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Model Forum / Radio Controlled / Air Models / June 2004over charge....ruined?
I left my rx & tx plugged in for 6 days on wall wart...what are the chances that I ruined them? Very unlikely I left my rx & tx plugged in for 6 days on wall wart...what are the chances that I ruined them? Pretty much zip. Gord Schindler MAAC 6694 I left my rx & tx plugged in for 6 days on wall wart...what are the chances that I ruined them? There are many cordless appliances and device that are on continious charge, dust busters, flashlights, electric tooth brushes, emergency lights to name a few. 6 days on C/10 put out by your wall wart would have an insignificant impact on your batteries. But there is a way you won't have to worry about it. Get an appliance timer and set it to charge only 1 hour a day after it goes through the first 23 hours. Here are the details from the Battery Clinic article. Using a Timer Can Improve Battery Life One of the failure modes in Ni-Cd cells is shorting. While many things can contribute to shorting one of the significant contributors is cadmium migration through the separator where it forms a conductive bridge, ultimately shorting the cell Cadmium migration is a function of the time the charge current is flowing through the battery and less a function of the level of current. Therefore we have found that high pulses of charge current to maintain the charge state are better than a steady low rate (trickle) current. This is very difficult to quantify as their are many other factors contributing to the life equation but improvements in battery life of 10 to 20 percent by pulse charging vs trickle are not unrealistic. Therefore we have found the sustaining a pack at the fully charged state by way of pulsing the charge is better than an continuous trickle charge. Some charges employ this technique. You can do the essentially the same thing rather simply and at a very low cost. Simply connect your regular wall module charger that came with your system to an appliance timer. Intermatic makes a good unit for around $5.00. Set the trigger pins on the timer so that it is on for 1 hour a day. When you return from a flying session turn the timer wheel so that the on off triggers come up in 14 to 16 hours. Then turn the timer knob to on. This will give your pack a full charge and then a sustaining charge for 1 hour a day. The battery can be left in this manner for a long time between flights and still be maintained at a fully charged state with minimal overcharge. If you only fly a couple of flights, you can just set the timer so that you get 6 or 8 hrs before you go into the 1 hr.day mode. If we assume a normal 2 hr flight time for a system and you only fly 20 minutes. Then the charge you need to return is 20/120 times 16 hours, or about 3 hours. -- Red S. Red's R/C Battery Clinic http://www.rcbatteryclinic.com Check us out for "revolting" information. I left my rx & tx plugged in for 6 days on wall wart...what are the chances that I ruined them? >There are many cordless appliances and device that are on continious charge, >dust busters, flashlights, electric tooth brushes, emergency lights to name [quoted text clipped - 45 lines] >I left my rx & tx plugged in for 6 days on wall wart...what are the chances >that I ruined them? This is a great idea by Red. I have been using this system for some time now & it works great!!! My equipment is always ready. I highly recommend that you take his advice. -- Ray I can't seem to find you listed in our royalty account. Please submit 2 cents for each year used. :-) Come to think of it my kick-back from Intermatic is also delinquent. -- Red S. Red's R/C Battery Clinic http://www.rcbatteryclinic.com Check us out for "revolting" information. "CRAngelo" <crangelo@aol.com> wrote in message > This is a great idea by Red. I have been using this system for some time now & > it works great!!! My equipment is always ready. I highly recommend that you > take his advice. -- Ray Never too late to learn somethin' new, like Red's excellent discourse on using a timer to establish an on-off 'duty cycle'. I have had my Tx NiCd pack on its wall-wart charger 24/7 for a little over four years, and the pack is still fine. It still supports a 2 hour flying session with no more perceptible sag than when it was new. This wall wart is specific to the xmittr, and it puts out rectified _but unfiltered_ DC. The result is a 50% duty cycle that is 'off' for 1/60 of a second and 'on' for 1/60 of a second. So based on Red's sage advice, i'm wonderin' if this might be related to my pack's long life and present good health. Bill(oc) Your good luck and long battery life is probably because you never let the pack run completely down. By now the separator system is mush. Unplug the battery and let it set for a few days and you will find one or more cells shorted. Its the old story we use to hear. "I don't understand it, my dustbuster/drill/shaver was working fine before we moved, but they all quit when we tried to use them in the new place." -- Red S. Red's R/C Battery Clinic http://www.rcbatteryclinic.com Check us out for "revolting" information. > Never too late to learn somethin' new, like Red's excellent discourse on > using a timer to establish an on-off 'duty cycle'. [quoted text clipped - 8 lines] > long life and present good health. > Bill(oc) | There are many cordless appliances and device that are on continious charge, | dust busters, flashlights, electric tooth brushes, emergency lights to name | a few. Of course, to play devil's advocate, charging something at C/10, day in and day out, DOES wear out the NiCd batteries, and DOES cause voltage depression (often incorrectly referred to as `memory'.) And you'll find that the batteries in these things generally don't last very long because of it. If anything benefits from a good cycling, it's those rechargable appliances that are kept charging 24/7 for months at a time. I've brought back lots of cordless phone batteries from the dead by simply setting them to cycle a few times. It works on the other devices as well, but they don't always give direct access to the batteries to discharge them, making it more work. (Of course, a good quality rechargable appliance could conceivably stop charging when the battery is full, but the low end NiCd/NiMH stuff certainly doesn't. (For Li-ion, Li-poly, lead-acid and gel-cell batteries, it's more important to stop charging when full, as bad things happen much sooner, but fortunately the electronics needed to stop charging when full for these is a lot simpler.) But just one week of C/10 charging of a NiCd won't hurt it by any signifigant degree. | 6 days on C/10 put out by your wall wart would have an insignificant | impact on your batteries. But there is a way you won't have to worry | about it. Get an appliance timer and set it to charge only 1 hour a | day after it goes through the first 23 hours. Now that's a good plan. The same trick works for things like dust busters, flashlights and electric tooth brushes too. Alas, cordless phones don't usually work when unplugged, so it's not so easy to do. (You can leave the phone out of the cradle, but then it's typically discharging so you need to remember to put it back every once in a while, and after any long usage.)  SignatureDoug McLaren, dougmc@frenzy.com Lisa! In this house we obey the Laws of Thermodynamics! --Homer Simpson > There are many cordless appliances and device that are on continious charge, > dust busters, flashlights, electric tooth brushes, emergency lights to name [quoted text clipped - 9 lines] > migration through the separator where it forms a conductive bridge, > ultimately shorting the cell Good idea. All Electronics now has them on sale for 4 bucks. www.allelectronics.com/cgi-bin/category.cgi?category=779&type=store >>There are many cordless appliances and device that are on continious charge, >>dust busters, flashlights, electric tooth brushes, emergency lights to name [quoted text clipped - 13 lines] > > www.allelectronics.com/cgi-bin/category.cgi?category=779&type=store Still cheaper to go to your local hardware store. After you have paid S&H of $6.00, you have paid $10.00 for a $5.00 item locally. SignatureHugs are great gifts, One size fits all. > I left my rx & tx plugged in for 6 days on wall wart...what are the > chances that I ruined them? Significant http://www.batteryuniversity.com/partone-11.htm Convert your wall wart into a 1 hour per day timer-charger http://www.oldhouseweb.com/cgi-bin/davesamazon/products_feed.cgi?input_mode=kitc hen&input_string=Switches++ | > I left my rx & tx plugged in for 6 days on wall wart...what are the | > chances that I ruined them? | | Significant | http://www.batteryuniversity.com/partone-11.htm Signifigant changes that the batteries were ruined? The site you quoted says nothing of the sort. The only things that even come close to supporting that argument are : nickel-based batteries prefer fast-charge. Lingering slow charges cause crystalline formation (memory). ... nothing that discharging the battery and charging again won't fix. If not used immediately, remove the battery from the charger and apply a topping-charge before use. Do not leave nickel-based battery in the charger for more than a few days, even if on trickle charge. Reasonable advice, but it says nothing about ruining the cells. If he leaves his batteries on the Wal-Wart for a year, they're probably ruined. It's not good for the batteries, granted, but doing it just once will not ruin them. SignatureDoug McLaren, dougmc@frenzy.com You've done it now! YOU'VE GONE TOO FAR! |
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