Cruisers Forum

Join CruisersForum Today

Thread Tools Rate Thread Display Modes
Old 23-09-2011, 07:58   #1
Dockhead's Avatar

Cruisers Forum Supporter

Join Date: Mar 2009
Location: [S]Hamble (Spring and Fall)[/S], Cowes (Winter), Baltic (Summer) (the boat!); somewhere in the air (me!)
Boat: Cutter-Rigged Moody 54
Posts: 16,468
Absorption Voltage?

My Victron charger/inverter -- newly installed this summer -- has an option to set the absorption voltage at 29.4 or 30.0 volts instead of the default 28.8 volts (equivalent, obviously, to 14.7 or 15 volts instead of 14.4 volts for a 12 volt system).

The manual says: "

Absorption time
The absortion time depends on the bulk time (adaptive charge curve), so that the battery is optimally charged. If the ‘fixed’ charging characteristic is selected, the absorption time is fixed. For most batteries, a maximum absorption time of eight hours is suitable. If an extra high absorption voltage is selected for rapid charging (only possible for open, flooded batteries!), four hours is preferable. With DIP switches, a time of eight or four hours can be set. For the adaptive charge curve, this determines the maximum absorption time."

I am struggling to get the specific gravity of my batteries up to normal after letting them go flat in May. I am wondering if a higher absorption voltage would improve the efficiency of the charging process.

I am using Varta Leisure Hobby semi-traction batteries. I have temperature and voltage sensors on the batteries.

Oh, and one other question: Anyone know how to hook up a computer to the late-model VE-Bus Victron charger/inverters? The manual is infuriatingly vague.

Dockhead is offline   Reply With Quote
Old 23-09-2011, 09:11   #2
Moderator Emeritus
GordMay's Avatar

Cruisers Forum Supporter

Join Date: Mar 2003
Location: Thunder Bay, Ontario - 48-29N x 89-20W
Boat: (Cruiser Living On Dirt)
Posts: 29,377
Images: 240
Re: Absorption Voltage?

According to the VARTA Instruction Manual

“... Recommendation:
a.) Standard charging method:
IU charging characteristics with I = 10 % of nominal capacity.
The maximum charging voltage should be 14.1 – 14.4 V.
b.) Permanent charge:
Limit charging voltage to 13.38 V (2.23 V/cell).
If charging voltage is below 13.2 V (2.20 V/cell) an additional charge with
higher voltage is necessary in regular intervals to ensure the battery is
completely charged.
In alternative use charger with IUoU charging characteristics with I = 10 %
of nominal capacity.

c.) Charging to avoid acid stratification
Use IU charging characteristics with a higher charging voltage (up to 16 V).
This „overcharge“ should only be used for short time period to avoid
water loss.

- The OCV (open-circuit voltage) after charge should be 12.7 – 12.8 V.
- For every 0.1 V difference to 12.7/12.8 V the battery should be charged for
1 hour.
Gord May
"If you didn't have the time or money to do it right in the first place, when will you get the time/$ to fix it?"

GordMay is online now   Reply With Quote

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
Battery Isolator with Battery Drain Bensigler Electrical: Batteries, Generators & Solar 83 28-11-2011 12:50
Battery Monitor vs Voltage sailorboy1 Electrical: Batteries, Generators & Solar 51 20-08-2011 17:12
Voltage Drop . . . How Does it Affect Amps? MarkJ Electrical: Batteries, Generators & Solar 43 17-08-2011 13:41
For Sale: Laptop 12vdc to ~17vdc Voltage Booster lucseawalker Classifieds Archive 0 14-08-2011 16:16
Charging Voltage on Mixed Banks truant Electrical: Batteries, Generators & Solar 1 09-07-2011 02:16

Our Communities

Our communities encompass many different hobbies and interests, but each one is built on friendly, intelligent membership.

» More about our Communities

Automotive Communities

Our Automotive communities encompass many different makes and models. From U.S. domestics to European Saloons.

» More about our Automotive Communities

Marine Communities

Our Marine websites focus on Cruising and Sailing Vessels, including forums and the largest cruising Wiki project on the web today.

» More about our Marine Communities

Copyright 2002-2015 Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 06:10.

Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2016, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2016, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.