Solved RC plane battery power pack: LiPo, LiFePo4, NiMH, what else?

[agupt108]

I am trying to see which would be the best option to power a 2300 kv motor powered by a 30 amp esc. Prop is 7x5. I have not had a great experience with lipos. Out of LiFePo4 and NiMh and others which is the best option to make a powerpack to power this plane. This is for a ft mini scout so a smaller battery size would be great. Would something like 123A battery work? Thank you! Also something that is hopefully not so reactive as lipos to fires!

 

[MrKilometer]

LiPos aren't unsafe as long as you're careful. Store them in an ammo can or LiPo bag, get a good charger and use the right settings, don't discharge them below 3.7v/cell in flight, and you probably won't have issues. What has been your bad experience exactly?

 

[agupt108]

The lipo discharged without any use to 2.1 v per cell...it was kept without any power usage

 

[RossFPV]

The lipo discharged without any use to 2.1 v per cell...it was kept without any power usage

If a lipo is not at storage voltage (3.8v) it will discharge overtime without connecting the battery to anything. Most lipo chargers have a storage mode to charge it to 3.8v but if yours doesn’t you can fly the plane until it is at 3.8v.

 

[agupt108]

If a lipo is not at storage voltage (3.8v) it will discharge overtime without connecting the battery to anything. Most lipo chargers have a storage mode to charge it to 3.8v but if yours doesn’t you can fly the plane until it is at 3.8v.

good point....just out of curiosity though, is it possible to make a li ion, lifepo4, nimh or a123 battery pack as an alternative?

 

[RossFPV]

good point....just out of curiosity though, is it possible to make a li ion, lifepo4, nimh or a123 battery pack as an alternative?

Im not sure, i dont any experience with batteries other than lipo.

 

[MrKilometer]

I only have experience with LiPo and NiMh, but anything with Lithium is going to be reactive. NiMh is generally heavier and provides less power than LiPo.

 

[agupt108]

Im not sure, i dont any experience with batteries other than lipo.

Ok thanks for your help!

 

[agupt108]

I only have experience with LiPo and NiMh, but anything with Lithium is going to be reactive. NiMh is generally heavier and provides less power than LiPo.

ok so lipo seems like the best power for the weight and price probably?

 

[MrKilometer]

In my experience, yes

 

[agupt108]

In my experience, yes

Thank you again!!

 

[Inq]

I am trying to see which would be the best option to power a 2300 kv motor powered by a 30 amp esc. Prop is 7x5. I have not had a great experience with lipos. Out of LiFePo4 and NiMh and others which is the best option to make a powerpack to power this plane. This is for a ft mini scout so a smaller battery size would be great. Would something like 123A battery work? Thank you! Also something that is hopefully not so reactive as lipos to fires!

If you are talking about a indoor plane using a motor like

you might get away making a battery pack with LiFePo4 and NiMh. But you'll quickly find that those chemistries will not permit the high-discharge rates required. I use LiFePo4 in a high discharge battery bank for my boat "house" bank. It is fully able to drive a 1800 W microwave, hot plate etc. HOWEVER in the case of high rate for LiFePO4 is 2C!
Even a small brushless motor like a A2212 can pull 20 Amps... from a 1500 mAh, that is 13C. LiFePo4 can't do that. NiMh can't even pull 1C. Even the ubiquitous LiIon 18650 is only good up about 10C in very special models made for vape dispensers. The normal ones don't do more than about 2C. Note in a typical top quality LiIon... it can only do 4.5 amps for short durations. That is ONLY 1.9C.

It believe the second best after LiPo is Lithium Titanate, but it is very expensive and it too can't handle anywhere near the 60C, 120C that you'll see marked on common everyday hobby LiPo.

 

[Inq]

To continue... LiPo's are only perceived as unsafe (by some) because of the way we abuse them. You trying discharging at 30C, then recharging at high rates so you can fly in a half hour any other chemistry and they'd either fail, catch fire or explode... immediately. Not like LiPo's that do it in the rare cases when they're damaged by a crash. I've seen 40 year experts (even in my AMA club) go fly their EDF then pop them on the charger and wonder why they started smoking. Happened just last week. EVERY failed battery I've heard of was because of user error. Sure there are the occassionaly failed batteries but they're in the 1 in 10,000 caused by a faulty cell or assembly at the factory... again because the public requires the cheapest available batteries. Often QC is compromised is such units because they didn't do them in some Chinese factory.

 

[agupt108]

To continue... LiPo's are only perceived as unsafe (by some) because of the way we abuse them. You trying discharging at 30C, then recharging at high rates so you can fly in a half hour any other chemistry and they'd either fail, catch fire or explode... immediately. Not like LiPo's that do it in the rare cases when they're damaged by a crash. I've seen 40 year experts (even in my AMA club) go fly their EDF then pop them on the charger and wonder why they started smoking. Happened just last week. EVERY failed battery I've heard of was because of user error. Sure there are the occassionaly failed batteries but they're in the 1 in 10,000 caused by a faulty cell or assembly at the factory... again because the public requires the cheapest available batteries. Often QC is compromised is such units because they didn't do them in some Chinese factory.

Thanks for your help...i think i will stick to lipos!

 

[Inq]

Thanks for your help...i think i will stick to lipos!

I re-read my post... In the wrong light, it could be interpreted negatively. I apologize. I was just trying to give you technical reasons for the things you've observed so you can understand why LiPo's are the best choice for RC plane, drones, cars and boats. The second choices aren't even close IMO. Even though I use bunches of LiIon 18650's and LiFePO4 batteries in other scenarios, there isn't really anything even close to using the massive amounts of power that RC demand. I had the same question and tried using 18650's in a 3S on a brushless ESC/Motor. It wasn't pretty! I'd hate for you to waste your time and money experimenting for a certain failure.

But I have heard what you experienced. LiPo do seem to have a higher self-depletion than other chemistries. My LiFePo4 boat battery bank has a BlueTooth interface and even after a year of no use, I can see hardly any depletion even though it is serving the BMS / Bluetooth monitor. But it is also 280 Amp Hours worth of cells. Not something that goes into an RC plane.

Good luck.

 

[quorneng]

Inq makes a valid point.
My first RC plane used a 1000mAh 8 cell NiMH battery and a brushed motor. It flew well enough but when I changed it to a 1500 mAh 3s LiPo and a brushless motor it ad twice the thrust, twice the endurance and was 20% lighter overall. People tend to forget just what an advance LiPo/brushless was.
Yes a LiPo needs care and attention but it is packing a lot of energy in a small package.

I have flown a specially built plane using six 'standard' 18650 cells in a 2s3p configuration but for the weight involved the performance was at best only 'mild' and at even at a low 3c discharge rate the cells did not deliver anything like their claimed capacity.

An interesting exercise but no match for a LiPo