electrical engineer help? recharging batteries from different cordless drivers
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From: west, mich, usa
electrical engineer help? recharging batteries from different cordless drivers
my hf cordless impact wrench has a bad charger. it is a 19.8V system.
i also have a sears cordless drill set that is 16.8V. the two have the same battery configuration as far the charger is concerned. the sears charger puts out 24V.
i am thinking if the 24V charger can charge a 16.8V system, it can charge a 19.8V battery but it will take longer and the electronics that show the "green light" charge complete may not be as accurate.
anyone using different chargers from different systems?
i would not be trying this the other way and trying to use a 19.8V system to charge the 16.8V systems but wanted to ask some EE types.
tia, tom
i also have a sears cordless drill set that is 16.8V. the two have the same battery configuration as far the charger is concerned. the sears charger puts out 24V.
i am thinking if the 24V charger can charge a 16.8V system, it can charge a 19.8V battery but it will take longer and the electronics that show the "green light" charge complete may not be as accurate.
anyone using different chargers from different systems?
i would not be trying this the other way and trying to use a 19.8V system to charge the 16.8V systems but wanted to ask some EE types.
tia, tom
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From: Chicagoland, IL
Re: electrical engineer help? recharging batteries from different cordless drivers (tom91ita)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tom91ita »</TD></TR><TR><TD CLASS="quote">my hf cordless impact wrench has a bad charger. it is a 19.8V system.
i also have a sears cordless drill set that is 16.8V. the two have the same battery configuration as far the charger is concerned. the sears charger puts out 24V.
i am thinking if the 24V charger can charge a 16.8V system, it can charge a 19.8V battery but it will take longer and the electronics that show the "green light" charge complete may not be as accurate.
anyone using different chargers from different systems?
i would not be trying this the other way and trying to use a 19.8V system to charge the 16.8V systems but wanted to ask some EE types.
tia, tom</TD></TR></TABLE>
It is going to be very dependent on the circuitry of that charger.
That being said-- I've charged cell phone (li-ion) batteries using a plain-jane power supply before. Just keep the Amp-hours or milliamp-hours in mind when doing it that way
If I was designing said charger for a 16.8 volt system... it'd protect batteries from getting too much voltage, especially when it was full. A partly charged 19.8V battery might look like a fully charged battery.
If I was *you*, I'd toss the batteries on the charger and keep an eye on the voltage every 30 minutes or hour. Greater than 20V means it's charging. Assume about 5 ohms for a battery, as an example, and if you have 21.8 volts, it'll be ~0.4 amps of charging. It'll take a few hours to get charged and it'll charge slower as it gets full.. but you might charge it completely.
v=ir, and you measure amp-hours in, well, current times time. Good luck on the rest!
I can't imagine a possible way you'd break the charger, but let us know how it goes.
i also have a sears cordless drill set that is 16.8V. the two have the same battery configuration as far the charger is concerned. the sears charger puts out 24V.
i am thinking if the 24V charger can charge a 16.8V system, it can charge a 19.8V battery but it will take longer and the electronics that show the "green light" charge complete may not be as accurate.
anyone using different chargers from different systems?
i would not be trying this the other way and trying to use a 19.8V system to charge the 16.8V systems but wanted to ask some EE types.
tia, tom</TD></TR></TABLE>
It is going to be very dependent on the circuitry of that charger.
That being said-- I've charged cell phone (li-ion) batteries using a plain-jane power supply before. Just keep the Amp-hours or milliamp-hours in mind when doing it that way
If I was designing said charger for a 16.8 volt system... it'd protect batteries from getting too much voltage, especially when it was full. A partly charged 19.8V battery might look like a fully charged battery.
If I was *you*, I'd toss the batteries on the charger and keep an eye on the voltage every 30 minutes or hour. Greater than 20V means it's charging.
Assume about 5 ohms for a battery, as an example, and if you have 21.8 volts, it'll be ~0.4 amps of charging. It'll take a few hours to get charged and it'll charge slower as it gets full.. but you might charge it completely.v=ir, and you measure amp-hours in, well, current times time. Good luck on the rest!
I can't imagine a possible way you'd break the charger, but let us know how it goes.
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