18650 cell questions

silverbear

The Boy Who Never Grew Up
Jul 9, 2009
8,243
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northeastern Minnesota
Run two of these for $156.

http://www.ebay.com/itm/Taotuo-22-2...988089?hash=item5440893a79:g:JZkAAOSwj85YONps

These would be great for a 48v system because the low cut voltage usually around 42v is in line with the 3.5v/cell generally used a max discharge. You can run em on a 36v or even a 24v if you use a voltage alarm to alert you on the low voltage cut. Cost about $11 and runs off one of the packs balance plugs. The motor doesn't care how much voltage is put to it with in reason, usually depending on phase wire size. Most controllers have 63v caps so they easily handle close to that. Its just the LVC that is different and of course max amperage output. A 24v controller will have slower acceleration and hill climbing than a 48v because the 48v has a higher max amperage. However the 24v controller will still give the max voltage.

I have one total(motor/controller) 24v system that I run on 12s which is 50.4v off charge. Never had an issue with it.

Moral of this story is with in parameters you can pretty much do what you want with the systems. There are some modded 9c 48v hub motors running over 100v over at the Sphere.
Hello, my friend. It has been a long time I’ve been away and good to see you are still posting, You were a great help to me in the past with gas bikes and now I’m asking for some help with an Ebike. I have started a new thread called Pedal Coupe and have a lot to learn. The bike is a four wheeler and recumbent, came primarily as a pedal bike with a 24 volt motor and two 12 volt lead acid batteries. I want to upgrade to 52 volts using 18650 cells. I understand that I will need to replace the controller with compatible voltage. What I don’t know is how difficult is it to wire up a controller to the motor when they were not part of a package? Is this a pretty straight forward - they’re all pretty much the same- thing to do or you’d better have a good schematic not written in Chinese? And offhand is there a plain Jane controller you would recommend? I don’t care about programmable, etc. ..just the basics. Turn the throttle and go. How likely is a 24 V motor going to accept 52 volts without sparks and fire? I’d rather not replace the motor if possible. Not looking for top performance or speed and budget is always a major consideration. Thanks! Anyone else have an opinion?
SB
 

Tony01

Well-Known Member
Nov 28, 2012
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The 24v is going to run double the speed at double the volts. You can reduce battery amps by half (draw, not capacity) to keep the same overall power. Overvolting is fine as long as you run same overall power which is volts times amps.

52v nominal sounds like a 14-series battery, with a max charge voltage of 58.8v. You’ll need a charger that charges to that exact voltage. Controller wise, most will do 36-72v nominal.

A 48v spec usually means 13s, but it can also be 12s, 14s. Just be sure and check. Your charger just has to not overcharge whatever battery spec you run.

if your motor is brushless, you will need a brushless motor controller. Ie... 3 motor wires with halls? Brushless. Two wires? DC brushed. Hooking it all up is simple and will work without being part of a package. Only thing is you will have to mess with positions of hall sensor wires for the motor to run correctly- 3 wires so 3!=6 combinations to try.
 

silverbear

The Boy Who Never Grew Up
Jul 9, 2009
8,243
308
83
northeastern Minnesota
Thanks for the thoughtful and informative response, Tony. That's a next thing on my to do list... determining whether it is brushed or brushless. I'll have to dig in to the wiring some to see what's what. The pedalcoupe is supposed to be my winter project, but it is hard to stay away from it when it enters into dreamtime at night. Lots of other things are demanding time right now with remodeling an old cabin and preparing to shut things down there for the coming winter. This is the time of the build to gather information and getting what parts I'll need ordered. I appreciate your input and will try to digest the whole sometimes confusing business of Voltage, wattage and amperage. Being invisible makes it all the more esoteric.
SB
 

indian22

Well-Known Member
Dec 31, 2014
4,247
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Oklahoma
Glad to see your post SB and a new build started. Tony01 is the most experienced and knowledgeable guy I'm aware of on this forum as regards electric power. He has built some excellent gas bikes as well.
I too am building some bikes with electrics for 3 years now, yet still learning the tech. Riding them is a lot of fun.

Rick C.

Rick C.
 
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silverbear

The Boy Who Never Grew Up
Jul 9, 2009
8,243
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northeastern Minnesota
Hey Rick,
A lot has happened since I last posted. Fall has turned to winter among other things and a change in building plans as well. My partner Sue got interested in what I was planning to do and the pedal car was now going to be for her and the two wheeled "American Flyer" for me. Then her sister in Florida offered her a retired Terratrike Rover tadpole and it was shipped to us via Fedex. I put it back together and realized it was a pretty cool trike and a great candidate for a mid drive electric conversion. Sue's brother in law then offered me his retired Rover and it was shipped north as well. We did some riding late fall and I realized that the recumbent Rover was a great ride. I also had the pedal coupe going as a pedal rider by then and concluded that the trike was a better proposition, much having to do with the 49 gear choice derailleur setup on the pedal coupe as opposed to an 8 speed internally geared rear wheel on the Terratrike. Easy shifting and comfortable to ride. We ordered two Bagfang 750 watt motor kits and before long I had both trikes electrified. What a hoot that is!
Friends and neighbors at our lake cabin twelve miles from our winter home in Ely, just south of the Canadian border saw what we were doing and found two used Terratrikes in Minnesota with the understanding that I would do the electric conversion for them which is underway now also with Bafang 750 watt motors. So that's four Terratrike Rovers. By now I have a pretty good idea how to go about it.
We bought a couple ready made batteries and I've accumulated cells for building more batteries which will come later this winter. It's been fun, but I 'm also ready for something different. Seven below last night and a foot or so of new snow, so winter is officially here and too cold for the wood stove in my work garage to compete with the cold. When it get's up around 20-30 above zero I can finish up the neighbors' trikes and start on the pedalcoupe and American Flyer which I'm looking forward to. The winter season is passing by more quickly with all these projects and it gives something to do besides thinking about the weird and precarious times we're living (and dying) in.
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I ordered a 52 volt scooter motor of 750 watts and controller for the pedal coupe and have pretty much everything in components for the flyer. Nice to be spending time out in the shop with the wood stove going and snow outside the window. Good to hear from you Rick.
SB
 

indian22

Well-Known Member
Dec 31, 2014
4,247
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Oklahoma
Wow you have been busy and with such nice projects. I assembled a German built tadpole about 18 months for a friend who ha taken a fall on his mountain bike and determined not to ride again, but thought some type of 3 wheel would be ok. Farely expensive around 4k but really well designed and had the 8 speed hub which I really like. Assembled it was even more impressive. It did not have electric assist, but that was an option. Our plan was to add a mid motor to it if it proved to hard to pedal uphill. That didn't happen as he was afraid to ride it because of traffic danger in town and dogs etc. And so it sits unused. People are funny. This is a very small town with little traffic and few dogs running loose. He's just afraid.

I think the Baffang the best mid motor kit value out there and for 95% of users 48 or 52v the best battery choice. 72v is a hot rod battery and way high in price for 20amp hr pack, which I've decided to use from here on out. 48v 20amp packs with 50amp BMS and 50 amp continuous controller. I think are good choices. Good range and power. I have a couple of bikes with 36v 16amp packs which are ok but range is a problem unless you peddle full time.

I really like the electrics, but like the gas bikes also.

So glad that you shared with me/us. You have been greatly missed!

Rick C.
 
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