Dry Cell AAs in Radio. Do you use them?

[skom25]

Hi,

I am looking for new radio. Unfortunately, it seems that it will not work properly with rechargeable AAs, because of lower nominal Voltage and Low Voltage Alarm in Radio.

I know that there is possibility to use LiFe packs, but they are not available in my area or are very, very expensive. Talking shortly: no go.

In my current Radio I used Dry Cell AAs but I read some opinions, that they can leak. It is always an issue, but hurts bit less in 80$ Radio than in 200$ +.

Do you use Dry Cell AAs in Radios? Any issues with them?

As I wrote, I already used them but my experience is so small, that I cannot say anything about long term issues.

[Jonathon Gillham]

I've had no issues at all. Batteries leaking has only happened when they've been sitting for years (like 10yrs plus) For a tx that is used regularly I can't see you having an issue 

[Twinfan]

Not in Tx, but I use dry cells in odd things around the house including TV remotes.  You only get an issue if the battery is left in something long term.  For something you use regularly, and will therefore be replacing batteries routinely, you won't have a problem.  If you're ever not using your gear for a long time (months...) then just take the batteries out  

[Badcrumble]

1 hour ago, Twinfan said:

Not in Tx, but I use dry cells in odd things around the house including TV remotes.  You only get an issue if the battery is left in something long term.  For something you use regularly, and will therefore be replacing batteries routinely, you won't have a problem.  If you're ever not using your gear for a long time (months...) then just take the batteries out  

I do exactly that. My RC sessions are infrequent so tx batteries come out as soon as we finish - just like the cars.

[Mad Ax]

I have recently swapped all my Tx batteries over from dry cell to rechargeable.  It's so much more convenient to have a stash of charged batteries ready to swap in than to have to keep remembering to but AA and AAA batteries on the shopping list.  With kids toys and other things burning through batteries at a horrific rate, it's been way cheaper this way.

Dry cell batteries are much better than they were 30 years ago when you pretty much had to leave something for a few days before it leaked, however I have had a few leakers in toys, especially where there's a risk of moisture.  My problem is I can easily put something away for what I plan to be a few days, then forget all about it for 2 or 3 years.  My Turnigy 9X transmitter was a case in point, which sat with batteries in it for well over 2 years because I shelved the project unexpectedly and the Tx got put out of sight, out of mind.

I'd wonder what Tx doesn't work with rechargeables, and if it genuinely doesn't work at all.  All of my Txs work perfectly well with rechargeables, even if they do show a low battery warning a little earlier than they would with a good dry cell battery installed.  I'd be inclined to try it with rechargeables before making a decision.

 

[skom25]

23 minutes ago, Mad Ax said:

I have recently swapped all my Tx batteries over from dry cell to rechargeable.  It's so much more convenient to have a stash of charged batteries ready to swap in than to have to keep remembering to but AA and AAA batteries on the shopping list.  With kids toys and other things burning through batteries at a horrific rate, it's been way cheaper this way.

Dry cell batteries are much better than they were 30 years ago when you pretty much had to leave something for a few days before it leaked, however I have had a few leakers in toys, especially where there's a risk of moisture.  My problem is I can easily put something away for what I plan to be a few days, then forget all about it for 2 or 3 years.  My Turnigy 9X transmitter was a case in point, which sat with batteries in it for well over 2 years because I shelved the project unexpectedly and the Tx got put out of sight, out of mind.

I'd wonder what Tx doesn't work with rechargeables, and if it genuinely doesn't work at all.  All of my Txs work perfectly well with rechargeables, even if they do show a low battery warning a little earlier than they would with a good dry cell battery installed.  I'd be inclined to try it with rechargeables before making a decision.

 

Futaba 4PM, which uses only 3 batteries. Alarm is set to 4.1V. It seems that it can be reached very quickly with rechargeable batteries. 

[El Gecko]

I've never bothered with rechargeables for transmitters, mostly because of the voltage difference.

Nominally a dry cell alkaline is 1.5V and a rechargeable NiCd or NiMH is 1.2V, for a difference of 0.3V per cell.

If your radio uses 3 batteries, multiply by 3 to get 0.9V, nearly a whole volt down from the alkalines.

It's even worse with 4 batteries, the difference is 1.2V which is the voltage of an entire additional rechargeable cell.

So you could theoretically add an extra NiMH cell to get the radio back up to "proper" operating voltage, however there's no space to put that additional cell (unless you taped it to the outside or something).

The 4AA alkalines in my radios seem to last for months, and it's super easy to just keep a fresh pack of 4 in my carry bag. I've never had a situation where rechargeables would have been an improvement.

[Twinfan]

Like Mad Ax, I use 4xAA rechargeables in my Carson transmitter with no issues whatsoever and they last for absolutely ages.

So I think any issues will be transmitter dependent.

[markbt73]

I've always used regular old alkaline dry cell AAs in radios. Rechargeables aren't worth the hassle to me, when I can just slap in 4 or 8 new Duracells and be done.

I don't, however, use the garbage non-alkaline ones that are sometimes included. I save those for TV remotes or flashlights.

[Man1c M0nk3y]

Looks like you’ve bought the 3PV from your other thread which is what I have and what the daughter uses as it fits her  hand better than the Absima (?) one we originally bought for her. 

For reference I have already ran it with some relatively cheap and lower capacity rechargeable batteries from ikea mainly because we had them and have never had an issue. The battery(s) in the car always run out before any issues with the TX. 

These are what we are currently using.

https://www.ikea.com/gb/en/p/ladda-rechargeable-battery-hr06-aa-1-2v-00509814/

[Nikko85]

https://www.amazon.co.uk/Rechargeable-Household-Batteries-Lithium-Ion/s?keywords=Rechargeable+Household+Batteries&rh=n%3A431411031%2Cp_n_feature_browse-bin%3A431549031&c=ts&ts_id=431411031

Could rechargeable Li Ions work? I have a shaver that needs AA batteries and won't work with NiMH ones, so got something like this

Andrew

[Mouc-RC]

1 hour ago, Nikko85 said:

https://www.amazon.co.uk/Rechargeable-Household-Batteries-Lithium-Ion/s?keywords=Rechargeable+Household+Batteries&rh=n%3A431411031%2Cp_n_feature_browse-bin%3A431549031&c=ts&ts_id=431411031 [...]

1.5 Volts rechargeable? Sounds like "the best of both worlds" ...

[one_hit]

A 2S LiFe pack is $26 shipped from AliExpress. Why not just buy one and call it a day?

[skom25]

4 hours ago, Man1c M0nk3y said:

Looks like you’ve bought the 3PV from your other thread which is what I have and what the daughter uses as it fits her  hand better than the Absima (?) one we originally bought for her. 

For reference I have already ran it with some relatively cheap and lower capacity rechargeable batteries from ikea mainly because we had them and have never had an issue. The battery(s) in the car always run out before any issues with the TX. 

These are what we are currently using.

https://www.ikea.com/gb/en/p/ladda-rechargeable-battery-hr06-aa-1-2v-00509814/

I have exactly the same set. 

[Man1c M0nk3y]

31 minutes ago, skom25 said:

I have exactly the same set. 

Well unless something has changed between when I bought our 3PV and your version then I don’t think you’ll have any issue unless maybe you are out for extended periods. We get 45-60 minutes no issue then she’s ready to do something else anyway but confident we’d get more without issue if she wanted. 

[BigJag]

On 4/24/2024 at 6:41 PM, one_hit said:

A 2S LiFe pack is $26 shipped from AliExpress. Why not just buy one and call it a day?

Hi. How does the 2s LiFe pack fit and connect in a transmitter?

I'm still using my old twin stick and pistol grip transmitters. They all currently use 8 rechargeable AA batteries.I've been wondering if there is an alternative to the AAs. 

 

[Tamiya Fan 1]

I've used both. Leaning more to rechargeable these days. You have to recharge them occasionally even if not used though. Same as vehicle battery. 

Sometimes the radio (digital) will allow you to set the battery voltage you are using. Check if yours does or maybe not. 

[BigJag]

My transmitters are quite old and basic. I've not noticed them having a battery voltage setting. I imagine that feature is available on a modern transmitter. Such as a Fly sky. That's something I'm looking at getting.

Going back to the power source for transmitters. Do the modern units still use AA batteries?

[Twinfan]

The ones I use or have come across do, including my Futaba 4GRS so it's not just a cheaper Tx thing.

[alvinlwh]

4 hours ago, BigJag said:

My transmitters are quite old and basic. I've not noticed them having a battery voltage setting. I imagine that feature is available on a modern transmitter. Such as a Fly sky. That's something I'm looking at getting.

Going back to the power source for transmitters. Do the modern units still use AA batteries?

My extremely cheap HotRC CT-8A {~£20} can take 4 x AA, 1 x 2S or 1 x 18650 and there is a setting for voltage setting as all 3 types are different. The AAs' battery tray has a 2S balance connector. Just pull it out and plug in a 2S by the balance plug. 

[BigJag]

Many thanks for that information. It's good to know that there are options. A quick Google of Hot RC revealed this very cool looking transmitter. Reminds me of a Scalextric controller.

 

[alvinlwh]

58 minutes ago, BigJag said:

Many thanks for that information. It's good to know that there are options. A quick Google of Hot RC revealed this very cool looking transmitter. Reminds me of a Scalextric controller.

 

That is not very good. Somehow it does not work as expected and some features simply don't work. It is cheap so you can still get one for a shot and the receiver will also work on the CT-6 or 8 so not a total lost. 

[one_hit]

On 12/8/2024 at 1:12 AM, BigJag said:

Hi. How does the 2s LiFe pack fit and connect in a transmitter?

I'm still using my old twin stick and pistol grip transmitters. They all currently use 8 rechargeable AA batteries.I've been wondering if there is an alternative to the AAs. 

 

Modern transmitters usually have a removable battery tray with a Futaba servo connector. The Life pack just replaces the battery tray and plugs to the radio the same way. For older radios that use 8 AA cells you could use a 3S lipo pack but space might be an issue

[BigJag]

Using a 3s Lipo pack would require a rewire of the transmitter. Is that a fairly simple task?

[Tamiya Fan 1]

In my opinion, I would say no. Get a new radio or continue the way you are.

It could be done though. Need to solder and be able to remove battery to charge it. (connector connection) Probably some cutting needed also. Not having radio in hand it is hard to say exactly.