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Charging time for Ultrafire 18650 6800 mAh battery

Started by Andy March 10, 2017
I would like to find out how long to charge the above battery.

Charger puts out 500 mAh.

Thanks.
Den lørdag den 11. marts 2017 kl. 00.47.23 UTC+1 skrev Andy:
> I would like to find out how long to charge the above battery. > > Charger puts out 500 mAh. > > Thanks.
ball park guess 6800mAh/500mA = ~14 hours
On 3/10/2017 6:47 PM, Andy wrote:
> I would like to find out how long to charge the above battery. > > Charger puts out 500 mAh. > > Thanks.
Unless this is a D cell or some highly specialized battery chemistry, there are no 6800 mAh AA cells. Any rechargable with "fire" in the name is a lie. They are well documented on the web. -- Rick C
On Friday, March 10, 2017 at 7:11:43 PM UTC-5, rickman wrote:

> > Unless this is a D cell or some highly specialized battery chemistry, > there are no 6800 mAh AA cells. Any rechargable with "fire" in the name > is a lie. They are well documented on the web. > > -- > > Rick C
You missed the 18650 in the subject title, But you are right anyway. There are no 6800 mah 18659 batteries. I think the best 18650 batteries are just over 2000 mah. Dan
On 3/10/2017 3:47 PM, Andy wrote:
> I would like to find out how long to charge the above battery. > > Charger puts out 500 mAh. > > Thanks. >
I'd guess about 3 hours to full charge. Not to be confused with the ADVERTISED 6800 mAh. My 4000 mAh Ultrafire cells perform far WORSE than cells removed from DEAD laptop batteries. Charging lithium cells safely is not a simple process. Assuming your charger is designed to charge those cells, it will do whatever it does. Rarely do the numbers on the package give you much useful information. As a cautionary note... I bought mine for a quarter at a garage sale, so I don't know where they came from. The included charger connects two cells directly in parallel. If you put in one dead one and a fully charged one, you may make some serious smoke/fire.
On Fri, 10 Mar 2017 15:47:15 -0800 (PST), Andy
<andrewkennedy775@gmail.com> wrote:

>I would like to find out how long to charge the above battery. >Charger puts out 500 mAh.
Not enough information to answer. There's more to charging a LiIon battery than cramming 500 mA (not mA-Hrs) into the battery. The charger has to know the SoC (state of charge) so that it doesn't overcharge your battery. It also has to make sure the charger NEVER goes over 4.2VDC and check if the battery is getting warm. Lots of things that can go wrong. Some good stuff on charging LiIon: <http://batteryuniversity.com/learn/article/charging_lithium_ion_batteries> What you should do is purchase a suitable charger for an 18650 cell. For example: <http://www.ebay.com/itm/172543493246> or a dual charger: <http://www.ebay.com/itm/291748570741> Also, your Ultrafire battery is certainly not going to deliver 6500 mA-hrs. My test of an Ultrafire 3000 18650 cell shows that it will deliver about 800 ma-hr with a 1.3A constant current discharge, which is what one of my flashlights like to draw. <http://802.11junk.com/jeffl/LiPo/Ultrafire%20LiPo%203000%20ma-hr%2018650%20test.jpg> <http://802.11junk.com/jeffl/LiPo/Ultrafire%2018650%20test.jpg That's a West Mountain Radio CBA-II discharge tester above: <http://www.westmountainradio.com/cba.php> Other tests of 18650 cells: <http://lygte-info.dk/review/batteries2012/Common18650Summary%20UK.html> Notice how the battery capacity drops as the load current increases. Such cells are normally tested at 20% of their rated capacity. So, a Panasonic 18650 BD cell, rated at 3000 mA-hr, is tested at 0.61A, and usually meets the spec sheet claims. In theory, your Ultrafire 18650 would be tested at 0.20 * 6.8A = 1.3A, which is exactly what my test graph uses. However, the results were far from 6800 mA-Hr and instead produced 800 mA-Hr. That rather suggests that the 6800 mA-Hr number is bogus. In my experience, most everything with the word "fire" in the name is over-rated. -- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558
On Fri, 10 Mar 2017 16:38:37 -0800 (PST), the renowned
"dcaster@krl.org" <dcaster@krl.org> wrote:

>On Friday, March 10, 2017 at 7:11:43 PM UTC-5, rickman wrote: > >> >> Unless this is a D cell or some highly specialized battery chemistry, >> there are no 6800 mAh AA cells. Any rechargable with "fire" in the name >> is a lie. They are well documented on the web. >> >> -- >> >> Rick C > >You missed the 18650 in the subject title, But you are right anyway. There are no 6800 mah 18659 batteries. I think the best 18650 batteries are just over 2000 mah. > > Dan
There are some that are as good as 3500mAh +/-, but 'Ultrafire' is known *not* to be a source of such product. Your estimate of 1800-2000 is probably reasonably good. I've been meaning to set up the logger and electronic load but it probably won't happen soon. --sp -- Best regards, Spehro Pefhany
On Fri, 10 Mar 2017 15:47:15 -0800 (PST), Andy
<andrewkennedy775@gmail.com> wrote:

>I would like to find out how long to charge the above battery. > >Charger puts out 500 mAh.
Several things. There is no such thing as a 6800 mah 18650 cell. That's chinese lying again. If you go to http://www.dx.com (a chinese vendor of among other things, flashlights, batteries and parts), you'll find probably a hundred different 18650 batteries for sale with the claimed mah as the page title and the actual tested mah in parenthesis. The very best 18650 that we consumers can buy is the Panasonic "red tube" 3200 mah cell. Not only is the spec real but the cell has a very low impedance which makes the cell useful in hotrod flashlights that I make as a hobby. Charging. Do NOT try to charge a LiIon cell by time. The best you will do is destroy the cell. The worst you will do is cause a violent, rocket-like fire!!! LiIon cells are charged to a specified termination voltage and then the charger turns off. There is a tradeoff between life and capacity, and termination voltage. I charge my Panasonics to 4.20 volts. That gives me maximum capacity but reduces the life. I don't care much about life. I can buy more. Here they are: http://www.dx.com/p/panasonic-ncr18650bf-super-max-3-7v-3400mah-rechargeable-18650-li-ion-battery-red-356976 John John DeArmond http://www.neon-john.com http://www.tnduction.com Tellico Plains, Occupied TN See website for email address
Andy wrote:
> I would like to find out how long to charge the above battery. > > Charger puts out 500 mAh. > > Thanks.
Most batteries are specified to be (safely) charged at C/20, some at C/10.
On Tue, 14 Mar 2017 22:52:52 -0800, Robert Baer
<robertbaer@localnet.com> wrote:

>Andy wrote: >> I would like to find out how long to charge the above battery. >> >> Charger puts out 500 mAh. >> >> Thanks.
> Most batteries are specified to be (safely) charged at C/20, some at >C/10.
Wrong. The *DISCHARGE* rate is C/20 for the sole purpose of providing a uniform test of battery capacity in ma-hr. If one charged a 3000 ma-hr cell at that rate, it would take over 20 hrs for this battery to be fully charged. Obviously, that's not happening. Maximum charge and discharge current rating vary by battery chemistry and construction. As an example, a 2 cell 1000 ma-hr battery pack: <https://hobbyking.com/en_us/turnigy-1000mah-2s-30c-lipo-pack.html> is rated at: 30C (30 amps) constant discharge 40C (40 amps) intermittent discharge 2C (2 amps) maximum charge rate. -- Jeff Liebermann jeffl@cruzio.com 150 Felker St #D http://www.LearnByDestroying.com Santa Cruz CA 95060 http://802.11junk.com Skype: JeffLiebermann AE6KS 831-336-2558