How to charge a battery when you don't have the right charger?

[dennis thompson]

I have a Panasonic cordless drill but no charger. It has a 14.4 li-ion battery. I have a charger from one of my cordless drills that is 12v li-ion. Is there any reason I couldn't simply run two leads from the positive and negative terminals of the 12v charger to the positive and negative terminals on the 14.4v battery to charge it? Both sets of terminals are easy to get at without taking anything apart.
Thanks

[Pat Barry]

Will the drill run on 12V?

late edit - 12V not 1V

[Brian Henderson]

You buy the right charger?

[Allan Speers]

You might as well try it, if it's an "emergency" situation, since there's no way you'd damage anything.

However, the 12v charger might not stop the cycling at the right time, so make sure to not overcharge the battery.

[Myk Rian]

Buy the correct charger. 12v isn't going to charge a 14v battery.

[David C. Roseman]

Buy the correct charger. 12v isn't going to charge a 14v battery.

Agree with Myk. The voltage rating of your 12v charger expresses the nominal electric potential, or electric pressure, the charger is capable of producing in a battery. So your charger could at most charge the 14.4v battery to a nominal 12v. Your Panasonic drill won't run well on that potential.

[John Lanciani]

Agree with Myk. The voltage rating of your 12v charger expresses the nominal electric potential, or electric pressure, the charger is capable of producing in a battery. So your charger could at most charge the 14.4v battery to a nominal 12v. Your Panasonic drill won't run well on that potential.

Not entirely true, it depends on the charger. I have a few DeWalt chargers that are rated to charge batteries from 7.2 to 18 volts.

[Wade Lippman]

I wouldn't screw with a lithium battery. They explode when you charge them wrong.

[John Kananis]

I wouldn't screw with a lithium battery. They explode when you charge them wrong.


Pretty much, even if you're using a proper laboratory power supply, you have to ensure that you are also monitoring with a couple of meters or the supply has a built-in battery charge operation (Agilent, Tektronix, Rigol, there are others too).

[David C. Roseman]

Not entirely true, it depends on the charger. I have a few DeWalt chargers that are rated to charge batteries from 7.2 to 18 volts.

Your multivoltage charger has onboard diagnostics to sense when the load battery approaches full charge, whatever its rated voltage, within the 7.2 to 18v range. I don't know if DeWalt does this by monitoring delta voltage (change in voltage) or cell temperature, or some other parameters to gauge when the battery is likely to be full. Very cool, indeed, but I don't see how even your sophisticated charger could charge above its max 18v rating, e.g., a 24 or 36 volt battery. Once the voltage of the load battery approaches the max output voltage, potential equalizes as between the charger and the battery. That was my only point about the OP proposing to use a 12v charger to charge a 14.4v battery.

[dennis thompson]

Well it turns out there is a universal battery charger called a Tenergy universal smart charger . It will charge li ion batteries from 3.7v to 14.8v with 1 to 4 cells ,(my 14.4v Panasonic has 4 cells.) It only cost $22, so I ordered it. I'm still not completely confident it will work, but for that price I thought I'd try it and if it doesn't work I'll just send it back to Amazon.:)

[dennis thompson]

I got the Tenergy universal charger from Amazon ($21) and hooked it up to my Panasonic li-ion battery and it worked.:) You can set it to charge anywhere from 3.7v to 14,8v. Very simple to operate.