AJsToyz

Has anyone tried a Lipo in there transmitter ? Theres a hobby shop selling them but haven't heard anything from people using them. I need a new battery for My 7C , figure if I'm going to spend the money I'd like to get the longest lasting battery I can for the money.

exeter_acres

My Feedback: (2)

I know lots of t people do it....

but I have never understood why???

Just get a higher capacity Ni battery for half the price and it is great...

I put a 2700mAh battery in my 9C and can fly for days without recharging....
the ones I bought are here
http://radicalrc.secure-mall.com/sho...20&cart=668749
about 1/2 way down the page...
another great option is the Fromeco battery (the Tx battery)
http://www.fromeco.org/atranzorker%20packs.htm

to get the same capacity with LiPo will cost $70 or up (for a quality pack) and you will need to remove it for charging....


Just my .02

AJsToyz

Some of the cheaper Lipo's hold a great charge they are just a little on the heavy side. I could even use an extra Heli battery for the Radio , just checking all my options.

BarracudaHockey

My Feedback: (11)

The problem with Lipo transmitter batteries is if you leave the thing on, and its not a radio like the 9z that will power down after x minutes of inactivity, then it will over discharge the lipo long before you get a low voltage warning alarm. Do you want a lipo doing the silver sausuage in the back of your expensive radio?

AJsToyz

I like the way you word things.... I don't need a Lipo , I was just looking for pros and cons , that would be a con. I guess a good Nimh would be just fine.

Foamaholic

My Feedback: (1)

A friend couldn't get good time out of his 2500 NiMh so he bought a 2500 lipo and can now fly for days without recharging. I use one too and love the long "on" time. Worth the risk of leaving it turned on for us. When I get home I always check to see that the tx is turned off. Just our experience.

rmh

as strange as it may seem - 2500ma is 2500ma

if 2500macells -NiMh are properly formed they put out 2500ma
however LiPos unless they are low cutoff voltage protected simply become an expensive experiment
as you may have guessed -I am no fan of using LiPos for that application. Jeeze -I see guys trying stuf Li pos in everything -for simply the sake of saying they use LiPos - frankly if I did not need em for my little electric models I would not have one in the house --

BTerry

My Feedback: (8)

... except for your cellphone, iPod, etc.

NiMh batteries are great for transmitters, as long as they are high-quality, low-impedence Sanyo batteries. I have a 2500 mAh battery in my transmitter. I left it turned on a few weeks ago and the low-voltage cutoff shut it down at 9 hrs 47 minutes (I reset the system timer after I recharge it). That is PLENTY of flying time! It recharges quickly too.

A.T.

Is this the one currently being promoted RC Groups? Finally a 2650mAh Lipo pack to replace Flat NiMH pack in Futaba & Hitec. Note, advertised for use in Futaba and Hitec TX but use of a 3S lipo pack does void Hitec warranty. Consenus in this and all other similar threads is that NiMH cells provide similar running time without the risks of early burn out of TX components from over voltage of a fully charged Lipol, over discharge and subsequent waste of a Lipol or rupture of the Lipol.
Regards
Alan T.
Alan's Hobby, Model & RC FAQ Web Links

Gulliver

Over voltage is not aproblem since all transmitters have an internal voltage regultor.

Being an infrequent flier, the main reason I use a Xt lipo is that it can sit a week or longer and not need recharging.

BarracudaHockey

My Feedback: (11)

They use lithium ion.

A.T.

Over voltage is a problem with many TX, the regulators are for internal demand from a nominal 9.6V supply (NiCad or NiMH) and some upto 8 X AA alkaline batteries = 12.0v and can fail under the repeated excess voltage of 12.45v+ supplied by fully charged 3S LiPol. [FWIW an increasing number of TX now use 6 cell NiMH packs]
Use of 3S Lithium Polymer (Lipol) packs in at least Hitec Transmitters voids the warranty as per some previous posts on the topic.
Lipo replacement in Optic6
Lipo replacement in Hitec TX
OPTIC 6 TX Battery charge
3s Lipol voids warranty
to calculate approximate "time on" from a fresh battery
Hitec battery drain rates
Regards
Alan T.
Alan's Hobby, Model & RC FAQ Web Links[/

XJet

Hell, I have NiMH packs in all my transmitters and some of them sit on the shelf for a couple of months between uses -- when I turn them on they're still charged enough to give me a full day's flying. If your experiences are any different then you're not using decent quality cells.

Good NiMH cells have a self-discharge rate of around 0.5% per day. That means, if you fully charge your 2500mAH pack and leave it on the shelf for a month it'll still have well over 2,000mAH left in it -- enough for a very full weekend's flying (and some) -- in fact about 10 hours for most transmitters.

So what was the problem again? :-)

AJsToyz

Alkaline batteries have a full charge new of 1.63 - 1.65 volts per battery. That was actually part of the reason for the question , and I guess I should have asked. I have put alkalines in my old Conquest AM and it pegs the meter at full. I'm not very worried about that old radio but I don't really want to hurt my 7C.

Andy

rmh

The urge to pack around a month's worth of battery for a few hours use -mystifies me
The DX7 will fly non stop for most of a day (well-- 8 hrs ) and the little low current wall wart can be left plugged in till you decide to go fly.
no fuss ,no muss, no overcharging, no risk -on and on -
I think some guys just like to play with different batts out of sheer boredom.

AJsToyz

Dick,

What type of battery does your DX7 have ? My stock battery only packs about an hour and half tops, thats just anoying . Like I said, I'm personally just exploring options.

Andy

Rafael23cc

My Feedback: (6)

It's called experimenting. Some people like to do it, for whatever reason. seems like you do too.
[link]http://www.rcuniverse.com/forum/fb.asp?m=6215723[/link]
That is one of the purposes of the hobby, without experimenters, there would be no advances in technology.

Rafael

rmh

have you fully charged it ?
mine lasts all day
it is the battery which came with it

AJsToyz

Dick,

I have charged it on its charger , I have cycled it , I have charged it and discharged it on my Triton out of the radio, it does not matter. I can take it off the charger at 8 am , head to the field , start flying at 10 am and it down from 11.3 to 10.5 at this time. The radio is not turn on till I get to the field , and I check the voltage when its done charging. If I'm at the field and do not turn it off for some reason , I'm going to have a very short day or need to recharge it while I'm out.

Andy

BarracudaHockey

My Feedback: (11)

So are you saying you can't fly at 10.5?

rmh

very possibly your Triton dun you in - but - IF you take the new radio - plug in th wall wart - leave it on for a day - then the cells get a chance to "form"
I use only the wall wart -all you need for this radio
fast chargers are good PROVIDED the cells are formed first.
the radio works down into the 9 volt range -9. something -I forget -
I have chargers for all kinds of batts and up to 8 amps but first - I study up on the cells to be used .
measure the current in a full pack.

Rafael23cc

My Feedback: (6)

Even with a standard pack (600mah) on my 8103 (72mhz) I was able to fly several flights a day (helicopter, RC combat and gliders) and come home close to or a little below 9.6v. I usually left home about 10am and came back at 8pm, on a typical day. With a 2300mah nimh pack in my radio i can "forget" to recharge midweek and I don't have to worry about it. It seems that it holds at 10.3v forever.

There is definitely something wrong with your battery pack.

Rafael

AJsToyz

Not at all , I'm saying when I first got the radio the battery didn't just drop .8 volts for no reason. It is kind of a pain when you have to bird dog your Tx to make sure its turned off or you might not be flying.

AJsToyz

Rafael , Dick ,

I do think the Triton killed it , and I do think the battery has seen better days . Now its time to decide on the new battery.

Andy

Eplane65

My Feedback: (16)

I'd like to stick my 2 cents in.

I've considered LiPos in my transmitters, but as someone previously said, if you forget to turn the TX off (which sometimes I do), then you risk damage to the TX. I've ruled out that option.[sm=thumbs_down.gif]

I bought a hi capacity NiMH pack with Sanyo cells. I'ts ok except that it self discharges pretty quick. You can't charge it, then go fly 3 days later because the voltage will drop from 11.2 to 9.8 in that time.[sm=thumbs_down.gif]

I feel the best option is a high capacity Nicad pack (1100) along with a quick peak charger like a Sirius that can charge the pack in less than an hour. These wall chargers that come with the radios are not much good.