Hi, I would like to post my eppg project here. I’ve tried to find most of the components in Europe.
My project will not be dyi homebuild, but more like home assembling and the components are:
- SP-140 frame and loop with netting.
- MAD M50 34kw motor with 140cm prop and openppg prop quick release
- MAD AMPX 300A 24S ESC (not totaly decided yet…)
- Custom made 24s 8p (2,8kw) li ion battery from Samsung INR21700-40T (40T3) 4000mAh - 35A cells.
- Dudek comfort harness
- Aluminium arms from Simplify (not sure yet)
- homemade hand controller
- custom made 20mm/100-130mm aluminium motor standoffs with M6 or M8 bolt through them.
- custom made motor plate from 6mm 7075 aluminium aloy.
About the battery…
Because I’ve never built li ion batteries, reading through here about high voltages above 60v made me decide to split it in three and make smaller 8s 8p packs.
The individual 30v batteries will be each one in its aluminium case, separated one from another, with cables connected on the outside.
-I won’t be using an BMS, and I’ll be able to balance charge them with my ISDT T8 battery charger.
-Each pack will have a temperature probe in the middle, that gows to a 12V Temperature Controller that activates an alarm when a preset temp is reached, also I’ll be able to monitor the temp in flight.
-Each pack will have an xt60 plug for charging and an 8s balance plug to which I will have voltage alarm dispalys that will monitor the individual cell voltage.
-The connections between packs like from the positive of one to the negative of the other I will have two 10AWG wires with same polarity going to both terminals of an xt90 connector so I think it will handle the amps.
-For the main plugs to the ESC I went for the AS 150 antispark that are rated at 150-200A. The reason for thinking they will be enough is that I’ll have consumption like 50-100A (4-9kw) most of the time and above that probably just for seconds…
- On the cells in paralel I’ve used one 0.15/10mm of pure nickel strip and between series 7 pcs of 14 AWG (rated 55A each) silicone cables. I’m also new to spot welding.
- The alu batt case walls on the interior will be insulated with fiberglass and maybe some foam to secure them inside.
The reasons I went for a more complicated and with lots of cables three pack design:
- I feel better knowing I’m working, and storing in the apartment smaller 30v li-ion batteries.
- I can use my hobby charger which I’m familiar with and see very often the state of balance between cells on it or on the small volt dispalys on the batt case.
- If something happens to o cell or a pack, it’s 1/3 of the whole batt not whole of it.
- If the voltage of a group of series cells drops, the alarm gows on, if one pack overheats, the alarm gows on, in both cases I AM the one deciding what to do, if I need another 10 sec of power to pass an obstacle or turn into wind and land safely I’ll have it. Of course, I would land immediately.
The three aluminium batt boxes will be held together into one single battery by aluminium corner profile bolted along the four corners. Unfortunately, because the cells are in plastic holders and distances in the boxes, the total battery will be very long, about 62cm/22cm/9cm (the SP 140 has it at 48/26/9,6cm). But because I’ll have some distance between the frame and motor plate I’ll be able to recline it so it won’t hit the cage when handling it…in theory.
Any advice, idea and opinion are welcome!
Thermometer probe: