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Battery

#1
Hallo!
Im building a plane for a school project and i dont want to spend to much money. So i have all the parts i need but i dont know if the battery's a have ad home are good enough. They are NIKKO Ni-Cd battery packs they are 9,6v 650mAh (i have 2 of them) can someone help me
 

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FDS

Well-known member
#2
What motor and prop are you using?
Those batteries you have are heavy and not very powerful. They would power servos in a glider but not much else.
 
#3
Before hooking that into any motor or ESC you will really want to check the "C" rating of that battery or it's continuous discharge rate. If it can only discharge 5 amps and you hook a 20 amp ESC/motor combo, at best you'll ruin the battery quickly, at worst you'll be dealing with a battery fire.... on an airplane.... mixed with cadmium....
 
#5
Before hooking that into any motor or ESC you will really want to check the "C" rating of that battery or it's continuous discharge rate. If it can only discharge 5 amps and you hook a 20 amp ESC/motor combo, at best you'll ruin the battery quickly, at worst you'll be dealing with a battery fire.... on an airplane.... mixed with cadmium....
Well its not an option than i think i have a 30 amp ESC do you know any cheap battery options
 

Hai-Lee

Old and Bold RC PILOT
#6
Well its not an option than i think i have a 30 amp ESC do you know any cheap battery options
You do not mention the motor voltage capability though I assume that it will be 3S or 12Volts. For the motor fully loaded and pulling the full 342 Watts your poor old battery will be supplying 30 Amps. Not sure what weight or capacity your are considering but remember the battery must have a 'C" rating such that the battery can supply 30A safely and continuously or the battery could be damaged or worse.

Let us know the motor voltage range and the battery capacity you are contemplating for a better guide.

Have fun!
 

The Hangar

Well-known member
#7
You do not mention the motor voltage capability though I assume that it will be 3S or 12Volts. For the motor fully loaded and pulling the full 342 Watts your poor old battery will be supplying 30 Amps. Not sure what weight or capacity your are considering but remember the battery must have a 'C" rating such that the battery can supply 30A safely and continuously or the battery could be damaged or worse.

Let us know the motor voltage range and the battery capacity you are contemplating for a better guide.

Have fun!
So if I’m using a 30 amp esc, I need at least a 30 c battery?
 

FDS

Well-known member
#8
If your motor power in W (with chosen prop) divided by the operating voltage = 30A then you want a battery that can supply more than that, or the voltage will sag very fast. Note capacity comment in relation to C rating below.
@Stijn You can get small, powerful lipo batteries for under $10. You will need a charger as well tho, which will be another $10 minimum. Why don’t you take your plans to a local hobby store and ask for help?
You could also contact your local model flying club for help, someone might even lend you the battery you need. Which country are you in?
The battery you have will not power that motor. It could be used to set up and test the electronics but not for flying or setting the centre of gravity.
 
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Hai-Lee

Old and Bold RC PILOT
#9
So if I’m using a 30 amp esc, I need at least a 30 c battery?
The battery 'C" rating refers to the stated capacity. A 2200mA battery has a Capacity of 2200mA, (2.2 Amps). If you need to draw 30 Amps then you would need "30/2.2" of a "C" rating of about 15C whereas if you were using a 1000mA (1.0 Amp) battery and drawing 30 Amps you would need to use a batteryqith a "C" rating of "30/1.0" or a minimum of 30C.

So the size/capacity of the battery is important in determining what "C" rating you require.

What size of battery do you envisage using?

Have fun!
 

The Hangar

Well-known member
#10
The battery 'C" rating refers to the stated capacity. A 2200mA battery has a Capacity of 2200mA, (2.2 Amps). If you need to draw 30 Amps then you would need "30/2.2" of a "C" rating of about 15C whereas if you were using a 1000mA (1.0 Amp) battery and drawing 30 Amps you would need to use a batteryqith a "C" rating of "30/1.0" or a minimum of 30C.

So the size/capacity of the battery is important in determining what "C" rating you require.

What size of battery do you envisage using?

Have fun!
I was just wondering if the batteries I’ve been using are adequate. I fly off of 1500 mah 25 c packs and 1000 mah 25 c packs with my planes that use 20 amp esc’s and 30 amp esc’s. I think @Headbang said that the emax old c pack motors on 3s dont draw more than 20 amps, and I know that the old ba pack motors don’t, so I think I should be fine. Maybe I should invest in better gear soon😉
 

FDS

Well-known member
#11
I never buy 1000mah or less packs with a rating below 40C. Bigger ones you can go less, for example a 2200mah 30c is actually capable of 2.2x30A = 66A (approx).
Higher discharge packs will have lower internal resistance and be much less prone to voltage sag. 25C are a receiver pack IMO.
In quads you really feel the difference, I had a little 2.5” gremlin sized thing, which I test flew on 850mah 40c lipos from my TT whilst I waited for better ones. You would take off and the voltage would crash to 3.5v per cell average within about 30 secs. That quad was only supposed to be 25-30A peak.
In my TT that would give me 8-10 mins worth an 1806/2400 motor and a 6x3 prop. Final voltage would usually be 3.6v per cell.
 

Headbang

Well-known member
#12
The battery 'C" rating refers to the stated capacity. A 2200mA battery has a Capacity of 2200mA, (2.2 Amps). If you need to draw 30 Amps then you would need "30/2.2" of a "C" rating of about 15C whereas if you were using a 1000mA (1.0 Amp) battery and drawing 30 Amps you would need to use a batteryqith a "C" rating of "30/1.0" or a minimum of 30C.

So the size/capacity of the battery is important in determining what "C" rating you require.

What size of battery do you envisage using?

Have fun!
Do not forget to factor in the manufacture fudge. There have been tests done over and over to prove that no C rating is a true attainable real world number, some manufactures get closer to the stated C rating then others. Some manufactures blatantly lie. So as a rule it is best to take whatever the rating is and half it to be safe unless you know from experience otherwise with a specific manufacturer.
 

Hai-Lee

Old and Bold RC PILOT
#13
Do not forget to factor in the manufacture fudge. There have been tests done over and over to prove that no C rating is a true attainable real world number, some manufactures get closer to the stated C rating then others. Some manufactures blatantly lie. So as a rule it is best to take whatever the rating is and half it to be safe unless you know from experience otherwise with a specific manufacturer.
Actually the real issue in the variations is simply that the capacity of a battery is specified or calculated at the one hour discharge rate, (somewhat an industry standard). Even though the internal resistance and construction can vary considerably. The "C" rating is a rough measure of the maximum discharge current that the battery can supply without permanent damage or marked permanent degradation.

Now here is the big one! The manufacturers do not supply a guarantee as to how many maximum "C" discharges the battery can endure before damage will occur, (often due to internal heating). When you factor in the age of the battery, (how long it sat on the retailers shelf or in the distribution warehouse before being purchased). Even at storage charge there is a very slow increase in internal resistance.

The best way to get a battery that is actually very close to stated capacity and "C" rating discharge current is to go for a freshly manufactured battery or one that is sold in high volumes. Beware discounted high quality batteries that have sat on the shelf for years!

If you want to get a long life, (large number of flights) I always go for a higher "C" rating than I require and I manage the cell temperatures to avoid cell damage.

It works for me!

Have fun!
 
#14
If your motor power in W (with chosen prop) divided by the operating voltage = 30A then you want a battery that can supply more than that, or the voltage will sag very fast. Note capacity comment in relation to C rating below.
@Stijn You can get small, powerful lipo batteries for under $10. You will need a charger as well tho, which will be another $10 minimum. Why don’t you take your plans to a local hobby store and ask for help?
You could also contact your local model flying club for help, someone might even lend you the battery you need. Which country are you in?
The battery you have will not power that motor. It could be used to set up and test the electronics but not for flying or setting the centre of gravity.
I live in Holland, we don't really have a flying club here but i could try a hobby shop. Tnx for your help!
 
#15
You do not mention the motor voltage capability though I assume that it will be 3S or 12Volts. For the motor fully loaded and pulling the full 342 Watts your poor old battery will be supplying 30 Amps. Not sure what weight or capacity your are considering but remember the battery must have a 'C" rating such that the battery can supply 30A safely and continuously or the battery could be damaged or worse.

Let us know the motor voltage range and the battery capacity you are contemplating for a better guide.

Have fun!
These are the onely specs i could find i hope these are enough
A2212 2200kv Motor Specification:

KV: 2200

Ri(M Ω): 0.033

Battery: 2-3Li-Po

Max Power: 342W

Test Prop: 7x3/7x4


30A Brushless ESC Specification:

BEC: 3A

Constant Current: 30A

Max Current: 45A (less than 12s)

Low-voltage Cutoff: Auto detect

Input: 2-3 LiPo or 5/10 NiMH
 

FDS

Well-known member
#16
That motor will only run a smaller propellor, it’s quite high KV. You could run a 6x3 or 6x4 slow fly type on it. It will want at least 20A continuous discharge, which is about 2-3x what the packs you have are capable of.
The Netherlands has a very active RC flying community. Here’s the website for the overall organisation, they can help you find a local club.
https://www.knvvl.nl/modelvliegsport

Theres also a dedicated Dutch forum where you might find more local help-
http://www.modelbouwforum.nl/
 
#17
That motor will only run a smaller propellor, it’s quite high KV. You could run a 6x3 or 6x4 slow fly type on it. It will want at least 20A continuous discharge, which is about 2-3x what the packs you have are capable of.
The Netherlands has a very active RC flying community. Here’s the website for the overall organisation, they can help you find a local club.
https://www.knvvl.nl/modelvliegsport

Theres also a dedicated Dutch forum where you might find more local help-
http://www.modelbouwforum.nl/
Thanks for all your help man! I appreciate it!