Area 51 Posted April 8, 2015 Share Posted April 8, 2015 Hi there, just wanted to ask if any / many are using sub c cells for RX power supply?. I havent got any but I am thinking of switching from my Nimh AA packs; mainly to take advantage of greater capacity.. I do not fly aircraft with massive Rx battery power drain, just want a bit more security and longevity at the field.. I like to stay airborne for upto 20mins a trip where possible; looking at 3300mah etc Any experience, recommedations or guidance on choices greatly appreciated. Thanks in advance Quote Link to comment Share on other sites More sharing options...
john stones 1 - Moderator Posted April 8, 2015 Share Posted April 8, 2015 I used them for ages, never had a problem, gone over to life now though John Quote Link to comment Share on other sites More sharing options...
Chris Barlow Posted April 8, 2015 Share Posted April 8, 2015 I have a 3800 mah sub c in a glider simply for the extra nose weight. Other than that I find 2000-2500mah 6v AA packs are fine. Over Easter I flew my Acrowot on a 2500mah 6v AA for 3 days totaling 12-13 flights, each one around 14 minutes and it's still on the top green light on the on-board battery checker. Quote Link to comment Share on other sites More sharing options...
iqon Posted April 8, 2015 Share Posted April 8, 2015 use sub c on all my petrol for security and weight...... Quote Link to comment Share on other sites More sharing options...
Andy Green Posted April 9, 2015 Share Posted April 9, 2015 Another + 1 for sub C's. I have them in my Astro Hog and big Extra, needed nose weight and made sense to have bigger batteries than dead lead. Andy Quote Link to comment Share on other sites More sharing options...
Matt Jones Posted April 9, 2015 Share Posted April 9, 2015 I think if you're looking for 20 mins per flight then Sub C's are simply not needed. My longest flight was just over 5 hours on a slope soarer on a 4 cell, 700mah, AA pack. It should also be noted that AA packs are up to around 2600mah+, you could fly all day on that. Quote Link to comment Share on other sites More sharing options...
stuey Posted April 9, 2015 Share Posted April 9, 2015 I use a 5 cell sub c pack in my Seagull Sea Fury, that has 8 servos and electric retracts. I use two HD switches in parallel, connected via the deans plug charge lead. I have this setup as it needed some weight up front, and with the possibility of a high load the sub c pack can handle it better than an AA pack, in my opinion! Quote Link to comment Share on other sites More sharing options...
Area 51 Posted April 9, 2015 Author Share Posted April 9, 2015 Posted by Chris Barlow on 08/04/2015 23:06:04: I have a 3800 mah sub c in a glider simply for the extra nose weight. Other than that I find 2000-2500mah 6v AA packs are fine. Over Easter I flew my Acrowot on a 2500mah 6v AA for 3 days totaling 12-13 flights, each one around 14 minutes and it's still on the top green light on the on-board battery checker. Hi there, thanks all for the comments here.. Chris, this pretty much covers my expectations and needs for flying so thanks again for the input; Acrowot 12-13 flights.. Ideal. Reading all comments, I think I can stick with AA packs for now unless I need the weight and then I will go Sub C to achieve this; also extra services of retracts/flaps etc. John, may I ask where the LiFe batteries are coming from? Just out of interest/to compare. Once again, thanks all for taking the time to respond with your thoughts and expereince. Edited By Area 51 on 09/04/2015 09:57:43 Quote Link to comment Share on other sites More sharing options...
Phil Green Posted April 9, 2015 Share Posted April 9, 2015 Posted by Matt Jones on 09/04/2015 08:39:15: It should also be noted that AA packs are up to around 2600mah+ The higher capacity AA cells have a higher ESR and will sag under a heavy load. Sub-C cells of the same capacity will have a lower ESR and consequently a lower drop under load. Lifepo4 cells have a very low ESR, for example the original A123 M1 cell will happily give a continuous 70 amps. The disadvantage of Lifepo4 is the sudden drop-off as they approach full discharge - difficult to predict without measuring actual mAh taken. Cheers Phil Quote Link to comment Share on other sites More sharing options...
Paul Marsh Posted April 9, 2015 Share Posted April 9, 2015 On larger models, such as the BH Trojan, I have 2 x 4000mah 5 cell packs running via powerbox or Spektrum dual input thingy. Quote Link to comment Share on other sites More sharing options...
john stones 1 - Moderator Posted April 9, 2015 Share Posted April 9, 2015 Hobby King sell Life batterys they are 6.6v Area 51 John Quote Link to comment Share on other sites More sharing options...
iqon Posted April 10, 2015 Share Posted April 10, 2015 before deciding on Life batteries . Can you charge them ?. Can you check them .? Have a read up on them first, I thought it was a way forward, like a lipo but safer, but have since reverted to sub c Quote Link to comment Share on other sites More sharing options...
Chris Berry Posted April 10, 2015 Share Posted April 10, 2015 Using twin sub C, 5 cell 3300 packs on my TF Giant P47, Flair Stearman, 1/4 Chippy, 1/3 DVII and DB SE5, once charged for the first time I usually charge for about 4 hours and load at 2 amps and they all give about 6.5v and remain strong even after 3 or 4 flights. Trick is to check and load them regularly, and having 2 is always useful, but like most batteries when they go, they go! Quote Link to comment Share on other sites More sharing options...
Area 51 Posted April 10, 2015 Author Share Posted April 10, 2015 Thanks for the added input here, really grateful to all as its given me a few pointers and good reading as a result.. My charger can cope with LiFe Lilon etc.. but I think I will have a go a making some 3300mah Sub C (found an excellent you tube video) this I feel will provide more capacity than I am likely to need. Fast charge (at the field) is not an issue at this time as I am only after Rx packs, additionally I wont get anywhere near draining them.. Thanks all again for the variety of ideas and answers.. much appreciate. Cheers Quote Link to comment Share on other sites More sharing options...
Former Member Posted April 10, 2015 Share Posted April 10, 2015 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Focae Posted April 11, 2015 Share Posted April 11, 2015 Life batteries are far superior to NiMh or NiCd batteries. They hold their charge better and are just so much more reliable. Quote Link to comment Share on other sites More sharing options...
Chris Berry Posted April 12, 2015 Share Posted April 12, 2015 I use component shop for my Sub C packs. Had four gentle 10min flights on my Flair Stearman the other week and still showed 6.2v at 1amp load. Quote Link to comment Share on other sites More sharing options...
Area 51 Posted April 12, 2015 Author Share Posted April 12, 2015 Hi Chris, did you use NiCd, NiMh or A123? I am looking to order some A123 3.3v 3300mah and a ubec switch. Quote Link to comment Share on other sites More sharing options...
Frank Skilbeck Posted April 13, 2015 Share Posted April 13, 2015 Unless you are using 4.8v servos you don't need a UBEC with a 2s Life battery as the fully charged volts are on par with a 5 cell Nimh battery. Also you don't need 3300mah for 20 mins flight time, I use 3300 mah batteries in my large scale gliders for a full days aerotowing (plus I need the nose weight ) and the fact that they can delivery a large current without a significant voltage drop. Quote Link to comment Share on other sites More sharing options...
Phil Green Posted April 13, 2015 Share Posted April 13, 2015 Posted by Area 51 on 12/04/2015 23:10:53: I am looking to order some A123 3.3v 3300mah and a ubec switch. If they're 3300mAh they're unlikely to be genuine A123 systems cells as they dont make that size. They have uprated the old M1B spec to 2.5Ah, the 18650s stay at 1100mAh and the newer 32113 is 4.4Ah. Cheers Phil Quote Link to comment Share on other sites More sharing options...
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