hey all,

thought id start a project thread on something i have more of a hope of completing

INTRO. ive taken a golf trolley motor and gearbox, my pedal bike and some other bits and bobs and created a pedal assist electric push bike.

this was it a few days ago



since then ive swapped dirt for road tyres and added better/extra rear mudguard. this pic also shows my battery backpack, its a 12v 26ah golf trolley battery. that little black box infornt of the motor is a 12v-24v dc-dc step up transformer, it works as a primative (non variable) motor controller. it doubles my motor speed+torque but halfs my battery life down to an hour. probably doesnt help the brushes either



heres what happens if you try and use a plastic golf trolley gearbox



and heres where i made it all, My garage/workshop



it needs some things, like some freewheeling sprockets on the motor side, but other than that its good

its fast, 20mph uphill 40mph downhill (if my cycle computer is correct)

so yeah
questions or comments welcome

thanks

jim

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the world is changed by people in sheds

Any videos?

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Senior Test Automation Engineer for the 306GTi6 Owners Club Forum

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sadly not yet. i might get one done when its not raining or dark. or i get one of my reluctant friends to help me out with my sad little project

i like the battery in the bag. although its a higher centre of gravity, it means the mass of the battery is under my control. it feels like i can handle it better (not that i have tried it mounted to the bike)

my aim was not to have a heavy bulky conspicuous looking bike. there are laws governing electric bikes of which this meets......none : (

200w max power equates to around 0.3bhp which is s**t. so is the 15mph limit. thers are loads more but have a look yourself.

so already im breaking the law wether a copper gives two s**ts is another matter, im currently at around 240watts and plan on going to around 360 or 480 with the current motor. i had a look at similar sized brushless and they end up in the 1-3kw range. so yeah plenty of scope for all illegal improvement :s

the motor and control box sit neatly within the centre. the plan is i blank them off with two large black plastic triangles. this hopefiully will make the bike look a lot less conspicuous.

not quite sure about the motor shaft n chain...... could fab something up to cover it but i dont know if that woukd draw more attention or not.

what do you reacon guys?

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the world is changed by people in sheds

holy crap that motors big.....brushless? what voltage/wattage?

um......... its not the most complex of wirings and my paint drawing is terrible but hopefully youll get the idea



i have no speed controll...not that i need it....... the dc -dc step up transformer acts as a primative motor controller as it works by pwm and provides a "soft start" for the motor

hopefully prolonging the brush life and battery life etc etc....

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the world is changed by people in sheds

ah your running direct drive with no speed control only the ramp up of the PWM controlled via a relay switch

lol it wouldnt run that motor of mine
its a 6.5Kw brushed motor @ 24v dc.
the kart was running full electronic speed control 0-30mph with forward and reverse drive

I think its the 26 amps for 1 hour, if it were 26 amps for 20 hours think how much charging that would also take. Charging at even 5A would take well over 100 hours.

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'90 1.6 205 GTi, '98 306 GTi-6

thanks for your replies...yeah......i read over a few things again at work to try and make sense of it all.

the 20hr rating.....actually is the test period time of which the manufacturers drew 26AH in total from the battery.

annoyingly this fact compounds when u take more amperage from the battery over a shorter time period. making for less overall available amp hours in the battery..... so my 26ah battery will produce more like 15-20AH over an hour

however

i checked how many amps my charger put back into the battery this morning from my 2 hour ride... and it was just over 7amps...... meaning im only taking an average of 3.5amps an hour

meaning i could keep riding for nearly 6 hours ...things are looking up

i thought my amp draw was more than this as i can blow a 10amp fuse if i put extra strain on the motor from a complete standing start, uphill and not using the pedals to assist. 10amps was my peak, not my continuous which is probably closer to 2.5-3amps.

im gonna fit the 48v booster over the weekend, see what happens.
theoretically it should double the motors torque/speed again.
shame that my theory (as prooved above) hasnt been brilliant with predictions

im worried ill hit magnetic saturation at this higher voltage.
or burn out my brushes or coil.
or explode the gearbox/snap a chain
or the pedals turn so fast i mash my legs up in them :s

so a 3 in 4 chance for soime epic video footage

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the world is changed by people in sheds

im at work at the moment and youtube it blocked so cant get a video link of the cart at Ace cafe london

here is by build thread the kart went through two setups firts being 11mph the last being the big 6.5kw motor @30mph

http://www.youtube.com/watch?v=klxTxE0Chl8

http://306oc.co.uk/forum/thread-3216-post-71683.html#pid71683

replace them with the same farrad but higher voltage also look for the higer temp rated ones ie: 105c not 95c ones

possably!
it will be mor than likly of been reverse voltage though
when you pedal and force the motor to generate

got a much narrower chain and thinned the motor gear.

so far so good

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the world is changed by people in sheds

ive aldo made a second electric bike. with no pedals. purley motor powered. same bike+golf trolley motor+battery) setup but no pedals. more like an electric motorbike



at 10mph its slow but its only 12v atm. i plan on an extra battery, a twist throttle, a 24v speed controller

heres a closeup of the motor



ask some questions if you like

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the world is changed by people in sheds

i managed to gear the thing properly today, had to take apart the rear freewheel n cog so i could get the smallest teeth gear (14T) in a position where it lined up properly with the motor shafts 13T gear. so the chain didnt rub on the bike frame

it was on a 20T one but now ive swapped it over its a wee bit faster on the top end. almost a 1:1 ratio from the wormdrive output

just been out on this second electric "motorbike" for an hour varying between 10 - 15mph up n downhills.

was most enjoyable, and the battery wasnt even flat on my return.

ive bought a job lot of 4 of the same "broken" golf trolleys on ebay. besides new motors ill have 4 more battery holders ready to double available voltage and amperage

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the world is changed by people in sheds