Why should I discharge My battery packs... what are the PROS...

Not much reason to do this to receiver and tx packs in ordinary use. However, on first installing them, it can help to cycle the receiver packs a few times to get full capacity.

Dave Segal

You don't need to overdo the charging / discharging stuff, but, especially when they get a bit older, NiCads have a habit of 'remembering' how much you discharged them before and, if you didn't completely discharge them, you might find they won't charge fully.

There are plenty of threads on the subject here in RCUniverse that will give you a better informed answer than me, but, as a rule of thumb, I tend to cycle the batteries once every ten chargings.

-David C.

Do yourself a favor and search for other threads. Spend some time in the battery forum. It is essential to understand the different technologies and methods associated with our power systems. Anyone just entering the hobby needs to know what keeps our planes in the air or disaster is imminent. This past weekend at our field was a perfect example. A newcomer was flying around rather nicely with his new belchfire .40 and wingthing plane when all of a sudden there was a loud THUD First of all, he never warned anyone he was in trouble. BAD!! The plane went in full throttle just behind the flightline. Always yell, please. Anyway, we picked up the pieces, shook off the dirt and went back to survey the damage. I grabs the battery pack to check the voltage, and voila--there wasn't any I asked when the new batts were charged last and how long. Hold on, here it comes___He told me that the batteries were on the charger that came with his new radio since Thanksgiving! YIKES. Take the time to read about our batteries and chargers. You'll be glad you did_bob

- - as the scientists in the control room at Houston said when they were trying to get Apollo 13 down after the near disaster in space ..

'You can talk all you like about what we need to do to get them safely down but me must confine ourselves to what is possible with the power they have on board'.

'Power is everything'

-David C.

How very true and i'll never forget that unlucky #13 flight.
The whole world prayed and thats where the power came from.
As for the battery question if you ask 1 question you may get 20 different answers.
I was on that thread a few days ago.
If you use NMH batteries (and i'm building all my packs with them) You don't have to worry about recycling them but they take a bit longer to charge

NiCads and NiMH batteries can and will develop mAh capacities based on their discharge/charge amounts. NiCads are the worst about this and NiMH aren't as bad...but they will develop a memory, too.

Typically I use a battery for a day's flying and then when back at the shop I hook it up to an ACE Super Smart Tester that drains the battery pack down to 1.05 volts per cell and also tells you how many mAh's were left in the pack. This way the batteries have been fully discharged and are ready to accept a FULL charge.

When I get a new battery pack I go through 3 slow charge/discharge cycles to "form" the battery pack. The ACE tester is used again so I know how many mAh's are on the battery pack. If three cycles don't bring it up to the pack's capacity rating...do it time or two more and then it should be up to par.

Older battery packs should be cycled to check for their condition at the beginning of the season and if you want to, more often. IMO, if a battery pack can't produce at least 90% of it's listed capacity...toss it!

Like a running engine, electrical power is your friend!

I'm with the first posters to this thread. I use all nicads, and I only discharge (cycle) once a year in the spring to check the packs to see how good they are. The rest of the year they are on trickle charge and right after flying for any length of time they go on an overnight charge, then back to trickle. I've never had a problem with maintaining my packs this way. I also like Ace battery management products. I have lots of Auto Add a trickles, a Digipace II, and I just got a Super Digipulse. I love all of their units.

First I ever heard of the NMH having memory problems.
On every pack I buy it states the advantage of not having the memory problem of Ni-Cads.
mah capacities yes but memory NO.
I don't know of any ham radio Op in my area that has any of the fancy gear to recycle batteries but most of us now have NMH.
I guess in RC you don't want to take a chance but there are many RC flyers who just drain the battery with a resistor or a few Auto # 1157 bulbs

I have spent my lifetime in the airospace field, primarily in instrumention, and know first hand that the myth about NiCads having memory is just that. Back in the 50's and 60's several of the major battery manufacturers tried their best to create such a trait in their NiCads and could not get any test results to substantuate the so called memory fault. True, NiCads wear out due to oxidation of their insulators but this is not memory, it is gradual loss of capacity that is not recoverable. Due to similar structure in NiMh, I doubt if they can ever be proven to have a memory either. Old myths die hard so if you must believe in NiCads having a memory, so be it; just don't bet your life on it.

So your saying all the high priced recyclers on the market are of no real help in extending the life of a battery?
What about some of the curve charts put out by the battery manufacture?
Their wrong?

If this is true, then what is it that makes a NiCad battery lose its ability to change to the full; something anybody who uses them knows only too well is happening?

David C.

Well,
All I can say is all my light duty ham gear comes with instructions on recycling the NiCads
I have an older HT here that will receive only for about 14 hours.
I recycle that and i'm back close to 24 hours.
I don't have all the fancy recycle gear many of the other RC Guys do but I do use 2 bulbs and a resistor.
You buy a modern cordless today and the instructions tell you about recycling the battery.
I don't want to beat this topic to death but I have salvaged to many DEAD NiCad batteries back to life and put them back in service.
I saw some of the curve charts.
It shows how the voltage will ease down to a certain level then take a steep dive.
Recycle that same pack 2-3 times and that sharp curve is gone.
I'm only going by what I see here, battery recycling items selling for over a $100.00 and my own observations, plus seeing dead packs put back to good use.
Don't sound like an old myth to me
The reality is that Nicads do have memory

You might like to check out www.nas.com/~petes/nicad/htm for an interesting discussion on NiCad memory and NiCad care. There are several quotes/ recommendations from the battery manufacturers there. You can also go to any of the search engines and look for NiCad memory. You will find several sources that do say or at least imply that NiCads have a memory but: also note who they are--most are suppliers of smart chargers or devices that will sell to those who think they may have memory problems (biased perhaps??).

Is this why when you leave an older cordless phone (Nicad) plugged in after every call that you eventually can't make it though a single call? Sounds like memory to me. I also am more willing ot go on the advise of the guys on the EZone who know a whole lot more about electrics than most of us here, and they know that Nicads have memory.

Rodney has it right and the manufacturers agree with him.
The reason most batteries in cordless phones go South is the same as the reason for loss of capacity often erroneously referred to as "MEMORY" . The reason is OVERCHARGING. Overcharging kills many batteries before their time.
An occasional discharge ?charge cycle can help equal out the charge between individual cells in a pack. When cells are discharged the voltage betrween the cells may vary . The weakest cell in the pack will be a large determining factor as to when the PACK is deemed "discharged" Since the voltage drops very quickly in NiCads when they reach 1.0 volt , the lowest may well go BELOW 1.0 Volt while another in the string may still be at 1.18 or so. When recharged ,the lowest cell may not get a full charge and so the vicous cycle goes .....
Some manufacturers reccomend a SLIGHT ,OCCASIONAL overcharge to help bring the lowest cell up to full charge. A slight overcharge at a low charge rate is easily tolerated by modern NiCads. Not to be confused with repeated overcharge or sustained trickle charge (a practice most manufactuers frown upon.

Whirley bird made some comment about matching his cells in home made packs by cycling them befrore soldering them up . This is an excellent practice as matched cells will minimize the effects of the lowest cell in the string.

The people who make the radios don't make the batteries and the myth of memory is an urban legend that has a pretty good hold. It has gone so far that you will often hear of people cycling their lead - acid batteries . This practice will usually do nothing but shorten a lead acid batteries useful life.