I HAVE A DYNUM SUPER CUB ELECTRIC RTF I RECEIVED AS A B-DAY PRESENT AND IAM HAVING PROBLEMS GETTING THE ENCLOSED DYNUM LI-PO BATTERY (1250Mah 3-CELL 11.1V 10C DISCHARGE)TO FULLY CHARGE. THE ENCLOSED DYNUM BALANCE CHARGER,CHARGER'S LIGHTS NEVER CHANGE COLORS AS STATED IN THE MANUAL EITHER. THE FACRORY CHARGE LASTED 10 MIN APPROXIMENTLY ( LOW I PRESUME FOR THI BATTERY) AND FOLLOWING CHARGES ONLYLAST APROXIMENTLY 5 MIN. ANY SUGGESTIONS ON HOW TO SOLVE THIS PROBLEM.

You could have a bad charger or bad battery or neither.

Assume the manual is wrong.

Put the pack on the charger and wait until the lights change, give it at least 45 minutes.

If the charger is working correctly it will automatically cut the current to the battery to prevent it from being damaged.

Then put the pack in the plane and see if you can rev the motor up to full throttle.

If so bring the throttle to about 75% of full and time how long it takes before the motor stops.

Report your results.

Maybe you can measure the battery's voltage. It should be about 12.6 volts when fully charged.

That's not a good indicator with LiPo packs.

LiPo packs have a fairly flat discharge curve, so you can get decent readings even when the pack is almost depleated.

You are mixed up. A resting voltage is one of the best indicators of SOD. It won't tell you the actual capacity , but it will tell you the % remaining. Maybe you are thinking of NI types?

Nope...

Take a discharged LiPo and put a meter on it.

You'll easily get 12v with no load.

Voltage is a poor indicator of LiPo charge state.

Sorry you are mistaken. All my packs are at 11.1 volts.

Ouch, they must drop the second a load is present.

Here's something for you to read

[link=http://electronics.stackexchange.com/questions/2601/how-can-i-tell-how-much-juice-a-lipo-battery-still-has-in-it]Click me![/link]

Note what is said about how impossible it is to determine charge state based upon voltages....

Thanks  for the info

I TRIED ONCE AGAIN TO RECHARGE THE BATTERY THEN CHECK TO SEE IF THE BATTERY WOULD GO TO FULL THROTTLE (NOPE) ABOUT 1/2 THEN FOR ONLY ABOUT THREE MINUTES. I HAVE CONTACTED <u>NITROPLANES</u> AND THEY ARE SUPPOSED TO SEND ME A NEW CHARGER AND THEN IF NOT CORRECTED A NEW BATTERY. ITSUCKS BECAUSE ALL MY PLANE STUFF IS GONE (LONG STORY)AND HAD TO BUY THIS TO BE ABLE TO FLY AGAIN. IT REALLY SUCKS BEING GROUNDED!! SUCKS AS MUCH NOT HAVING MY EQUIPMENT TO CHECK ALL OF THIS ANYMORE.</p>

SEEKING KNOWLEDGE NEW TO ELECTRIC AND WANT TO KNOWABOUT DISCHARGE RATTING ON BATTERY. I HAVE A 11.1V 10C DISCHARGE 1250Mah3-CELLLI-PO battery and wish to know if i can go to a larger discharge like 20 and not damage the the set up in this plane and what will a larger discharge rate provide for me?

Yes, the discharge rate has to do with the battery's ability to deliver voltage at certain currents. All you have to do is use 10C or higher. 20 C will be fine as the 10C is a minimum rating. You may also notice cooler battery and a bit higher voltage (power)

IN otherwords if the spec calls for 10C then you can use 10C or higher.

Here's the correct info for lipos SOD and resting voltage. Sorry about the formatting.

Resting Voltage Chart
4.00V84% 4.2=100%
3.96-77% 4.1=80
3.93-70%
3.90-63% 4.0=60
3.86-56% 3.9=40
3.83-48%
3.80-43% 3.8=20
3.76-35% 3.7=0%
3.73-27%
3.70-21%
3.67-14%


100.00% 4.2
90 4.13
80 4.06
70 3.99
60 3.92
50 3.85
40 3.78
30 3.71
20 3.64
10 3.57
0.00% 3.5


another chart

3.7=0%
3.8=20
3.9=40
4.0=60
4.1=80
4.2=100%

And a couple of Fuel tables I generated. My specific info on specific packs is so accurate that it allows me to estimate the SOD and charge from empty to full in 4 minutes.

You do realize that the curve changes completely from one vendor or type of pack to another?

That's one of the nice things about LiPo's that the discharge curve is relatively flat, particularly on the better packs.

In turn that's what makes determining charge state from voltage so useless.

No, they are all identical. I see what's going on here when you speak about flat curves and varying voltages from vendors. You are talking about loaded voltages and I agree that it is extremely unreliable to guess the SOD from a loaded voltage. I'm talking about unloaded or "resting" voltage.

The reason I brought this up was to help the OP get an indication on the SOD and if he'll use one of my charts (when resting of course) it is possible to tell the state of charge with surprising accuracy. In otherwords going from the post 1.

If user can simply measure the open voltage then the pack can be verified that it is full at 12.6 volts. If it is 11.1 then it's discharged. The TOPS of my graphs are open voltages after a rest period long enough to get a good springback and measurement. The BOTTOMS of my graphs are the part that your talking about and depending upon the load and pack can be all over the place from 1-4 volts at ANY state of charge. This is why we must rely ONLY on an open voltage reading.