Alternative TX batteries for Futaba T6X Transmitter

[GARY BLANDFORD-HULL]

Hi everyone. Looking for some advice on battery selection for a 35Mhz Futaba T6X Ripmax 50th Special Limited edition Transmitter.  I have recently obtained several models and this transmitter but without a TX battery. The user manual lists the TX battery as a 9.6v Ni-Cd battery. I see that Ni-Cd is not so popular these days and most places seem to suggest using a Ni-MH battery.

Would an Ni-MH battery be a straight replacement?  Do I need a specific Ni-MH mains charger of will my Ni-Cd charger work OK?  If I use an Ni-MH battery in the transmitter can I re-charge the battery through the transmitter charging jack?

I know these are pretty basic questions but trying to get back into model flying after a break of 25 years away from it and things have obviously moved on.

Many thanks,

Gary

[paul devereux]

I recently bought this for a Futaba 7c, seems fine:9.6v Battery Pack 2500mAh Nimh *Square* Insatance Vapextech RX LSD

Edit: the original Futaba charger for Tx (and Rx) that plugs into the Tx works fine. 

Edited May 31, 2023 by paul devereux

[paul devereux]

I've just had a look at a picture of your Tx, you might need the same specs, but a flat battery pack. Have a look.

[Engine Doctor]

1 hour ago, paul devereux said:

I recently bought this for a Futaba 7c, seems fine:9.6v Battery Pack 2500mAh Nimh *Square* Insatance Vapextech RX LSD

Edit: the original Futaba charger for Tx (and Rx) that plugs into the Tx works fine. 

I think the T6x uses a flat pack but Nimhs0 will be fine. Use the ready to go or LSD Nihms that Paul list in link (Low Self Discharge) as they dont self discharge like the standard type and will hold a charge for ages while in storage. I made my pack using 2100 mah ready charged and still going strong after 5 + years. They will discharge in use a lot quicker with 35 meg gear but still last very well compared to the 700mah packs that came as standard.

Edited May 31, 2023 by Engine Doctor

[Paul De Tourtoulon]

I think that it is the square pack NT8s, unlike  my T6exa, which looks like the same 'box' it takes a flat pack.page 13,,,

http://manuals.hobbico.com/fut/7c-2_4ghz-manual.pdf

Edited May 31, 2023 by Paul De Tourtoulon

[John Lee]

Component Shop & Overlander both do bespoke 9.6v Tx packs in various configurations.

 

Re your charger.

 

Trickle chargers should be fine.

 

But if it is a peak detection charger it may or may not work. The peak voltage is slightly different between the Cadmium & Metal Hydride chemistries so it depends on the calibration of the charger. If there is a protection diode in the Tx it can also affect the peak detection. The only way is to try it & see if the charger cuts out before the pack gets too warm, when it is fully charged.

 

 

[Peter Christy]

Bear in mind that the original pack was probably only 5 or 600mAH, so the trickle charger will be designed for a a 10 hour charge rate for that pack - 50 or 60 mA. To recharge a fully flat 2000mAH NiMh pack on such a charger could take 40 hours!

The charge rate should be shown on the charger, so its easy enough to work out - simply divide the pack capacity by the charge rate: 2000/50=40.

[Frank Skilbeck]

Component shop do a selection of tx batteries, https://www.componentshop.co.uk/batteries/radio-control/transmitter.html

 

Before you splash out check your tx Is working, it you can, I have one of those transmitters, and last time I checked the LED display was faulty.

[kc]

I am going to say - find the price of the nicad and decide if it's worth spending that on a 35MHZ Tx that might not be reliable,before you buy!    Most people use 2.4 Mhz now and thats the standard.   If it's in good condition and has several Rx and you have matching TX & RX crystals then it just might be worth it.   ( crystals are rare now so if you lack those don't bother! )  

My T6X 2.4ghz FASST seems to use the same nicad as my old 35 mHz T6X.   The 2.4 T6X is still OK but it too is nearly an obsolete system as if the Tx fails only a very expensive Tx can be used with the FASST Rx, so I wouldn't invest much in FASST stuff now.    Futaba is still quality equip though but the modern ( cheaper ) stuff is not compatible with the older 2.4ghz FASST system. 

 

In any case check out the switch harness and everything else for black wire corrosion.   Also beware that TX control is sadly lacking now in clubs and you must check nobody else is using 35 before using .   And it's all too easy to forget to extend the aerial as nobody else will notice and they won't shout out like they used to!    Other than that 35Mhz is still OK but so little used that it might not continue too long I fear.

Edited May 31, 2023 by kc

[kc]

39 minutes ago, kc said:

  Most people use 2.4 Mhz now and thats the standard.

Of course I meant 2.4 Ghz!

 

I checked my 35Mhz T6X and it looks like the flat NiMH version is used.

 

I reckon the Rx nicads might be dodgy if old so I suggest replacing those too.   Electric models often use BEC so don't use Rx nicads/NiMH anyway.

[GARY BLANDFORD-HULL]

Thanks everyone for your response. Very much appreciated.

I have an 2.4GHz tranny, but I also have a draw full of 35Mhz receivers, so will use  on my older models for the time being.

Gary

[Peter Christy]

Nothing wrong with 35 MHz (or indeed 27 MHz before it) at all. We used both very reliably for decades! The only issue now is that no new equipment seems to be manufactured for those bands, and a lot of the gear is getting quite old. As long as it has been stored correctly, the only thing that should need changing is the batteries.

 

We stopped using 27 MHz when CB radio arrived and swamped the band. I can't remember the last time I heard any CB activity on 27 MHz where I live, though it may be different near a busy motorway. 35 MHz was exclusive to model aircraft use in the UK. Both 27 MHz and 35 MHz did require some discipline amongst their users to avoid frequency clashes, but this was generally a minor inconvenience.

 

No reason why a good quality 35 MHz set should not give years of useful service, if looked after.

[steve too]

17 minutes ago, Peter Christy said:

No reason why a good quality 35 MHz set should not give years of useful service, if looked after.

 

I'm still flying some of my glow engined models on 35MHz. There is one other person at my usual club who sometimes uses it. Whenever I scan the frequency, there is never anything else on it.

[Rich Griff]

Be very causiiuse about "black wire corrosion" which can happen in other coloured wire insulation as well. Have found even copper PCB track suffering as well.

 

My challenger futaba set tx had this, stored well and batteries removed. It can happen in Rx stuff too.

 

Still going round in circles with a futaba skysport set. Got supposedly new crystals but still not working. Tx carrier wave spot on and Rx servos glitch/centre when Rx powered up. Will give this set a further "chance" as I was told it did work.

 

Self disciplined 27 meg sets to RC cars and slow speed boats.

 

Noticed at a pass event no peg boards, rather undisciplined flying and "landing" shout not heard at all !

 

A model did collide with a flyer who was retrieving his landed model at the time. No injury or blood.

 

Safe flying is no accident.

 

Prefer being a lone flier or Very small group.