rms59

I just noticed that my Hitec Laser 6 TX nicad battery pack is 7 years old. It still performs well but just curious how long you keep them.

Dick

Edit: Are Nimh's better than Nicads for TX?

koolkrabber47

Hello and welcome to wattflyer.......to answer your questions, nimh is newer technology than nicd, so yes it is better......how long your battery will last, depends on how often you use it, how well you take care of it and do you charge/discharge properly.......the fact that it has lasted you 7 yrs., tell's me you are doing something right......depending on your particular situation, you might just want to replace the battery instead of upgrading to say LiPo......the stock replacement Nicd's and Nimh aren't cheap, a LiPo might be a better choice or you could upgrade to 2.4 Ghz. altogether.......if you feel comfortable flying in the area and enviroment where you fly and you don't feel the need for 2.4 yet, i would go with a aftermarket replacement Nicd or Nimh, preferably Nimh......don't buy just any off-brand you see on the internet, just like anything else there are good and bad aftermarket products......use these forums to start another thread and ask about the different brands and what is everybody else using and what do they recommend.......usually, somebody else on these forums has already performed the trial and error for you and can point you in the right direction......i'm not sure exactly how long a TX battery should last, i've never had one go bad, never had to replace one.....i've alway's been the type to keep up with the newest technology and replace my radio's about every 5 years......i have had to replace RX batteries many times and i usually change those when i notice they drain too fast when flying and they don't tend to take as good a charge at home anymore......if your radio is fairly new and you feel it is suiting your needs, then just change the battery......if the radio is kind of old, add to that the price of the new battery and it might be cheaper to replace the whole radio......with the recession and the bad economy, everybody is willing to fight for your hard earned dollars and the new, new technology is going pretty cheap.....hope this helped....sorry for the long response......i'll check back regularly and see how your doing.......you never know, maybe i'll even learn something......in the meanwhile, hope you have lot's of fun flying with this nice weather coming up.......thanx......(KOOLKRABBER47)......

radialarm

12 years is normal. I've had a few that went almost 20 years. I've got a pack in front of me now dated 05/97 that are still in great shape.

Larry3215

There are advantages and disadvantages to both.

NIMH have no memory like NICAD
NIMH have higher capacity for any given size so you can go longer between charges.
NICAD last longer - about twice as long in the same application.
NICAD can be charged faster if thats important.
NICAD have a lower self discharge rate

LIPOs on the other hand have a much larger capacity than either.
Lower self discharge rate than either
No memory
Can catch fire and burn up your radio, house, car etc.
Are risky to use if your tx cant handle the voltage difference.
Need a special charger.

Al_M

NICAD's don't have a memory. It is a myth that won't die.

koolkrabber47

thanx a million for your timely response.....i never new they could last that long......i've been flying for 25+ yrs. and kinda makes sense why i never had one go bad......i usually change my radios out as the new technology comes out @ every 5 yrs.......i usually wait 1-2 yrs. after a new radio comes out and wait for them to get rid of all the glitches......thanx again for all your help.......(KOOLKRABBER47).....

kyleservicetech

I personally observed that so called "memory" effect on Nicads we used where I worked before retiring. We were shipping 600 24 volt Nicad batteries for our circuit breaker controls every month. (That was for 30 years) And, working in the Service Department, I tested a lot of them before giving the customer warranty credit.

And, I did see memory effects on these batteries. What we ran across is a depressed voltage on the battery during discharge milliampere hour tests. That voltage on the batteries we used dropped down to about 1.05 or 1.1 volts per cell during the discharge test, rather than the normal 1.2 Volts.

And, discharging and recharging these batteries several times removed the problem.

But, because these batteries were backup power for 38,000 Volt 800 Ampere three phase power circuit breakers, we could not take any chance with them, and simply scrapped and replaced them. (Those breakers were rated to clear 16,000 Ampere faults)

Our customer recommendations were to replace these batteries every five years. But, that is for an application far more critical than for the radios we use for our models. (Even those flying wet turbines!) In recent years, we went to gel cell lead acid batteries for backup power, to gain more ampere hour capacity for the microprocessor operated circuit breaker controls.

For transmitter use IMHO, if you test them at least once a year for milliampere hour capacity, using something like the West Mountain CBA battery test equipment, and every thing passes OK, you are good to go. Nicad batteries generally slowly wear out, and don't normally suddenly quit, at least as how they are used in our transmitters. Things to watch for though, is cell leakage, visable as a white deposit around the cell seals. Any battery that has any cell leakage should be replaced. Period. These batteries that have had cell leakage can continue to work OK for a long time. But that stuff is corrosive. Not a good thing to have inside your transmitter. That internal chemical can also eat up the battery leads them selves!

As for the receiver batteries, I'd be inclined to replace them every few years in glow/gasoline models. They are subjected to far greater variations in battery current. And, they are subjected to vibration issues that can lead to problems after five years or so. If you ever crash a model, be especially careful about the receiver battery. They can check OK, but have broken spot welds on the individual cell connections under the shrink wrap. Not good.

koolkrabber47

Good morning,AL and thank you very much for your input......this is a very "busy" forum......does anyone out there have any "concrete" evidence on this one???....either way, i'm sure we'd all like to know......in my 25+ yrs. of flying, i've alway's heard that they did develop a memory......if i'm wrong and they don't, oh well so be it......sure like to know one way or the other.....BTW, this thread is turning into a dooozie, hope we can get a lot of questions answered and a lot of theories put to rest......let's just say, in my 25+ yrs. of flying, i only know what i've been taught......i'm no physicist or rocket scientist and have no way of testing what i've learned, so i just go with whatevers continued to work so far and alway's "error" on the side of caution......sorry for the long response.....hope we get some really good answers here, real soon.......again, thanx for you help,AL......(KOOLKRABBER47).........

koolkrabber47

Good morning, my good neighbor to the north, in Gig Harbor,Wa......i'm am right below you in Ilwaco,Wa., near Longbeach,Wa. & Astoria,Oregon......thank god were finally getting some good flying weather over here on our side of the planet......in my area it's supposed to be 60-65 degrees with 5 MPH winds today,tomorrow and sunday......geez, i sure hope i have enough fuel for all three day's, cause i'm gonna fly the piss out of my 15+ planes and make up for the last six months of precipitation......also, thanx for your contribution to this thread.......sure does help to clear up some information regarding Nicd and Nimh batteries......sure hope all the newbies are watching this one, cause we can all learn a lot from a good, clean, non-confrontational thread like this one......again, thanx for your input......sorry for the long response.....(KOOLKRABBER47).......

kyleservicetech

Add to this the Sanyo Eneloop cells. They have a very LONG shelf life. I bought 8 of them through the Internet for my camera. Before using them I ran a discharge test. They had near 90% milliampere hour charge, as received, before I charged them.

rms59

Thanks for all the replies. At the beginning of each flying season I will charge them, fly for a while, then check the voltage on each cell. Also, at least twice a season I will run them through a charge/discharge/charge cycle and so far haven't had a problem.

I prefer the Nicads over Nimhs for my transmitter just because of the decay rate since I sometimes make sudden decisions to go out flying.

Thanks again,

Dick

rcers

Here is what I am using in old 8 cell TX's these days. The LiFePO4 packs. 3s voltage is 9.9v nominal volts. They have about zero self discharge and hold voltage wonderfully. Cycle life is supposed to be 1K+ and they do not have the thermal runaway of LiPoly. Nice...

http://media.hyperion.hk/dn/fg3radio/

Mike

Rodneh

Those that say NiCad do not suffer from memory problems are correct. What those who say they do are confused by the voltage depression effect. Now this also effects NiMh as well as NiCad, just not as extreme. As one who has had to deal with the reliability of batteries and other electronic devices for some 40 years, I participated in tests covering several months of data proving that NiCad's do NOT the so called "memory effect". If you check into some of the manufacturer's more elaborate tests, you will find they found the same results; i.e. no memory effects and that most reports that started this erroneous fact based there finding on miss interpreting the voltage depression which does occur in both NiCad and NiMh.

kyleservicetech

Agreed:
People are calling that voltage depression a memory effect. If you have a properly designed electronic control, that voltage depression will not affect your device, and you'll never know you had the voltage depression issue.

If you run discharge tests on your airborne radio system Nicad or Nickel Hydride cells at least once a year, you even reduce or eliminate that voltage depression effect. (And, you should be testing those batteries at least once a year!)

koolkrabber47

now that's what i'm talking about.....rock solid, concrete information that we can all benefit from, you gotta love these forums........Thanx for the link, RC.......are there any of these LiFePO4 paks we can use for the RX, if so, please share, i'm sure everybody would like to know.......anybody else out there, feel free to jump in.......(KOOLKRABBER47).......

rcers

The 2s version can "likely" be used with no regulator. If you servos are OK with 6.6v you are good to go. I don't know if any receivers that will have an issue with that.

A fully charged 5 cell Nicad pack is about 7v but it drops to around 6.2v or so under load. So they are about .4v higher than a 5 cell flight pack.

koolkrabber47

again, thanx for the info and the fast response......i'm spending a good part of today, getting my batteries ready to fly "all day", both day's this weekend......it's supposed to be 60-65 degrees with 5 MPH winds for the next 7-9 day's.......i've been waiting 6 months for this weather......the less time i spend cycling batteries all day, i could be burning a whole in the sky instead......some of these modern batteries would be nice and only have to charge every so often.......about how many flights are you getting out of your RX LiFePO4 packs.......My RX packs are my main concern, the TX has indicator lights to let me know when to recharge, the rx's i check everytime i bring her down, just to be safe.......again, thanx for your help......i've been flying for over 25 yrs. but, we can alway's still learn something.......(KOOLKRABBER47)........

rcers

Number of flights depends on capacity of the pack. I use an 1100 pack and fly 4 flight before recharge (very safe).

Larry3215

I had to go do some searching on my own because I was SURE you were WROOOOONG!!!

But, turns out you are quite correct.

Its always a bitter sweat thing when one of your cherished, long held beliefs is shot full of holes.

The sweat part is you end up learning something new.

Thanks for that correction