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bassplayer142
professor emeritus
Reged: 10/03/11
Loc: Michigan
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Re: Very Inexpensive 12V Li-Ion Battery pack
[Re: TopherTheME]
#5672587 - 02/10/13 03:51 PM
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I opened the charger and verified myself that it is just a 12.6 static output. Not the correct type for charging Li-Ion but since I already had a charger that is not a big deal on my side. I just got done charging it and ended up with 12.3 Volts which is the ideal (4.1*3) = 12.3 Volts.
On a side note. These are Li-Ion and not Li-Polymers like many are posting. Not sure where this misconception came through.
Also, the battery pack has a led and switch built into it. I have not and probably won't open it up unless it dies. But assuming that it does have this extra circuitry rather than just a few cells. My plan is to to test it and measure the current when and if the voltage drops. If it does drop to zero, it should be safe to say that over discharge circuitry is present.
Edited by bassplayer142 (02/10/13 03:54 PM)
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ccs_hello
Postmaster
Reged: 07/03/04
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Re: Very Inexpensive 12V Li-Ion Battery pack
[Re: bassplayer142]
#5672673 - 02/10/13 04:45 PM
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The battery pack's label says
"Super polymer Lithium-Ion Battery".
That's Li-Po (Lithium Poly).
Li-Ion (the cell is in sealed metal can, since the electrolyte is not molded in polymer form) cell costs more.
Clear Skies!
ccs_hello
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ccs_hello
Postmaster
Reged: 07/03/04
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Re: Very Inexpensive 12V Li-Ion Battery pack
[Re: ccs_hello]
#5672703 - 02/10/13 05:05 PM Attachment (8 downloads)
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Add a picture:
Left Li-Ion (metal can, Samsung)
Right: Li-Po (plastic pack, Tenergy)
Both are dead with pressurized gas inside.
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FlorinAndrei
scholastic sledgehammer
Reged: 09/28/10
Loc: California
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Re: Very Inexpensive 12V Li-Ion Battery pack
[Re: Gene7]
#5672884 - 02/10/13 07:07 PM
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Quote:
Do go to Battery University and read about Lithium Ion batteries and charging. I would charge no higher than 4.1 V per cell. Gene
With Li-ion, do NOT attempt to do anything manually. Get a specialized charger, and let the charger cut off the current when the battery is full.
Also, when in use, a special circuit must be used to either cut off the battery when it's empty, or at least give you a visual or audio warning.
Basically, never manage a Li-ion battery yourself, you'll end up frying it. Let the electronics do it.
Quote:
A Li-any type battery with that capacity and cost isn't going to live for very long. I'd give it 50 cycles max before its capacity is cut in half.
If properly managed, a Li-ion battery can last a very long time, through many many charge-discharge cycles.
But I agree that high capacity + low price = there must be a catch somewhere.
Quote:
If you still want to use Li batteries I recommend HobbyKing.com for batteries. They're not great, but for the money they perform fine for astro stuff and usually live a couple years before a cell goes bad. I like to use the 4s1p 5000mAh lipoly packs connected up to a LDO 12V regulator that I built.
Hobby King is a great supplier for Li-ion stuff. Make sure you get an appropriate charger for the batteries. Li-ion are very fussy with charging. If charged appropriately, a Li-ion pack will last a long time.
Another issue is that Li-ion batteries for RC projects, like the ones on Hobby King, are generally not protected, which means the battery does not shut down automatically when overcharged or overdischarged. If you don't cut it off in time, you'll damage it. For this reason, many RC projects use buzzers to warn you when the battery is close to the low point, and then it's up to you to stop. This works well for an RC project such as a mini-helicopter, but may or may not work well for other applications.
Here's a 12V Li-ion battery for RC projects. It is NOT protected:
http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idproduct=11927
Here's a good charger for such batteries, it includes protection:
http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idproduct=6478
Here's a buzzer for unprotected batteries:
http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idproduct=7223
Here's a protected battery:
http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idproduct=31315
---
Another route to take is the 18650 cells. These are Li-ion cells used in laptop batteries, but can be purchased separately, and chargers as well. I use 18650 for flashlights, I purchased a charger, several cells, and 3 flashlights, one of which is installed on my bicycle.
http://www.amazon.com/lumen-5Watt-18650-Flashlight-Holster/dp/B004L7D8SY/
http://www.amazon.com/Flashlight-Mount-for-Bike-Handlebar/dp/B004OADU22/
The flashlights are extremely bright, last a very long time, yet are very small.
Make sure the 18650 cells you purchase are protected.
Here's a couple links, but I'm sure you could google more:
http://www.batteryjunction.com/18650.html
http://www.batteryjunction.com/lithiumionchargers.html
I intend to use 18650 cells for a telescope fan combo, I'll post the results when it's done.
---
Bottom line is this:
Li-ion provide more energy per weight than lead-acid, but require some care. If the battery is protected, and a good charger is used, then it should be fine.
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ccs_hello
Postmaster
Reged: 07/03/04
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Re: Very Inexpensive 12V Li-Ion Battery pack
[Re: FlorinAndrei]
#5672992 - 02/10/13 08:25 PM
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Li-Po has the nominal voltage of 3.7V and fully charged at 4.2V.
Li-Ion is tricky, depends on the Electrolyte used, the voltage will be different. The are two popular types:
- Nominal 3.6V Fully charged at 4.1V
- Nominal 3.7V Fully charged at 4.2V
Detailed Li-Ion batt spec. will have this info. Charging 3.6V type to 4.2V (0.1V higher) is slightly off-spec.
Clear Skies!
ccs_hello
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Gene7
scholastic sledgehammer
Reged: 06/10/10
Loc: Mid Ohio, USA
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Re: Very Inexpensive 12V Li-Ion Battery pack
[Re: ccs_hello]
#5673639 - 02/11/13 08:51 AM
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Do not expect the UltraFire 18650 cells to put out more than about half of their advertised capacity. Gene
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Daud
sage
Reged: 08/05/06
Loc: AZ, Scottsdale
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Re: Very Inexpensive 12V Li-Ion Battery pack
[Re: Gene7]
#5674125 - 02/11/13 01:59 PM
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Quote:
Do not expect the UltraFire 18650 cells to put out more than about half of their advertised capacity. Gene
Can this be countered by having 3 pairs wired together for doubling up on capacity ? Any similar battery holders around ? I suppose I would need the balanced charger mentioned above.
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bassplayer142
professor emeritus
Reged: 10/03/11
Loc: Michigan
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Re: Very Inexpensive 12V Li-Ion Battery pack
[Re: Daud]
#5674662 - 02/11/13 07:26 PM
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Now I'm not sure if the pack is Li-Ion or in fact Li-Po. I failed to notice the polymer before since they are usually advertised and displayed clearer than this. I've messaged the seller but they will be out for another 5 days due to the Chinese new year.
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ccs_hello
Postmaster
Reged: 07/03/04
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Re: Very Inexpensive 12V Li-Ion Battery pack
[Re: Daud]
#5674833 - 02/11/13 09:29 PM
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Quote:
... 18650 ...
Can this be countered by having 3 pairs wired together for doubling up on capacity? Any similar battery holders around ? I suppose I would need the balanced charger mentioned above.
Some balance chargers can do 3.6V type as well as 3.7V type Li-Ion, user selectable. Some can only do 3.7V.
Both Li-Ion and Li-Ion Poly (Li-Po) use very similar charge profile so just need to watch out for the 3.6 or 3.7 type.
In fleabay, you can buy 18650 cell holder, but for most of them, you have to relocate Positive terminal wiring because it might touch the casing (negative) in cell's front-side! That's going to be very bad!!!
These cells are parallelable (double the capacity, the original batt pack in the first post has two 2300mAh cell wired in parallel to get 4600mAh), then has 3 sets in series to form 3 x 3.7V = 11.1V pack.
Industry standard would call it: 11.1V 4600mAH 51WH unprotected Li-Po batt pack.
Re: 18650 source...
I have my private sources and I only get SONY and Panny 18650. Good quality and very inexpensive, if you know the trick to fetch them  .
And it's a big Yes. You have to treat these cells with respect and a lot of TLC.
Clear Skies!
ccs_hello
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FlorinAndrei
scholastic sledgehammer
Reged: 09/28/10
Loc: California
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Re: Very Inexpensive 12V Li-Ion Battery pack
[Re: Gene7]
#5675094 - 02/12/13 01:00 AM
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Quote:
Do not expect the UltraFire 18650 cells to put out more than about half of their advertised capacity. Gene
That is an unfortunate fact of life. Some of those batteries are not as good as the others.
Avoid the super extra tempting deals and you'll be fine - usually.
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