Lnewqban

One question about radio batteries:

My Rx and Tx batteries are 4.8v and 9.6v Sanyo NiCd.
They have worked very well for three years, for each weekend of sport flying.

They have been charged with a Futaba wall charger right after a flying day for 15 hours.
However, they have not been cycled.

They have powered one of my models for five to six flights each weekend.
However, they don't last beyond four flights lately.

What is the lifespan of regular NiCd Rx and Tx packs?

Thanks

(Edited for clarity)

Highflight

My Feedback: (4)

Lifespan offer depends more on use and care more than brand or age.

In the 30 years I've been in the hobby, all my Nicad packs that I always build myself last at least 5+ years.
But I always charge at C10, and I cycle them every three or four charges so that I can not only know what their cycle times are, but so that I can keep track of those cycle times over time.
When my packs get down to 85% (my arbitrary number) of their new capacity, I toss them and build a new replacement.

Three years isn't a very good lifetime, in general, for a Nicad pack unless you fast charge them all the time and/or leave them unused for months at a time. Or, if you are saying that you use them as many times as you say each and every day of the week, then maybe you did get a good run out of them. But that's a lot of use for hobby batteries.

Mickstix

That's a good question! I have some transmitter packs (9.6v) that are still good after a decade in storage.. But I dont know how many actual charge/discharge cycles they've been through.. Probably not many, as far as RC batteries go.. A sigle charge of the transmitter will last me at least 4 "race" days before needing recharged.. But Rx batts get worked alot more than the Tx batts, since they power servo's and any other add on bits ya might have..

Lnewqban

Highflight-RCU,

I have edited my original post, since it was confusing.
No, I have never fast charged my packs, but I have not cycled them either.
Besides, the usage has been weekends only, five to six flights of ten to twelve minutes, feeding four standard servos plus Rx and Tx.

Mickstix,

You are correct, when the Rx battery is too low to fly, the Tx seems to be just 95%.

Thank you both.

Rodney

Under ideal care and use, NiCad will provide 1000 charge/recharge cycles, NiMh half that or about 500 charge/recharge cycles. Fast charging, high heat at times, reverse charging (letting a pack discharge to deeply will reverse charge the weaker cells) will seriously hurt life time.

Lnewqban

Those are amazing numbers, Rodney.

Those are much more cycles that what my cells have seen in these three years.

At one cycle per week, 3 years x 52 weeks = 156 cycles

Even, making them 200 cycles for additional weekdays flights, that's only 20% of the potential time you stated.

Here is how I have deviated from "ideal care and use", and probably caused some damage and/or memory development:

A) For some weekends, I have not been able to complete so many flights as to reach the minimum voltage, and, without further discharge, I have followed with 15 additional hours of charging at the end of the week, just to get ready for the following Sunday.

B) In the believe that regular use has been equivalent to cycling, I have never cycled my packs on purpose.

C) Maybe more than once the pack has discharged too deeply, due to accidental switch movement to on during transportation back home.

Now, two additional questions:

1) Is it possible that cycling them every three or four charges, as explained by Highflight-RCU above, reactivate the lost capacity?

2) Is there any practical advantage by switching to NiMh for a new Rx package, eliminating the memory issue? I have learned that the voltage of NiMh is lower than NiCd's. Any need to jump to 5 cells due to that fact?

Again, I appreciate your advices.