Tx batteries. Futaba 9C

[JayDBaltimore]

I have the Futaba 9CH Tx. I hope I didn't botch recharging. I wanted to cycle my batteries to get rid of any memory. The way I read the instructions is just leave it on and let the battery discharge. Then fully charge it for 15 - 18 hours. But now it only shows rougly 11.3 volts instead of 12.4. I take it there is no protection from having a cell get reverse polarity huh. So now I have a hosed Tx pack don't I. One cell reversed polarity.

[PaulH]

The problem is that you discharged them to zero. You're supposed to stop when you reach one Volt (1V) per cell. You should buy a new pack before you use the transmitter again.

These are some of the best packs you'll find for the money:

http://www.hangtimes.com/txpacks.html

Scroll down a little until you see the 2700 mAh Tx pack. That should last you nearly an entire weekend of flying. Call them up if you have questions about cycling the pack.

[JayDBaltimore]

I'm such a nubcake. I SO knew better than to do that. :arggg:

[Steve Rogers]

You can also do as I did on my 9C. I got a FlightPower 1500 LiPo 3 Cell put in it. Chargers in about 1 hr, no memory to worry about & lots of flight time!

[PaulH]

Steve, the NiMH pack that I linked to has all of the benefits that you list, plus about twice the capacity of your LiPo. Seriously, you should consider it! :)

[JayDBaltimore]

OH and a handy dandy don't overdischarge device for $18.00. I'm thinking one of those is going to be in my ever expanding inventory soon! Thanks for the info.

[DavidH]

You haven't hurt the battery. Just the charger you have is probably not capable of fully charging it back properly. If your using the wall wart charger that came with the transmitter that is the problem. Get a charger that will charge the battery at 1 amp and charge it.
11.4 volts is about normal for a fully charged 9.6 volt battery. Since most 1.2 volt cells will only be fully charged at 1.4-1.5 volt range.
David

[Steve Rogers]

Steve, the NiMH pack that I linked to has all of the benefits that you list, plus about twice the capacity of your LiPo. Seriously, you should consider it! :)

Ya but I can charge mine today & fly it next month. Fast charging a NiCd or NiMh just dosent seem to last as long as a good 1C 16 hr charge.
I guess it boils down to what the end user wants :dontknow

[JayDBaltimore]

Well I didn't crash today so my budget allows for a $50.00 purchase! :glasses2: And what the heck. I can use the stock battery as a backup.

[DavidH]

Jay,
Ever which battery you get. Your going to need a proper charger to charge it up.
If you just have the wall wart that came with the transmitter. IT is not going to work for charging a higher capacity battery. I would not attempt to charge any type battery that is not nicad or nimh with it.

David

[ArthurKnowles]

I don't think you hurt your nicad or nimh packs. Going down to .9 volts a cell is the normal way to discharge them fully before recharging, but you can take a nicad/nimh to 0 without permanent damage.

However, I just replaced both my 8S & 9C batteries with a set of 2500 mah nimh batteries form Batteries America. I think I paid about $35 a piece with the Futaba connector presoldered to the pack.

I use my Hobbico multicharger (4 ports) to charge it at 250 mah for about 14 hours to a full charge.

[Bastian1337]

On actual NiMh you would damage the cells if discharged to 0 volts
It could work out with NiCd batteries but you would have to discharge each cell separatly, not in series. Discharging the pack in series too low would probably lead to at least one cell with reversed polarity.

[JayDBaltimore]

Awsome vendor. And now I am armed with my little discharge tool. Which with a 2700 mah pack I figure will take days to discharge:) Thanks for recommending hang time!

[BarracudaHockey]

If memory serves, the 9C has low voltage cut off so I doubt it drew the pack down to 0 volts anyways.

[JayDBaltimore]

Nope. I have a reversed cell. I ruined this pack by letting it discharge all the way. The instruction manual is a little vague. They have >charge< protection, but not discharge. And if they do, it doesn't work.