[Poll] Cool Vehicles/Projects for 18650 Batteries?

This weekend, in my adventures of being an Eco Warrior, I've been salvaging 18650 batteries from Ryobi Drill and Dyson Vacuum Batteries that were donated by people to me as the circuitry or PCB failed. I have collected 16 18650 batteries so far this weekend, and while they can be used in my Torches I'm wondering about a cool project I can work on.
Making a powerbank or larger 230v battery did not really appeal to me as I already have powerbanks.
The batteries are 3.7v and 1900-2000mah.

Electric Bike:
Electric Skateboard
Portable CPU Fan: https://www.youtube.com/watch?v=R629INh0wlw

I've also been thinking of fun but dumb ideas like an electric esky(Haven't seen one before on youtube, only petrol).
Some other ideas I came across without full instructions:
Battery Powered Raspberry Pi Livestream Webcam
Super longterm: DIY Tesla

Poll Options


  • +1
    Suggested Electric bike


  • Suggested Electric Scooter


  • +1
    Suggested Electric Esky


  • +1
    Suggested Electric Fan

    Electric Fan

  • Suggested Battery Powered Raspberry Pi Livestream Webcam

    Battery Powered Raspberry Pi Livestream Webcam

  • +4

    Power wall

    • We already have a solar setup, might be useful to add on.

      • +2

        Also illegal to connect to your 240v circuit so probably not 'useful' :)

        Also pretty pointless with the capacity you're talking.

        • Will keep that in mind unless I get a big donation of batteries

  • +1
    Suggested Power Wall for Solar

    Power wall for solar setup

  • Hoverboard

  • +1

    Put it this way, you are going to have about 60v @ 2Ah or 3.7 @ 32Ah. Best setup would be 4S4P giving you 14.8v @ 8Ah. Enough volts to run car related stuff, like electric motors or lights, but not enough storage for things like an electric esky that would go very far.

    What about an android auto/apple car play portable Bluetooth boom box?

    • Thanks for the useful information about voltage, I'm just learning right now
      I'm collecting more and more every day, people in my neighbourhood don't seem to know how to dispose of these.
      Yeah I saw a bluetooth speaker project but they are so cheap nowaways.

  • +1

    Eneloop Charger

    • Charge eneloops from my batteries I charged from the wall?
      That seems very inefficient but I think its a joke

  • +6

    I think you are a bit out of your knowledge depth here. You can't just string old lithium batteries in series and have a nice cute 230v battery. Particularly with salvaged cells. The cells need to be matched and balanced afaik. It's dangerous to mix them. You do not want to do that. You'll have a bad day, perhaps a bad week. I can't say more because i've reached the end of my knowledge here, but i suggest you do much more reading before you start soldering old cells together.

    • Yes a mate who is an electrical engineer alluded to this. I will do some further research but all the cells I've salvaged are tested on the multimeter 3.7v but I'll see if I can frankenstein anything like what youtubers have

      • +4

        Also you should wait for the drugs or alcohol to wear off before trying anything with those batteries.

    • Soldering/welding them together requires skill and good equipment to do safely.

      If you're going to work with lithium batteries, you should really know what you're doing. An accident can leave you with a permanent disability.

      • Holy shit. Read these links OP.

  • +2

    Whatever you do just do heaps of research and double, triple check your charging/discharging circuitry/rate. As harmless as may seem playing with 18650s could easily end up being the same as playing with fire (literally)

    Here is one good example:

    You most certainly don't want this to happen and will lead to even worse consequences if this happened when no one is at home. Not trying to discourage you but perhaps start small without thinking of DIY powerwalls, EV conversions or anything that would be left unattended charging and I'm sure there are plenty of small projects you can have a lot of fun with using 18650s as a "safe" DIY power source. Even Tesla sometimes cannot control their Li-Ion batteriesa after many years of pertise and research - https://www.theguardian.com/australia-news/2021/aug/02/tesla...

  • EV

  • Electric Boogaloo

  • +1

    I've repaired a few eBike battery packs, mostly by dropping the numbers of parallel cells and then using the surplus to replace any dead cells. There's a reduction in capacity of course, but as long as the total current draw is still Ok for the pack, it's worth it.

    That said, I would NEVER attempt to assemble a battery pack using mismatched secondhand cells harvested from a wide range of devices.

    • Are the capacity ratings all the same?
    • Are the cells all from the same manufacturer?
    • Have all of the cells had the same kind of discharge/recharge pattern over their lifetime?
    • Is their actual capacity the same? Or at least very similar? (This can only be determined with more expensive discharge monitoring equipment)

    Anything with more than a single cell will require a BMS and any pack you assemble will only be as strong as the weakest cell in it. If you're only using one cell, then it's hard to go wrong, but multiple cells are going to be a recipe for trouble - thermal runaway at worst. LiFePO4 are a safer chemistry than LiPO but are not without risk.

    • Thankyou, I won't try it then

  • +1

    Mismatched old cells with unknown actual capacity, what could go wrong.

  • Suggested Custom high powered Hitachi

    Custom high powered Hitachi personal massage wand.

  • This project, but it only uses 9648 batteries, not sure what you are going to do with the remaining 9002…

  • @Levity FYI you need to approve or reject the poll suggestions, if you have chosen to take poll suggestions (including your own), before people can vote on them.

    • Didn't know that

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