I am trying to figure out the setting I should use on my Xantrex Charger/Inverter for amp/hour capacity. I have three 8G8D batteries wired in parallel. On the battery spec sheet, is says: Capacity at C/100 = 265 Ah, Capacity at C/20 = 225 Ah, Capacity at C/5 = 188 Ah. Now I now to find the total capacity of all three batteries I add up the capacity of each battery. So, do I add up the C/100 of each battery to get 795 Ah and use that number for the setting on the Xantrex? If not, could you please explain what I should use for the correct number. Thanks in advance.
Bob
Bob
What model Xantrex do you have?
That would be a Xantrex Freedom 458 Series - 20, Inverter/Charger. Thanks
C/20 is the number that is used to describe what is commonly called amp/hours (ah). You would have 675 ah between the 3 batteries which you get by adding the three C/20s together.
Thanks - that is interesting. What exactly does the C/20 stand for? Would it be 20 percent? I would have never thought of using the number. I have now the original batteries in service and the unit was set for 440Ah. Interesting that Foretravel set it for that number and not 675. Again, thanks for the info.
Bob
mine is set for 130 amp bulk charge rate with three mk 8g8d's
A 458 may only charge at 100 although.
Roughly twenty percent of the rated amp hour capacity is a widely accepted bulk charge rate.
Matches the 160 amp alternator that Foretravel fit on my 97.
Power loss through the cables from the alternator to the isolator then to the batteries probably results in 130 at the batteries.
My two cents
Newer chargers have battery temp sensors to adjust the charge rate to match the temp of the battery at the cable
Why Does a Battery Have a C5, C20 and C100 AH Rating? Can't They Make Up... (http://solarhomestead.com/battery-amp-hour-ratings/)
I'll just provide you a link as it'll do a much better job of explaining it that I can but C/20 is the batteries discharge over 20 hours, which is the most commonly used number.
Thanks! Great article - Now I understand why the C20. Again, thanks
Bob