Is it ok to test a 1400kv motor with a 250mah 20c battery?

[guilhermefl]

Hi there guys I want to transition to a power glider situation. I boght a 1400kv motor from ali in a kit and the 2S 20c 250mah battery is the only one I have at the moment. yall think I'm able to test it a little with a low throttle without causing damage?

 

[Mr Man]

With low throttle yes, but I wouldn’t put a prop on it 👍

 

[guilhermefl]

With low throttle yes, but I wouldn’t put a prop on it 👍

Thank you for replying. What could happen in a low throttle + prop test?

 

[Mr Man]

Thank you for replying. What could happen in a low throttle + prop test?

Not sure, might not to any damage, but it;s always safe to do testing with prop off. You don’t want i]the motor to start spinning the prop on accident!

 

[guilhermefl]

Not sure, might not to any damage, but it;s always safe to do testing with prop off. You don’t want i]the motor to start spinning the prop on accident!

OH, I got you now lol. I'll make sure to keep that in mind. Thank you.

 

[Merv]

...What could happen in a low throttle + prop test?

You could ruin the battery, maybe even cause a fire.
The battery can only supply 5 amps. 250 mah x 20C / 1000 = 5
I have no idea what size of motor you are planning to test, no idea how many amps it will draw. But if it exceeds 5 amps, you run the risk of damaging the battery.

 

[guilhermefl]

You could ruin the battery, maybe even cause a fire.
The battery can only supply 5 amps. 250 mah x 20C / 1000 = 5
I have no idea what size of motor you are planning to test, no idea how many amps it will draw. But if it exceeds 5 amps, you run the risk of damaging the battery.

That's what I was afraid of, I got a white label 1400kv from ali it says it goes 4-10A (>75%). So I thoght I could try and power it with the 250 mah and use a multimiter to find how much it would draw.

 

[Piotrsko]

It will run, for a bit. Maybe 10 seconds, sometimes just 1 or 2. Lipos are famous for being to output ridiculous currents for a short while, typically limited by chemical conversions running out or (more typical) flowing so much current something catches fire which is the typical outcome. Probably won't see the meter register something unless it is a mechanical like my Simpson

 

[guilhermefl]

It will run, for a bit. Maybe 10 seconds, sometimes just 1 or 2. Lipos are famous for being to output ridiculous currents for a short while, typically limited by chemical conversions running out or (more typical) flowing so much current something catches fire which is the typical outcome. Probably won't see the meter register something unless it is a mechanical like my Simpson

What would be better in my case, a 2s 2200mah lipo or a 3s 2200mah lipo?

 

[Piotrsko]

3 S. The 3 means 3 times the voltage of a single which means more current through a fixed resistance, but not necessarily 3 times as much. The 2200 mah is the current rating on a single cell which means it can theoretically push 2.2 amps for one hour. ( it cant, I said theoretical)

 

[guilhermefl]

3 S. The 3 means 3 times the voltage of a single which means more current through a fixed resistance, but not necessarily 3 times as much. The 2200 mah is the current rating on a single cell which means it can theoretically push 2.2 amps for one hour. ( it cant, I said theoretical)

Wow, I was very wrong on my asumptions. Just did more research and found out the 3s would be heavier and last less time than a 2s, my mind has been blown. Thank you all for your responses.
I might go for the 2s for a more gentil and longer lasting or building a 2s with some old 18650s.

 

[Merv]

What would be better in my case, a 2s 2200mah lipo or a 3s 2200mah lipo?

Hard to say, you have not given us enough information. We need to know how big is the motor & how many amps will it draw at full throttle.
There is nearly a 10 x difference between a 250mah & a 2200 mah. There are plenty of choices of battery sizes in between.

Myself, I only use 2200 3S batteries. All of my planes are 25-30 oz, all of my motors are 2836 to 3536 in size, they all draw 40-50 amps.
I don't have any idea what size you are dealing with.

 

[guilhermefl]

Hard to say, you have not given us enough information. We need to know how big is the motor & how many amps will it draw at full throttle.
There is nearly a 10 x difference between a 250mah & a 2200 mah. There are plenty of choices of battery sizes in between.

Myself, I only use 2200 3S batteries. All of my planes are 25-30 oz, all of my motors are 2836 to 3536 in size, they all draw 40-50 amps.
I don't have any idea what size you are dealing with.

The motor from ali has this info.
A2212 1400kv Motor Specification:

• KV: 1400
• Maximum efficiency: 80%
• Maximum efficiency current: 4–10A (>75%)
• Current capacity: 12A/60s
• No-load current @ 10V: 0.5A
• Number of cells: 2–3 Li-Poly
• Motor dimensions: Φ27.5 × 30 mm
• Shaft diameter: Φ3.17 mm
• Weight: 47 g
  
  The planes I plan to build are probably going to be around 20 ounces like slope soarers but with an engine. The fact is that I found very hard and tricky to get the glide going without an engine. I'm more interested in flight time than super speed at this point.

 

[Merv]

...I'm more interested in flight time than super speed at this point.

Great info.

A 2 or 3S 2200 mah battery will work, a 2S may be the way to go. You should consider a smaller battery, maybe something in the 1000 to 1500 mah range. With a smaller battery, 3S becomes viable. With 3S, you can deliver the same watts with fewer amps. This will allow you to quickly get altitude to hunt for thermals.

If you are looking for duration, the 18650 is something to strongly consider. They will give you 3300 mah for less weight than a 2200 lipo. But the older ones have a tough time over 10 amps. Some of the newer ones can approach 20 amps.

In the right conditions, I've had 30 minute flights with my Versa on 2200 3S.

 

[guilhermefl]

Great info.

A 2 or 3S 2200 mah battery will work, a 2S may be the way to go. You should consider a smaller battery, maybe something in the 1000 to 1500 mah range. With a smaller battery, 3S becomes viable. With 3S, you can deliver the same watts with fewer amps. This will allow you to quickly get altitude to hunt for thermals.

If you are looking for duration, the 18650 is something to strongly consider. They will give you 3300 mah for less weight than a 2200 lipo. But the older ones have a tough time over 10 amps. Some of the newer ones can approach 20 amps.

In the right conditions, I've had 30 minute flights with my Versa on 2200 3S.

Thank you so much for this explanation. Now it makes sense how to balance it all based on my needs.

 

[quorneng]

guilhermefl
Just remember that it is the load (i.e. the prop) on a motor that really set the amps it will draw.
Without a prop the motor will only draw the "no load" current which in your case is given as 0.5A at 10V. It will be slightly less a on a 2s at 8.4v and slightly more on a 3s at 12.6V.
The object is to fit a prop that gives the required performance to the plane and keeps within the maximum capability of the motor, the battery and the "power on" endurance that isrequired.
You will soon discover there is no one single best solution as they all effect each other which is why if you want to experiment then get a Watt meter!
You can then measure what is actually happening electrically and follow it by test flights to confirm whether the plane better meets your objectives.
There is no perfect solution only one that gives the best set of compromises that satisfies you!
ps
It saves an awful lot of time if you start your experiment journey with a recommended prop, motor, battery combination for the plane!

 

[guilhermefl]

guilhermefl
Just remember that it is the load (i.e. the prop) on a motor that really set the amps it will draw.
Without a prop the motor will only draw the "no load" current which in your case is given as 0.5A at 10V. It will be slightly less a on a 2s at 8.4v and slightly more on a 3s at 12.6V.
The object is to fit a prop that gives the required performance to the plane and keeps within the maximum capability of the motor, the battery and the "power on" endurance that isrequired.
You will soon discover there is no one single best solution as they all effect each other which is why if you want to experiment then get a Watt meter!
You can then measure what is actually happening electrically and follow it by test flights to confirm whether the plane better meets your objectives.
There is no perfect solution only one that gives the best set of compromises that satisfies you!
ps
It saves an awful lot of time if you start your experiment journey with a recommended prop, motor, battery combination for the plane!

"It saves an awful lot of time if you start your experiment journey with a recommended prop, motor, battery combination for the plane!" This is what I was supposed to do lol, have I known all this now I would have gotten the same kit as the u-glider. But I was afraid I wouldn't be able to make my plane light enough and getting hurt by the powerplant configuration. So I opted on getting a kit with the very white lables esq, motor, prop that are a little bigger and heavier but it wold be a little less expensive and have some more battery life and engine power so I could have some room for error as I build this first motor glider.

 

[Piotrsko]

Need a fish scale to measure thrust. Bigger motor system just gets to the Crash a bit better with generally more disassembly

 

[guilhermefl]

Need a fish scale to measure thrust. Bigger motor system just gets to the Crash a bit better with generally more disassembly

I do have a scale that could be used to test thrust tho lol. Probably tuning it down so I can get used to it and stay in the air longer (hopefully).

 

[Piotrsko]

Good plan. Keep going faster in stages, eventually you'll know enough to deal with That fast because afaik, it aint easy. If it was easy, everyone could do it.