Laptop Powered E-Bike

rebelrider.mike

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May 25, 2017
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383
Finally: The whole reason I got into harvesting 18650s was to build an eBike without having to spend $500 on a lithium battery. I think I've got enough cells to get started. I'm learning as I go, so bare with me, LOL.

I have a regular bicycle I'll be converting. I'll get a picture and some specs at some point.

I'm considering a SmartPie5 from GoldenMotor.com. Here's the specs:
- Max phase current: 50A (not sure what this means)
- Continuous Current: 18A
- Open Voltage: 20V - 60V
- Rated power: 200W - 400W

Still learning to calculate what kind of battery to build. Especially since I'm using old laptop cells instead of new cells. But here's what I have so far.

The rated power, being between 200-400W means using a "48V" battery, with a voltage range between 42-58.8V means I'll come nowhere near the 18A limit, right? 18A would be for if I were using a battery as low as 20V to get the 400W power. So more Volts means less Amps, and that's good for these old cells. If I'm right about all that, then assuming a lower limit of 3V per cell, the most Amps I should ever demand from the system is about 9.5A when the battery is at its lowest of 42V.

A 14s battery will give me 58.8V maximum. If I want to keep the current at 0.5A per cell, I'll need 18p. So that would work out to 252 cells, which should be plenty for the Watt-Hours needed for power and range.

14s18p would be a pretty big battery, so I'm thinking of breaking it up into 6 7s6p batteries. Also, I'm thinking I'll make the batteries longer and thinnerby clustering parallel cells in groups of 2x6. I made a mock-up out of dead cells just to see how each battery would look:

image_xokgix.jpg


So 6 of these, 2s3p, would look like this:
[img=800x388]https://s-media-cache-ak0.pinimg.com/originals/ce/ee/0f/ceee0f8d74aef9c096c9ff2151a2de17.jpg[/img]

Seems like a lot of battery though. I wonder if I could get away with only 4 of these. That would require 0.8A per cell. That would save me 84 cells and 1/3 of the weight and space. And it would make charging much easier.

I'm thinking if I want to add lights, I'll put together a little 12V battery. Most things run on 12V nowadays.

Not sure what to do about charging. Chargers don't seem to balance, and all the BMSs out there seem to have very poor reviews.
 

daromer

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Charge it with a proper RC charger. Many of them do up to 7s and if you going to run 7s packs thats fine. For instance iCharger Duo and you got 2 ports and can do both of them. 308 or 4010 and you have ones that do 30-40A per port :)

Aff linked Ebay:
https://rover.ebay.com/rover/1/711-...100174?hash=item43f873140e:g:nIQAAOSwrddY7PLY


This is the one I use personally and it works like a charm for chargin larger packs like the one you plan for! And it does balancing very good.
 

Jeremy Choy

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May 10, 2017
Messages
60
Running a 14S8P from recycled Cells on a BBS02. they get quite warm along with the motor with 40-50km/h riding for 1/2 hour.
When cruising I was probably in the range of 7-10 amps and the batteries wouldn't get warm.
No BMS. At first I cared, now I'm pushing the pack harder. 1500km's and probably have 3-5% loss in charge from when I first built it. If I can get 4500km's I'll be happy out of this pack. I'm charging to 57.4v and usually draining it to 48v under load. it recovers to about 50v. charging twice a day.

I think you should be good with a 14S12P for average riding.
 

jdeadman

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Mar 28, 2017
Messages
941
I have a 24v lawnmower and my 7s8p gets to about 38 degrees Celsius after a full dump from 4.1 to 3.6v per cell (resting) so far each string is staying balanced but I use a external Ballance during charge that constantly keeps them in check (50ma drain)
 

Wattsup

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Feb 19, 2017
Messages
517
Power tool cells are SO much better than laptop cells for this, however I do understand sometimes you have to use what you have
 

jdeadman

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Mar 28, 2017
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Totally. I have room to double the cells in parallel so that will decrease the amps per cells which will make the battery cooler.
 

rebelrider.mike

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May 25, 2017
Messages
383
Here's the bike I have to convert:

image_ebusew.jpg

Its an old Raleigh of some kind. I put my own seat and handlebar on it. A friend of mine got me set up with custom cables since the originals were too short for the new bar. I've also got a replacement rear rack that will fit much better than this current one.

Still looking at the same motor/controller even after quite a bit of shopping around. I've also had a look at the cell database and most of the cells I'm using have a recommended discharge of 400-500mA. Now, I can get away with more for a short time I'm sure. Like going up a hill or needing to accelerate quickly, but I think I'll stick with my 6 7s6p battery design for now. I have the room and the cells, and I'm curious how much range I will get.

As far as charging... I'm disappointed so far with what seems to be out there for 48V charging. And I do want to charge the whole thing at once rather than one battery at a time. Six balance chargers is just too much money for me. So in keeping with the DIY spirit of this forum, I'm gonna build my own. I do appreciate all your comments and suggestions though. I've looked into all of them. :)

So I'm fascinated (or maybe obsessed) with TP4056 boards and how they behave while charging our beloved 18650s. And I'm planning to build a charger with them. I first had to solve the series shorting issue. Thanks to the great suggestions from this thread, and a bit of research, I think I've got a way to make them work together in series without shorting.

The two options I'm looking at are basically the same, but the chargers could be either wall chargers or bare boards. Now, there's a killer deal on eBay at the moment where I could get 42 wall chargers for about $32. Its a 4 for 2 sale. That route though will require power strips and USB ends. Here's a design for one of the 7s6p batteries (I'd need six.)
[img=800x602]https://s-media-cache-ak0.pinimg.com/originals/b0/72/0e/b0720e0ab3a8a3b10cda555b4fa188d2.jpg[/img]

The other option is to use bare boards to convert from 110VAC to 5VDC. There's a nice deal on Banggood.com if you buy in groups of 10. This would eliminate the power strips and USB ends, and could all be fit into a project box. So the whole thing would be less bulky and would contain a lot more of the wiring.
[img=800x602]https://s-media-cache-ak0.pinimg.com/originals/06/77/67/067767f7d772b84267a671b935866a39.jpg[/img]

The cost comparison of all the parts makes this route about $50 cheaper. And with so many little advantages, I think I'll do it this way. Now I just have to scale up to all 6 batteries. Gotta decide whether to use 6 project boxes, or one big one. And there's still some parallel issues to work out yet.
 

rebelrider.mike

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May 25, 2017
Messages
383
I've done a proof of concept on this thread, using separate AC to DC power supplies for each TP4056 charge controller. So now I know it will work, I'm looking at how I'll actually build a charger/balancer.
Here is a simplified version of how I plan to wire things up:
[img=800x602]https://s-media-cache-ak0.pinimg.com/originals/b7/4b/34/b74b34279b33eafdc4ed88d2dd195a0e.jpg[/img]
This will allow me to use 7s balance cables to charge each battery.

Since I'll have six of these batteries in a 2s 3p configuration, I have to solve the issue of the TP4056s being in parallel. They really don't get along with each other, LOL. To fix this, I'll wire up the batteries so that when disconnected from the motor controller, they'll no longer be in parallel. I'll do this by having a positive and negative lead from each series go through a 6 pin connector, and they won't meat up until after they're past that connector. So when its unplugged, only the balance cables will keep the batteries in parallel. And those will be disconnected in order to hook up the charger. Clear as mud? Here's a diagram of the charger disconnected, and the battery pack in use:
[img=800x602]https://s-media-cache-ak0.pinimg.com/originals/1d/ed/d1/1dedd14b332ad7accfd49c1aa6f7d4e8.jpg[/img]

And here is the battery pack being charged:
[img=800x601]https://s-media-cache-ak0.pinimg.com/originals/33/c9/2d/33c92d7a6dc76a8b25b5c5829e666aff.jpg[/img]

So with this design, all the parallel cells should stay balanced during use, and the series will be balanced with every charge, since each TP4056 will stop at (approximately) 4.2V. As for power consumption, each individual cell will be getting about 166mA. Kind of low, but each TP4056 will be charging 6 cells at a time. To add all that up, the charger will be providing 42A at 5V, which works out to about 1.7A at 118V (my actual voltage at home). Maybe a little more, since things are never 100% efficient. But that seems pretty close to the rated current of the store-bought bulk chargers. And they don't do balancing.

Well, does anyone see anything here that will melt, smoke, catch fire, or otherwise ruin my day?

Also, I wonder if I could find some kind of 12 pin on/off switch that would make unplugging the battery from the motor unnecessary?
It would have to handle 10A, though. Or maybe 4A through each lead? I think each lead would be providing 1/3 of the total current.
 

umop-episdn

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Sep 3, 2017
Messages
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Incredibly detailed work Mike. Loving it!

Browsing that Golden Motor site and many hopes and dreams are forming.
 

rebelrider.mike

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May 25, 2017
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383
Ok, got some goodies in the mail, including the isolated power supplies I was waiting for!

image_pgptzb.jpg


Also got a few other things, but those are for other projects. I did some soldering, and of course, I had to do a brief household powertest with my fingers (yep, still works). Anyway, I got my little test rig put together.

image_zsgzcn.jpg

So 120VAC from a boring old plug to two 120VAC to 5VDC isolated supplies, then to two TP4056 charge control boards to two cells hooked up in series. So far, no melting or burning or smoking. I still need to charge them up and make sure the TPs behave properly, but so far so good!

Also, I was removing some old, unused conduit from my house the other day, and found some old Type TW wire inside. No good to reuse as household wiring, but at 12 gauge (about 2mm) it will make good battery wire. I did the razor blade in the vice thing to get the insulation off. Then I had to clean of this oily stuff coating the wire itself, but I got several meters, which should last me for a few small projects.

image_sqqdrx.jpg


Very slow progress, but still progress. :)
 

rebelrider.mike

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May 25, 2017
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Still waiting for fuse wire and 22 gauge (0.64 mm) wire, but I've started to put some cells together anyway. The first battery will be mostly red and blue cells, arranged with help from the Pack Builder, but also by color to give me a visual aid as to how they are oriented. It will be in a 3x14 grid and wired up as 7s6p. Here's the actual cells I'll be using. No dummy cell mock-up this time!

image_hggqni.jpg


I plan to fuse the positives but not the negatives, and I think I'm going to wire it up in this configuration:
[img=800x362]https://s-media-cache-ak0.pinimg.com/originals/85/fd/e9/85fde994a690001af7250b55fa90873f.jpg[/img]
Though I could also wire it up this way.
[img=800x311]https://s-media-cache-ak0.pinimg.com/originals/50/b9/9c/50b99c60590ebde218b8fbc3c5519fa7.jpg[/img]
 

daromer

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2nd one is better since you got "2" wires instead of "1"
And the first one is not even in terms of length between cells and can cause balance issues and you will stress the one closest a bit more than the one last in chain.

The first one would work better if you use an O instead of U format. And instead of L in the end use same as you have on pack 2
 

Jeremy Choy

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May 10, 2017
Messages
60
what motor controller do you have with it? can you limit AMPs? When I started building my bike I limited to 10amps so I could run 14s4p battery to start while I collected and built my other batteries. you could do some testing and maybe you won't need such a big battery. I'm also using a 7201a charger to charge (not balance charge though) my bike. and a RC charger to balance every once in a while.

you'll probably start to find a big bank problematic and will want to get power cells. I've gone almost 2000km's and looking at power cells so I can run a 14s5p setup.
 

1958 greyhound

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May 13, 2017
Messages
269
I would be more worried about amp draw and what cells you used.

I used sanyo heaters on the kids power wheel battery and it gets HOT, you can hold it but its HOT.
So I'm capacity testing more battery's now and just going to triple the capacity.
 

rebelrider.mike

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May 25, 2017
Messages
383
JeremyChoy said:
what motor controller do you have with it? can you limit AMPs?
I'll be using the Smart Pie 4 with the built in controller. I think the Amps can be limited through an app, but I don't remember.

Started wiring the first eBike battery today.

image_apgusq.jpg


I started with the other configuration with the multiple wires, but in practice, they seemed too close together and I was worried about shorts. My first attempt at attaching fuses was a bit clumsy.

image_bfqohk.jpg


I had started out with the fuses soldered to the cells, then tried to attach them to the bus wire. My next attempt I did the opposite. I added the fuses to the bus wire first, then soldered the other end to the cells. I also staggered the fuses so they wouldn't be right on top of each cell, but to the side a little. This made attaching them to the cells much easier.

image_bkdguv.jpg


image_nrhmfw.jpg


For the negative, I'm using 22g bare copper. Not meant to be a fuse wire, just a conductor. But thin enough that very little heat is needed to solder it to the cells. Here's the first side finished:

image_crsykf.jpg


The fuses I'm using are 2A glass which AveRageJoe tested at 4 amps. Hopefully, this will allow me to use and charge the battery without blowing them, but also protect each cell from a dead short. They definitely protect against shorts. I've already blown 4 of them just by accidentally brushing the 22g wire against the positive of one of the adjacent cells. At some point I intend to test them myself, but I'm still waiting on parts to build a proper tester.

So the whole battery is wired up. I still have details like shrinking the shrink wrap and adding balancingwires, but for now, I get 26.5V on the multimeter. Near perfect as they were all around 3.8V when I started.

image_ilupgn.jpg
 

rebelrider.mike

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Battery #2 is all soldered up!

image_gqwodc.jpg


I've got more ready, but I'm waiting on fuses. They're super cheap, but it takes a long time to get the order delivered. Now that I know I like them and will use them, I've ordered another 300. More than enough to finish this project.
 

rebelrider.mike

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May 25, 2017
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More goodies in the mail!

image_kfudee.jpg


More solder, 300 more 2A glass fuses, and some tiny heat sinks which I might use in my DIY balance charger. Those heat sinks are the smallest I could find, and they're still 4x bigger than the TP4056 chips I want to help cool.

image_inpddv.jpg


I'm thinking I'll (very carefully) cut them in half so each piece will fit between the two capacitors without touching them, and glue the heat sink on with thermal glue. I wouldn't normally worry about heat from these guys, but I plan to have a lot of them inside a box, and I'm concerned that the cumulative heat might be an issue.

I've been corresponding with the folks over at Endless-Sphere.com, about the other components I'll need on my bike. I've learned quite a bit, and have gotten some good advice. So there's this dashboard accessory called the Cycle Analyst which not only shows tons of info about the motor and battery, but also adds a level of "smartness" and programmability to a compatible controller. So I'm definitely getting those two things from ebikes.ca. They also have reasonably priced throttles and "ebrake" levers too.

Unfortunately, I'm not sold on their motors. The selection they have is very small and very expensive. I'm not sure any of them will work for what I want. I may still go with a motor from Golden Motors, but I'll have to contact them to see if they will sell me a motor already laced into a rim. I don't see why they wouldn't, but their website only lists full kits or bare motors. There is also a motor I'm considering from AliExpress, called an MXUS FX39. From what I've seen on YouTube, this brand seems popular in Russia.

Here's a rough idea of the layout I'm thinking of as far as where all this stuff will be going.

image_qjdjhy.jpg
 

rebelrider.mike

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May 25, 2017
Messages
383
Slow progress on the eBike, but its still going.

The bicycle got a proper fitting rear rack installed. And a third battery got soldered together yesterday:

image_xgllcd.jpg

Check out those solders. I'm getting better!

image_vpilhf.jpg


I've also been considering the other components I'll need. Here's my list as of today:
- Controller:C4825-GR_STOKE
- Computer:CA3-DP
- eBrake levers:EBRAKEWUXD_SILVER
- Throttle:T-TWIST
- Hub motor: MXUSXF39 XF40

Still collecting parts to build the 14s balance charger. Not sure yet what its shape or size or weight will be. I'd like to have it mounted on the bike somewhere so its an easy plugin wherever. That will be determined later. And I'd still like to make the housings out of the old laptop battery shells. Haven't started that yet.
 

rbev

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Feb 13, 2018
Messages
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Hi Mike, some interesting ideas. Is there any update on your plans?
 

rebelrider.mike

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May 25, 2017
Messages
383
Sadly, no. I'm still trying to save up for the wheel/motor. Too many financial setbacks lately. The project is not dead though. Just waiting...
 
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