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Transmitter battery

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Steve McIntosh10/04/2020 15:08:36
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88 forum posts

Good afternoon all.

I have a Futaba T6EXA which I bought 2nd hand a few years ago. When I bought it there was already a battery fitted inside which I have used successfully for several years. However, I noted that I always only ever JUST got a days flying from the transmitter and only as long as it wasn't too intense. Maybe a couple of flights. After conversation with other club members they seem to get a lot longer out of their transmitters so I am assuming my battery is on its way out. The battery fitted is a 9.6v 700mAh Ni Cd. Within the box was an additional 11.1v 2200mAh LiPo. Can I use that in the transmitter or not. I seem to remember reading on here somewhere that I cannot. Any clarity greatly accepted before I go out(figuratively if not literally these days) and purchase another battery.

flight110/04/2020 15:52:29
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722 forum posts
36 photos

Well i would change the battery pack A.S.P to an eneloop pack as if you got a nicad pack they are the originals, so are very old .

measure the pack dimensions and order new from say . The 2000mah enloops wil last a lot longer and you can still use the wall wart charger, but if you got a multi charger use that at 400Mah it will be a lot quicker.

As for the lipo don't use as will be over voltage for this tx as is realy not needed and more hassel as you will have to take it out of the TX to charge etc

P.S Ibelieve that this tx as a diode on the charge port(Istand to be corrected) so a delta peak charger won't work, proberly best to stick with the 

'wall wort' style charger

 

Edited By flight1 on 10/04/2020 15:52:56

Edited By flight1 on 10/04/2020 16:00:55

Simon Chaddock10/04/2020 16:14:26
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5692 forum posts
3026 photos

My even older Skysport 6A (same 9.6 NiCd originally) happily uses a 'transmitter type' 2200 mAh 3s LiPo which runs it for days or with casual use - months!

The voltage indicator does show over 100% but does not seem to matter.

3sLiPo

The instant the indicator drop to 95% or 9 V stop immediately to avoid damaging the LiPo.

The battery (from Ebay) easily fits and comes with a suitable Futaba connector. Of course it has to be charged using a LiPo charger but suitable connectors are provided to balance charge.

Martin Harris10/04/2020 18:21:56
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9263 forum posts
245 photos

In this situation, an Eneloop would be a good choice but have you considered a 3S LiFe pack if one is available in the right physical size?

You do need to be aware of the charging "shortfall" if you use the supplied charger with NiMH packs - the normal overnight charge won't get anywhere near a full charge during any charge from deep discharge and more importantly, the initial forming charge which would take the best part of a day and a half. If you simply fly and recharge overnight, this may stress the battery due to overcharge - something tolerated quite well by NiCd cells but much less so by NiMH cells, on which technology Eneloop are based.

Best practice might be to measure hourly consumption and base recharging times on actual use, with occasional checks on a smart charger - removing the battery to charge it on a regular basis may lead to worn or damaged connectors. Regular checks on the pack temperature while charging should help avoid damaging overheating if charging continues once the pack is charged.

Martin McIntosh10/04/2020 19:02:18
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3330 forum posts
1178 photos

Definitely go for a Turnigy 3s 1500mA/hr LiFe. A fraction of the price of Eneloops, virtually indestructible and you could be looking at weeks, if not months, before recharging. It will fit the space of a 9.6V NiMh with room to spare.

Just remember that it will always show full voltage up to the moment when it dies.

Steve J10/04/2020 19:56:48
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1841 forum posts
53 photos
Posted by Martin McIntosh on 10/04/2020 19:02:18:

Just remember that it will always show full voltage up to the moment when it dies.

Which is why I wouldn't recommend LiFe batteries for a transmitter and am having second thoughts about using them for receivers.

My advice would to get a new NiHM pack, IMHO Eneloops are the best, Vapextech are OK.

Edited By Steve J on 10/04/2020 19:57:15

cymaz10/04/2020 20:03:17
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9196 forum posts
1186 photos

Got an eneloop pack in my 9 cap. It goes for weeks in regular use

flight110/04/2020 20:26:58
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722 forum posts
36 photos

I would stick to eneloop as using lipo causes complications, the volt meter is not accurate enough on those TX's to be safe near the voltage clif lipo's have when near empty

The enelopops they will last a ;long time and 2.8x in fact to what you allready have.

Martin McIntosh10/04/2020 20:57:22
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3330 forum posts
1178 photos

Steve, I have to disagree. For some unfathomable reason a 1500 LiFe lasts very much longer than a 1900 Eneloop, possibly because there is zero self discharge. I have now replaced almost all of the NiMh packs as they started to die in my i/c models with Life. Even the smallest 700mA/hr is huge compared with the old NiCads and an 1100 would give at least 15 flights even with a high load. An 1800 is a lot lighter than a 5 cell NiMh. I often even double these up via an electronic switch because they are so cheap and light and I generally need the nose weight anyway.

I have an 1100 which got very squashed in a bad crash. It still holds full capacity and gets used all the time for bench setting up. I have only had to recharge it once and this took just one hour.

Julian Murch11/04/2020 09:33:05
62 forum posts
4 photos

My Futaba tx had the same older NiCad battery which only held a charge for a day or so. Not yet used in anger but I was looking forward to trying my model built over winter this spring. Being over 70 I am of course now house bound fir the foreseeable future.

I have bought a Fujitsu 200mAh blue NiMH which is the same size as before and I did check the actual battery. However I could not close the battery hatch cover as the wire from the battery came out of the top and was too tight. The problem was the small plastic squares in the moulding designed I guess for where individual batteries were used.. It w tricky to remove them but having done that the battery fitted fine and is A OK.

My timing here has been lousy - I chose to get back into modelling when the new regulations came into force and finished the model when we are in lock down. It may be some time before I will be able to join a club and learn to fly. I have enjoyed the building so far of course.

leccyflyer11/04/2020 09:34:25
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1424 forum posts
317 photos

Agree with Martin on the efficacy of Life transmitter packs. One thing though, I typically charge all my lipos at 1C, but have found that you need to charge the Life at <1C - 0.8C is recommended, to get the desired long life.

Avoiding the sudden voltage drop is simply a matter of not chancing your luck and flying with a LiFe for weeks without charging. Just charge it regularly, perhaps every other time you go flying, or fly for a weekend and balance charge fully after that. In practice, even after a couple of days flying it doesn't take anywhere near a full charge to get back up to fully charged.

Martin McIntosh11/04/2020 09:52:56
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3330 forum posts
1178 photos

Strange, The TGY 1500 Tx packs state on them to charge at 1.5A, so going by that I charge the Rx packs at 1C also.

I obviously do not let packs get anywhere near discharged and it is amazing just how little it takes to top up compared with NiMi`s.

leccyflyer11/04/2020 11:03:14
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1424 forum posts
317 photos

I'm using the Hiobbyking 1500mah 3s1p LiFe packs. Their recommendation of for a 0.8C charge rate. The first one I had I missed that and charged at 1C, then I inadvertenlty let it discharge, due to leaving the TX on by mistake on the bench. The pack puffed up and it was only on the replacement that I noticed the 0.8C advice.

flight111/04/2020 11:09:13
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722 forum posts
36 photos
Posted by Martin McIntosh on 11/04/2020 09:52:56:

Strange, The TGY 1500 Tx packs state on them to charge at 1.5A, so going by that I charge the Rx packs at 1C also.

I obviously do not let packs get anywhere near discharged and it is amazing just how little it takes to top up compared with NiMi`s.

It is all about the usable power and efficiency each battery type has, life /lipo have 80%+ usable power without shortening life and causing damage , nimh have less and lead acid are really poor so when charging you have to make up for this by charging them longer to make up the batteries efficiency and actual power used.

Engine Doctor11/04/2020 11:15:05
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2469 forum posts
39 photos

yes + 1 for Eneloop 2000 or similar *. Simple to charge , no mods to case or lead .last really well , hold charge for months if not used.

* 7Dayshop.com supply read to go cells at very good price . Tx packs easy to make.

Kiss principle keep It Simplesmiley.

Martin McIntosh11/04/2020 12:30:09
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3330 forum posts
1178 photos

On checking, mine are in fact labelled `HobbyKing`, not TGY but they all state on them to charge at 1.5A. Never had a problem with them, and you can take the Rx packs down to zero V without damage as long as they are recharged straight away.

Maybe an update since I bought them.

One thing I really like is that you can leave a tranny unused for a year without worrying about the pack going flat.

Jon Laughton11/04/2020 12:44:48
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1209 forum posts
72 photos

Steve Overlander used to supply replacement NiMh batteries for that transmitter..

Jon Laughton11/04/2020 12:44:49
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1209 forum posts
72 photos

Steve Overlander used to supply replacement NiMh batteries for that transmitter..

leccyflyer11/04/2020 13:47:42
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1424 forum posts
317 photos
Posted by Martin McIntosh on 11/04/2020 12:30:09:

On checking, mine are in fact labelled `HobbyKing`, not TGY but they all state on them to charge at 1.5A. Never had a problem with them, and you can take the Rx packs down to zero V without damage as long as they are recharged straight away.

Maybe an update since I bought them.

One thing I really like is that you can leave a tranny unused for a year without worrying about the pack going flat.

Hobbyking do print charge at 1.5A on the battery, but some other vendors recommend a 0.8C charge for optimum performance.

**LINK**

Martin McIntosh11/04/2020 14:00:57
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3330 forum posts
1178 photos

Wow, have they bumped up the price. I could have bought four for that when they first appeared and it was affordable to replace them with new each year.

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