Absorbtion Voltage

[Pelagic]

I am just finishing the Victron Multiplus installation for charging the 8 x DC260-12 AGM Fullriver house bank of 1040AH @ 24v

I need to select the Absorbtion Voltage most suitable for 24v and Victron offers two choices within the battery manufacturer's guidelines of 28.8-29.8V

Either; 28.8V or 29.4V.

The equipment and batteries are both Temperature and Line Voltage Sensed and compensated. As my goal is to bulk charge as quickly as I can on generator power I am tempted to use the higher 29.4V but would appreciate any counsel on whether this would be hard on the batteries and lessen their lifespan.

Here are the Victron selectable profiles;

Absorption voltage Float voltage Storage voltage Suitable for

28.2....................27.6........... 26.4 ..............Gel Victron Long Life (OPzV)
.................................................. ................Gel Exide A600 (OPzV)
.................................................. ................Gel MK battery


28.8.................... 27.6 ...........26.4.............. Gel Victron Deep Discharge
.................................................. .................Gel Exide A200
.................................................. ..................AGM Victron Deep Discharge
.................................................. ..................Stationary tubular plate (OPzS)


29.4.................... 27.6 ............26.4................ AGM Victron Deep Discharge
.................................................. ....................Tubular plate traction batteries in
.................................................. .....................semi-float mode
.................................................. .....................AGM spiral cell


30.0.................... 27.6.............. 26.4................ Tubular plate traction batteries in
.................................................. .......................cyclic mode

BTW the Pukerts Exponent on those Fullriver batteries is 1.18... Not sure if that is a good thing?

Thanks again for your advice

[btrayfors]

Pelagic,

You can set the absorption voltage to anything you like. The easy way to do this is to download the Victron software ("VECONFIGURE.EXE) from their website and use it on a laptop with their adapter for serial ports (serial port to Ethernet). Just unplug the ethernet cable from the rear of the remote, and plug it into the adapter. You then have a serial port connection to the laptop.

While the adapter is a bit overpriced, it's a one-time purchase and it really makes programming the MultiPlus a breeze.

The veconfigure software allows you to set many, many parameters for the MultiPlus, including the bulk, absorption, float voltages, times, max amperage, etc., etc.

That's the easy way.

The harder way is to fool with the dip switches using Victron's instructions in the manual. It can be done, but takes more study and time, IMHO.

Bill

[Pelagic]

Thanks Bill,

I have the adapter and software ready to use but my question relates more to what those settings should be.

You hear about AGM batteries being overcharged which is why I decided to invest in a large bank to keep the AH deficit proportionally smaller between charges.

What I need to find out is how high a voltage is recommended for longevity?

[btrayfors]

Since you can set the Victron charger to whatever you want...and you already have the gear necessary to do that...I'd try hard to get a specific recommendation from Fullriver. If you keep after them long enough with a clear and very specific question, you'll probably get a decent response (since they've gotta stand behind their 5-year warranty).

By the way, how many MultiPlus units do you have? I believe these are each only capable of about 60A @ 24 volts charging (120A @ 12V).

Bill

[senormechanico]

FWIW, here is a page from Lifeline batteries. They have modified their previous numbers.

Lifeline Batteries - Marine & RV Deep Cycle Batteries

Steve B.

[Pelagic]

Thanks Bill and Steve,

I am not sure I did the right thing but with all the manufacturers tying in longevity graphs to minimizing the State of Discharge (SOG) I went overboard and put in a lot of AGMs so that my AH capacity is about 500% of what a normal 24 hr consumption deficit would be at anchor.

So I want to program the chargers to speedily, but safely recharge a 20% Ah deficit.

Bill, I have just the one Victron Multiplus 24/3000/70 combi which is a 4 phase “adaptive” 70 amp charger, but I also have the Victron Skyla 50amp charger that can also be programmed to charge at same time and parameters. (Giving me potentially 120A charging)

Fullriver’s export manager has been great at answering my specific questions and have just come back to say “Our engineer confirmed that it is OK to use the 29.4v Absorption level”

Bill, as you said “The veconfigure software allows you to set many, many parameters for the MultiPlus, including the bulk, absorption, float voltages, times, max amperage, etc”

I am just not sure what are the questions I should be asking Fullrver as it relates to my installation and use?