question

Paul B avatar image
Paul B asked

Blue smart ip65 12volt 25 amp has very low output amps

My blue smart charger is outputting only 0.8 amps. The voltage is at 11 volts.

It's currently in power supply mode but even in battery charger mode it's output does not go over 0.8 Amps as well.

Yet once the battery voltage increases to above 12 volts it's output then increases to its rated output.

So is thus a fault or is it a standard restriction.

It's charging a 300a/h lithium battery so there is no issue in the battery taking the amps.


Screenshot_20240507_215702.jpg

battery charging
2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

2 Answers
Justin Cook avatar image
Justin Cook answered ·

11v on a 12vNom lithium battery is in the danger zone of catastrophic damage to the cells, so it's entirely appropriate that the charge current is being restricted until the cell voltage has reached a safer threshold.

Judging by the behavior you describe, it's most likely nothing to do with the charger itself, this sounds like the battery's BMS is restricting current throughput until it sees the cells at a safe voltage to start full-bore charging.

2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

Paul B avatar image
Paul B answered ·

Hi thanks for your reply. I am well aware of the low battery cell issues and that is not what I am asking.

The batteries bms does not have a poor incoming current limited bms via a fet. So let's rule that out.

if I replace the unit with another non smart charger unit then full current is supplied


So going back to the issue is it normal for these units to restrict amps like this and if so what is the reasoning behind this.

It does not matter what mode it's in or what type of battery is selected the output current is restricted to 0.8 amps until 12v is reached.

Does anyone know if this is normal operation. Or a faulty unit

1 comment
2 |3000

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

Justin Cook avatar image Justin Cook ♦♦ commented ·

Removed the unnecessary epithet.

What you describe just sounds like the proper operation of "Recovery mode", as described in the user manual: https://www.victronenergy.com/media/pg/Blue_Smart_IP65_Charger_6V_12V/en/features---bsc---psc.html

0 Likes 0 ·