Hi I'm new to this forum and I've been working on an idea for how to power a road bike. The plan is to use a 9 cell lithium ion laptop battery to power a 100 watt motor. The key to this build is efficiency not speed and I would be happy to achieve a top speed of 10-12mph unassisted with a range of around 10 miles. The reason why I want to use a laptop battery is:
1. so I can simply plug it into my laptop when I need to recharge the battery.
2. It would be easily detachable from my computer or bike.
3. Extremely light weight.
4. I don't have to carry extra batteries because my laptop battery serves 2 functions
5. It's easy to find old laptop batteries & i can swap out the old cells for new ones.
6. Laptop batteries come with protection circuits built in.
7. The laptop battery is environmentally sealed in case I end up riding in the rain.
There's just one little problem with my plan though. I know lithium ion battery packs have a protection circuit inside them which is programed to automatically shut off the battery when driven too hard. I'm afraid that If i were to try running my motor with this battery it might trip the protection circuit which may destroy the battery pack all together. I've looked all over the internet trying to find a the data sheet on my battery pack but just cant find anything. Also the motor I'm using is rated for 12 volts & my battery pack is only 10.8 volts; will this significantly reduce the power output of my motor? Has anyone here been able to succesfully power thier E-bike off just laptop battery(s)?
Thinkpad T60 Battery specs:
Chemistry: Lithium Ion
Voltage: 10.8
Capacity 7.8AH
Cells: 9x 18650 cells
Here is A diagram of what I have in mind:
- Click image for larger view.
One laptop battery wouldn't take you very far, and might overheat doing the famous stinky smoke trick. Or just shut itself off. 11 volts won't go fast either, so what you will need is as many of em as can fit in the triangle. Maybe 6 packs, 2 paralelled, then each pair connected series for 33v? Then the drain on each pack will be a lot less. This is sort of what some do with drill batteries, keeping em in the case and charging with the drill charger.
Be the pack leader.
36 volt sla schwinn beach cruiser
36 volt lifepo4 mongoose mtb
24 volt sla + nicad EV Global
Laptop batteries are usually comprised of some number of 18650 Li-ion cells, each producing 3.6VDC at up to 2.4AH. It's possible to put ten in series to achieve 36VDC, then make as many parallel strings as required to achieve your desired current capacity. So, the answer is a conditional "yes".
HOWEVER...
The batteries used in scooters, bikes, etc. are designed to support high current loads with big swings between ON and OFF. The laptop, on the other hand, runs at a reasonably constant load. I suspect a good configuration of 18650 cells would work in a bike or scooter, but don't know how long they'd last. Of course, there's also the possibility of catastrophic failure under high current conditions... that would ruin your day.
I wondered about this also,mainly because I'm ignorant of batt tech enough to still ask can I do this? and why not?chasing down links until I forget what I was looking for.I'm told it has to do w/c discharge?I want to hook up sony 7.2v packs w/18650 S GR 1200mah(2)w built in bms(?)ENERGYTEC model LIP-201.They are no longer made so info other than what's here cannot be found by me.I have a bike that runs 52v (14p4s li ion 5ah pack)using bosch batts I think.could I make another pk out of the sonys?7p 10s for a 52v 12ah pk? 1)w/pks dimantled,reassembled? 2)w/pks intact?I realise I would need to do a lot of work but cash poor and am disabled.So time is what I got.Help?comments?Wild guesses?
gilnet
Would be 10p 7s, not 7p 10s.
P = Parallel connection, to "multiply" the current-handling capacity: 10p x 1.2 ah = 12 amp-hours.
S = Serial connection, to "multiply" the voltage.
High-current usages (charging or discharging) of standard "Lithium-ion" batteries can be dangerous, with fire and toxic gases being the real problen if they overheat. BE CAREFUL.
Cheers, Gary
XM-5000Li, wired for cell voltage measuring and logging.
Cheerio to you!please excuse my bleary eyed, up for to many hrs transposition of the Queens english.I'm having that tatooed on my grandson for easy access.Do you have any info more technical than li ion can be dangerous?I use li ion(sony)on my bike.I put the specs ,all I could find after extensive search for data,to see if someone is familiar with that particular Sony li ion cell and its comparison to the Konion that I and many others use every day.thank you for your care and concern.gilnet
gilnet
If you go to endless-sphere.com, you will see a topic about building battery packs, and there is at least one guy there who uses laptop batteries. He gets used ones in fairly large numbers, then tests and sorts them to match capacities and weed out the bad cells. They can make very good E-bike packs if you put the work in to match them, and add a BMS (battery management system).