Blue Smart IP22 charging algorithm and operation

Q&A and troubleshooting
, ,
1

Hi. I need someone to help me with a friendly disagreement.

I was told by someone that smart staging battery charging is a sales gimmick, and that a lead acid battery controls the charge current of the charger and the charger only supplies the voltage, current being determined by the battery (ie, there are no stages).

I mentioned that with my IP22 smart charger, it starts with a constant 30a current, and switches to constant voltage and current becomes variable exactly at absorption voltage (set to 14.7v) on mine, and that the same behavior would be the case even if one set the absorption voltage to 14.4 v or whatever value the user set it to. Further, the manual states that the absorption stage is adaptive and varied depending on the time it took to reach absorption voltage. Obviously, this all has to take place within the confines of charging a lead acid battery. I mentioned that the charger has to be able to regulate charging current for this to happen.

So my question…does the charger control the charging current within reason, and how does it accomplish this?

Thanks for any info you can provide.

FWIW, in my case I am charging a 2x gc2 lead acid golf cart battery bank in my travel trailer. Charger works great as does all my other Victron things.

2

You are both right… :slight_smile:

The charger is limiting the charging current during bulk stage, because otherwise this will rise quite high because of the battery internal resistance and the charger need to protect itself. It is now in the constant current stage.

Then, the battery is slowly rising in voltage and at some point, because it is getting close to the target voltage, the current will start to slowly drop until almost zero at target voltage. From the point the current is starting to decrease from that limited value, the charger will be in constant voltage stage.

I keep saying this… We have all learnt at school Kirchhoff’s and Ohm’s laws…

Additionally, take a look at this: https://www.rohm.com/electronics-basics/battery-charge/charging-method