Hey everyone, glad to be here, very interested in E-PPG. Great job on this design @Pdwhite, looking forward to buying a kit!
I stumbled across this video a few years ago regarding a company who designed cylindrical batteries for ultralights that were scalable to any size or power combination. The link should open to the point where he starts talking about them. I am interested to hear your thoughts if this is a viable alternative for the battery in this open design.
This video shows him flying an ultralight about 18 months ago along with more data on the motor and batteries.
I reached out to the owner, Chip, and he has some of these packs available for sale. They were designed specifically for flying and to minimize risk of fire. Made from Lithium, Cobalt and Nickle, they claim it has the highest power to weight ratio energy density of any battery available. He has developed a smaller battery with higher voltage for his new motor recently and he is getting back to me on the specs and pricing for all of those.
I am not an electrical engineer, I put together some of these specs from their old website a while back, hopefully they will be helpful. Feel free to correct anything if needed.
Ultra-Flite Battery Cylinder -
12s - 44.4V 65Ah draws 130 amps
2886 w or 2.9kw is around 44 lbs??
14s -57 V - 51 lbs, each cell is 3.5lbs 3705W or 3.7kW
13s@4.05 = 52.65V or 14s = 56.7V
On the 2nd video he mentions getting 1 hour of flight time w 21 packs in his ultralight then 2 hours to recharge. You can scale the number of cylinders up or down as needed.
Here is another link with more specs on the battery from their website.
maybe a useful note: we electro-pilots in europe fly since many years cells of Sony from the VTC series. Currently the VTC 6 which can be used without problems up to 15 A duration. so it is possible to use small batteries such as. 12 S -15 P in my competition concept. or in large projects such as. in a trike, it is also possible to allow peak currents of up to 300 A at start and 120 A in flight, then in 25 to 40 S -15 P configuration. regards
It’s interesting tech but not available for sale at this time. Once it is and has been tested then fine. Until that time I prefer to stick to known and available batteries. Elon Musk once said in an interview that there are dozens of battery “breakthroughs” every year, most to none of them are viable or any better than existing tech. If they were, Tesla would switch to them immediately.
Another update from Don, he has moved on from the cylindrical batteries and sticks to his custom built 18650 packs with LG cells and a custom programmed active battery management system. He claims that Active BMS is the key to reducing fire risk to the lowest possible level.
Fire, unfortunately, is lithium biggest hurdle and Telsa’s too. I wonder if maybe capacitors could be used instead of batteries. They would charge quickly but getting slow power out of them is where I’m still a little fuzzy. Technically speaking, You could design the whole unit(supporting structure) out of a ‘hard capacitor material’. Therefore the whole PPG or aircraft (or whatever design you want to make) is the power source. Crazy ideas!
Capacitors of equviolent ah would be huge, perhaps adding a reasonably small capacitor bank between the batteries and the motors might extanded battery longevity when pulling bursts of power. Not entirely sure but it could save some stress.
