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Need clarification on batteries....

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Patrick

Sat Dec 11 2010, 05:49AM

Registered Member #2431 Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639

i have a air hog 4 Channel chopper. i want to see if adding another battery is useful or wise.

i have a small battery from a no name mp3 player, but it has three wires red, black, and blue. is the blue one a safety thermistor, or a lower cell voltage tap? if the cell is 3.7 volts isnt that a lithium single cell voltage?

what is that blu wire for!

here is that pic:

Controller W/MOD:

1292046933 2431 FT1630 Sam 0232controller

Helo:

Ken M.

Sat Dec 11 2010, 05:59AM

Registered Member #618 Joined: Sat Mar 31 2007, 04:15AM
Location: Us-Great Lakes
Posts: 628

Yes 3.7V is single cell Lithium, so it could be a temp sensor output but unlikely, because a temp sensor would still draw current, drainging the battery and once a lithium gets below 2.8V its life span start to drop exponenantialy, and it the battery hits 0V, well lets say I've never heard of anybody bringing one back to life from 0V.

It code be a resistor lead, some lithium packs have a resistor in them to tell the charger chip and monitor what it's limit is, but most of them I think use 4 leads, (+,-, Rin,Rout).

Also Now I think about it, have you looked at the battery inside your copter? I have a plane that runs on single cell 160mAH and the battery is the size of a 28pin IC.

Patrick

Sat Dec 11 2010, 06:03AM

Registered Member #2431 Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639

Ken M. wrote ...

Also Now I think about it, have you looked at the battery inside your copter? I have a plane that runs on single cell 160mAH and the battery is the size of a 28pin IC.

i will post a pic in a 8 minutes its charging.

Ken M.

Sat Dec 11 2010, 06:13AM

Registered Member #618 Joined: Sat Mar 31 2007, 04:15AM
Location: Us-Great Lakes
Posts: 628

Here I'll just give you a reference from my spare battery thats dead, its sitting on the leads of a TO-247AB IGBT.

The blue IS indeed your reference wire, just looked at my my camera battery (which is fully charged reads 3.85V) but, from + to the pad Labeled T it reads 3.785, and its a 3.7 lithium pack (740mAH).

Patrick

Sat Dec 11 2010, 06:41AM

Registered Member #2431 Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639

here are the pics:

1292049654 2431 FT103007 Sam 0253helo Large

1292049654 2431 FT103007 Sam 0247helo Side

1292049654 2431 FT103007 Sam 0242controller Stud

1292049654 2431 FT103007 Sam 0239resized Helo

Ken M.

Sat Dec 11 2010, 06:51AM

Registered Member #618 Joined: Sat Mar 31 2007, 04:15AM
Location: Us-Great Lakes
Posts: 628

Hmm, I'm not sure how much room you have from the present battery to the other side of the body, but I believe you could either parallel the batterys and get possibly 3x the run time, or just use the MP3 player batter and get 2x plus a little extra run time, since they look about the same size, the only thing I may be concerned about though would be the C rating, which determines the Charge and Discharge of the battery, the one in you copter now has a 10C rating at 130mAH.

Patrick

Sat Dec 11 2010, 06:54AM

Registered Member #2431 Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639

Ken M. wrote ...

Hmm, I'm not sure how much room you have from the present battery to the other side of the body, but I believe you could either parallel the batterys and get possibly 3x the run time, or just use the MP3 player batter and get 2x plus a little extra run time, since they look about the same size, the only thing I may be concerned about though would be the C rating, which determines the Charge and Discharge of the battery, the one in you copter now has a 10C rating at 130mAH.

what is a C rating?

also the new batttery is 1.07Wh, the conventional one is 0.13Ah

these kind of conversions are really load dependent, so ill need tomeasure the current at 60% throttle. it wheighs in at 25-26 grams.

apparently 6 grams is enoughto get airborne +6-8 inches. ground effect must be helping. then it finds the ground quite easily.

Bjørn

Sat Dec 11 2010, 07:31AM

Registered Member #27 Joined: Fri Feb 03 2006, 02:20AM
Location: Hyperborea
Posts: 2058

C is the maximum discharge current in relation to the capacity. A 290 mAh battery that is marked 10 C can take a continious discharge current of 290 mA x 10 = 2.9 A. A battery with twice the capacity would have twice the electrode area and therefore double the maximum current. The third wire is often connected to a temperature sensor (always if it is labeled T).

Replacing the battery of a helicopter may cause several problems. The center of gravity must be unchanged or it will crash. Even if you keep it the same a difference in weight may cause the helicopter to behave differently. You can also burn out the motor and or the regulator.

There is only one way to find out, that is to try.

Ken M.

Sat Dec 11 2010, 08:01AM

Registered Member #618 Joined: Sat Mar 31 2007, 04:15AM
Location: Us-Great Lakes
Posts: 628

Try it and find out, like Bjorn said, as for swaping the batterys the worst you could do is have the battery bust, more then likely though you'll "puff" the pack, since I imagine the mp3 's battery is at most a 5C.

If your copter could handle more of a load I'd be willing to send you a 5000mAH 20C battery,

Patrick

Sat Dec 11 2010, 08:29AM

Registered Member #2431 Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639

Ken M. wrote ...

Try it and find out, like Bjorn said, as for swaping the batterys the worst you could do is have the battery bust, more then likely though you'll "puff" the pack, since I imagine the mp3 's battery is at most a 5C.

If your copter could handle more of a load I'd be willing to send you a 5000mAH 20C battery,

it cant lift more then 6 grams.it just barley get above the table, ill have to think about what elsewill work.

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