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Refresh an Li - ion battery like Sony NP-FM50

Refresh an Li - ion battery like Sony NP-FM50

Postby j8k3sp00n » Sun Apr 03, 2005 5:09 pm

Try refreshing your Li - ion battery before trashing it. What have you got to lose? :no

This describes how to refresh a Sony NP-FM50, 7.2v, 1180maH battery that seems to be used in many digital cameras, camcorders, and cell phones. Higher capacities, e.g. 1500maH, 1800maH, simply take longer to discharge. If the voltage happens to be different, just match the bulb referenced below to the voltage.

Li -Ion batteries work on passivation(a chemical layer that forms on the anode/cathode to prevent charge flow) of the "plates" that enable it to maintain its charge. If you haven't used the battery for awhile, completely discharge it using a 10ohm, 10watt resistor, and a 7v bulb in series. Recharge a couple of times, and it will probably start working normally again. Dont waste your money and resources by trashing a battery with life in it.

You should be able to get the resistor and bulb from stores like Radio Shack and Fry's. I discharged mine using 3 jumpers with alligator clips, a clothes pin, and piece of flashing. Just get the bulb lit up and go away until it goes out; very dim might be better if you're a stickler.

If you research this subject, you will find that complete discharges will ultimately reduce the overall capacity of the battery by a small amount. That is to be expected. Do you care as long as it works? :no
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Postby jmorgan » Mon Apr 11, 2005 8:55 pm

Lithium Ion notebook batteries wear down because of two factors: 1) active usage in your notebook battery and 2) natural aging of the notebook battery. Both will wear down your notebook battery over time; the trick is to minimize their impact while still getting the performance out of your laptop battery that you need.



The most important thing to understand about laptop batteries is that they are always losing a small bit of their charge. The hotter the temperature, the faster notebook batteries loose their charge. So rule number one is: keep your notebook battery cool. Notebook battery manufacturers store their products at around 60
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Postby phileysmiley » Mon Apr 11, 2005 9:23 pm

Excellent info, jmorgan! ^*^ Thanks for posting. :roleeyes
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Postby j8k3sp00n » Tue Apr 12, 2005 2:18 am

jmorgan wrote:Lithium Ion notebook batteries wear down ..........


Good answer; wrong question. I referred to Li-Ion batteries such as the Sony Battery Pack NP-FM50 used in some digital cameras and cell phones, not ones used in laptops.

I offered a way to continue using an NP-FM50 after the camera rejects it and it won't charge again without being discharged completely. At which point many people trash the battery and start looking for another while cursing Sony roundly.

Laptop batteries have a different charge/discharge characteristic, although I've got an el cheapo 6 year old laptop where the original battery still works, for how long I don't know. Probably has few charge/discharge cycles left; however, I've found that 3 complete discharges to nominal zilch followed by 3 charges keeps it working. I doubt that I've ever owned an Li-Ion battery for a laptop.
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Re: Refresh an Li - ion battery like Sony NP-FM50

Postby blackdiamondgreg » Mon Feb 11, 2013 7:52 am

I have had lots of experience with lithium batteries and have learned a few tricks. Lithium batteries should never never never ever be completely discharged! Whoever posted that assumes that lithium batteries are th same as crummy old ni-cd or good Ni-Mh batteries. Lithium batteries have no problems with "memory" like nicads do. They do have a limit to the amount they can safely be discharged in order to be usable again. This is around 3v in each cell of the battery. If a battery intentionally or accidentally discharges below that voltage the charger will not recognize it, although there is a solution to this problem. I have only tried this trick with lithium batteries although you may be able to use nicads or nimh batteries. I used an 11.1v 2000mah lipo battery to "tap" the terminals and give the battery a sufficient enough charge to be recognized by the charger. Attach the positive leads of the batteries together and then tap the negative terminals together. Do this for only a second if you see no spark. If you do see a spark you should disconnect immediately. Now proceed to charge your battery as you do normally. It should begin charging, if not repeat the tapping process.

Good luck :wave: ^*^
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