Has anyone tried to use off-the-shelf power tool battery packs? Could be a cost effective, safe and simple off the shelf solution for DIY starters. I am thinking about these Kobalt 6S (24V) packs. They come in 1P (2Ah) ,2P (4Ah) and 3P (6Ah) sizes. They have the INR 18650 15L cells which are rated at max 18A continuous discharge. Nice thing is that you can get them quickly on Amazon and in many hardware stores. The smaller packs you can even take on planes. Adapters have also already been designed, mostly for robotics use. For light users with efficient wing setups 2x 3P packs in series could be enough, else use 4. As an example, I have my small setup limited to 50A with the small Flipsky VESC and I use about 20A while foiling with my 180 pounds (~80kg), so with 2 of these packs Iād be foiling for ~15min. Thatās a good start imo, just add more packs for more ride time (and more weight).
An interesting concept for sure.
I think the company that brings out a system where you can split the packs up into sizes that are flight friendly would make some good cash!
Iād happily fly with a 7kg worth of flight friendly packsā¦
I doubt the BMS on top lets you discharge something in the range of 3 x 18A.
Those drills got about max. 250W, so at 6S it is ~10-15A.
I didnāt test any drill battery (yet), but I guess they got the short circuit/over current protection somewhere at 20-25A.
Having multible in parallel should work tho.
Also IMHO 100ā¬ for 144Wh is quite a lotā¦
Did my homework on that , assuming bms hold up , bigger ,more weight , twice expensive if you have the spot welder ā¦ but yes it can be done
I already modded my old power tool ā¦ nice ā¦ at the time I calculated 600ā¬ for 15A ( Ryobi )
We are testing packs in serial connection that have maximum 100WH, because that is the exception to carry them by air travel. so you can carry 5 or 10 of them with most airlines if below the above sizeā¦
We use Aldi battery packs that are available in Europe Aldi stores very cheapā¦ we put them in a donking station and it works already to fly for about 25min.
This would help to overcome the airtravel problem with efoils;-)
Our Inflatable board with motor system is carried already by air and works easy in a samsonite bag;-)
I see that the Aldi packs use Samsung 25R cells. Pity they are only 10S packs though. The charger is pretty heavy charging the packs at almost 2C. That will reduce life cycle of the battery a bit. But as you say, you will easily be able to fly with these packs which is a bonus.
This is a project I started for my old venture because there are almost no solutions. At that time I didnāt believe the market I was currently in was large enough to warrant putting all the effort in. The first thought was to run off the shelf drill packs in series and use one of those multi pack charging stands to charge them. That would make it a pretty slick system. Only thing is that drill packs donāt supply enough current.
If there is genuinely interest in this I can pick up where I left off. Coincidently the manufacturer I was talking with mailed me on thursday to see how things were going.
The drill packs just help with transporting the cells. Other than that I wouldnāt try to interconnect them at all. I would rather transfer the cells into a unit designed for purpose.
The ultimate setup would be to design a set of modules that could easily be transported by air. In the UK there is the unique challenge that they limit you to 2 spare batteries. But ultimately you could have 4 devices with 2 spare batteries each (that would give you 12 batteries). The camera guys travel like thisā¦
Agreed on the drill packs. The argument for would be that they are relatively cheap off the shelf in volume.
A dedicated pack is āeasy enoughā to do. The approach we took earlier was a higher C rating and keeping the packs under 100wh. Included in the kit would be 3 modules and a cable for connecting (or we would have integrated the wiring that would be in the cable into the product). Each module has itās own low voltage cutoff, temp check, current check and balancing and each module gets itās own charger (that was cheaper and easier than a single charger that charged all at once + safer). Clear markings kn the housing for voltage, capacity and general rules for lipoās on flight (for those pesky safety check guys). For that application we needed an 18s pack and capacity was less important.
I donāt think so either. Regardless of packaging itās still a hassle and only allowed on cargo planes if at all. But if it works it works. For the diyer you could have a āflyableā pack for 500 ish all together.
ā¦ but I google found it. Nice 14S packs but above the 100Wh flight limit, also for the smallest one. Interesting to read that their individual cells are wrapped in a phase-change material that is activated electrically when the battery reaches a certain temperature to turn liquid and draw heat out of the cells.
finally we have it readyā¦
We optimised our system to very low power consumption and used conventional power Tool battery that most airlines allow to carry in the handbag (LiIon packs<100Wh).
Now finally with this setup you are able to ride for 20minutes with 160ā¬ battery investment or 40minutes with 320ā¬battery budget and as it all fits in a big Samsonite luggage, it is the first inflatable efoil kit that you can legally carry by plane to maldives, Seychelles &Co.
We think that is fair enough and with our infatable system & Carbonfibre box all up weight is only 21kg. This improoves handling by 100% compared to the efoils on the market with more than 35kgā¦
So now that you know it is possible to foil with those tool battery packs (available around the corner, go for it and build your own;-) Video of test run with tool battery packs
