Charger question

Batteries and Chargers Rechargeable Batteries
1

Using Imax B6.

Put a battery in that reads with a meter 3.95 before charging.

B6 seems to ramp up the voltage as it starts to charge maybe to 4.07 as an example.

Is this because the charger is applying 4.2 to the battery ?

Display shows it takes it to 4.2 then controls the amperage once the battery reaches 4.2

Am i understanding correctly ?

2

I'm sure someone smarter than me will be able to answer your question.

In the mean time...

Welcome to BLF, mike20!

3

I just ordered an imax b6 tonight so I can’t answer your question but I can welcome you to BLF. So welcome.

4

Thanks much

5

Aloha and welcome to BLF mike20!

6

As long as the voltage is below 4.2 volt it will supply a constant current. When it reaches 4.2 volt the voltage will stay constant and the current will drop, until the charger terminates.

If you put it in a chart, it looks like this:

7

Kind of how I was guessing how it was.

Just making sure all my meters aren't bad.

The battery goes on the charger at say 3.90 and when the charger starts to apply 4.20 the B6 shows a higher voltage [maybe 4.06]

I'm assuming the higher B6 voltage reading is not resting battery voltage but [resting + the 4.20 being applied].

Might seem like a dumb question but I don't want to assume anything when I'm trying to stay safe.

Thanks, Mike

8

It's caused by battery's internal resistance. The older battery is, the longer CV stage will take (and the less mAh CC stage will put in battery).

IMR batteries for example have very low internal resistance so voltage under charging is not much higher than resting (OCV) voltage.

9

You are still not guessing how it is. If the charger applied 4.2V, 4.2V would be there.

10

A battery that is 3.91V at rest is pretty full. So when you put that in a charger, the voltage will go up to 4.2V pretty quickly and hold there as the current drops.

Just the same way, if you were to start discharging a battery that was at 3.91V at rest, the voltage would drop to 3.6V or so very quickly due to normal sag under load.

11

Not a problem, CC/CV is the charge algorithm for LiCO2 rechargeable.