Comparing Panasonic A, Panasonic B, Sanyo, and Ultrafire cells (2023)

Comparing Panasonic A, Panasonic B, Sanyo, and Ultrafire cells (1)

Cells deconstructed from the top, Panasonic A, Panasonic B, Sanyo FM showing various lengths of electrolyte foils.

This blog article will explore the differences between a sampling of Panasonic, Sanyo, and Ultrafire 18650 batteries.

To do so I will exclusively refer to a paper published herein 2015.


Lithium-ion was first made available in 1991. Since then it has become more apparent that it is the best solution for energy storage. However one problem with lithium-ion and the 18650 battery is the difficulty in getting reliable, honest ratings.

It’s hard to know whether the specifications are true because:

  1. Possible rating inflation from manufacturers
  2. Person rating is not educated on how to accurately test cells
  3. Difficulty obtaining authentic cells and proper equipment

Overview: Important physical characteristics

Cells tested

Comparing Panasonic A, Panasonic B, Sanyo, and Ultrafire cells (2)

The cells tested from left to right are:

  1. UltraFire TR18650 4200 mAh
  2. UltraFire TR18650 4900 mAh
  3. Sanyo UR18650FM
  4. Panasonic NCR18650A
  5. Panasonic NCR18650B

The most important physical characteristics that distinguish the 18650 are:

  • size
  • weight
  • shape

The 18650 (18mm by 65mm) has evolved as the best trade-off between capacity and charge/discharge ability in terms of these characteristics.

Other 18650 battery characteristics

There are many conditions that will alter the performance of your cells.

  • Max and min voltage
  • Capacity of cell at beginning of life
    • Capacity at different charge / discharge rates
    • Capacity at different temperatures

The max and min voltage can be reduced from the extremes.

For example instead of charging a battery to 4.2 V and discharging to 2.5 V, one might only use a range between 3.2 V and 3.8 V. This can lead to an increased cell cycle life.

(Video) 18650 battery compare - Panasonic, LG, Sanyo (2017)

The capacity at the beginning will be greater than any proceeding time because of natural cell degradation.

An increase in charge or discharge amperage will decrease the working capacity and life cycle of a cell.

Furthermore, any deviation from the testing temperature of 25 degrees Celcius the cells will result in reduced performance. This is especially true under 0 degrees and above 60.

Other testing variables that should be accounted for when accurately testing cells:

  • cell chemistry
  • capacity
  • formats
  • charging, discharge profiles
  • temperature
  • test set-up

Initial results

P3100P 3400S 2600UF 4200UF 4900
Typ. Charge Capacity (mAh)30703350260042004900
Min. Charge Capacity (mAh)295032502500--
Meas. Charge Capacityb (mAh)2862 (2961)3166 (3267)2480757.1579.4
– (% of typical)93.2 (96.4)94.5 (97.5)95.41811.8
Meas. Energy Capacity (Wh)10.19 (10.61)11.33 (11.78)9.252.741.96
Nominal Weight (g)≤47.5≤48.5≤48--
Measured Weight (g)44.6646.745.6232.2437.98
Nominal Length (mm)≤65.3≤65.364.9±0.2--
Measured Lengthd (mm)65.0867.3464.9665.7465.44
Nominal Diameter (mm)≤18.5≤18.518.3±0.2--
Measured Diametere (mm)18.2818.5718.2818.2718.22
Specific Energy (Wh/kg)228.3 (237.6)242.6 (252.3)202.884.851.6
Energy Density (Wh/l)596.9 (621.3)621.3 (646.2)542.6158.7114.8
Cost per Cell (AU$)11.4813.485.311.451.63
Cost/Meas. Capacity ($/kWh)1125.9 (1081.8)1189.7 (1144.0)574.1530.1831.7
Cost/Meas. SE ($kg/kWh)50.2955.5626.1917.0931.59

How the test works

Step 1: Charge and discharge

Charge to 4.2 V at 1A and then taper charge to 50 mAh and terminate.


Discharge at 1A

  • First 5 cycles discharged to 2.8 V
  • For discharge 6 and 8, the Panasonic cells were discharged to 2.5V (because these cells offer a lower cut-off voltage, allowing the researchers more comparability)

Stage 2: Weight and dimensions

Taking measurement of weights especially enable comparisons of 18650 battery energy density. Weight is a critical constraint in electric vehicles especially as it reduces the km driven per charge.

Stage 3: Impedance

Checking the impedance - cells tested at a frequency range of .1 Hz and 100 kHz.

Step 4: Aging and life cycle of cells.

Testing to conclude after 100 cycles, or by the end of the month whichever happened first - how much the capacity has faded and impedance has changed.

Step 5: Rest and test

(Video) The best 18650 cells ever (Panasonic, Samsung, Sony, Sanyo and LG)

Let the cells rest for anywhere between a couple days to a few weeks. And then take a final capacity test in the same conditions as the very first test. That will show how much the cell degraded between first and last test.

Initial testing:


All 18650 cells are actually slightly larger than 18mm by 65mm. The paper found the diameter is 3.2% and the length is 3.6% larger than the 18650 standard. It’s important for those who want to create large battery packs with thousands of cells.

Interestingly, it also skews the “lithium-ion energy density measurements” that everyone uses as the size is a critical component of the formula and seldom is it accounted for.


BatterymAhCycleAv. Capacity Reduction per 100 Wh Throughout (%)

Panasonic cells achieved over 93% of their advertised rated charge capacity. The Panasonic cells did not reach their full capacity because they did not use the proper cut-off voltage (2.5V) and they used a “fast” charge current of 1A where they might use .5A or lower. Furthermore optimizing the temperature would have likely allowed them to reach their full potential.

Ultrafire cells were between 12% and 18% worse. There is no surprise here.

Full Cycle Life

Comparing Panasonic A, Panasonic B, Sanyo, and Ultrafire cells (3)

Note, the solid lines are for full cycles of 4.2 V to a cut-off voltage of 2.8 V. The dashed lines are partial cycles of 4.0 v to 3.2 V.

View full-size chart here.

There is clear downwards aging trend after 50 - 130 cycles

Partial Cycle Depth of discharge study

Comparing Panasonic A, Panasonic B, Sanyo, and Ultrafire cells (4)

Again, the dashed lines are partial cycles, and the solid lines are full cycles. Note how crazy the Ultrafire cells cycle.

(Video) 3500mAh batteries: Sanyo NCR18650GA vs Panasonic NCR18650GA vs LG MJ1 vs Samsung INR18650-35E

View full-size chart here.

Charge and discharge from 3.2 to 4.0 V, to decrease the depth of discharge. This should offer an increase in the cycle life of the cells.

Note, the Depth of discharge, or (DOD) differs from the state of charge (SoC) by being an alternate way of measuring charge, albeit somewhat reversely. When one goes up, the other goes down.

The comparison between cells fully cycled and cells partially cycled is interesting because it can help you decide between two options:

  1. To buy expensive high capacity cells and do partial discharge
  2. Or buy cheap low capacity cells and do full discharge

If we look at the chart we can see that the Panasonic cells to degrade slower when having a decreased voltage range. Unfortunately, the Ultrafire cells do something not expected for 18650 batteries - they degrade much faster.

Unfortunately, this makes the data (because of the cells) unreliable - calling for more cells to be tested for conclusive comparisons.

However if you just focus on the Panasonic and Sanyo cells you can see by limiting the depth of discharge there is some improvement in the life cycle.

Impedance Study

Panasonic Cells

  • The main difference was charge transfer capacitance - it decreased by two orders of magnitude
  • At the same time, the electrode diffusion capacitance increased by two orders of magnitude.

What is charge transfer?

Now most readers have no idea what charge transfer capacitance is, but if you are curious you want to know. It begins with something called the charge transfer coefficient.

In lithium-ion cells, charge transferis defined as the fraction of over-potential that affects currentdensity.

Overpotentialis a measure that directly translates tovoltage efficiency (using more or less energy than thermodynamics require). Inefficiencies are seen as a loss of usable energy in the form of heat.

Sanyo Cells

The same thing happened to these cells (charge transfer capacitance decrease, diffusion increase).

The difference between the Sanyo and the Panasonic cells are an increase in ohmic resistance (how much is the cell opposing the flow of current). This is due to the battery chemistry type, notably the electrolyte formulation which is outdated.

(Video) Comparing 18650 cells for DIY battery - Q&A#5

Ultrafire Cells

The same trend continues here.

The big difference is the Ultrafire cells had a much higher increase in ohmic resistance. This could have been predicted - these cells are terrible.

Paper Conclusions

Initial capacity testing found the Panasonic and Sanyo cells performed within 8% of their rated capacity.

Panasonic and Sanyo cells:

  • Capacity: Within 8% of rated capacity
  • Life Cycle: 2-6% degradation after 50 - 80 cycles (700 Wh)
  • Resistance: Low rise in ohmic resistance


  • Capacity: Less than 20% of rated capacity (one cell died)
  • Life Cycle: 6% (300 Wh) - 20% (30 Wh) degradation
  • Resistance: High-rise in ohmic resistance

More on the Ultrafire cells

Comparing Panasonic A, Panasonic B, Sanyo, and Ultrafire cells (5)

The authors of the paper found that actually inside many Ultrafire batteries are smaller batteries. It’s not Russian dolls, it’s cheap 18650 batteries!

Counterfeiters purchase blank 18650 steel tubes and then don’t fill them up all the way. It’s the classic potato chip bag bait-and-switch.

Comparing Panasonic A, Panasonic B, Sanyo, and Ultrafire cells (6)

Comparing Panasonic A, Panasonic B, Sanyo, and Ultrafire cells (7)

The electrolyte foils were found to only comprise 73% to 74% of the space the Panasonic or Sanyo cells did.

Comparing Panasonic A, Panasonic B, Sanyo, and Ultrafire cells (8)

CT scan of Ultrafire batteries.

Comparing Panasonic A, Panasonic B, Sanyo, and Ultrafire cells (9)

(Video) NCR18650B Panasonic. Simple FAKE vs Genuine test

Last picture - the Ultrafire 4200 from this article cut in half.


Vyroubal, P., et al. "3D Modelling and Study of Electrochemical Characteristics and Thermal Stability of Commercial Accumulator by Simulation Methods." Int. J. Electrochem. Sci 11 (2016): 1938-1950.


Are Sanyo batteries good? ›

High-Drain Replacement Batteries

These Sanyo batteries are designed for use in battery packs to power high-power electronics, such as an electric bicycle and EV powertrains. These rechargeable cells have some of the highest-rated capacities currently on the market, as well as excellent discharge rates.

Are UltraFire batteries good? ›

Some UltraFire 18650 battery reviews have blamed the poor battery life on bad cells. But the majority of users suggest that these particular batteries are merely cheap and poorly manufactured.

Is there a better battery than the 18650? ›

21700 – were designed to be a larger and higher capacity replacement for 18650 batteries. Like the 18650, the 21700 has a nominal voltage of 3.6/3.7V. The 21700 was designed to replace the 18650 in EV battery packs. The capacity of these batteries ranges from about 4,000 to 5,000 mAh.

What is the most powerful 18650 battery? ›

Highest Capacity 18650 Battery - Molicel M35A

In it's distinctive blue wrap, securing the vote for the highest capacity battery is the Molicel M35A 18650 Battery. This model offers great consistency throughout its life cycle, and an astounding 3500mAh - the highest capacity of any 18650 battery.

Is Panasonic and Sanyo the same? ›

On December 21, 2009, Panasonic completed a 400 billion yen ($4.5 billion) acquisition of a 50.2% stake in Sanyo, making Sanyo a subsidiary of Panasonic. In April 2011, Sanyo became a wholly owned subsidiary of Panasonic, with its assets integrated into the latter's portfolio.

Which brand of lithium battery is the best? ›

Best Lithium Battery 2022 • 6 Lithium Batteries Reviews
  • Panasonic. CR123A.
  • Makita. BL1820B.
  • Duracell. 2032.
  • Amvolt. CR2032.
  • Energizer. Ultimate Lithium AA Batteries.
  • EGO Power+ BA1400.

Where is Ultrafire made? ›

Ultrafire is a China-based vendor of 18650 lithium-ion cells. One can buy their 18650 cells from eBay, Amazon and lots of other web-based stores.

What brand of 18650 does Tesla use? ›

Tesla Model S Batteries are Used Lithium-Ion batteries that are based around 444 Panasonic NCR18650B cells running in a configuration of 6s74p. These batteries have been pulled from wrecked Tesla Vehicles.

Which cell battery is best? ›

Lithium Batteries

They offer the highest energy density of any other battery cell, meaning they store more energy than other batteries, such as alkaline. Lithium batteries are only sold in AA, AAA, and 9V sizes; however, their mAh ratings exceed every other non-rechargeable battery.

Which battery type lasts the longest? ›

Results. The Duracell battery lasts the longest, closely followed by Energizer and then Eveready. In general, the alkaline batteries are found to perform better than their non-alkaline counterparts.

What is the lifespan of A 18650 battery? ›

Most modern 18650 batteries have a typical cycle life of 300 - 500 (charge, discharge cycles). When in high-amp or high-drain situations, this can decrease substantially to 200 cycles.

Where are Sanyo 18650 batteries made? ›

Advantages of Sanyo 18650 battery:

Made in Japan.

How many 18650 batteries make A 100Ah battery? ›

What if we use Lifepo4 18650 cells(which are rated 3.2V 1.5Ah)? we would need 264 cells in total with 4S66P configuration to get the same total capacity of 11.1V 100Ah(actual capacity is 12.8V 99Ah). Want More Details: Download our battery design ebook.

How do I choose A 18650 battery? ›

Choosing the Right 18650 Battery for the Job

The most important trait to consider when looking at 18650 batteries is the continuous discharge rating (CDR), also known as amperage capacity. The CDR is the rate at which current---measured in amps (A)---can be pulled from the battery without it overheating.

Why did Sanyo fail? ›

Sanyo: Bought by Panasonic

By the 2000s, the company was facing a prolonged shakeout, grappling with competition from China and South Korea. The strength of the yen also made Japanese exports more expensive, putting pressure on manufacturers to merge. Sure enough, Panasonic (PCRFF) took over Sanyo in 2009.

Is Sanyo a good brand? ›

A Foundation of Solid Dependability - The #1 Japanese TV Brand in USA* With over 65 years total history, 50 of which were in America, SANYO has provided trusted home entertainment that has withstood the test of time by building relationships with over 40 million customers.

Which is a better brand Samsung or Panasonic? ›

Panasonic's brand is ranked #826 in the list of Global Top 1000 Brands, as rated by customers of Panasonic. Their current market cap is $17.40B. Samsung's brand is ranked #103 in the list of Global Top 1000 Brands, as rated by customers of Samsung.
Panasonic vs Samsung.

Is there a difference in quality of battery brands? ›

The higher quality batteries are labeled Ultra, or Industrial, while the lowest grades get sold to companies that label them with their own names. MAh is short for milliamp hours, a way to measure the capacity of the battery. So as you can see, the industrial batteries will outperform the regular Copper Top.

What is the most promising new battery technology? ›

Sila Nanotechnologies is replacing the graphite anode that forms a lot of the bulk and about 15% of the weight of today's lithium-ion batteries with a form of silicon that it claims will give battery cells a 20 to 40% increase in energy density while also charging faster.

What company makes it forever battery? ›

Thus, QuantumScape has addressed the two largest short-comings of solid-state battery chemistry. And it's positioned itself to create a new class of EV batteries that are much cheaper, last much longer and charge much faster than traditional lithium-ions.

What brand of lithium battery lasts the longest? ›

Nothing outlasts Energizer® Ultimate Lithium AA batteries. The Energizer® Ultimate Lithium batteries are not only the #1 longest-lasting AA batteries…they are complete with leak resistance and performance in extreme temperatures (-40ºF to 140ºF or -40ºC to 60ºC).

Who are the top 5 lithium producers? ›

Overall, Australia, Chile and China produce 90% of lithium production in the world. Argentina is the fourth largest lithium producing country with 5.6% market share and Brazil ranks 5th with 1.4% global lithium mining share. Portugal and US share the 6th spot each with 0.8% global share.

Are all lithium batteries the same quality? ›

Lithium Cell Grade And Quality

A common misconception is that all lithium cells are of the same quality. In reality, Lithium is graded into three types. A grade, B grade and used, and depending on which grade is in your battery, will determine the longevity and contribute to the product's final cost.

Where are Panasonic 18650 cells made? ›

Panasonic 18650 Li-ion rechargeable battery NCR18650A, the real capacity of 3100mAh-industrial strength. Made in Japan. Made by Panasonic Industrial Division. Energy density 675 Wh/L .

What is the size of the Ultrafire battery? ›

Product Specifications for Replacement Ultrafire 18650 Button Top Rechargeable Battery
BM Part #:FLB-18650-3-0
Battery Size:18650
4 more rows

Can you charge 18650 batteries in a normal charger? ›

18650 Li-Ion packs can be charged with any battery charger with Lithium Ion battery charging feature, in other words, charging process should terminate at 4.2V . You can charge single cells with a constant 4.2V supply if you are unable to source a charger. But Lithium battery packs need Special balance chargers.

Who is Tesla's biggest battery supplier? ›

CATL is the world's largest electric vehicle battery maker and supplier to the likes of Tesla and Ford.

What batteries does Elon Musk use? ›

In late 2020, Musk announced that Tesla aims to halve the costs of the most expensive part of an EV by producing its own batteries. Tesla's 4680 lithium-ion batteries - with 46-millimeter diameter and 80-millimeter length - hold about five times the energy of its current smaller 2170 cells.

Why is 4680 battery better? ›

The 4680 battery pack only needs 830 cells and Tesla has changed the design so that there are only two weld points per cell, slashing the welding to 1,660 points and leading to significant cost savings. Most of the advantages of the cell right now comes from the bigger cell format itself.

Are Panasonic batteries good? ›

Verdict. Super cheap, the Panasonic Alkaline Power AA are useful for low-drain jobs, such as remote controls. However, performance for high-drain devices isn't very good, with these batteries behind all of the competition. For greater versatility, look elsewhere.

Are there batteries that last 10 years? ›

Ultralife 9V Lithium Battery - Lasts up to 10 Years!

Should you store 18650 batteries fully charged? ›

For the most part, the maximum time for 18650 storage before recharge is about one year. If you are intending long term 18650 storage, a storage charge closer to 50% of usable capacity (~3.7V) rather than 100% (4.2V) will prevent faster battery degradation.

How many times can a 18650 battery be recharged? ›

Most 18650 cells are rated for between 300 and 500 cycles. That means your cell can charge up to 4.2 volts, and discharge down to 2.5 - 2.8 volts, a maximum of 300 to 500 times without too much much loss in performance.

Why are 18650 batteries so popular? ›

Popular in flashlights and portable electronic devices (PEDs) such as laptops, lithium-ion (li-ion) batteries are used extensively for a variety of reasons - they have a higher capacity, give higher output and do not leak over longer periods of time (like alkaline batteries can).

Who produces the best lithium ion company? ›

The leading battery supplier, CATL, expanded its market share from 32% in 2021 to 34% in 2022. One-third of the world's EV batteries come from the Chinese company. CATL provides lithium-ion batteries to Tesla, Peugeot, Hyundai, Honda, BMW, Toyota, Volkswagen, and Volvo.

Who is the largest manufacturer of lithium batteries in the US? ›

Tesla- Panasonic's US gigafactory is the world's largest lithium-ion manufacturing factory.

Is it better to have 2 100Ah lithium batteries or 1 200ah lithium battery? ›

A: As far as capacity goes it's the same. However, 2 100 ah batteries would be better than 1 200 ah battery.

Does putting batteries in series increase ah? ›

Connecting batteries in series increases the amount of voltage. It doesn't increase the ampere capacity. For example, if you connect two 12V 30Ah batteries in series, you get a combined voltage of 24V. The capacity, 30 amp hours (Ah), stays the same.

How many 18650 cells are in a Tesla battery? ›

The modules consist of 444 Panasonic 18650 cells of about 3400 mAh nominal capacity.

Is it better to have a higher mAh? ›

Higher mAh ratings for the same battery type will generally mean longer run times. This does not apply when comparing different types of batteries. This means that you may not be able to predict how long your electronic device will run just by looking at the capacity rating of a battery.

Where are Sanyo batteries made? ›

The Made in Japan batteries for the Japanese -, North American- and European market.

Which is the most durable battery? ›

The Bell has produced approximately 10 billion rings since 1840 and holds the Guinness World Record as "the world's most durable battery [delivering] ceaseless tintinnabulation".

Is it worth buying name brand batteries? ›

It depends. In Consumer Reports' Ratings of AA batteries, our technicians found real differences among well-known names and value brands. And in the case of energy-hungry devices such as digital cameras, you're probably best off with a brand, such as Energizer Ultimate—a top performer in our battery tests.

Who makes eneloop Sanyo or Panasonic? ›

Eneloop (Japanese: エネループ, Hepburn: Enerūpu) (stylized as eneloop) is a brand of 1.2-volt low self-discharge nickel–metal hydride (NiMH) rechargeable batteries and accessories developed by Sanyo and introduced in 2005.

Why did Panasonic buy Sanyo? ›

Panasonic owns 51 percent of Panasonic Electric Works, a maker of housing materials and lighting equipment, and took a 50 percent stake in Sanyo last year to gain control of the world's top maker of rechargeable batteries used in electronics and cars.

Did Sanyo buy Panasonic? ›

Osaka, Japan - Panasonic Corporation announced today that it has completed acquisition of a majority of the voting stock of SANYO Electric Co., Ltd. With this acquisition, SANYO has become a consolidated subsidiary of Panasonic and will continue pursuing its business as a Panasonic Group company.

Which battery cell is best? ›

Lithium Batteries

They offer the highest energy density of any other battery cell, meaning they store more energy than other batteries, such as alkaline. Lithium batteries are only sold in AA, AAA, and 9V sizes; however, their mAh ratings exceed every other non-rechargeable battery.

Who makes the longest lasting batteries? ›

Energizer AA Lithium Batteries, World's Longest Lasting Double A Battery, Ultimate Lithium (2 Battery Count)


1. 18650 Lithium Ion Cell Comparison
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2. Panasonic NCR18650G 3600mAh - the mysterious cell's capacity test
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3. Will China's 18650 Battery Beat LG, Samsung, Sony & Panasonic? Let's find out!
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4. Panasonic's NEW Battery Plant will BOOST Tesla and Toyota in America
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5. Fist look at the chinease version of the Sanyo NCR18650GA
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