Victron 12/25 battery charger.

[Nightwatch]

Some eight years ago we had an electrical overhaul in the injun ole and associated bits and bobs.

 

Part of this was the installation of a Victron Blue 12/25 battery charger. Since, we haven’t really been in a Marina for any length of time, but we are now.

 

In another thread regarding our Eberspacher boiler, it was identified the lack of full charge to our reasonably new battery back. 4x120 wet acid. According to the Victron BMS 702 I think, the reading was something in the region of 12.6 volts.

 

We started the engine and the battery bank via the alternator went up to 14.5 volts or thereabouts. (Still didn’t flash up the boiler, but that’s another issue.)

 

So, should I be expecting the battery charger to be charging to a higher extent than the 12.6. (Ish) volts that it is actually achieving? 
 

We are of course on shore power.

 

Would it make a difference to the higher voltage charge (float) to fit a larger charger? Do we have a defective charger? Is there a setting that can be changed on the charger to achieve higher charge?

 

Treat me nicely, simple terms please.

 

Thank you.

 

 

Edited December 7, 2022 by Nightwatch

[nicknorman]

Once the charger has charged the batteries, it goes to a float voltage of 13.2v, according to the spec. So if you are only getting 12.6v something is not right, and the batteries will not be fully charged. But there are some caveats:

 

Is the 12.6v seen when there is no load on the batteries? If there is a lot of load such as an Eber trying to start up plus the usual fridge etc, then this exceeds the maximum output current of the charger and the voltage will decrease below 13.2v. This is normal.

 

So, what is the voltage with no significant loads on? If it is 13.2v then that is ok. If it is 12.6v then that is not OK.

 

One thing to try is to cycle the power on the charger (turn the charger off, wait a bit, turn it on again) and monitor the voltage and current on the BMV. One would expect to see a fair bit of current initially, decreasing fairly quickly as the voltage rises to 14.4v. If nothing much happens, voltage stays around 12.6v then the charger is faulty. If there are several hours of high current before the charger goes to float, then something is up with the float phase, maybe the boat’s loads have been too much for the charger.

 

Anyway, do a bit of experimenting and report back..

 

[GUMPY]

The Victron isn't in power supply mode is it?

Power supply mode puts out a fixed voltage irrespective of the SOC of the batteries.

 

[Nightwatch]

1 hour ago, Loddon said:

The Victron isn't in power supply mode is it?

Power supply mode puts out a fixed voltage irrespective of the SOC of the batteries.

 

I will look at the unit. 

1 hour ago, nicknorman said:

Once the charger has charged the batteries, it goes to a float voltage of 13.2v, according to the spec. So if you are only getting 12.6v something is not right, and the batteries will not be fully charged. But there are some caveats:

 

Is the 12.6v seen when there is no load on the batteries? If there is a lot of load such as an Eber trying to start up plus the usual fridge etc, then this exceeds the maximum output current of the charger and the voltage will decrease below 13.2v. This is normal.

 

So, what is the voltage with no significant loads on? If it is 13.2v then that is ok. If it is 12.6v then that is not OK.

 

One thing to try is to cycle the power on the charger (turn the charger off, wait a bit, turn it on again) and monitor the voltage and current on the BMV. One would expect to see a fair bit of current initially, decreasing fairly quickly as the voltage rises to 14.4v. If nothing much happens, voltage stays around 12.6v then the charger is faulty. If there are several hours of high current before the charger goes to float, then something is up with the float phase, maybe the boat’s loads have been too much for the charger.

 

Anyway, do a bit of experimenting and report back..

 

Checked just now. It is showing a fluctuating reading of no less than 13.5 and upper reading to 13.8. So all seems well. I will isolate shore power and monitor what happens.