CuriousOne
Enlightened
- Joined
- Oct 14, 2012
- Messages
- 813
Recently, there was a thread here, where people from around the world, were complaining, that it's getting hard to buy lithium batteries around the world online, most companies are refusing to send them overseas. Someone suggested to try a vape sites, as they mostly deal with batteries, so they should know some workaround with logistics. As for a certain project I needed some 26650 cells, I decided to buy some and test them. So I've ordered a pair of Avatar INR26650 batteries from sourcemore (since they confirmed that they can ship batteries everywhere, including AU and NZ) - http://www.sourcemore.com/avatar-inr-26650-rechargeable-li-ion-battery-3-7v-4200mah-2pcs.html and pair of LiitoKalla 26650 batteries from gearbest - http://www.gearbest.com/batteries/pp_360841.html I also wanted to order some cells from fasttech, but they've refused to deliver them to US. Both companies shipped at nearly same time, but gearbest shipped using Czech Post (RRxxxxxxxCZ tracking), which took almost 1 month to deliver to US, NJ. Sourcemore shipped via PostNL (RSxxxxxxNL) and delivery to NJ took 14 days. Since Avatars arrived first, I will review them first, and later will do LiitoKalla review.
A little introduction, why this review is needed at all. Lithium batteries come in different shapes and sizes and capacities, but besides that, there is two large group of batteries on the market. The first group are batteries manufactured by major brands, such as Samsung, LG, Panasonic, Sony, etc. And second group consists of relatively less or good known Chinese companies, such are BAK, ChanJiang, Yodeli, ATL and so on. But, there is another specific factor to be considered. Major brands only do 18650, 18500, 16650, 14500 cells. So all 26650 cells are made by Chinese factories (Panasonic had small run of 26650 cells about 10 years ago, but they were inly 2600 mah, and shortly phased out). What this all means? This means that in case of above mentioned battery sizes, you can go and buy battery made by major brands, and you will be sure that it will have specs within manufacturer declared ranges (of course, if you won't run into fakes). Contrary, all 26650 cells are made by non-major brands, so in most cases, no specs available, or these specs are overrated. This is why test/review of Chinese cells is so important.
Another thing to consider. Since this forum is dedicated to flashlights, I will test and review batteries in the ways, that they may experience during actual usage in flashlight. So I will focus on the following aspects, that are critical for flashlight usage:
- Capacity at 10A discharge / does it matches declared value
- How hot battery gets at 10A current (Some testers allow batteries to heat to 80C, but hey, can you hold 80C flashlight in hand? So I will limit maximum temperature within 50C range)
- Exact dimensions of battery, terminals
So, I will start with specs for these batteries, as they are given by manufacturer. PLEASE NOTE: This is data as provided by manufacturer, it does not means that battery has the specs, show below:
Typical capacity @ 0.2C: 4230mAh
Minimum capacity @ 0.2C: 4200mAh
Nominal voltage: 3.7 volts
Standard charge: 0.2C 4.20V
Standard discharge: 0.2C 3.00V
Discharge cutoff: 3 V
Cycle life: Over 300 cycles, while retaining 80% of capacity.
Quick charge current: 4.5A
Quick discharge current: 21A
Max discharge current: 29.4A
Initial impedance: <=55 milliohms
Weight: 90+- 3 grams
Charging temperature: 0C-45C
Discharging temperature: -20C-60C
Specs look quite impressive, now let's see the actual battery:
Batteries are packed in carton boxes, and additionally insulated with heat shrink wrapping. Design is quite appealing, and it even shows "60A", next to battery model, which someone might consider as max discharge current indicator, but I prefer to threat it as a part of décor
I've measured some actual specs of the batteries, and they are as follows (Cell A first, cell B next):
Weight: 91.3 and 90.5 grams.
Dimensions: Both measure 26.14mm in diameter and 66.2mm in length, including positive terminal. As you can see, these are flat top batteries, but positive terminal protrudes for about 2mm, so batteries make good contact, when run in series.
Inner resistance: 23 and 27 milliohms
Initial voltage: 3.826 and 3.825 volts
Discharge with 10A current: 4.125 Ah, 14.17 Wh and 4.084 Ah, 14.05 wh.
Maximum temperature during the discharge at 10A current does not exceeds 46C for both cells.
I've conducted a test discharge at 20A, but cell temperature reached 60C quite quickly, so I've terminated the test.
Cells track almost perfectly, just there was slight temperature variation between them, as you can see on the picture:
Conclusion:
Cells track very well
At 10A, they don't get extremely hot
Capacity is within declared range
Possibly, cells can be used at 20A discharge current, but with some precautions
Least possibly, these cells can provide 30A pulsed discharge current
And for sure, I don't believe in 60A discharge current, under any circumstances (but hey, have you seen such flashlight ever? or even 20A one?)
Since cells had similar voltage when delivered, weight and capacity differences are minimal, discharge curves look similar, all above can be considered as indirect indication of fact, that these cells, at least are made at normal factory, and have constant manufacturing quality. Regarding the price, they appear to be a bit pricey, for the price of these two, you can get 4 of LiitoKallas, but they are available only on Gearbest, which does not deliver them worldwide, and this store delivers these Avatars worldwide (at least, they say so). These batteries will be installed in high drain device, so I will update this thread in 2-3 months, if something goes wrong.
I bought these batteries using my own money, they WERE NOT provided free for the review.
A little introduction, why this review is needed at all. Lithium batteries come in different shapes and sizes and capacities, but besides that, there is two large group of batteries on the market. The first group are batteries manufactured by major brands, such as Samsung, LG, Panasonic, Sony, etc. And second group consists of relatively less or good known Chinese companies, such are BAK, ChanJiang, Yodeli, ATL and so on. But, there is another specific factor to be considered. Major brands only do 18650, 18500, 16650, 14500 cells. So all 26650 cells are made by Chinese factories (Panasonic had small run of 26650 cells about 10 years ago, but they were inly 2600 mah, and shortly phased out). What this all means? This means that in case of above mentioned battery sizes, you can go and buy battery made by major brands, and you will be sure that it will have specs within manufacturer declared ranges (of course, if you won't run into fakes). Contrary, all 26650 cells are made by non-major brands, so in most cases, no specs available, or these specs are overrated. This is why test/review of Chinese cells is so important.
Another thing to consider. Since this forum is dedicated to flashlights, I will test and review batteries in the ways, that they may experience during actual usage in flashlight. So I will focus on the following aspects, that are critical for flashlight usage:
- Capacity at 10A discharge / does it matches declared value
- How hot battery gets at 10A current (Some testers allow batteries to heat to 80C, but hey, can you hold 80C flashlight in hand? So I will limit maximum temperature within 50C range)
- Exact dimensions of battery, terminals
So, I will start with specs for these batteries, as they are given by manufacturer. PLEASE NOTE: This is data as provided by manufacturer, it does not means that battery has the specs, show below:
Typical capacity @ 0.2C: 4230mAh
Minimum capacity @ 0.2C: 4200mAh
Nominal voltage: 3.7 volts
Standard charge: 0.2C 4.20V
Standard discharge: 0.2C 3.00V
Discharge cutoff: 3 V
Cycle life: Over 300 cycles, while retaining 80% of capacity.
Quick charge current: 4.5A
Quick discharge current: 21A
Max discharge current: 29.4A
Initial impedance: <=55 milliohms
Weight: 90+- 3 grams
Charging temperature: 0C-45C
Discharging temperature: -20C-60C
Specs look quite impressive, now let's see the actual battery:
Batteries are packed in carton boxes, and additionally insulated with heat shrink wrapping. Design is quite appealing, and it even shows "60A", next to battery model, which someone might consider as max discharge current indicator, but I prefer to threat it as a part of décor
I've measured some actual specs of the batteries, and they are as follows (Cell A first, cell B next):
Weight: 91.3 and 90.5 grams.
Dimensions: Both measure 26.14mm in diameter and 66.2mm in length, including positive terminal. As you can see, these are flat top batteries, but positive terminal protrudes for about 2mm, so batteries make good contact, when run in series.
Inner resistance: 23 and 27 milliohms
Initial voltage: 3.826 and 3.825 volts
Discharge with 10A current: 4.125 Ah, 14.17 Wh and 4.084 Ah, 14.05 wh.
Maximum temperature during the discharge at 10A current does not exceeds 46C for both cells.
I've conducted a test discharge at 20A, but cell temperature reached 60C quite quickly, so I've terminated the test.
Cells track almost perfectly, just there was slight temperature variation between them, as you can see on the picture:
Conclusion:
Cells track very well
At 10A, they don't get extremely hot
Capacity is within declared range
Possibly, cells can be used at 20A discharge current, but with some precautions
Least possibly, these cells can provide 30A pulsed discharge current
And for sure, I don't believe in 60A discharge current, under any circumstances (but hey, have you seen such flashlight ever? or even 20A one?)
Since cells had similar voltage when delivered, weight and capacity differences are minimal, discharge curves look similar, all above can be considered as indirect indication of fact, that these cells, at least are made at normal factory, and have constant manufacturing quality. Regarding the price, they appear to be a bit pricey, for the price of these two, you can get 4 of LiitoKallas, but they are available only on Gearbest, which does not deliver them worldwide, and this store delivers these Avatars worldwide (at least, they say so). These batteries will be installed in high drain device, so I will update this thread in 2-3 months, if something goes wrong.
I bought these batteries using my own money, they WERE NOT provided free for the review.
