strategy can make them acceptable for a daily ride. If you buy quality ones when they are on sale it can be a very cheap source of energy even if they only last for 250 charging cycles. I can be around when they are charging so it isn't an issue for me.
 

D8ve

Esteemed Pedelecer
Jan 30, 2013
2,142
1,294
Bristol
2016-05-27 07.36.40.jpg 10s 16ah plus connectors cost me £110 but it's only 10c so I can't run over 160amps :eek:. I think my motor is set for around 14 amp anyway so I don't expect to much battery sag
 
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davidg

Pedelecer
Jun 13, 2016
26
11
54
France
I've been away a week but I've restarted the commute and just clicked over 225km. The motor is sometimes a bit slow picking up the slack when you've been bowling along at 30kph then hit a hill. I'll post some more thoughts later.
 

trex

Esteemed Pedelecer
May 15, 2011
7,703
2,671
I always try to keep the RPM on the high side by shifting to a lower gear before hitting the hill.
 

anotherkiwi

Esteemed Pedelecer
Jan 26, 2015
7,845
5,785
The European Union
I have changed controllers and the motor seems to prefer the no name 14 A controller to the 09 bottle battery one. No more run on, more and smoother power delivery (a mystery - 14 A vs 18 A...).

And I have traded speed for comfort, I must be feeling my age! :confused: Top speed downhill is between 45 and 55 km/h but I am sitting up on a bigger bike so air resistance is playing a bigger factor. Overall on average I have knocked a couple of km/h off.

Climbing my big long hill yesterday I was in second instead of first, I am only just getting the hang of how it climbs compared to the hub motor. I have a derailleur issue which doesn't surprise me - it came from a wrecked bike with unknown history and I have put about 3500 km on the clock since then. It is very lazy changing between 3rd, 4th and 5th gears.
 

davidg

Pedelecer
Jun 13, 2016
26
11
54
France
Went out on a longer climb today. 550 meters vertical. Battery was on 2 bars by the end on the display or 3 Leds on the battery.

Beat Simon Yates' time on the climb.
 
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davidg

Pedelecer
Jun 13, 2016
26
11
54
France
I've just charged the battery, took 2 hours 45 minutes but the young lad did about 10km on it when I got back riding round the square.

Here is the unboxing of the kit


darn, no idea who the young lady is !
 

davidg

Pedelecer
Jun 13, 2016
26
11
54
France
I'm at nearly 400km now, haven't been doing my long commute due to a bad hip but the short one is 22km. I can to 2 short commutes and one long commute on a charge - that's about 80km but I guess the motor is not doing much work when I'm riding at 27-28km on the flat.

There is a bit of side to side movement on the bottom bracket now - I will have to see what needs tightening.
 

davidg

Pedelecer
Jun 13, 2016
26
11
54
France
I clicked over 500km earlier in the week and now heading for 600km territory. Had a crank come loose one day, which is pretty common I hear do to the allen key bolts not tightening enough. Half of the riding this year has been in 30C + temperatures (afternoon commute home) so the motor doesn't seem to have too much problem with those conditions. Not many long climbs though and boy does the battery empty fast when you are pulling big amps.
 

Woosh

Trade Member
May 19, 2012
19,407
16,387
Southend on Sea
wooshbikes.co.uk
Lovely pic.
Can you tell us where it was?
 

davidg

Pedelecer
Jun 13, 2016
26
11
54
France
Lovely pic.
Can you tell us where it was?
Yes, that's in the French Chartreuse mountains. If you want any better pics in the future PM me. I'm on about 900km at the moment as I've not been cycling much over winter as the roads are heavily salted.