Tweet
Sunday was a nice clear day, and so I decided to do some in flight battery testing with trex 250.
I ordered a 3S lipo checker from ebay 6 weeks ago which finally turned up, its a small board with 3 sets of LEDs so shows pack status, >3.6v cell shows green LED, <3.6v red LED flashes, then <3.3v the beeper sounds (very loudly) - checker fits neatly under canopy on top of pack, with canopy slightly pushed up, I was surprised how much difference the extra weight made to trim, I put 6 clicks of back cyclic in and still wasn't quite neutral, so I don't plan to fly the checker every flight, but its a really nice tool to have for checking new/old packs now and again - and for £2.52 delivered I think everyone should have one) (mine was from ebay seller cntbh (7.4V -11.1V RC Lipo Battery low voltage Alarm Indicator).
So I can compare the lipos between flights, I tried to fly the same flight pattern each time, hovering for first minute, then some full power climbs to about 40ft, with some flips every 20-30 seconds with hovering gentle circuits between. My transmitter timer was set to 4m30 (which is what I normally fly with), and once timer had beeped I just bounced heli up and down full throttle to about 40ft, then back down to ground, then up again, over and over until the lipo beeper beeped (first cell below 3.3v).
First I flew the Align 850mah 30C pack which came with my 250, flight was fine, flew through the 4m30 no problem, and beeper finally went at 6 minutes. Recharged put 518mah back in (cellpro 4S at 2C) - this generally seems to be the best performing 250 pack.
Next up was cheap ebay GE Power RC Pack 860mah 20C (constant 20C, peak 35C?) bought from ebay seller rc-arch (4x 11.1v 20c 850mAh 3 Cell Lipo Battery Trex 250 - I paid £26 delivered for four).
I have been flying these packs for a few months, sport flying with 4m30sec timer, and they are fantastic, slightly less punch than the Align pack, but hardly noticable, and I am very happy flying these packs day in day out. The battery wires seem quite thin, and are generously long but this doesn't seem to cause any problems in use.
Test again flew through 4m30 timer absolutely fine, and beeper finally went around 5m45sec, so very slightly less than the Align pack - Recharged put back in 516mah (cellpro 4S at 2C) - very pleased with this pack for the money - I ordered another couple after this.
I bought some other cheap HK Lipos on ebay, which didn't do well at all.
RC modelpart lipo, marked 20C bought from ebay seller wasp2018 (2x 11.1v 20c 850mAh RC Lipo Battery For Align Trex 250 paid £12.30 delivered for two)
The lipo alarm started beeping 2min20secs into flight, so I landed - previously I have flown a few sport flights with these packs - they feel noticably less powerful than the other packs, full pitch head speed drops noticably, and after zooming around was hovering in front of me when LVC cut in on ESC (I have set to middle!) this was only 3min30secs into flight - my take on this is these packs are nothing like 20C, more like 10C constant, and are not really suitable for the Trex 250.
Next up was latest purchase, Black swift 900mah lipo, bought from ebay seller etectonic1127 (2 x 900mAh Max 25C 11.1V 3S Lipo Battery paid £12 delivered for two) - I liked the look of these as they have meaty power wires !
Postie delivered these literally as I was doing test flights, so I charged them and flew straight away - lipo alarm beeped after about 1 minute of flight, so I landed. I then stuck them on 8Amp discharge (about 10C constant), for 4min30secs, the voltage initially dropped down to 10.3v, but then started climbing back up, and stayed above this for the full 4min30secs, lipo monitor flashed red on one cell (<3.6v) but no beeper (<3.3v), I wonder if these packs will improve with a few cycles, the other packs have all completed multiple cycles. I have since bench tested these at 12Amps (almost 15C) they only held for 29seconds, at 16 Amps (not even 20C) they only held for 12 seconds, so I believe these are actually 10C packs which have been misdescribed.
From my experience, the Align30C packs are best but at £16 a pop they should be, the GE power packs for almost a third of that price (~£6.50 each) are fantastic packs for sport/general flying, and I will keep using them as my main pack.
Hope this is helpful info to others.
I ordered a 3S lipo checker from ebay 6 weeks ago which finally turned up, its a small board with 3 sets of LEDs so shows pack status, >3.6v cell shows green LED, <3.6v red LED flashes, then <3.3v the beeper sounds (very loudly) - checker fits neatly under canopy on top of pack, with canopy slightly pushed up, I was surprised how much difference the extra weight made to trim, I put 6 clicks of back cyclic in and still wasn't quite neutral, so I don't plan to fly the checker every flight, but its a really nice tool to have for checking new/old packs now and again - and for £2.52 delivered I think everyone should have one) (mine was from ebay seller cntbh (7.4V -11.1V RC Lipo Battery low voltage Alarm Indicator).
So I can compare the lipos between flights, I tried to fly the same flight pattern each time, hovering for first minute, then some full power climbs to about 40ft, with some flips every 20-30 seconds with hovering gentle circuits between. My transmitter timer was set to 4m30 (which is what I normally fly with), and once timer had beeped I just bounced heli up and down full throttle to about 40ft, then back down to ground, then up again, over and over until the lipo beeper beeped (first cell below 3.3v).
First I flew the Align 850mah 30C pack which came with my 250, flight was fine, flew through the 4m30 no problem, and beeper finally went at 6 minutes. Recharged put 518mah back in (cellpro 4S at 2C) - this generally seems to be the best performing 250 pack.
Next up was cheap ebay GE Power RC Pack 860mah 20C (constant 20C, peak 35C?) bought from ebay seller rc-arch (4x 11.1v 20c 850mAh 3 Cell Lipo Battery Trex 250 - I paid £26 delivered for four).
I have been flying these packs for a few months, sport flying with 4m30sec timer, and they are fantastic, slightly less punch than the Align pack, but hardly noticable, and I am very happy flying these packs day in day out. The battery wires seem quite thin, and are generously long but this doesn't seem to cause any problems in use.
Test again flew through 4m30 timer absolutely fine, and beeper finally went around 5m45sec, so very slightly less than the Align pack - Recharged put back in 516mah (cellpro 4S at 2C) - very pleased with this pack for the money - I ordered another couple after this.
I bought some other cheap HK Lipos on ebay, which didn't do well at all.
RC modelpart lipo, marked 20C bought from ebay seller wasp2018 (2x 11.1v 20c 850mAh RC Lipo Battery For Align Trex 250 paid £12.30 delivered for two)
The lipo alarm started beeping 2min20secs into flight, so I landed - previously I have flown a few sport flights with these packs - they feel noticably less powerful than the other packs, full pitch head speed drops noticably, and after zooming around was hovering in front of me when LVC cut in on ESC (I have set to middle!) this was only 3min30secs into flight - my take on this is these packs are nothing like 20C, more like 10C constant, and are not really suitable for the Trex 250.
Next up was latest purchase, Black swift 900mah lipo, bought from ebay seller etectonic1127 (2 x 900mAh Max 25C 11.1V 3S Lipo Battery paid £12 delivered for two) - I liked the look of these as they have meaty power wires !
Postie delivered these literally as I was doing test flights, so I charged them and flew straight away - lipo alarm beeped after about 1 minute of flight, so I landed. I then stuck them on 8Amp discharge (about 10C constant), for 4min30secs, the voltage initially dropped down to 10.3v, but then started climbing back up, and stayed above this for the full 4min30secs, lipo monitor flashed red on one cell (<3.6v) but no beeper (<3.3v), I wonder if these packs will improve with a few cycles, the other packs have all completed multiple cycles. I have since bench tested these at 12Amps (almost 15C) they only held for 29seconds, at 16 Amps (not even 20C) they only held for 12 seconds, so I believe these are actually 10C packs which have been misdescribed.
From my experience, the Align30C packs are best but at £16 a pop they should be, the GE power packs for almost a third of that price (~£6.50 each) are fantastic packs for sport/general flying, and I will keep using them as my main pack.
Hope this is helpful info to others.
E.G.S.
Comment