CastorTroy2150

My Feedback: (10)

Has anyone had any success with a Lipo in a Tranmiter or Reciever? There is a fellow at my field who uses one in both and saya he loves it. He rarely has to charge them as apposed to normal Nicad batteries. Just curious, I use a Futaba 7 CAP, Tower seems to have some but I am just unsure of brands and what to get. Any help would be great. I am jsut really fed up with my batteries, they just dont seem to hold a charge anymore, I am unsure if this is because they have developed a memory or what.

TedMo

I see no good reasons to use Li Po's as TX or RX batteries. Present batteries are available with more than sufficient capacity for both rx and tx without the intricasies of Li Po's. If you are having peoblems at present you have not been charging properly.

BarracudaHockey

My Feedback: (11)

Lots of reasons, though they may not apply to everyone.

Lipo transmitter batteries last forever and have no self discharge. If I charge my radio today it will be ready to go this weekend or Christmas morning without topping off the charge.
Here's the ones I use http://www.helidirect.com/product_in...oducts_id=6466

As for the reciever, a regulated power system with a lithium battery has constant voltage from the start to finish of the day or days and is lighter than a comparable nickel battery. Its not for everyone but its a good solution depending on your needs.

pilotpete2

Well, your old Nicds may well be due for replacement. Just how old are they? If they are relatively new, try cycling them, with a Tx like the 7C, this is easy to do, even without a battery cycler. Just fully charge the battery, reset the timer that records the transmitter on time, make sure the antenna is fully extended (unless its the 2.4G version) then just let it sit on your workbench until the low voltage warning goes off and note the time. You can look up the transmitters current consumption in the manual, then just multiply by the number of hours it ran, this will give you a good idea if the cells are starting to poop out
A fully charged 3S lipo is 12.6V, way over the fully charged voltage of an 8 cell Nixx pack, not good for the output transistor in the RF stage if it's on 72Mhz, and is also harder on t he voltage regulator for the digital circuitry of the transmitter.
A number of places are now offering the Sanyo Eneloop cells in standard size transmitter packs, these give you 2000mAh capacity, with self discharge rates similar to lipo, and the correct voltage.
For receiver use a 2S lipo is waaaay to high voltage for todays servos without using a regulator of some kind, of course if you're flying an electric with a BEC providing the receiver voltage, that's a different story.
What is a viable alternate, and many folks flying larger gas/glow powered models are switching to the A123 type cells, 2S of these cells provide a very close match to a 5 cell Nixx pack, with tremendous ability to maintain voltage under load (Nimh in general, and AA size in particular stink in this regard) very fast charge capability and very low self discharge.
Many newer lipo chargers offer A123 charging capability, the very popular FMA Cellpro is a very good example.
Good luck,
Pete

Four Stroker

With amazing consistency, batteries fail one cell at a time. Will you be able to land with a 2 cell pack with one dead cell - any chemistry ?

Bozarth

My Feedback: (15)

I use lipos exclusively in my tranmitters and with my receivers. www.2dogrc.com sells transmitter lipos, and so does hobbycity. I can fly for three hours at our indoor fly-in and then again the next afternoon without charging the tx battery. I love it. No reason not to enjoy the benifits of technology.

Kurt Bozarth

pilotpete2

A single A123 cell is equal to a four cell Nixx pack with a shorted cell.
Those A123 (lifepo4) type cells are waaaay more tolerant of abuse than Nixx cells.
Ive had one cell failure in twenty years flying with nicads, I was able to land it, today with a Spektrum receiver, I wouldn't bet on it, on the other hand, a fasst system would probably be OK, as they have a reputation for working lower than the servos, as long as it's not too hot out
Pete

dirtybird

My Feedback: (5)

There is a reason. If you forget and leave your transmitter on you have lost your expensive battery and possibly your transmitter.
In the receiver you also have the complexity of a regulator that has a history of failure.

Bozarth

My Feedback: (15)

Deleted.

BuschBarber

My Feedback: (2)

Lithium Ions and Lithium Polymer packs work reliably as Rx packs. They are much lighter and recharge much faster. You can put these batteries on charge, between flights, and fly indefinitely if you so desire. You can use 2S2P packs and get Twice the capacity and still have Redundancy in case a cell fails. They hold their charge for months. You just have to be careful not to discharge them too far or charge them incorrectly. I disconnect the Rx packs at the end of the day.

With regards to LiPos in the Tx, I am using TrueRC 3cell LiPo packs in both of my XP9303 Tx's, my 8103 Tx, and my 9CAP Tx. There is an electronic component you can purchase to drop the Tx voltage to a safe level and still use LiPos in the Tx.

A123 cells are great, as well, and take a beating. They are a bit heavier than LiPos. I do not know if they will fit in a Tx.

I am tired of NiMh dishcarging in my Tx and False Peaking my chargers. I went through the process of initially Cycling the NiMh Tx packs, multiple times, to Form the cells, and still I get inconsistent performance.

I have been flying RC since 1978. Lithium batteries RULE!!!

dirtybird

My Feedback: (5)

Any time you add a part you reduce the reliability
With a 2S2P in the receiver you still need the regulator.
A123's are the answer. The 1100 mah units will fit in the transmitter just fine. They are the same size as ni-cds and you only need three of them.
In the receiver you just need two and you don't need the regulator.
A123's also have a hard case and they don't catch fire. You don't have to remove them and put them in a crock pot to charge them.

Coke

There's just been a case reported in the UK of a transmitter failure after 8 months use of a lipo in the T/X. It was sent in for service and came back with the report that it had failed due to the slow degradation of the onboard voltage regulator and some of the transistors due to the over voltage supplied by the 3S lipo. This I believe was a JR/Spectrum T/X and as they have previously put out an advisory note against lipo use in the trannie must have worrying consequenses in respect of any third party insurance claims let alone the loss of the model [:-]

rmh

A few JR guys are using LiPos as RX batts a large voltage reg is also used
You have to have a Jones for LiPo's to go to this trouble - but anyway - It is a workable option (for those who care)
My A123 cells are so EZ to use and soooo reliable -i can't imagine going back to LiPos .or other rx stuff.
My TX -and LiPo's ??
not a chance- there are really good-safe reliable options now - notably th new generation of camera cells - -Ihave three types I an fiddlin with - Eneloop- Hybrids, and Kodak.
and my wal wart will charge em all - and they can set- till I want to use the tx because no failure danger and no measurable losses on the shelf.
How cool is that?

A.T.

Not recommended, well covered under previous threads
Lithium Polymer - Do Not use in transmitters
Servo - Operating Voltage Range - usuage with Lipol & A123 batteries
Regards
Alan T.
Alan's Hobby, Model & RC FAQ Web Links

Julez

http://www.rcgroups.com/forums/showt...=3#post6526055