Nicads
 

How long is it OK to leave a nicad pack on trickle after it is fully charged? I have a 1000mah flight pack installed in an airplane that I do not intend to fly for at least 6 months.

RE: Nicads
 

I left a 600 mAh NiCd on a 50 mA charger for three or four weeks one time by accident. It did not seem to hurt it. But if you're not going to fly, I would not leave it on any charger. Just let it sit and cycle it before the next season.

RE: Nicads
 

i would discharge it most of the way and let it sit, then when you need it charge her back up

RE: Nicads
 

You can trickle charge for ever. Do not store nicds or nimh discharged, they will die.

If you just store them, store them charged and once a month cycle them.

RE: Nicads
 

If you are using the charger supplied with your radio system it is not a "trickle charger". No radio comes with a trickle charger- what you have is an overnight charger. You can buy an after-market trickle charger if you wish.

RE: Nicads
 

Per NASA, the best way to store NiCad's is to slowly discharge them to zero, place a shorting bar across each individual cell and store at a low temperature near 30 degrees F. When ready to use, let warm up to room temperature and then charge for 16 hours at 0.1C. I've not seen the recommendations for NiMh but since both are nickle based chemistry, a similar procedure will probably be in effect. You will not ruin a NiCad by discharging to zero as long as the discharge rate is not so high as to unduly raise the internal temperature of the cell. You can cause damage to any Nixx cell though by excessive overcharge. Check out Red's Battery Clinic for some good advice on how to care for your inactive Nixx cells, he recommends a 1 hour slow charge each 24 hours after having first done the overnight charge at 0.1C. A continuous slow charge can cause a slow degradation, primarily due to causing the crystals to form in larger than normal sizes which increases internal resistance and causes some loss in capacity. Http://www.hangtimes.com/redsbatteryclinic.html has a wealth of good and accurate info if you take the time to read it all.

RE: Nicads
 

Right you are. For the last 30 years I have been giving my batteries an overnight charge (slow charge, C/10) for 15 hours or fast charge, C/5 for 7 hours, when I return from the field. Then I switch to a trickle charge, C/50, which I leave them on until the next time I go flying. Every few months I will cycle them to check capacity. My batteries last for years. Also I use SR batteries.

Bruce

RE: Nicads
 

are you going to be away from the plane for that long??? If you are going to be around it, I would take it off chage and let it sit for a couple of months. Put it back on charge over nite and take it off for a couple more months. Repete this for the 6 months.

I don't run/dischage my plane battery down to "zero" volts ever. I go to 1.1 volts per cell, " thats 4.4volts for a 4 cell pack.".

Really, if they are charged up. they are able to sit in a warm area and be alright for the six months. It would be hard on the cells to leave them on any charge for six months.

sticks

RE: Nicads
 

Sparky,
Are you thoroughly confused now? I know I am. I think Rodney gave you the best advise when he gave you the link to red's battery clinic. Follow it and it will be well worth your time to read it.

wcb

RE: Nicads
 

Mine are always on trickle, some of them are over 4 years old and other then when I go flying I just leave them on the charger?? Someone calls me tonight to go fly tomorrow I'm all set to go.

RE: Nicads
 

A quote from "Red's" website: "A battery left on trickle charge will seldom short out since it is in the charged condition and any short that tries to develope will be zapped by the charge in the cell."

RE: Nicads
 

Even on trickle you will be putting in more charge than the batterys they need, and they must give off the extra energy some how.

I have to agree with this, its hard to decide what to do. One thing I though of was, using a timer. Put the timer to turn on for 4 or 6 hours a day,with them on trickle and they should be good forever.

RE: Nicads
 

Nicd and Nimh self discharge. Trikle charging is designed to replace this amount. The rate is c/50. It's not enough to damage any battery pack and it's not enough to charge a battery. It only maintains the charged state once the battery is charged. Most batteries in commercial use have trickle chargers keeping them in the charge state., so if called on for use thay are not dead.

Charge them and if you intend to store them, trickle charge. If you are using the batteries, say evey weekend or every other weekend, you do not need to trickle charge.

RE: Nicads
 

I just got out a plane that was stored for about 4 to 5 months . The 2500 NiMh only took 175ma to take it to full charge after all that time.

I flew it three flights and it took 350ma to bring it back up. I have heard that MiMh's don't like long term trickle.

back to the nicad's, still don't think it will hurt to let them sit. I used to do it every winter, and never had a problem with the 600 ma's we had back then.

sticks

RE: Nicads
 

Stick 40, NiMh batteries do not mind a trickle charge as long as it is a true trickle, i.e. C/50 rate or 20 ma's for a 1000 mah NiMh battery. The problem with NiMh is if they start to get warm from too fast a charge, then they can be damaged.

Bruce

RE: Nicads
 

some one posted that they left a MiHh on trickle for a couple of months and it killed the pack. It could be that the trickle was too high, don't know. But that was the what the thread said, don't leave MiMh on trickle for too long.

just passing it along, and you may be right about the amount of charge rate.

sticks

RE: Nicads
 

Stick 40, many people have the misconception that charging with a wall wart charger is "trickle" charging. Wall warts are designed to charge at a C/10 rate which is called a "slow" or over night charge. I have a 900 mah NiMh battery which has been on trickle charge for 2 years. I charge it at a slow rate for 15 hours after flying and then leave it on trickle until the next flying session.

Bruce

RE: Nicads
 

Trickle charge, be definition, is that amount of current that just compensates for any leakage current occurring when a battery is not being used. This is a very indeterminate value as it varies with age of the battery and the temperature, an increase in either usually increasing that value. It can vary from just a few microamperes to several milliamperes in the batteries usually use with RC equipment. By definition, slow charge is usually specified as a charge rate equal to 0.1C but is not really specified anywhere as a standard, it is whatever the manufacturer wants to call it. I've seen it defined as anywhere from 0.1C to 0.5C. To prevent miss understanding, any time you are referring to questions regarding current, it is best to specify the current in actual values or in terms as a percentage of C. The terms "trickle" and/or "slow" are essentially non definative.

RE: Nicads
 

Rodney, I agree that the intent of trickle charge is to replace that capacity that would be lost through self discharge. I also agree that no standards body has defined the terms trickle, slow, and fast charge. But certain conventions have been establish in the RC industry over the last 37 years that I have been flying RC. They are

Trickle charge:C/50 or .02C

Slow charge: C/10 or .1C

Fast charge: C/5 or .2C

For example, the Ace R/C Automatic Add-A-Trickle for wall wart chargers defines trickle charge as 1/5th the charger's normal rate which is assumed to be a slow rate. The Kraft wall wart charger (circa 1976) has a switch to select between slow (50ma) and fast (100ma) charging and is designed for the 500mah NiCd batteries in common use at the time. Today there is a wide spread in the battery pack capacity from 250 mah to as high a 3200 mah flight packs. Therefore the Hobbico Accu-Cycle charger allows you to select a charge current of 25, 50, or 125 ma. This seems close enough to handle packs up to 1500 mah capacity with the trickle charge rates of 5, 10, or 25 ma. On the other hand, the Accu-Cycle Elite allows you to enter both the desired normal charge rate and trickle charge rate you want. This works best.

As I have said before, I have been in the habit of puting my batteries on slow (over night) charge for 15 hours after returning from flying and then switching to trickle charge until I next go flying. Right now I have 11 planes on trickle charge with flight pack capacity of 700, 900(NiMh pack), 1000, 1200, 1300, 1500 mah. Some of those packs are over 6 years old and all hold at least 90% of their original capacity.

Bruce

RE: Nicads
 

you are not charging for a long period of time. The only way tell, whats going on is checking the voltage level of the batterys..Batterys peek out at the high point of charge, thats the peek. after the peek voltage, anymore charge is extra and given off as heat.

granted. a small amount is not big problem.

sticks

RE: Nicads
 

Stick 40, I do not understand your statement that I am not charging long enough. I charge a slow rate, C/10, for 15 hours after flying. That puts back in 150% of the batteries rated capacity and is the universally recommended amount for NiCd's and NiMh's. I then trickle charge, C/50, until after flying the next time. I do cycle my batteries about every 3 months and when I do they all have 100% of their capacity.

Bruce

RE: Nicads
 

I think you guys lost Sparky.