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  • 8s....

    Ordered the 8S motor upgrade for the F15.....6S just wasn't getting it done.....I purchased the EC 5 adapter and also the Admiral 2S 5000 50c that I will use with my 6S 5000 50c....my question is this.......Can I use different C ratings on the batteries when using the adapter.....I have a few Genesis 5000 65c batteries I was thinking of using....is it ok to use these with the 2S 5000 50c ? .......

  • #2
    Anyone...

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    • #3
      Hey Rick227,
      Good question...wish i had a for sure answer for you. But just wanted to assure you that one of the guys/gals here will jump in for you.
      Lon

      EFlite F-16 80mm, EFite DRACO, EFlite Night Radian, E-Flite P51 1.5m
      Freewing A-10 80mm, F-86 80mm, F-15 90mm, Avanti. FMS DHC-2 Beaver, Fliteline P-38L ,Flyzone DHC-2 Beaver Island Wings, Freewing Pandora.

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      • #4
        It's best not to mix MA and/or C ratings. One pack will most likely drain faster then the other. But, considering the small difference between the two mentioned you should be able to get away with it.
        I would suggest a bit of static testing with watt meter and individual cell monitors before taking it airborne though.
        My YouTube Videos https://www.youtube.com/channel/UCrz...4Q-xrOOtP2C-8w

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        • #5
          In the context of the OP's question, it is best to keep packs the same brand, mAh, and C rating.
          Live Q&A every Tuesday and Friday at 9pm EST on my Twitch Livestream

          Live chat with me and other RC Nuts on my Discord

          Camp my Instagram @Alpha.Makes

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          • #6
            Originally posted by Rick227 View Post
            Ordered the 8S motor upgrade for the F15.....6S just wasn't getting it done.....I purchased the EC 5 adapter and also the Admiral 2S 5000 50c that I will use with my 6S 5000 50c....my question is this.......Can I use different C ratings on the batteries when using the adapter.....I have a few Genesis 5000 65c batteries I was thinking of using....is it ok to use these with the 2S 5000 50c ? .......
            I use an Admiral Pro 4S 5000 mah 60C pack and the same Admiral 2S 5000 mah 50C you mention in combination all the time in my 6S jets and have not noticed any difference. I would not hesitate to combine the 2S with the Turnigy Heavy Duty 6S 5000 mah 60C pack to get 8S if they would fit in a plane.

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            • #7
              Thank you for the responses, I can understand wanting to keep c rating the same but don't understand why you would have to use same brand??.....

              Comment


              • #8
                It's a valid question, certainly. All I can say is that I've inspected several of the battery factories that produce, under many different label names, probably 80% of the lipo batteries in the RC hobby grade industry today. There are quite a few differences in how different batteries are assembled, the quality of materials, the QC, the grading process, maturation, storage, cycling, etc. Using the same brand, same C, same connector, same wire gauge... the key to reducing outlier issues, which is really what we're talking about here, is maximizing Consistency. Using the same brand simply ensures the highest level of consistency across all CELLS within a pack by negating the chance that Brand A and Brand B are using imbalanced cell qualities (labels with numbers aside!). More Consistency directly correlates to a lower risk of developing an imbalanced cell or one failing under load or some other issue (which, under the right circumstances, could kill one's aircraft).

                In the context of this topic, we are using an 8 cell battery, comprised of 8 cells that happen to be in two packages, one with 6 cells, and one with 2. But the same could be said if we were connecting four 2 cell batteries in series. Would someone really say connecting four different brands of 2 cell batteries together to create an 8s pack, has less potential imbalance challenges than if all four of those batteries had been produced under the same brand and thus under the same Q/QC/grading conditions? Now, I'm not suggesting that connecting different brands will cause an explosion or guarantee some sort of cell imbalance, but, technically speaking, for the ultimate in safety [read: consistency], I always group my series packs together having been purchased from the same brand and similar if not same batch, and I keep them together, charge them together, fly them together, balance them together. I've had packs last a long time this way, over hundreds of flights, and their IR/aging remains --there's that word again-- consistent.

                The other factor in all this is that labels with numbers on them are labels with numbers on them. A "30c" from one brand isn't necessarily a "30c" from another brand, and one risks a slippery assumption that they are both 30c. At the factory, each cell is graded and matched within a given pack. I for one would prefer to hedge my bets by operating with as close a matched pack (comprised of two or more sub packs). But because customers can't access the individual cell performance report, then the best way to maximize consistency is, again, to use the same brand, preferably purchased within the same timeframe.

                Of course, all this talk really boils down to Precautionary Measures. I am admittedly more cautious than maybe sometimes I need to be. Many people just fly what's "close enough" and it works for them under their usage load, which is great. On the other hand, I have never lost a matched series pack in flight that was cared for under the regimen proscribed above. And consider, as one can imagine with a job description like mine, I fly A LOT, as in hundreds of flights a month from 2s 350 to 12s 6600, so my sample size is fairly large. Seeing how the RC batteries we all use are actually made, though, from scratch, drives a lot of my reasoning behind all this procedural blabbering. :)
                Live Q&A every Tuesday and Friday at 9pm EST on my Twitch Livestream

                Live chat with me and other RC Nuts on my Discord

                Camp my Instagram @Alpha.Makes

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                • #9
                  Keep the C the same,brand the same and age the same. All of my series packs are put in pairs and not used for anything other than flying in series. When done this way they age the same which keeps them both equal. Otherwise you will get one that has a lower or higher resistance which can cause them to drain unevenly.

                  Also you can use a 6s with a 2s so long as they are the same brand, Capacity and C as well...
                  Check me out on youtube at https://www.youtube.com/user/gooniac33
                  I am an RC addict and innovator that loves to share my knowledge with those that need help. Ask me anything via PM if you need help! Check out my Website here https://www.gooniac33.me/

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                  • #10
                    Agreed...I never mix up my batteries...They are always the same brand, capacity and C rating. Good insight Alpha...
                    My YouTube RC videos:
                    https://www.youtube.com/channel/UCDZ..._bdGEJBmtV7YUw

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                    • #11
                      I concurr with what has been said so far. I have been flying giant scale electric for a while now and always use a combination of packs. One of my more common set-ups has been a 9S using a 5S 5000mah 30C and a 4S 5000mah 30C-40C pack. All are the same brand, capacity and age. I fly them as a pair. I have found that power consumption from both packs are the same. I have several rules I follow when doing this. The first is I never over stress the batteries. They come down at 3.8v+. I try to keep power usage below the lowest C rated pack. I always balance charge the packs at 1C. I've been flying some of the packs for 4 years now and they are doing fine. And I monitor the health of the packs using a Sky RC charger that measures each cell voltage and IR. I've never had any issues.

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                      • #12
                        There are a number of electric helicopter pilots at our field and all of them have said to keep the batteries the same for the reason mentioned above. They fly them all in pairs that stay together.

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                        • #13
                          Originally posted by Twowingtj View Post
                          I concurr with what has been said so far. I have been flying giant scale electric for a while now and always use a combination of packs. One of my more common set-ups has been a 9S using a 5S 5000mah 30C and a 4S 5000mah 30C-40C pack. All are the same brand, capacity and age. I fly them as a pair. I have found that power consumption from both packs are the same. I have several rules I follow when doing this. The first is I never over stress the batteries. They come down at 3.8v+. I try to keep power usage below the lowest C rated pack. I always balance charge the packs at 1C. I've been flying some of the packs for 4 years now and they are doing fine. And I monitor the health of the packs using a Sky RC charger that measures each cell voltage and IR. I've never had any issues.
                          Exactly!! This is one of the reasons I prefer to use capacity to determine my discharge rate instead of an over inflated C rating. I almost always land my planes with 3.75-8v per cell... And never charge over 1c...
                          Check me out on youtube at https://www.youtube.com/user/gooniac33
                          I am an RC addict and innovator that loves to share my knowledge with those that need help. Ask me anything via PM if you need help! Check out my Website here https://www.gooniac33.me/

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                          • #14
                            Since most of our charging setups provide data each pack and individual cell characteristics, I cant imagine that there would be a true problem if the rested IR values were similar across all cells. You can always do a flight and check battery temps/voltages and connector temps to see if there are potential issues. You just have to yield to the lower performing of the two batteries and not overfly it. I've mixed brands - the main feature I pay attention too is equivalent pack age. I think some guys could still get into trouble with same brand packs when adding a new 2S pack to a mature 6S pack, but in reality these setups are bound to be flying anyway.

                            A safe way to optimize flight times and pack life is to not fly below 80% of the available pack capacity. Voltage is load dependent and it is possible to see < 3.7 volt/cell after a hard run- warm pack and still be under 80% consumption. Most folks who have telemetry monitor both, but the mah used is the true gas gauge.

                            Sorry if this is repetitious.
                            Last edited by 0nemildot; Feb 21, 2017, 01:07 PM. Reason: clarification

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                            • #15
                              So I'm looking to run a Admiral 4000mAh, 4s, 40c with a 3s but all I can in the Admiral brand 3s is a 3700mAh, 40c. Is that close enough to work?
                              thanks

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                              • #16
                                Originally posted by Drd View Post
                                So I'm looking to run a Admiral 4000mAh, 4s, 40c with a 3s but all I can in the Admiral brand 3s is a 3700mAh, 40c. Is that close enough to work?
                                thanks
                                Didn't like the answer I provided here for the same question??? :Smug:
                                https://www.hobbysquawk.com/forum/el...502#post102502
                                Warbird Charlie
                                HSD Skyraider FlightLine OV-10, Sea Fury FMS 1400: P-40B, P-51, F4U, F6F, T-28, P-40E, Pitts, 1700 F4U & F7F, FOX glider Freewing A-6,T-33, P-51 VQ P-39 Dynam ME-262, FW-190, Waco ASM A-26; ESM F7F-3 LX PBJ-1 EFL CZ T-28, C-150

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                                • #17
                                  Originally posted by gooniac33 View Post
                                  Keep the C the same,brand the same and age the same. All of my series packs are put in pairs and not used for anything other than flying in series. When done this way they age the same which keeps them both equal. Otherwise you will get one that has a lower or higher resistance which can cause them to drain unevenly.

                                  Also you can use a 6s with a 2s so long as they are the same brand, Capacity and C as well...
                                  I think this answers my PM question to you, no?
                                  I can do what i think i can do and it should not only be the correct way to do it, but will also work...(?) Will find out later today when the adapters are delivered... as long as they're the correct ones... :)
                                  HRB 3s and 4s, both 5000 / 50c rated...
                                  Should end up with 7s 5000 50c packs...?

                                  Comment


                                  • #18
                                    You are correct. Been doing this for years with good results.

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                                    • #19
                                      Originally posted by jasmith41 View Post

                                      I think this answers my PM question to you, no?
                                      I can do what i think i can do and it should not only be the correct way to do it, but will also work...(?) Will find out later today when the adapters are delivered... as long as they're the correct ones... :)
                                      HRB 3s and 4s, both 5000 / 50c rated...
                                      Should end up with 7s 5000 50c packs...?
                                      Yes it does!! Good luck!! I still replied though...
                                      Check me out on youtube at https://www.youtube.com/user/gooniac33
                                      I am an RC addict and innovator that loves to share my knowledge with those that need help. Ask me anything via PM if you need help! Check out my Website here https://www.gooniac33.me/

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