Understanding batteries and charging

[madmax1609]

Dear Friends

Just wondering if someone can help me with the following:
I have the following batteries and would really like to try and understand the charge rate etc... I am a complete beginner when it comes to electric as I have been flying on nitro for quite sometime.

3 cell 11.1V 25C lipo 2200 zippy battery - What does it all mean ??

My field charger asks me to select the charge rate 1a etc... can someone help ?

[tehlump]

most batteries should be charged at 1C, in your case that would be 2.2 amps, some batteries can be charged at higher rates, but don't try it unless it is specifically recommended by the battery manufacturer.

to further elaborate on your battery:

3 cell-just what it sounds like, the battery pack consists of 3 LIPO cells, each 3.7 volts

11.1V- the cells are wired in series (which adds each pack's voltage to the total voltage) 3.7 * 3 =11.1V total

25C is the max discharge rate- 1C for that battery is 2.2 so 25C * 2.2 = 55 Amps max discharge rate

Lipo indicates the battery's chemistry = lithium polymer

2200 indicates the capacity of the battery in miliamp hours or MaH...the battery will supply 2200 MaH (or 2.2 Amps) for one hour...multiply that out to get an idea of how long it will last in a plane, ie 22amps for 1/10th of an hour or 6 minutes...

I'm fairly new to this as well, and I was confused by the "C" rating, I'm not sure where it came from, but just remember that it is different for batteries of differing capacity, 2200MaH-1C=2.2, 5300Mah-1C=5.3 etc...

[slipstick]

Lots of discussion about batteries and charging in the Batteries and Chargers forum just down the page a bit . But to get you started:

3S - 3 cells. Each cell is 3.7V nominal so that's 11.1V total

2200 will actually be 2200mAh (or 2.2Ah - different way of saying the same thing) and that's the battery capacity. I.e. it will deliver 2.2A for one hour, or 22A for 1/10th of an hour etc.

25C means it can (in theory) give you a maximum of 25 x capacity i.e. 25 x 2.2A = 55A.

Charge rate is generally 1C unless it tells you different. So 1 x 2.2 = 2.2A

Steve

[Simon]

Hi there, further to what the gentlemen have already said, if you battery is this one: ZIPPY Flightmax 2200mAh 3S1P 25C, then you can charge it at a maximum of 2C, or 4.4 Amps.

You can get a turnigy nanotech battery here that's can be charged at 5C, or 11 Amps.
But wait, the marketing suggests that it gets even better, with some batteries being capable of a 15C charge rate That's some 33 Amps, or some 363 Watts

Can't wait until the production improves to such an extent that all of the cells manufactured in a batch can reliably be charged(and presumably abusively discharged) at such a high rate. Guess it all comes down to keeping internal resistance super-low, to avoid resistive heating effects.

Don't you just love the Zippys? I've got a pair of them(rhinos) that have 3/4 the capacity of some eflite batteries, yet cost 1/6 as much, provide 25% more constant-discharge power (208 watts vs 166 watts, on account of being 25C instead of just 15C) , are accordingly 25% lighter, yet still seem to provide longer flight times. If I didn't own them and see for myself, I wouldn't believe it to be possible - it seems like a contradiction, yet (while considering the possibility of bias, and being prepared to accept the chance of being affected by it, though slim) they seem to make the invention of sliced bread look like it needs superceeding as a bench-mark.

I'm embarrased to admit that a $23 purchase of some 12 units of nanotech 1S 130mah 25-40C cells left me in such disbelief at the value and power in flight that I have since spend some hundreds of dollars on goodies at that store and and left the helis I first got into at Christmas time collecting dust while my mind races - thinking of new planes and construction techniques/ideas and my body is filled with adrenaline from successfully(i.e only touching the ground when I choose to land) flying 4 batteries one after another in a plane with a $4.70 home-made airframe that bounces when I crash it at 20mph and flies again as soon as I can pick it back up, straighten the prop, apply the throttle and toss it into the air! rather than crashing the heli after just half a battery at an average cost of about $18. - (i'm sure an attempt at forming a sentence that long would be punishable by death is some parts )

If it wasn't for those cells, I wouldn't have tried planes (yet?) I'm just kicking myself that I don't have a higher power charger and some 3S 850 nanotechs, because at nearly an hour to charge each battery it's killin me while I wait for all 4 to be ready for action again
While the nanos would all be charged in just 12 mins each, or 48 mins rather than 4 hours. I reckon that at 3 hours less time between flights the extra money for the nanotechs is trivial

[CrimzonRider]

Huge amount of info in this sticky....

http://www.wattflyer.com/forums/showthread.php?t=31368

have a good one
cr

[Rodneh]

Just remember, your batteries will last longer (more charge/discharge cycles) if you do not charge at the maximum allowable rates. It is best to not exceed a charge rate of 1C, 2.2 amps in your case. Do use a balancing charger if possible. If you do not, it is possible to overcharge the lower capacity cells in the battery. Note that 4.2 volts/cell is a full charge.

[CrimzonRider]

Looks like this thread is getting ready to be a lot more interesting, there has been multiple debates on charging at or below 1c rates......

In my personal short experience with watt flying, for new batterys it does seem to make them last a little longer during the flight(or until you make your battery a lawn dart)but it just takes forever to charge.....

have a good one
cr

[kyleservicetech]

Originally Posted by madmax1609

Dear Friends

Just wondering if someone can help me with the following:
I have the following batteries and would really like to try and understand the charge rate etc... I am a complete beginner when it comes to electric as I have been flying on nitro for quite sometime.

3 cell 11.1V 25C lipo 2200 zippy battery - What does it all mean ??

My field charger asks me to select the charge rate 1a etc... can someone help ?

And some more info on this line
Thread on 70 size glow engine conversion to electric
http://www.wattflyer.com/forums/showthread.php?t=45222

[tehlump]

Originally Posted by CrimzonRider

Looks like this thread is getting ready to be a lot more interesting, there has been multiple debates on charging at or below 1c rates......

In my personal short experience with watt flying, for new batterys it does seem to make them last a little longer during the flight(or until you make your battery a lawn dart)but it just takes forever to charge.....

have a good one
cr

I don't have nearly enough experience with LiPo to join that debate, but I've always been of the opinion that if the manufacturer says it's OK?....wait, did I just join the debate?

[Wrongway-Feldman]

Batteries are so incredibly inexpensive now that it just doesn't make sense to diligently try to squeeze every last cycle from them anymore.
Most batteries I use cost less than $15. By the time I need to replace them they will cost less still.
I charge mine at the max safe rate. With safe I mean not puffing or igniting the cells. I do not mean safe as in trying get 10% more cycles out of them. Ill leave that to the hobbiest that logs every mili amp used and charged back into each of their cells.

[CrimzonRider]

Originally Posted by tehlump

I don't have nearly enough experience with LiPo to join that debate, but I've always been of the opinion that if the manufacturer says it's OK?....wait, did I just join the debate?

I barely have enough exp. too. Only just what Ive seen....lol
There is quite possibly close to a 100 threads about this.....
IMHO Some of which is bad/wrong info....so be smart, its not rocket science.


have a good one
cr