On 2017-03-15, Jeff Liebermann <jeffl@cruzio.com> wrote:> 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.C/20 is a safe constant charge current for NiMH batteries if you don't have a fast charger, C/10 for NiCd, neither applies to Lead-Acid or lithium. -- This email has not been checked by half-arsed antivirus software
Charging time for Ultrafire 18650 6800 mAh battery
Started by ●March 10, 2017
Reply by ●March 15, 20172017-03-15
Reply by ●March 15, 20172017-03-15
On Wed, 15 Mar 2017 00:28:00 -0700, Jeff Liebermann <jeffl@cruzio.com> wrote:>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.Read what he wrote. A C/20 *charge* is safe. A C or 2C or even 10C charge might be possible but you have to be really careful.> >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.
Reply by ●March 15, 20172017-03-15
On 12/03/17 17:17, Spehro Pefhany wrote:> 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. >> 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.> There are some that are as good as 3500mAh +/-Panasonic make them. They just recently improved from 3400mAh, as tested by a night-hiking mate of mine.> Your estimate of 1800-2000 is probably reasonably good.Unless you get repackaged spent cells, which *fire is known for. Then you're lucky to get 800mAh. Clifford Heath.
Reply by ●March 16, 20172017-03-16
On 15 Mar 2017 08:51:04 GMT, Jasen Betts <jasen@xnet.co.nz> wrote:>On 2017-03-15, Jeff Liebermann <jeffl@cruzio.com> wrote: >> 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.>C/20 is a safe constant charge current for NiMH batteries if you don't >have a fast charger, C/10 for NiCd, neither applies to Lead-Acid or >lithium.Please note that the title of this thread is "Charging time for Ultrafire 18650 6800 mAh battery". To the best of my limited knowledge, neither NiMH, NiCd, lead-acid, or carbon zinc batteries are available in an 18650 form factor or are sold under the name of "Ultrafire". However, you're wrong again about NiMH "safe" charge rate. The NiMH chargers that I own (Maha, iMax B6, Sanyo Eneloop, etc all use a negative dV/dT slope to detect EoC (end-o-charge). The charge rate varies, but the average is somewhere between 0.5C and 1.0C. Charging NiMH cells at C/20 is considered a "slow charge" and is a great way to kill a NiMH battery because of the lack of a negative dV/dT slope to signal EoC: <http://batteryuniversity.com/learn/article/charging_nickel_metal_hydride> "It is difficult, if not impossible, to slow charge a NiMH battery. At a C rate of 0.1C to 0.3C, the voltage and temperature profiles do not exhibit defined characteristics to trigger full-charge detection, and the charger must depend on a timer. Harmful overcharge can occur when charging partially or fully charged batteries, even if the battery remains cold." -- 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
Reply by ●November 23, 20182018-11-23
Reply by ●November 23, 20182018-11-23
carlonunez34@gmail.com wrote in news:89fccd51-9ff3-425b-acdb- d4509cefa905@googlegroups.com:> how many hours to charge a 18650?please be inform me >There is no such thing as an 18650 that can do 6800mAh. But as far as a standard 18650, which is about all that can be packed into one, is on google. Google is you friend. I found charging tables on this page: https://lygte-info.dk/info/BatteryChargePercent%20UK.html
Reply by ●November 23, 20182018-11-23
On 24/11/2018 9:48 am, carlonunez34@gmail.com wrote:> how many hours to charge a 18650?please be inform me >1
Reply by ●November 23, 20182018-11-23
carlonunez34@gmail.com wrote in news:89fccd51-9ff3-425b-acdb- d4509cefa905@googlegroups.com:> how many hours to charge a 18650?please be inform me >Look at the specs on this data sheet for a product. There is a nice data sheet for that battery. Yours will be similar. http://www.crazell.com/product/sanyo-ur18650aa/
Reply by ●November 23, 20182018-11-23
On Fri, 23 Nov 2018 17:48:51 -0800 (PST), carlonunez34@gmail.com wrote:>how many hours to charge a 18650?please be inform meHow do you know your battery is 6800mAh? Did Amazon or, even better yet, Alibaba tell you it was 6800mAh? (This should be good).
Reply by ●November 24, 20182018-11-24
