Battery Musing: Does charging your batteries slowly lead to a more complete charge?

[Mooch]

I had an interesting conversation with a fellow vaper about whether charging at different current levels affected how much capacity you could get from the battery. Does charging slowly result in a more complete charge and more vaping time?

Let's find out.

I charged a Samsung 25R at four different rates, from 0.5A to 4A, and then discharged it at 5A each time. As you can see in the graph below, the capacity the battery delivered down to 2.5V only changed by 1/4 of 1% (0.25%) across all four discharges. This is well within the normal variance you would see between any two discharges even if charged at the same rate.



Bottom line: Charging speed does not change the completeness of the charge by much, if at all.

Why? The li-ion chargers we use continue to charge until the battery is "topped off" and the charging current has dropped to somewhere between 10mA-100mA (0.01A -0.1A), depending on the charger. No matter how fast the battery was charged the charger will still wait until the battery is stuffed full of charge and the charging current has dropped to that level. This negates the effect of using different charging current settings.

Higher charging current settings will, up to a point, still speed up the charging process though. But higher charge rates can damage your batteries! Just be sure not to exceed the recommended rates for your batteries. Charging at 1A is a good compromise between charging speed and overall battery life for 18650's and 26650's. A rate of 0.5A is good for smaller batteries. Slower will never hurt anything though.

Part 2:
Does charging your batteries slowly lead to a more complete charge? -- Part 2

 

[Zipslack]

Thanks for this test! I'm comfortable (and feel safer) using 0.5A charging. It's nice to know for future purchase considerations.

 

[WharfRat1976]

Mooch, I have always wanted to know if higher amp charging on a standard charger affects overall battery life. Does it reduce overall battery life?

I always assumed higher amp charging was similar to lower amp charging as to the quality of the charge.

Thanks for the information as usual.

 

[Mooch]

Mooch, I have always wanted to know if higher amp charging on a standard charger affects overall battery life. Does it reduce overall battery life?

I always assumed higher amp charging was similar to lower amp charging as to the quality of the charge.

Thanks for the information as usual.

High amp charging does indeed affect your battery, depending on how high...
Battery Musing: Can fast charging damage your battery?

 

[Chemical Bromance]

All these considerations were giving me sleepless nights; trying to decide the best way to charge my Therion and Triade. Both mods have a ....ty rep for shredding the battery wrappers. Eventually, I decided to just give up and charge the batts in the mod. They're plugged to a multi-port high-speed USB charger, putting out 2.4Ah per port. I'll let the DNA boards reg the power being fed to the batts.

Thanks for all the work you've been doing, Mooch. You're a godsend!

 

[Assi]

I agree with Mooch and wanted to add just one small issue. If you Charge a battery with low current (up to 0,5C), you can use it directly after it has finished to Charge. Using high current (above 1C) will require a certain break (battery have to cool down).
Mooch mentioned that high charging current affect the life-cycle of a battery. This is one of the biggest Challenges of the Electric car industry. How you can Charge the battery as fast as only possible without affecting the cycle-life of a battery and without needing any break after charging.