A few things. First, you will need at least 3 of those batteries to handle the current required. that equates to a minimum of $2160 in batteries. There is less than $1300 worth of cells and bms systems in those packs, so if possible just make your own.
Also be really careful with those cheap ESC’s. Most of the time they cant handle weird fluctuations of current in these very large motors.
I must be missing something, according to the previous comments I understand flying an e-ppg takes “around 4.2 to 4.5 kilowatts” (I guess this is peak) so on a 72v battery pack it takes only 62A.
Which one of this kind pump-up ebike battery could handle.
Am I missing something? why would get in the trooubles of sending 200A in M40 motor to achieve 70kg of thurst when 20kg seems enough?
I’m new to e-ppg and only did a couple of flight with combustion ppg, but I built some other electrical stuff like eboat and ebikes and I am an electronic engineer with some spare time. So once I’m up to speed with your knowledge I would like to help to make a really afordable way to fly.
During takeoff and the initial climb most people want somewhere in the range of 100-130lb thrust which equates to something in the range of 12-15kw of real world power usage and they often need to hold it for minutes at a time. Also the cells being used in the battery pack(Panasonic nrc18650ga) don’t handle high currents well for very long without overheating and loosing efficiency. So in my opinion even 3 packs may be pushing it depending on your style of flight, location(elevation and terrain), and wing size.
The thing to realize about flight is that the boundary between the ground and the air is the most critical. Getting off the ground and to a safe height is a very challenging problem and continues to be a limiting factor. It’s a shame to have to spec an entire system around 1% of its operational envelope, but getting that wrong literally means a crash.
The upshot is that you want to climb hard and fast to an altitude at which you have breathing room. Once you’re there you can throttle back and enter cruise mode. But getting there is a slog, and it’s a long enough slog that you can’t assume peak power is different from steady-state power. By the time you’ve run your batteries/ESC/motors for 60-180 seconds, you’ve gotten pretty close to steady-state temps.
Yes I agree this is such a waste to dimension a system for 1/60of its use time! Wait… a very large discharge current is needed for a very short period of time… It sounds like a job for a supercapacitor! The supercapacitor will be used as an energy buffer when you need a current boost, and could be recharged in flight when you are not using the engine at full capacity.
To do a quick approximation:
But some research talk about energy density of 110 Wh/kg that should in our case be in a near future a super capacitor of about 1kg could help to reduce drastically the size/weight of the battery pack. No wonder why Tesla bought bought Maxwell a supercapacitor company for 218 Millions
If it helps the opinion of the MAD motor company, I just found that the SP140 is using a MAD M50 motor that’s not even in production yet.
There is an M50 C35 PRO EEE on their homepage, but it is not linked under the paramotor category in the main menu (yet). Check: https://mad-motor.com/product/mad-m50c35/
Spec claims:
… and one picture on the MAD homepage can also be found on this page here 
Wow that took them a while to post it. I knew about the M50 a long time before even posting the previous comment. The one thing I didn’t know is that there is a 40kv version which should provide more usable rpm for a sub 60 inch prop.
Hi, could I use the MAD M50 34kv or 40kv with just 16s instead of 24s? For safety reasons considering I’m building my battery. On their page the tests are only at 24s, and they are not that great email answers either. If I knew that I can get 15Kw (60v x 250A) with the 16s instead of 20 kw, I would probably go for it. What do you think?
Last thing I want is to have to deal with and keep in the house a thing that me or a curious kid may touch and…die.
hello, you have to take into account that with liion cells the voltage under load drops to around 3 volts at the end. that means you have as an example 16 S * 3 = 48 volts times 40 kv = 1920 rpm minus 15% = 1630 rpm available at the propeller at full throttle. that’s enough to end the cruising flight without loss of altitude.
Therefore it is basically possible to fly with the 40 kv variant and 16 S!
However, you need at least a 140 cm three-blade propeller with a lot of pitch to fly well. the whole thing is super quiet, like I usually fly in my setups. the only downside is that the whole thing is ideal for normal ppg flight speeds of up to around 40 km/h.
Above that ( with full reflex speed wings), a faster rotating propeller makes more sense. but that is a different topic. in a nutshell. the setup fits for standard eppg. as a propeller you can use the e props, for example, which are otherwise intended for the hpd from geiger. or the sp 140 model if you dont need much startpower.
Geiger from Germany also works at low speeds with his Motors to fly quietly. as an example. the hacker qsl 150 has 54 kv and is operated with 14 S or 15 S. here you are in the ideal range for e-ppg from 35 to 50 km/h. hope helps you a little.
another thing to mention: the higher the voltage, the higher the efficiency with a well-coordinated propeller adjustment. That means at 60 V and 250 A you are definitely at the possible limit of the mad motor. it’s only very short. but it’s enough if you have 10 to 12 kw to start. I weigh 85 kilograms myself and often fly with an eppg that only has a total output of 10 kilowatts with around 140 to 150 kilograms depending on the additional battery weight. That’s enough power with standard wings.
in the video: total weight 150 kilograms, 132 cm propeller 2 blades and around 10 kilowatts of maximum power. goes from the technical side performance to the flight weight without any problems.
Thanks bratwurst and congratulations for the record flight!
I am 68kgs and fly a 26 square meters nova prion 5 en-a wing certified also for ppg to max 125kgs. With an 30kg eppg I hope to be under 110kg take off total weight including wing and reserve. So I won’t be heavy and I won’t need speed in flight with this beginners wing.
Because everybody is after power and eficiency makes me think if to go the less eficient route 16s with less voltage for this M50.
Considering these weight/wing measurements, and chosing the Mad M50 because it seems the best option for me regarding power/big prop/price, if there wasn’t any voltage limit in Europe, what would you chose? 24s or 16s for this motor?
(I was planing of doing a 2,8kw battery 24s8p. If I do it 16s it should be 12p to be 2,8kw but between the motor standoffs only 11p fit so 16s11p will be only 2,5kw.)
