Is this too much? Battery question

[Westwind]

Hi, I'm new, names Nathan. don't have much experience with planes, I'm building a fun cub. With the fun cub power pack. I want to know what you guys think of running a venom 5000mah 35C 11.1V lipo on it.
Thanks

Sent from my GT-I9000 using Tapatalk 2

[mclarkson]

A Multiplex FunCub? A 5000mAh battery would be massive on that.

[JetPlaneFlyer]

The Fun Cub is meant to take a 3s 2200mAh battery.
Putting a 5000mAh in would screw up the CG and make the model about 300g overweight. You also almost certainly wouldnt be able to fit the battery in without some butchery.


Bottom line is i dont think it's a good idea and cant really see any good reason to do it unless you need to fly for half an hour (which would be boring!)

[firemanbill]

I doubt you could get it off the ground with all the extra weight, and if you did it would be like flying a tank.

What is the point of trying to do this? Curious...

[BBCorvette18]

My cousins fun cub fits a turnigy 3s 3000mah no problem and he said it flys no different. I'd bet you could run a 5000 with minimal work. Just have to make sure the cg is decent I'm going to maiden my fun cub today but will be using 2200-3000 mah batts

[JetPlaneFlyer]

Originally Posted by BBCorvette18

My cousins fun cub fits a turnigy 3s 3000mah no problem and he said it flys no different. I'd bet you could run a 5000 with minimal work. Just have to make sure the cg is decent I'm going to maiden my fun cub today but will be using 2200-3000 mah batts

There is a big difference between a 3000mah, which is 65g heavier than the standard battery, and a 5000mAh which is about 230g or so heavier than standard. That assumes you can physically fit it in and slide it back far enough to get the CG right.

I'm sure the Cub would still fly but you would be adding about 25% to it's flying weight, which is something that's going to have a significant effect on the way it flies.

Question would be; why would you want to do it?

[flydiver]

Heavier > flies worse (crashes more likely), crashes harder (more mass to stop) = more damage.

[Westwind]

The only reason is that I have the battery just around collecting dust and it looks like it would fit. If I can put it to work and get a 20 min run great. I just dont want to harm the power system buy doing so.

Sent from my GT-I9000 using Tapatalk 2

[flydiver]

You won't harm the power system, most everything else will be compromised as indicated above.

[firemanbill]

volts are volts, 11.1 2300, or 11.1 5000, makes no difference other than the weight disadvantage. the advantage is a little longer longer run times if it can fly the extra weight.

Prepare for it to be sluggish to control input.

[hayofstacks]

if it flies, fly it. I got a lot of the same response from my dad when I ran a 1800mah 3 cell on my slow stick, now his is setup that way.

I don't expect it to fly well, but it will prolly fly.

[BBCorvette18]

I would throw it in and see if you can get the CG right and put it in the air and try it. Just be prepared for it to fly a little faster and heavier. By my calculations it will be about an extra 8oz and I think it'll fly just fine. If I had a 5000 3s I would try it.

[solentlife]

What we don't know is the C rating of this 5000 LiPo ... that makes a massive difference to a packs weight.... and physical size.

If it's a Cub and as I assume doesn't need a high C rated pack ... you could fit a much higher capacity pack with low C rating .... benefiting from long run times.

Let's be honest - flying with factory spec size LiPo ,... who does that ? I have a pet theory that factory's state smallest pack possible based on 5 mins. First thing I do with a model is trial with a bigger pack !!

Nigel

[Westwind]

The pack is rated at 3d C

Sent from my GT-I9000 using Tapatalk 2

[Westwind]

Sorry 35 C

Sent from my GT-I9000 using Tapatalk 2

[JetPlaneFlyer]

Originally Posted by solentlife

Let's be honest - flying with factory spec size LiPo ,... who does that ?

I do I usually tend to end up toward the lower end of the battery size range, i guess I'd rather have plane that's light and is manoeuvrable and climbs well etc, than one that is overweight and sluggish. Even if the sluggish plane flew for longer.

Of course these things arent black and white. It depends on what sort of flying you are doing but with my medium sized 3D models I'm getting 6 -7 minutes of pretty hard flying which is enough for me.

Oddly when I compare to some flying larger batteries on the same planes I'm getting just as long in the air. This may come down to how far you want to push the battery, I aim for 3.7V per cell min (about 80% used) where some flying larger batteries aim for 3.8V which is only about 55-60% used. Plus of course lugging extra battery weight around means that you need to use more power to fly. The the increase in flight time isn't as much as you would expect based purely on battery capacity, the law of diminishing returns applies.

[solentlife]

Originally Posted by Westwind

Sorry 35 C

Sent from my GT-I9000 using Tapatalk 2

That's likely well over required C rating and will be a heavy pack !

IMHO - save it for a better cause !

Nigel

[BBCorvette18]

What motor setup do you have on the fun cub? I'm running a Turnigy D3536/8 1000KV on 3s and scale flight speed is half throttle. same as my cousins. He's got floats aftermarket landing gear and has put a go pro on his with no issues. If you can get the battery to fit it will fly. with my setup with 2200mah batts I get 12 minutes and when I throw the batts on the charger they are at 3.85-3.7v per cell

[hayofstacks]

Originally Posted by JetPlaneFlyer

I do I usually tend to end up toward the lower end of the battery size range, i guess I'd rather have plane that's light and is manoeuvrable and climbs well etc, than one that is overweight and sluggish. Even if the sluggish plane flew for longer.

Of course these things arent black and white. It depends on what sort of flying you are doing but with my medium sized 3D models I'm getting 6 -7 minutes of pretty hard flying which is enough for me.

Oddly when I compare to some flying larger batteries on the same planes I'm getting just as long in the air. This may come down to how far you want to push the battery, I aim for 3.7V per cell min (about 80% used) where some flying larger batteries aim for 3.8V which is only about 55-60% used. Plus of course lugging extra battery weight around means that you need to use more power to fly. The the increase in flight time isn't as much as you would expect based purely on battery capacity, the law of diminishing returns applies.

Stock slow stick with a 1800mah battery.

https://www.youtube.com/watch?v=IsuM...e_gdata_player

My ideal slow stick battery is a 1000mah 3 cell. But the 10 minute flight times and sluggish verticle after a bit of flying kill it. With a 1300 you can easily get 20 minutes of putt around flying and the 1800-2200's that I do fly on are pleanty manuverable with up to 45 minute flight times.

[solentlife]

Of course there will always be exceptions and some models that fly well and give good run times on stock ...

But I bet you can also name quite easily models that factory spec packs are 'inadequate' .....

Nigel

[squidger]

I have flown my funcub with a 4500 mah battery and it flew as normal but quicker in a dive.Got about 18 mins of spirited flying and had 32 % left in battery. There is loads of room for a large battery on the funcub and the battery sits pretty close to the cg so no worries there.

[solentlife]

As illustration .... my Cessna 182 is factory specc'd for 3S 1300 pack. She flies fine on that ... but put my 3S 2280 pack in and she now carves up the sky much better ........ CoG still same as it sits on CoG mid point.
That little extra weight makes her punch wind better, can deliver higher amps, gives loooooong run time .... a much better all-round model for it.

Nigel

[Watts Cooking]

I have a fun cub and I fly it with 4s 3000mah batteries like others said a little extra weight helps fight the wind. My fun cub is highly over powered and has no problem with extra weight. The 5000mah batt might give you a hard time trying to fit it in more than anything.

[BBCorvette18]

Damn 4s whats your motor combo? My 3536 1000kv on 3s is way overpowered

[Watts Cooking]

It's a turnigy G25 610kv pulling 60 amps and a little over 800 watts. It takes off in less than a foot and tows up very large gliders with no problem. I also put my GoPro on it and fly that around without any problem.