Need help with IMAX B6

[itsallgood]

Not sure if I am using this charger properly. I want to charge a 4S bank of 25Ah LIFEP04 using the IMAX B6 V2.
Setting the charge "profile" for 4S LiFE only gives me a voltage of 13.2v. I want to charge the pack up to full capacity or just under (14v) I can't figure out how to get the voltage up as I am assuming I need to in order to charge the battery up to nearly 100%. If I go into the setup to set a profile in memory there is a TVC setting that defaults to 3.6v but when I save the profile it still only says 13.2v 4S. What am I not getting or not doing right. It is not set for a balance charge but do I need the balance port on the IMAX connected to the battery anyway?

Really appreciate some insight. Thanks

 

[krby]

I don't have that IMAX charger, but it is similar to other balancing chargers that I am familiar with, so let's see if I can help.

Most of these chargers to charge in two stages, CC/CV. Constant Current then Constant Voltage. When you pick your profile, there is a termination voltage set, For LiFe, that is likely 3.65 per cell or a little above. Then you typically pick a charge current. Let's say for this battey, you chose 12A (so you end up charging at little less than C/2)

Constant Current
In the first stage (Constant Current), the charger looks at the battery's voltage and then applies whatever voltage it needs to in order to have 12A of current flowing into the battery. At first, this will be less than the termination voltage of 3.65V per cell. As the voltage of the battery rises, the charger raises its own voltage in order to keep the amps to the battery right at 12A. At some point, the charger's voltage hits the termination voltage and it doesn't raise any higher. The charger is now in the CV (Constant Voltage) stage.

Constant Voltage
Because the charger is keeping the voltage at this terminal level, the amps to the battery will naturally drop as the battery's voltage gets closer and closer to the charger's terminal voltage. These chargers typically stop charging when the current to the battery drops to some level like 1/10 or 1/20th of your initial max current setting. So if you're charging at 12A, the CV phase would end when the amps to the battery drops to 1.2A (1/10th) or 0.6A (1/20th of 10A).

So, if you're seeing the charger at some voltage lower than 3.65 when you first start charging, that is expected. It should keep rising toward 3.65V, then stay there (or a little above) until the charging current drops.

 

[itsallgood]

OK. Understand. I might just start charging and see what it does and hope that it does what you describe. Thanks for your response.