2 3cell or 1 6cell Lipo

[Sevans16]

I am needing a 6 cell set up for my plane. Direction say to go with two 3 cell packs wired in series. Is there much difference between going with a 6 cell pack?

[gareth.ky]

I would consider 4 things when buying that many cells:

• Cost - Do two packs cost more than one? Lots of 3 cells packs out there, it might be cheaper to buy two.
• Mounting - Do you have space to mount two packs vs. one packs. Check the dimensions maybe even make a mockup.
• Charging - This is a big one, you are going to need two charger OR wait two hours between flights. This would probably swing me towards a single pack.
• Cooling - Fewer cells in the pack will cool better.

Lets hear a little bit more about your setup and application.

[Sevans16]

I am looking at FP packs. Price is about 10.00 difference. You are spot on with charging. I am looking at getting a second charger or a TP 1010. Either way I need more charging power. I am setting up a GP Reactor .46-.51. I went with the Rimfire 42-62-480 motor per instructions. The manual calls for two 3s 3200mah packs in series. I am looking at the FP 6s 5350mah EvoLite pack. It only weighs 1.5oz more that the GP bat setup.

[gareth.ky]

I hear good things about the FlightPower packs from the electric guy at our local field. He has some big 90 - 50cc sized electrics. Even has a portable generator to charge them off of. Hes switched over to FlightPower for all his big setups.

So the motor spec is 45A/830W continuous, 80A/1480W burst. You'll have 133W continuous (@ 25C) on tap with the 5350 pack. They also make smaller capacities in 6S (3700, 4350) that would also work if you don't want the extra 1.5oz on board. Any of those packs have a continuous rating higher than the burst rating of the motor.

Also looking at Towers website it seems Great Planes doesn't sell anything bigger than 4S so thats probably why they recommended 2 x 3S. So they could recommend their own product.

I would probably go for the single pack for charging reasons. Anyone got a good reason not to?

[Sevans16]

I was looking at the 5350 mainly for flight time. I don't have any idea about how long flight times would be? Is is a straight curve IE:if say a 3200mah would last 6mins would a 6400 last 12mins? or is there a diminished return?

[gareth.ky]

Well, there is a trade-off. You can make the batteries bigger to the point where the airplane will no longer fly because your too heavy to take off. You can also make them so small the motor smokes them. Somewhere in between is the ideal pack for that airplane.

Best advice I can give you is to go over to 'R C Groups' and check to see if someone else has figured out what the right size is.

For 3D, lighter is going to be more enjoyable to fly. You may not get the epic flight times but you will have more fun. You'll have to mess with the pack size and prop until you get something that hovers between 1/2 and 2/3 throttle without killing the motor. Got too heavy and you will need too much throttle to do everything and the airplane will feel sluggish and snappy. Also at some point you'll not get any more flight time because the motor just works harder to pull the extra weight.

Picking the right pack and prop for a given application is kind of a black art. Sorry I cant give you a specific recommendation.

[Sevans16]

I completely understand what your saying. THe GP 3s 3200 packs from the manual are 9.52oz each so 19.1oz. THe evolite 6s 5350 pack weighs 20.6oz. So I am lookin at a 1.4oz addition. There is an evo 25c series 3700mah weighing in at 19.9oz. THese are the lightest 6s I have seen. The TP are about 4-6oz more. These evolites seem to be new but really light. Granted a lot more expensive. I believe, build it right the first time. I do not cut corners on setup.