7Ch Futaba on Lipo battery?

[supertrex2]

Can the 7.1 V 2S lipo handle this radio? or do I need to go 11.1V?

The radio spec says its 9.6VDC. but I cant find any lipo with 9.6 Volts...

any suggestions?

[DavidH]

You will need 3 cells to power the Transmitter.That would be 11.1 volts. When fully charged it would be about 12.6 volts. The transmitter will handle it just fine. I used Li-Ion on my 9Z for years.

David

[supertrex2]

ohh ok... thanks

[BarracudaHockey]

http://www.hangtimes.com get a NoBS Batteries high capacity NiMH pack and be done with it, my 1650 pack lasts all weekend on a charge and I fly alot, its not unusual for me to have 2 or 3 helis and a plane or two at the field all day.

[Skiddz]

I 2nd the batts from hangtimes.. I got a 2700mah NiMh for my 9CHP and it lasts 12 continuous hours easy...

[supertrex2]

Ive notice that all the long hours are from 9C radio.

I bought the 2100mAh for my 9Z radio and it didnt even last 2 hrs. Continues usage.

Full charge 11.2 V then after maybe 12 flights... battery is already 9.9V. ...

[DavidH]

The battery is a 8 cell 9.6 volt battery.
At 9.9 volts your in the prime discharge zone of the battery.
The transmitter battery can be used down to 9.2 to 9.3 volts with no problems.

I have used transmitter batteries till the low voltage alarm ( 9Z) has came on at 8.4 volts. Still have about 10 mins of time when that happens.
If your recharging at 9.9 volts. Your not doing anything but putting a surface charge back on the battery.
Use the battery like it was designed to be used.
9Z would show 11.2-11.3 fresh from charger. After couple of flights it should be in the mid to low 10 volt range. Then it will get below 10 volts and stay there for a long time. With the 1100 mah nicad that came with the WC2. I could get 4 hrs of continous on usage time with no problem.

David

[supertrex2]

ahh... I didnt want my pack to go lower than 10. but... since it goes longer in 9+ range then i'll prolly try it...

Its not bad for the battery pack if I charge it back even its only 10.4V right?

[DavidH]

Its not bad for the battery pack if I charge it back even its only 10.4V right?

I would not make a habit of doing that. It is always best to let the battery capacity get low and then recharge it.

David

[BarracudaHockey]

David, I wish I had (or could borrow) a CBA to plot the discharge curve of some popular batteries as this comes up so often, once you see a plot it makes pretty good sense.

[DavidH]

Andy,
I have never had a need for reason to chart the discharge curve. On my models I check the batteries before every flight. That way I learn how each battery does. I always used 4.8 volt batteries down to 4.5-4.6 volts. I have seen the discharge curves before on the different chemistry batteries.

David

[BarracudaHockey]

I agree, I'd just like to track down the info and do a sticky post in the beginners forum because I believe that there's a lot of people under utilizing thier batteries. Also to explain that loaded testing is really the only way to accurately check batteries.