Would it be possible to use a 3S Etec 1200 lithium pack to power my 9C. I know using alkalines in radios is 12volts but the 9C comes with a 9.6volt tx pack. I just want to make sure the unit will handle the 12.6volt charge the lithium will have.

Parts of the transmitter are regulated and parts are not. Also, the transmitter is certified with the NiCd pack. We'd not know the affect if a higher-voltage battery pack were used. It wasn't certified with drycells.

We'd have to suggest that you make up a 1100mAH NiCd pack. You can get such packs that are virtually the same physical size as the standard 600mAH pack. NiMh packs would also work because they are of a similar size to NiCd packs.

Since a properly-regulated and properly-protected Li-poly or Li-Ion battery pack is not availble for the 9C yet, we'd be quite reluctant to install one, especially a home-made one.

Thanks again Bill. I didn't want to assume the 9C could handle 12volts only to end up smoking the poor thing. I did try looking for the operating voltage in the instruction and online with no luck.

So using a home made pack of 2000 mAH NiMH cells would work OK?

AA size at 1.2 v per cell.

Will this cause any problems?

Cameron,

NiCd packs of 8 cells will work fine. You're not changing voltage, just how much charge is stored.

I created a 1600 NmHi pack using RadioShcack 8 Cell AA car Batteries. They are only about 18 bucks for the pack and work perfectly. There is no reason to raise the voltage reallyin a TX. You want more time not more power.

I also use a 9.6 volt 1600 Mah NiMH pack in my 9c, no probs so far. At full charge the meter reads 11.3 volts.

Great!!!!!!!!
Didn't think there would be a problem, but better safe than sorry.

Now to convince a radio supplier to sell me the 9C tx, with no charger or battery.
Could be a battle!!!!!!!!!

Thankyou,
Cameron McDonald

I use lithium packs in my Multiplex Cockpit everyday. The standard Multiplex pack is a 7.2V NiCad/NiMH so it's not a big jump to go with a 2 cell lithium pack at a nominal voltage of 7.4V.

Unfortunately I belive Futaba uses 9.6V packs and the closest lithium pack would be a nominal 11.1V. I'd be interested in seeing what happens if someone were to try this.

Someone could certainly rig up a tiny voltage modulator to fit in the huge void of the 9C's battery compartment with the Etec 3s 1200 pack!

If someone would make a regulator at 11.3 volts a 3S pack would be a great replacement. If not, just discharge the pack to 11.3 volts but that would be a pain in the derniere.

The nominal load voltage on Li cells is 3.7V--not 4.2V so the 3 cell pack voltage under load would be 11.1V. I understand the 9C puts quite a load on the batteries so the depressed voltage value should be relevant. Problem solved?

I think nominal voltage for li-ion is 3.7 and li-poly is 3.6, I'm not sure but anyway it's close.
A fully charged 8 cell tx pack reaches 11.3 volts whereas a fully charged 3S lithium pack reaches 12.6 volts. 1.3 volts may not seem like very much but I'd rather not have to buy another tx, I like mine very much.

The load of a 9C is only 280mah so a fully charged LiPo pack would still be over 12 volts for a while. Tower, as well as several other places sell 1650 NiMh packs that drop right in. I have them in my 8U and have one ordered for my 9C.
basmntdweller

I use a 1650 Nihm pack in my 9c, and it works great!

I understand that NiCd and NiMH work flawlessly in the 9C.

Lithium chemistry, however, could offer several times the capacity of the best NiMH. Or a much lighter radio at the same battery capacity.

NiCDs and NiMH will be dinosaurs in a few years as lithium captures more and more market share. And it's not just for low amp applications--look at Jason Shulman with his Thunder Power equipped Funtana or the amazing 20C, 340mAh cells from Kokam that are now being used in speed 400 pylon.

As more and more people switch over to lithium and radio manufactures make gear compatible with lithium voltages (or people use aftermarket voltage regulators) nickel chemistry packs will be nothing more than paper weights.

My point exactly, the whole reason for starting this thread! Lithiums are superior to nicad/nimh's. You won't have to charge as often, they weigh less, won't discharge if you don't use it for a while and take up less space as one cell equals 3 of it's counterpart.
The drawback is that they are more expensive but if you look at performance between the types it really is cheaper to get one lithium pack instead of several nicad/nimh's. In our case we would need a 3S regulated at ~11.3 volts. With it a full charge or 12.6 volts, it'll go a long way before needing to be recharged. It can be done as they do have regulators for the 2S, 7.2 volt packs, to be used as rx packs for the ic models.
Yes, the larger capacity AA packs are the way to go for now, I had to buy an 1800 mah pack because the stock 700 mah pack doesn't last long when my park flyer lasts for 45 minutes plus on one 2S pack.

How long is your 1800mAh lasting?

I have the pack but no connector so haven't even used it yet.