EFlite Viper 90mm Custom built 14s Li-ion pack and seven minute flight.

[@deadstickduck2025]

Nope..... 14s 1P only 4500mah and all 4 flights this morning used 3900-4000mAh a pack for @88% capacity. All 6:50~7:00min like clockwork. 1057g with the 3D printed spacers and 0.15mm copper spot welding. AUW 3993g. That includes 2s2800nAh Rx battery

[@sendit_rc]

Awesome!! What is the total battery weight thanks

[@deadstickduck2025]

1060g 14s of the new Molicel-p45b cells. It's nice to be able to build your own packs.

[@adamtrzaskowski3901]

14S2P of Molicel P45B is ca. 1950g. A lot. I had my Freewing F-22 fly on a setup like this - but without landing gear (so a lot lighter). Does this Viper maintain good flying characteristics compared to a standard setup?

[@TheLowelllife]

It flew on 14s4500, f was 3993g not much more or equal to flying stock setup on a 6s7000 lipo. 50% throttle is only 20A so going full power for 3~5 seconds at a time got either a greater that 1:1 vertical or a fast pass accomplished. Cruising at 60~75% just 60A or so.... 4000mAh with just decent throttle management gets 7min like clockwork. She flew lite compared to my other ones flying 6s3p13500(18 cels) or 8s9000 (16 cells). Going high voltage efficiency meant smaller 14s esc and keeping motor kv @1000 meant 104A max @45V..... Molicel P45B can handle 100A for dozens of 3sec bursts.... and 50~60A continuous if inside an EDF with attention to massive battery bay cooling. Which acts like cheater holes for easier fan breathing... more efficiency. When LVC of 2.9V starts vibrating/voice calling voltage under heavy throttle, I know to back off a litte until the next timecI wantvabove 65% stick. Temperatures climb fast inside the cells so that's why I made 3D printed cell spacers to maximize airflow and take advantage of the huge battery compartment lol.... Telemetry calls out temperature as well so I know when I'm getting over 60C.... these can go to 90C but I always keep below 75C as a rule.... no gain in killing them too fast. Charge as 2x 7s4500mAh at 10A to 4.20v... on lipo setting. Puts 3900~4000mAh back into the pack in @45min. Can charge at 3C if you have a fan keep them cool. With 4 packs in rotation one could rinse and repeat the whole day. My cost to assemble each pack $125. Can't buy 1000g worth of 12s lipos for that and get 4000 usable capacity. That would be the same as 2x 6s5000 for under 1000g....... If you can, or have a battery building buddy lol, Li-Ion is the way to go on 90mm+ EDF. My 120mm HSD F-86 and 2.3M 130mm Odyssey will be using 16s4p18000 Li-Ion.

[@deadstickduck2025]

Going higher cell count helped with efficiency and lowering the current demands on a single pack. Didn't need to run parallel to handle the load..... a big negative for Liion... but it's getting better as an alternative fuel tank if you have the ability to assemble yourself.

[@adamtrzaskowski3901]

@@TheLowelllife The 1080 motor (I assume it's HET 700-83-1080, 460grams) and the 104A (I assumed its a continuous load) suggested it's a 2P setup. In this case, you could use a smaller motor, like HET 700-68-1125, which could take this power output no problem, but its 150g lighter. What 14S ESC did you use? I only know of Hobbywing Flyfun that can take 14S, but I am looking for something lighter.

[@sendit_rc]

@@adamtrzaskowski3901 scorpion makes a 14s esc but they are $700

[@deadstickduck2025]

I bought a new APD 200AFX3 ESC and HET 700-83-1080kv off rcgroups classifieds. The ESC is quite light and at 100A the ESC doesn't even need a huge case/heat sink. There are pictures of this in the rcgroups thread EDF playing with Li-Ion. If I had a charger that could handle 14s the battery pack could shave 50g in extra weight not needing double the wires and simply a straight 14s and not two 7s in the same brick. And the 1080kv motor convenient due to decent price when I was gathering components. The plane also has 2s2800 18650 liion/BEC power 120g...... so, definitely can get this bird to under 3695g..... Would be even better of running the BEC of main pack. But I wanted this to be safe in cast the main battery failed for any reason. I may end up putting the 1080 motor in a larger 110mm fan and go with the motor you show and go for 3700g. Awesome plane!