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Discussion Starter #1 (Edited)
Hi ALL from a rather damp [today] english south coast.

First a bit about myself. Iv spent the last 40 odd years fabricating one off frames & making / machining one off parts for custom choppers & trikes, many of which have been featured in most of the worlds custom bike magazines. iv loads of custom show trophys, most of them for BEST ENGINEERING. Although i have a ultra rare unfired 120CI JOHN HARMAN street motor, a couple of big inch harley motors, a long row of large jap 4 motors & a couple of triumph tripples, i recon its time i got into the EV game.

Due to very bad diabetic foot ulcers i had a below knee right leg amputation in the summer 2014 & the left leg off below knee summer off 17. i can walk about as normal on prothetic legs, but developed a pressure ulcer on the point of the left stump last year so iv been wheelchair bound since last November.

I spent my life buying machine tools & tooling, or spending money on long weekends away at custom shows, 3 day partys etc, so now im disabled, retired with no savings i dont have much money to spare for a EV build.

The aim is to build a electric reverse trike from scratch, for as cheap a price as possible. i have a free source of 18650 laptop cells to recycle via my best mate who works part time doing PC repairs in a shop. I have also email,d another dozen PC repair place,s around my area to donate their old cell packs to me instead of chucking into their bins.

I will be building 8 packs of 7S 80-90 or possibly 100P, i have not made up my mind as yet, i want around a 200 mile range but as i want to win a few more show trophys the trike will have to also look astheticly pleasing to the eye. 100 cells P may be a touch too long so will make my mind up as i build. the plan for the cell packs is lay out a single row in P, use double sided tape all along top & bottoms of the cells, stick on 10x10mm wood or plastic strips, two more lengths of double sided tape another row of cells then repeat upto 7S. bind all together with zip ties, fully fuse both ends with 6 amp wire then spray a few coats of shelac to hopefully waterproof them. will build two casings holding 4 packs each & use as main frame spines. by mounting high volume fans at the front ends i will get forced air cooling or heating as weather demands with addition of fan heaters in winter, not that its ever very cold here. air cooling although not as efficient as liquid will save on overall mass.

My prefference is AC, but can not afford any of the motors or controllers iv so far been able to see whilst surfing the web, so instead will be buying a pair of PRIUS gen 2 gearbox,s. under £200 ea on british ebay. will strip out both mg2s & join together on a single shaft with a 3" belt drive & motor plate between them, will make billet cases to hold them. 3" belt will drive a harley evo 5 speed box & then duel 530 chains to a pair of rear wheels, in british law if the tyre to tarmac contact patch,s are less than 28" apart the 2 wheels are classed as a single wheel. so will be a 4 wheeled trike.

Will control with a PRIUS gen 3 inverter converter, i can do the low & high voltage wiring, but i am totally brainless & a proper numpty regaurding electronic boards, reverse engineering, so will be seeking outside help wheni get to that stage.

All for now. T
 

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Sounds like you've thought it through pretty well.

How fast do you want your tadpole trike to go? Bicycle speeds? Highway speeds?

Note that laptop cells are optimized for high energy storage, but not high power discharge. You should be testing the capacity of the cells if possible.

If you can't afford a capacity tester, or afford the time it takes to test them (usually 4+ hours per cycle if you have a pre- and post-charge outside of the tester, most testers can do 4 at a time), then I suggest leaving some extra capacity and not being strict about 100p.

So, what you do is maybe do 90P. Charge 'em up. And then either individually per parallel group, or together in series, discharge them. Keep an eye on every voltage from time to time as you go. If you're doing parallel packs one at a time, record the time it takes to discharge to a certain voltage. If you're doing all packs together, then just selectively disconnect the lowest pack when it reaches lowest, or, just extrapolate based on voltage how strong each pack is.

Then, take your strongest pack, figure that is 100%, and then for each of the weaker packs, add enough cells to what you think would be the same capacity as the best pack.

I.E. Same load, and maybe this is your results:

1 - 27 minutes
2 - 33 minutes
3 - 32 minutes
4 - 30 minutes
5 - 33 minutes
6 - 29 minutes
7 - 31 minutes

So 33 was your best, so those are 100%.

1 - Needs 20% more cells added.
2 - Max
3 - 3% more cells
4 - 10% more cells
5 - Max
6 - 12% more cells
7 - 6% more cells

So you'll end up with different cell counts per parallel group, but as long as the symmetry doesn't bother you, they should have pretty close capacities.
 

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Discussion Starter #3 (Edited)
Yes thank you very muchly for that info, i am currently cycling through 2k odd of cells for the 3rd time. first charged & volt readings noted, left for 8 weeks, discharged for a week then recharged & volts checked, any that dropped more than 5% have been weeded out. left for another 8 weeks then repeated, now on 3rd time around. will take capacitys @ the end of this batch cycle. i am only using cells over 4.1 & when trike is done limiting the charging to 4 volts. discharge to 3.1. i hope if i can find enough cells to use only those above 2.5k mah.

Speed depends on the journey & distance im doing on any particular day, for instance if im staying around local area i would expect upto 70mph ish, if on a longer trip i would control my need for speed & keep it down to around 50 -55 to max out distance between charges, a front sprocket on a harley 5 speed box is 23 - 24 teeth depending on the modle harley its fitted on, i will set my final drive ratio a bit higher with 26 teeth front & 41 rear sprockets. yes acceleration will be well down, but will ease the voltage drain @ constant motorway speeds on longer journeys.

i have researched everything i could find on spuwtube EV wize, hundreds of viddys downloaded so not stuck for how to info, however im gratefull to you for suggesting i vary the pack cell counts. id not come across that aspect of multi pack building on the tube.
 

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Discussion Starter #4
i hope to get this trike built @ under 1000 lbs, i wont need it mounted for localish journeys, but for distance i have a ww2 army single cylinder battlefront 12 - 24v generator to use as a range extender. top end is cast iron so hope to find a modern all ally single cylinder motor, @ a affordable price before my first long journey.
 
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