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Author Topic: TRANSMITTER BATTERIES  (Read 1471 times)

John W E

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TRANSMITTER BATTERIES
« on: March 28, 2017, 07:11:45 PM »

Hi there

Whilst having a 'once every 5 year clean out' of the workshop - I have come across my manual for the Futaba 4-channel 40 MHz - and having a read of it for the first time :-) as we classic modellers do (now and then we do get round to reading instructions) :-)  .    I have noticed that it states when not flying the model, or sailing in our case, store the digital proportional R/C set with a nicd battery in the discharged state.   Recharge the nicd battery before the next flight or sail.

then it goes on to say

if a partially discharged nicd battery is recharged many times, its memory effect will reduce the flight/sail time substantially and may cause a crash/sinking, even if the battery is recharged.

I am wondering how many of us actually do this?

I must confess that when I have finished sailing and bring the handset home - I normally recharge the handset along with the receiver set of batteries as well.   Does everyone else do this?

John
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unbuiltnautilus

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Re: TRANSMITTER BATTERIES
« Reply #1 on: March 28, 2017, 09:34:21 PM »

Guilty.
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chas

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Re: TRANSMITTER BATTERIES
« Reply #2 on: March 28, 2017, 10:58:06 PM »

I haven't seen a nicad for years, those batteries must be getting on a bit. I believe NiMH batteries are no problem, thank goodness, because I never do that either.

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Colin Bishop

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Re: TRANSMITTER BATTERIES
« Reply #3 on: March 28, 2017, 11:19:16 PM »

Surprised that anyone is using NiCads these days.

Colin
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roycv

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Re: TRANSMITTER BATTERIES
« Reply #4 on: March 29, 2017, 09:46:32 AM »

Hi all, I still use nicads.  They are there, they still work, so I use them.  While in use they do not cause any pollution and I am not buying Nimh, just to replace them, could be considered environmentally friendly?
I think the memory thing is not that common, more common is the black wire problem from the negative battery wire, worth checking on.
I do not need very high amp hour capacity batteries for the transmitter as they will easily run for a full sailing session and I would charge or change batteries at the begining of a session anyway.
I have some nicads that must be 15+ years old and still work.
Please beware the exagerated claims of amp hour capacity printed on some new batteries out of the far east.  I have an electronic device for checking capacity and one battery I bought was actually only 1/3rd. of the stated capacity, that was Nimh.  You can make a useful check by weighing them against a known battery.
Buy from our established suppliers only.
regards Roy
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malcolmfrary

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Re: TRANSMITTER BATTERIES
« Reply #5 on: March 29, 2017, 10:06:49 AM »

For new use, NiCads have pretty much vanished from the market, but properly looked after, good ones have a heck of a long life expectancy.  The big problem with storing them was that they would self discharge, and if they did that rather than be discharged, different chemistry happened, and they wouldn't recharge properly.  The correct method of storage was to discharge them fully, then before use - WELL before use - to bring them back up to full charge by reforming them by repeated charge/discharge cycling.  Not something that the average modeler would be inclined to do.
I suspect that the alleged "memory" was nothing more than inconsistent manufacture of the individual cells, and that if you combined poor storage with one weak cell in a pack, you soon got to the stage where one cell would not charge properly, and you had a weak link in the chain.  As soon as the incompletely charged cell became discharged under load, the current being drawn from the pack would try to reverse charge it, dropping the pack voltage by two cells-worth suddenly.
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JimG

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Re: TRANSMITTER BATTERIES
« Reply #6 on: March 29, 2017, 12:13:21 PM »

Just a bit of history. The NiCd discharge memory problem first came up when they were used as the backup power supply in satellites. In sunlight the solar cells powered the satellite and charged the cells. Out of sunlight the cells provided power. It was found that the cells would be discharged to exactly the same level every orbit and slowly lost capacity until they ended up with no spare capacity, only enough for one orbit. In normal use when they are usually discharged to a different level everytime they were shown to have little or no memory effect and any memory could be removed by cycling the cells. So just use them as normal and don't worry.

Jim
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Bob K

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Re: TRANSMITTER BATTERIES
« Reply #7 on: March 29, 2017, 01:18:01 PM »

Not sure if this is a leftover from the early days of rechargeables, but I have had the same set of NiCads in my transmitter for over five years.  After every two hour sailing session - (usually twice a week) - I recharge them.
Never had any problems.  They still charge up to the same voltage, and after two hours have dropped slightly to the voltage they usually do.   OK, rechargables are 1.2V instead of the 1.5V for disposables, but as long as the set of four does not drop below 4.8V then you should have no problem with range etc.

An obvious point here, this is with good quality 'name' batteries.  I would never trust my luck with cheap Chinese copies.
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Re: TRANSMITTER BATTERIES
« Reply #8 on: March 29, 2017, 06:18:23 PM »

I just charged an old nicad set up from a 35mhz radio. Absolutely  fine in a 40mhz radio so far. Been out with it 3 times for an hour each time. Not recharged yet. I thought it would die in about 40 mins but was wrong.
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unbuiltnautilus

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Re: TRANSMITTER BATTERIES
« Reply #9 on: March 29, 2017, 06:28:33 PM »

I had an interesting chat with one of our suppliers, more of a 'remember the good old days' than anything useful, but it went a bit like this..
The latest batteries such as LiPos can produce vast amounts of power to weight, but require much care to stop them from failing completely and permanently. They have short lifespans compared to other types.
NiMh batteries are environmentally friendly, have high capacities compared to the older NiCads, but if left unused for a number of months, are difficult to impossible to recover back to capacity.
NiCads can be lurking in a cupboard for twenty years, and after a small number of charge/discharge cycles, can be back up to a usable capacity.


The above can have many holes shot in it, but generally it can be stated that cell technology has advanced greatly in forty years, but the resulting battery types are delicate flowers, that need to be treated with far greater respect than older cell types. Feel free to post on here in three years, telling me that you are still using the same LiPo packs, I will take it all back :-))
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Paul2407

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Re: TRANSMITTER BATTERIES
« Reply #10 on: March 31, 2017, 09:01:05 PM »

I had an interesting chat with one of our suppliers, more of a 'remember the good old days' than anything useful, but it went a bit like this..
The latest batteries such as LiPos can produce vast amounts of power to weight, but require much care to stop them from failing completely and permanently. They have short lifespans compared to other types.
NiMh batteries are environmentally friendly, have high capacities compared to the older NiCads, but if left unused for a number of months, are difficult to impossible to recover back to capacity.
NiCads can be lurking in a cupboard for twenty years, and after a small number of charge/discharge cycles, can be back up to a usable capacity.


The above can have many holes shot in it, but generally it can be stated that cell technology has advanced greatly in forty years, but the resulting battery types are delicate flowers, that need to be treated with far greater respect than older cell types. Feel free to post on here in three years, telling me that you are still using the same LiPo packs, I will take it all back :-))

Your quite right about Lipo's personally I think they should be banned, you might think that's a little drastic but I used to race 1/8th truggys and used 4s and 6s lipos I've now had 3 fail on me, once my truggy caught fire costing me around 350 in repairs then 4 months after putting it back racing I took a hard cased pack out of truggy after a race and the battery exploded in my hand luckily for me I had gloves on and I had very minor burns but it could have been so much worse if I had let my son take the battery out which he normally did but thankfully he had gone to the toilet.
So for me I'll use anything else but I'll never knowingly use a Lipo battery ever again
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