Hand held charging with a timer

[W4KRR]

Anyone have any first hand experience with hand held battery charging using timers to stop the charge after a set period?

Will leaving the factory supplied wall wart charger connected to a hand held scanner cause any detrimental effect if no power is applied to the wall wart? Will this cause the batteries to discharge back into the wall wart?

I was thinking about the possibility of using a timer to cut the power to the wall wart charger after like 24 hours so the batteries would not overcharge. But years ago I remember reading that leaving a wall wart charger with no power applied plugged into a scanner would kill the batteries quickly.

 

[scanbc780]

My assumption is that the diode in the charge jack that protects the scanner from the wrong polarity adapter would keep the power from going out the jack.

 

[K5MAR]

Anyone have any first hand experience with hand held battery charging using timers to stop the charge after a set period?

Will leaving the factory supplied wall wart charger connected to a hand held scanner cause any detrimental effect if no power is applied to the wall wart? Will this cause the batteries to discharge back into the wall wart?

I was thinking about the possibility of using a timer to cut the power to the wall wart charger after like 24 hours so the batteries would not overcharge. But years ago I remember reading that leaving a wall wart charger with no power applied plugged into a scanner would kill the batteries quickly.

Do it all the time. I have one of those timers that uses the little plugin dongles to turn the timer on and off, so I use just the off dongle. Set the timer at 12, and put the dongle in for however many hours of charge is recommended. But I do unplug the scanner as soon as possible after the timer has shut off. I've been doing this for 4-5 years at least without any detectable problems. Sure beats risking overchargeing the batteries and ruining them.

Mark S.

 

[brwkem]

Battery recs

What charger and battery models do you reccomend?

thx

 

[JnglMassiv]

Hmm..I'll often leave mine (BC245xlt) plugged in for a week at a time with no ill effects. I've always assumed that the charging circuit cuts off at around 5 volts or so, preventing any overcharging and keeping the batteries peaked.

And since I installed higher power NiHM cells (2300mAh), it would need longer than 24 hours in even the best of circumstances.

Assuming 100% charging efficiency and nominal specs, the radio, providing 80mA of charge current, will charge in:
2300mAh / 80mA = 28.75hours!

And this incorrectly assumes 100% of that 80mA goes to charging the cells.

 

[K5MAR]

I don't have any battery packs that large, so using the timer isn't a problem. The BC245 manual says to disconnect the ac adapter when charging is complete. It doesn't say anything about a maint. charge. You may be right, then again you may just be lucky! :lol:

Mark S.