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discharge a battery?

Old 01-28-2007, 12:42 AM
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KI8FR
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Default discharge a battery?

What is a good way to discharge a battery in the plane and the radio.. I do not have a cycler. and I do not know if I need to get one or not.. I had a prob with a battery last year and I do not want to have that again...
Any info would be nice on how I can cycle a battery with out getting a cycler
Paul
Old 01-28-2007, 01:03 AM
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alan0899
 
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Default RE: discharge a battery?

G'day Mate,
In my experience, the reason for cycling batteries is to know what the capacity of the batteries is, so a cycler is a very useful tool, it will tell you what your battery condition is, & also give an indication of faulty cells or packs.
You can just turn on the TX, & let it run down, same for you RX battery, BUT, this does not give you any data as to the condition of your batteries, & you will probably damage them by discharging too far, nicads are flat at 1.1Volts per cell.
So buy a cycler/ charger/discharger, & keep note of the readings for each & every battery pack you own.
Old 02-13-2007, 05:25 AM
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rcdivot
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Default RE: discharge a battery?

I simply turn on my transmitter and receiver and let them run dead. After about 15 minutes I give them a 16-18 hour charge with my "wall wart". If I don't fly for a week, I give them another 4-5 hours right before I go fly.

To test my batteries, I simply turn on my transmitter and receiver and record the time it takes for them to go dead. Normally about 3-4 hours.

IMHO I beleive charging and discharging batteries the fast way only harms the batteries.

You can keep track of all you want, but that won't tell you when a battery is going to go dead on you at the spur of the moment.

I've been doing this since 1973 and I've never had a problem with any of my batteries.

Good Luck
Old 02-13-2007, 06:48 AM
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jetmech05
 
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Default RE: discharge a battery?

the reason you discharge a ni-cad battery is to prevent the battery from developing a memory. in other words you continually discharge it to a certain point and recharge when you need it to go beyond the point you have usually discharged it to, the battery can rapidly discharge to nothing. You only need to do this once a month or so.
I use an expanded scale volt meter to discharge the aircraft battery and turn on the transmitter to discharge its battery.(tx's are usually diode protected so you cant discharge from the charge jack)
If you discharge below 1.1 volt a cell you run a risk of thermal runaway while recharging your batteries.
Sorry rcdivot remember i said you run a risk of thermal runaway not that you'd get thermal runaway.
An expanded scale voltmeter is 14 bucks or so from tower and you need to buy leads also. but unlike digital voltmeters an expanded scale voltmeter will but a load on the batteries and give you a better idea what the batteries are capable of doing.
the best the thing to do is keep your eye on the volt meter on tour tx while flying.... always charge the the night before you fly 15 to 17 hours with the wall wart
Old 02-13-2007, 03:09 PM
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Rodney
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Default RE: discharge a battery?

It is not a good idea to discharge your batteries by turning on the transmitter on leaving it on until the battery is dead. You risk ruining your transmitter if you are running with the antenna collapsed as it will overheat the output stage and, if you run with the transmitter up, you are risking interferring with other spectrum users. Also, if you discharge the batteries to a point where one of the cells goes to zero volts, it now takes on a reverse charge and will almost certainly be damaged to a degree. Note; contrary to one of the above posts, it does not hurt a nickle based battery to be discharged to zero (in fact some of the factory tests do this on purpose) but; it can severely hurt it to get a reverse charge. Also, the memory factor is for all practical purposes a myth, especially with modern day batteries. Check out www.rcbatteryclinic.com and/or http://members.aol.com/davthacker/balancecharging.htm for good reliable info on the use and care of your batteries. You will get more missinformation (most not intentional) on batteries in the forums than on any other subject.

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