Tx modify from dry cell to rechargeable battery pack

[Ian Harrison 4Participant @ianharrison4]

Hi, I have been given a brand new Futaba 6TL Sport 2.4 radio set and would like to get rid of the Tx dry cells and have a rechargeable battery pack. Has anyone done this and even, is it possible. I would use the outfit in model boats, changing from my old very reliable Futaba 40 meg outfits.

Thanks all and stay safe.

Ian

[Ian Harrison 4Participant @ianharrison4]

[ashley needhamParticipant @ashleyneedham69188]

Ian. I use ordinary rechargeable AA batts in my transmitters. Seem to last a good time and are easy to recharge in one of those little socket type chargers. Saves a fortune in dry cell types.

Ashley

[Ray Wood 3Participant @raywood3]

Hi Ian,

Duracell will last a year with normal weekly use I find, quite amazing really 😄

Regards Ray

[Colin BishopModerator @colinbishop34627]

The low self discharge types give you the best of both worlds.

**LINK**

Colin

[Ian Harrison 4Participant @ianharrison4]

Thank you everyone, I really had not thought it through and rechargeable cells makes absolute sense. Cost is as cheap as quality dry cells, but reusable dozens of times. I already have the specialist chargers, so no cost there. Looking forward to getting the new system up and running and getting back on the water once it reopens. Best regards everyone and stay safe. Ian

[Malcolm FraryParticipant @malcolmfrary95515]

Looking at the instructions, it is designed for a 6 volt battery pack, being 4 of 1.5 volt AA cells. Rechargeables generally start at a lower voltage, 4 of them giving 4.8 volts nominally, which is quite near an alkaline being empty. The transmitter might well warn of low voltage earlier than expected, but it just means recharging more often.

[Empire ParkstoneParticipant @empireparkstone]

Why not a 6v rechargable pack

[Dave MilbournParticipant @davemilbourn48782]

What Malcom said, plus –

A 6v NiMH pack can be over 7.0v when fully charged, and there's no indication what the terminal voltage of the Tx circuitry is;

Five AA cells will not fit inside the case;

There is no mention of fitting rechargeable cells in the instructions and no charging socket provided should you wish to do so;

The components in a modern transmitter use far less current than those of even a few years ago. Like Ray says, a set can last a season and you can pick up a 4-pack for less than a quid here Vapex High Power AA batteries

I reckon that's enough hints to use 4 x AA alkalines. Just avoid those horrible twelve-for-a-quid 'bargain-shop' batteries!

Dave M

 

Edited By Dave Milbourn on 09/06/2020 11:13:15

[Ian Harrison 4Participant @ianharrison4]

Sorry for the delay getting back to everyone, Thank you so much for all the comments and I am going to use good quality rechargeable batteries, already ordered. It makes absolute sense.

It just proves that if you ask the question, you get the right advice.

Thanks again and all stay safe.

Ian.

[Charles OatesParticipant @charlesoates31738]

Hi Ian, I must have my stupid head on today. Can you explain that choice to me?

Decent AA cells = at least a year of running

NiMH cells, possibly needs an extra battery and regular topping up if they are the self discharging type. Or normal number of cells and being on the low voltage brink.

I'm not criticising, just interested in your reasons

[Ray Wood 3Participant @raywood3]

Hi Ian,

Thanks for coming back with your reply , so often a question is asked out of the blue, we all pile in with more answers than you can shake a stick at and ,…………. Nothing 😄

Enjoy your radio & batteries 👍

Regards Ray

[Dave MilbournParticipant @davemilbourn48782]

Like Chas, I'm also a little confused about what "the right advice" might mean in this context. Along with another current thread on this forum the poster seems to interpret it as "If you ask the question then sooner or later someone will give you the answer you wanted to hear", irrespective of a majority of contradictory but valid views.

To be fair, at least this chap stated his intentions at the outset, which rather begs the question "Why ask?". I shall be more wary of replying to posts like this in future.

Dave M

[Malcolm FraryParticipant @malcolmfrary95515]

My preference is for rechargables and a transmitter with a charge socket, but not for battery life . More because I am perfectly capable of forgetting to turn the transmitter off or accidentally nudging it on. This tends to disappointment a few days later at the poolside, but at least I have the option to swap to the emergency dry cells hiding in the door pocket of my car, or, if I spot the goof at home, recharge.

My 8 cell transmitters have internal regulators allowing a wide range of battery voltage. 4 cell ones have less voltage headroom and very often no charge port, so there is a built-in bias to Alkalines. Using rechargables would involve a lot of removing and replacing cells for recharging, the high capacity and long life of Alkalines reduces this level of messing about. Choices, choices.

[john jones 23Participant @johnjones23]

I have a Futaba T6L and can confirm it does not work using 4 rechargeable AA batteries. The batteries were new,supplied by Component shop and fully charged . Two sets of batteries were tried,neither worked. Set works fine using dry AA's.

John

[Charles OatesParticipant @charlesoates31738]

Thanks for that helpful reply John. That was my suspicion based on problems with rechargeables with a different Futuba transmitter. I hate the idea of risking a model because of a dodgy power supply.

Chas

[Ian Harrison 4Participant @ianharrison4]

Hi everyone.

First of all would like to apologise if my question and response has cause offence, this is something I would never want to do.

Let me start at the beginning, I have anyways had transmitters with rechargeable battery packs, just plugging in a charger when returning home and never worrying about them being flat. I always steered clear of ordinary batteries as they were expensive, didn't last long and had a problem with leaking and causing damage to the unit.

I have been given this new Futaba outfit and the first thing that struck me was that it takes ordinary dry cell batteries and was wondering if it was possible to fit a battery charger socket and battery pack. The cost of quality dry cell batteries is still expensive compared with the initial cost of rechargeable battery pack, the dry cell battery is thrown away as soon as exhausted whereas the rechargeable packl can last for many, many years. I thought the suggestion of using simple rechargeable cells made sense, so saving having to modify the transmitter. The comment from John that rechargeable cells don't work in the outfit is worrying, so I could be back to actual dry cells.

I am sorry if I have caused any offence, but I was only asking for advice which I thought the forum was for, I won't bother in future.

Best regards and stay safe.

Ian

[ashley needhamParticipant @ashleyneedham69188]

Ian. You didn’t cause any offence, you asked a perfectly sensible straightforward question. I don’t think I detected any offence in the posts??

I suggested rechargeable AA batts, but someone has said that rechargeable do not work in your set.

Fair enough. Lacking a charge socket, you are left with using Duracell batteries.

Unfortunately you normally get more than you ask for in the way of info on the forum, which can be confusing sometimes. Please do not get the hump.

Ashley

[Dave MilbournParticipant @davemilbourn48782]

No lasting offence taken.

Since the days of 500 mAH DEAC cells in my old Digimax 4-channel set I have always used rechargeable batteries in my transmitters, but that's because the sets I have came fitted with a rechargeable pack, charger and socket. I've also had a couple of sets where dry batteries were shown in the manual but the option of using rechargeable cells was specifically indicated and a charging socket was already fitted for the purpose. As Malcolm says, the units are generally fitted with voltage regulators which will come into play where the higher-voltage batteries are fitted. My experience with Futaba is that they will always cover fundamental stuff like this, so when I read the instructions for T6L and saw that they weren't mentioned – even as an option – I concluded that their use wasn't a good idea. You don't need to be an electronics wizard to get there by that route. I'm certainly not.

I take no pleasure in the fact that, despite the advice you sought and were given, you ignored it and have ended up with four cells which you can't use. Incidentally Duracells are expensive; try the link I mentioned.

Dave M

Edited By Dave Milbourn on 18/06/2020 17:37:53

[Ian Harrison 4Participant @ianharrison4]

Thanks to everyone for the comments, the rechargeable cells I ordered will not go to waste we have loads of battery items and the grandchildren's electric toys. I have already ordered a stock of Vapex batteries so hope they are as good as stated.

I think we now draw a line under this forum entry.

Ian

[Colin BishopModerator @colinbishop34627]

Yes, time to put it to bed. Just one thing worth mentioning is that with older 27 and 40 meg TXs 8 cells were required and the sets were relatively power hungry. You could use 8 alkaline or 8 NiCads and they would be happy but rechargeables were the best option in view of the power consumption.

The modern 2.4 GHz sets use both less power and on a lower voltage. Some of those I have function OK on low memory loss rechargeables but others seem to run indefinitely on alkaline cells so the latter are indeed the safer option.

Colin

Edited By Colin Bishop on 18/06/2020 21:11:17

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