Charging the last 25%

[jelarv]

I’ve had my Mavic 2 Zoom for 1.5 years and I know that the standard charge time is 80 to 90 minutes for the battery. But what drives me crazy is when I will have less than 25% left to charge on a stored battery and it will take way more than the 22 minutes that’s require for “25%”of a charge. Is it me or is it something about the last 25% that takes longer? Or is it that when there’s only one blinking quarter of a green circle on a stored battery there’s actually more than 25% left to charge?

 

[MAvic_South_Oz]

I must say I haven't noticed this with my Spark or M1P batteries . . . in lead acid batteries the last stages of charging are deliberately slower for outgassing / chemical reasons, but lipos don't like trickle charging.

Have you checked your cell balances ?

 

[Pappy]

The charging amperage is reduced as the battery gets closer to the 100% charge voltage level. I see this with the Hanatora charger which has a digital display showing the charging amps. This reduction in amperage to top off the battery is why it takes longer to charge the last 10% or so versus going from a 20% to 70% charge.

Here's a graph showing how the charging amps slope starts to level out as when the battery gets close


Source: How lipo chargers work

 

[brett8883]

Yea this is how lithium based batteries get charged it’s just more noticeable with bigger batteries.