When these batteries completely discharge beyond their set point the factory chargers usually will not charge them anymore, i.e., the light flashes or ?? depending on the charger. The solution is to simply charge then with a power supply set just above the rated voltage for awhile and then put them in the factory charger for completing the charge. This is a simple way to restore batteries that appear dead.
Sounds good, I guess, but I'd make sure of the circuit breaker and charge them on a surface that can't burn!
quixdraw wrote:
Sounds good, I guess, but I'd make sure of the circuit breaker and charge them on a surface that can't burn!
Is there a reason that they make smart chargers that won't charge a bad battery?
Check internet sources for the several steps, and safety notes, on how to recharge such batteries.
TriX
Loc: Raleigh, NC
quixdraw wrote:
Sounds good, I guess, but I'd make sure of the circuit breaker and charge them on a surface that can't burn!
Absolutely! You need to charge them at their rated voltage or a little above with careful monitoring of the current (a supply with adjustable current limiting is a good choice). As Quixdraw said, place it in something like a Pyrex dish and monitor the current very carefully as it can increase rapidly at some point. When that happens, place it on the regular charger which typically has a method of monitoring and current limiting to finish the charge. And if the case starts to swell from outgassing, stop immediately.
Part of the problem with "chargers" that come with most cameras (in this case) is that they really aren't chargers but, maintainers. If the voltage in the battery drops below a certain point, they're useless. The battery may still be good IF you can find a charger that is strong enough to kick it back up. Example - if a 12 volt battery drops below about 10.5 volts, a trickle charger/maintainer that puts out less than 3 amps won't recover it. I work at Batteries Plus. It's not uncommon to have a car battery come in at say 6-7 volts that when we put it on a 20 amp charger for 3-4 hours, we can switch it to a 2 amp charge overnight & save the battery. Charging any lithium battery above it's rated charging voltage is inviting problems.
procrastinater wrote:
When these batteries completely discharge beyond their set point the factory chargers usually will not charge them anymore, i.e., the light flashes or ?? depending on the charger. The solution is to simply charge then with a power supply set just above the rated voltage for awhile and then put them in the factory charger for completing the charge. This is a simple way to restore batteries that appear dead.
What does "just above rated voltage" means? 10-20-30-40 percent? Do you have a variable output power supply? Does not sound like a 'simple' way to restore batteries to the average user.
Julian wrote:
What does "just above rated voltage" means? 10-20-30-40 percent? Do you have a variable output power supply? Does not sound like a 'simple' way to restore batteries to the average user.
Since most users are not battery design engineers, the safest thing would be to simply replace it.
Checking and topping off each month as required would be more prudent.
After paying over a thousand or two for a camera I am not going to fiddle around with a semi defective battery. I know I could possibly save a few bucks but would rather know what is in the camera. Just me!
procrastinater wrote:
When these batteries completely discharge beyond their set point the factory chargers usually will not charge them anymore, i.e., the light flashes or ?? depending on the charger. The solution is to simply charge then with a power supply set just above the rated voltage for awhile and then put them in the factory charger for completing the charge. This is a simple way to restore batteries that appear dead.
Lithium-ion batteries should not be allowed to be discharged below their critical low voltage. They can become permanently damaged. That is why many good batteries have internal circuits to prevent this. Also, most devices using these batteries have undervolt protection. When you charge li-ion batteries to boot then back to life you are playing with fire-literally. The cost of the battery is seldom worth the risk of fire. This is why a good charger will refuse to charge a low volt battery.
TriX and nicksr's comments are on point. When I said just above the rated voltage I mean like just a few tenths of a volt, i.e., if rated voltage is 3.7 then limit charge voltage to 4.0 max and monitor current draw. It should never exceed an amp for more than a few seconds. I always set the current limiter to 0.75 amps once it drops down, and never charge any battery on a surface that can burn.
I just bought some very inexpensive ttl off camera flash transmitters/ receivers. They use double A batteries, as do my three flashes. I have a bunch of rechargeable batteries, and wouldn't mind using them to save some rubles, but there is no way I'm going through all that hassle. It was hassle in the first place that led me to set the flashes aside for many months.
captivecookie wrote:
I just bought some very inexpensive ttl off camera flash transmitters/ receivers. They use double A batteries, as do my three flashes. I have a bunch of rechargeable batteries, and wouldn't mind using them to save some rubles, but there is no way I'm going through all that hassle. It was hassle in the first place that led me to set the flashes aside for many months.
If your rechargeable AAs are not li-ion, no worries. NiMH batteries do not suffer from undervoltage. They can be discharged to zero and still recharge.
procrastinater wrote:
TriX and nicksr's comments are on point. When I said just above the rated voltage I mean like just a few tenths of a volt, i.e., if rated voltage is 3.7 then limit charge voltage to 4.0 max and monitor current draw. It should never exceed an amp for more than a few seconds. I always set the current limiter to 0.75 amps once it drops down, and never charge any battery on a surface that can burn.
Once the battery is below its critical voltage (for a 3.7 volt cell that is about 2.8 volts), it is damaged permanently. Even if you can boot it up to or over 2.8 volts you still have a damaged battery. Nothing you can do will fix it. Why take chances with a damaged li-ion battery????
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