Voltage compatibility of different 18650 cells

[bestsystem]

Recalling a few discharge voltage curves from various 18650 cells from LG, samsung and panasonic, they all have sightly different discharge curves.

High capacity cells from Panasonic have a more linear discharge characteristic which voltage continuously decrease with state of charge. It also appears that Panasonic is extending the capacity by allowing deeper discharge voltage. Unfortunately, many of my appliances like USB power bank, better flashlights and camera have some internal protection that will shut down itself at say 3.2-3.0V, so I reckon panasonic cells are often not suitable.

On the other hand some old formula (cobalt) may deliver near the same (gauged by running a camera, number of shots) runtime as a 3400mah.

So what is your opinion?

 

[bestsystem]

Also I have never owned a 3.8V (4.35V) 18650 cell, since they need a 4.35V charger.

I don't know what will my 4.2V gadgets respond to 4.35V cells? Will the battery monitor IC refuse to turn on or no problem?

Will it display 110% battery :laughing:

From t

 

[18650]

Also I have never owned a 3.8V (4.35V) 18650 cell, since they need a 4.35V charger. I don't know what will my 4.2V gadgets respond to 4.35V cells? Will the battery monitor IC refuse to turn on or no problem? Will it display 110% battery :laughing: From t

You don't do it unless you know the circuitry is designed to handle the higher voltage. It may or may not kill whatever it is you are trying to power and it may not be at all apparent at first. It could fail at some point in the near future instead of right away.

 

[cistallus]

Also I have never owned a 3.8V (4.35V) 18650 cell, since they need a 4.35V charger.

I don't know what will my 4.2V gadgets respond to 4.35V cells? Will the battery monitor IC refuse to turn on or no problem?

Will it display 110% battery :laughing:

From t

You don't do it unless you know the circuitry is designed to handle the higher voltage. It may or may not kill whatever it is you are trying to power and it may not be at all apparent at first. It could fail at some point in the near future instead of right away.

Actually, it should be fine. From 4.20 to 4.35V is only 3.57%; most electronic components have a 5% or 10% tolerance; even a regular cell can be within spec at 4.25V. If the light has a built-in state-of-charge indicator then yes it may throw it off a bit. The exception would be lights with built-in charging systems, they aren't going to completely charge a 4.35V cell.

I think the only way to really know which cell will give you the absolute longest runtime in a given device is to try different ones. Besides, this gives an excellent excuse to get more batteries, and then of course you need more lights to use those batteries.

 

[HKJ]

So what is your opinion?

Not an opinion, but tests: http://lygte-info.dk/review/batteries2012/Common18650Summary UK.html

Look for the charts called "Discharge, Capacity down to x.x volt"

 

[rc4u]

at my hobby store we sell a lot of chargers and batteries for airpanes helis and car.truck ect...good chargers can be set to what ever level of amps of discharge or charge rates, battery types ect....i just never see these type of chargers on the forums for lites...just the little wall warts that are preset ect....i dont use them as i have access to the better chargers...many have usb hookup to see actual curves ect for charging and disharging at whatever amps you desire....so doesnt any of the flashaholics have anything better for chargers or just the wallwarts...the internal resistance is the best indicator for best battery..which the better chargers tell you ..then you can match batterys to resistance....before lipos i did a LOT of nimh matching with my chargers...jeff

 

[SilverFox]

Hello Jeff,

Welcome to CPF.

A lot of people are just getting started. After spending $50 on a light, many hesitate spending another $50 or more on a charger. In addition, many are interested in lights and less interested in batteries.

Many of those that get interested in batteries gravitate to more advanced chargers. By that time they are willing to take the time to learn how to maximize the potential of the charger.

Tom