My 19 Year old GT MB conversion

rosjen

Pedelecer
Oct 27, 2008
69
0
Well, after much researching and searching I finally came up with my perfect power stealth kit.

Frank Scheftlein probably helped more than any shop could have in terms of what he thought I should have and even completed the wiring on the controller with plugs that I couldn't make a mistake with. He claims his controller is better as he has resolved this issue of pedelec sensor delay (stopping when the rider stops peddling), I can't fully confirm this yet but in my 3 mile test run it stopped when I stopped so all would seem fine - did have one issue of a false start when I was walking the bike though?

The kit arrived very quickly, 5 days from order - Frank suggested a ping battery that took a lot longer due to airline delay - which is what Mr Ping said.

Frank is so patient, my email exchange was 24 messages in total and he came back very quickly on every single question.

Anyway here are the specs

Bafang Rear wheel motor - which I laced (my first) with the help of a very useful website (link later), 248mm length spokes on my 26" wheel. Stupid me I tried to use the old freewheel but that badboy was welded on :) So had to get new. Still kept my original rim though! Lacing is time consuming - spent 3 nights getting the wheel true.

Ping 10AH v2.5 36V battery

LED auto lighting system - if you get this go for the smallest one I got the 7 LED one and it's big - too big. I also covered all the (LOOK AT ME I'M ELECTRIC decals off)

Franks custom controller. with a 3 stage switch to change the level of assistance

And of course my dear 19 year old GT Talera still with factory running gear other than the gear shifts that I had to replace due to a lame thumb (ulnar nerve busted), but better now. This is one strong bike - when I first got it I used it for actual mounting biking and dumped it in ditches more time than I can remember. Steel rules!

Weight - the down side; As a normal bike it weighed in at 14kg, now fully loaded it weighs 23kg - this is heavy to lift but the bike strength is there in bucket loads.

I weigh 95kg so those tiers better hold out:)

It is so much fun, 16.7mph in about 100 yards (that stiff frame transfers all the power to the floor) - it can pull from stand still no problem

Almost no motor noise at all, only when it is under a lot of load will you hear the gears.

Anyway pics:

The Rebirth


Subtle - motor wire cover from an old hard drive twisted into shape.


continued.... this forum software can't count images!
 

rosjen

Pedelecer
Oct 27, 2008
69
0
Plastic CD holder is perfect for the controller and wires - £2.99 TESCOs



My reversed sensor, would not mount the other side or this side so came up with this mod.


Small motor


Big light - taken apart and now feeds the rear light with power when the light sensor detects dark - removed decals


Continued.....
 

wurly

Esteemed Pedelecer
Aug 2, 2008
501
9
Yeovil, Somerset
Thumbs up for DIYer's. Lets see some more....

Is 16.7 mph maximum speed? and is that motor only?

Lacing a wheel gets easier the more you do. It certainly doesn't look electric. I think my next one will have a rear motor they tuck away nicely behind the rear gears. I like the idea of the cd case for the controller, good idea.

Nice conversion.....
 

rosjen

Pedelecer
Oct 27, 2008
69
0
Wurly, yes 16.7mph no pedalling that's when the controller cuts power, but today I covered almost 5 miles in 12 minutes, faster time than driving which is about 24mph average, the car journey is 18mph average. The guys here at work can't believe just how good it is.

Thunderblue, it does feel a bit more enjoyable doing it DIY, I got what I wanted.
 

Trevor Holloway

Pedelecer
May 4, 2010
136
0
That looks like what I want to do with my Peugeot Hybrid ie rear wheel drive but hide battery under panniers on the rear rack.
If you don't mind letting us know, what was the final price of the whole conversion ?
 

rosjen

Pedelecer
Oct 27, 2008
69
0
Trevor, details below, all inc postage - the link to the parts is on my 3rd post

motor, controller, lights, switches, £140
battery £300,
spokes £14
freewheel £8

Rob
 

wurly

Esteemed Pedelecer
Aug 2, 2008
501
9
Yeovil, Somerset
Rob, a couple of questions.
Do you know what rpm motor you have?
The link to his site says they are 195. Can't see how you get 16.7 mph unless you have a 235 rpm motor, which is what i am hoping they are. 16.7mph is approx 217rpm.
I've ordered a Bafang front motor and controller (but not from there).
When it cuts power, do you mean it doesn't offer anymore power because you have reached the max rpm and you are then running on the freewheel in the motor? or does the controller literally cut out?
 
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rosjen

Pedelecer
Oct 27, 2008
69
0
I think it is safe to say that 195 rpm is dependent on the controller, the 195 number is basically a gearing ratio for the wheel size, if you have big tires then that 195 is still 195 but has the effect of maybe 200. The controller can keep pushing power to motor and gain more rpm way after 195.

second question

Yes it just cuts in and out, depending on the controllers idea of 15mph - I know these controllers can be programmed just like a cars EMS can be, and that gives the supplier and you options.

trust me - getting to 15mph without effort is so much fun but pushing it up to 24+ on your own is even better. Most of the effort in riding is starting, maintaining speed is actually not that hard.

Where did you order your kit from?
 
the diameter of the tyre is one point but the main point is the voltage.

the 26" bafang motor have around 195rpm on 36v leadacid Battery but a full loaded modern lifepo battery have more than 40v and each single volt brings you another 5,5rpm.

If you connect 48v to this conversion-kit the speed raise up to 35km/h and a full loaded 48v battery would have 58v and with this voltage you feel the support up to 40km/h but at this speed the motor need more and more power for to fight against the wind and so the speed cant go the same way higher like the jump from 36v to 48v.

The controller never cut the speed , the controller give you what is possible with the voltage you connect to him and what the motor is able to give with this voltage

frank
 

wurly

Esteemed Pedelecer
Aug 2, 2008
501
9
Yeovil, Somerset
Interesting, thanks for that Frank.
I only have experiance with Tongxin hub/controllers. There is no difference to max speed between SLA and a fully charged 36v Ping battery. I hooked up a scope to the phase wires on the tongxin controller and can see the PWM waveform. When it's full signal it is 'flat out' altering voltage just made the waveform amplitude slightly smaller. Different controller, different characteristics i guess?
Looking forward to getting my Bafang to see what it will do.
It's coming from EV-Assemble Rob......i hope!!!!)
 
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Different controller, different characteristics i guess?
yes and another point is that you can choose on my controller the characteristics of the Motor/Controller combo because you can setup my controller with computer in many points, if you also buy the software and the USB-data-transferwire :D

regards
frank
 
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rosjen

Pedelecer
Oct 27, 2008
69
0
Ah, thats' you Frank

Why didn't you try and sell me that usb connection? I love playing around with hardware settings :) but to be honest the setup is just fine and i may end up breaking it all:) Being able to modify the pedelec startup speed would be a good switch though, I have a lot of traffic to contend with.

Open question to those that know ping batteries (the v2.5), after my normal commute the battery meter is still on full, but I bought two chargers and keep one at work so charge there as well, is this needed? Does charging at 80% (est) reduce the life of the battery?
 

wurly

Esteemed Pedelecer
Aug 2, 2008
501
9
Yeovil, Somerset
The answer i had from Ping about how far to discharge the pack was between 80-90%. That is the tricky bit, knowing how far to keep using it before charging up again. On a regular journey you will soon find out. I use a turnigy meter to measure the charge in and out of my pack.
Not sure how accurate it is but i have found that more Wh's go in when charging than Wh's i drain out of it. There is always an amount of power being drained by the BMS which would probably account for it.