So, more of a joke project... but I motorized a beer cooler with some surplus hoverboard wheels and made a build video. hope you all find it humorous!
So, more of a joke project... but I motorized a beer cooler with some surplus hoverboard wheels and made a build video. hope you all find it humorous!
so yeah, first time making an electric vehicle. the intent is to reuse the battery and ESC on an ebike.
A lovely person at the event i brought the motorized cooler kart to traded vehicles with me for 10 minutes, and i got to ride his electric mountain bike with a mid mount motor, and it was awesome, so i have the itch for that now.
Anyway, more of a goofy and fun project, I wouldn't say it was practical, and definitely won't change the world, but hopefully is brings some entertainment to your lives! :)
Nice build video! I'm also a sucker for a funny unit conversion from meters/metres to burger units. And wood- and metal-working, batteries, speed controllers, motors, micromobility, and beer? Instant subscribed.
You mentioned crimping versus soldering, and I'm poised to agree, especially in a mobile application with vibrations. Although I wanted to mention another reason for crimping: in the event of an unfused, high-current short, there may be sufficient energy from the cells to instantly vaporize the solder, causing hot spall to fly everywhere, potentially combusting flammable material. For this same reason, ham radio towers will always crimp their grounding conductors in case of a lightning strike.
Have you considered cross-posting to !imadethis@lemm.ee ? Also, did you have a booth at Open Sauce?
oh, thats a good point on the heat issue with solder... i mean the BMS and fuse should save it, but i hadn't thought of that. Do you have recomendations for how to attach the main bus wires coming off the battery in a non soldered way? cause with flat top 18650 based batteries, you have to spot weld nickel strips, and soldering the main wire to the strip before spot welding is the only thing i can think of. If you go with something like headway lifepo4, they are screw top, so you could fab a contact plate that the wire crimps into, then screws to the battery, but yeah - no idea how to do something like that with flat top batteries.
I'm not an expert with building battery packs, but I think solder isn't a problem for connecting the nickel strips, so long as it's only a fraction of the whole pack. And if it's encased within the battery housing, spall won't be as bad of a problem. The highest currents would be where the "strings" are aggregated together in parallel, and that's usually when heavy gauge copper is used.
I recall that Aging Wheels has done videos on cell replacement, and I think maybe there was some sort of copper/brass busbar which aggregated the various nickel strips and then had large screw-down terminations for attaching external cables.
Rewatching your video again, do I understand that your emergency cut-off is inline with the full battery voltage? If your design had a smaller auxiliary 12v battery for powering the electronics, you could have a low-voltage control signal that closes a normally-open contactor that connects the main battery. Your emergency cut-off would be in-series of the control signal, so that loss of the signal immediately cuts off main battery voltage.
The same signal wire could be routed around to other safety sensors to isolate the main battery if something is wrong. In the most extreme case, the wire could be routed so that severe structural damage would automatically sever the wire.
This would also reduce the amount of heavy wire to only where it's needed, with some weight savings. Air conditioner condensers do this same trick, so that the safety sensors don't have to be rated for full 240 VAC.