question

tom-bell avatar image
tom-bell asked

Hope this is not too simple. On my sailboat I recently replaced batteries with 6 145Ah sealed lead acid and have 1 year old Centaur 12V/100A charger. When charging SOC reveals 100% but input still reads as much as 20+ amps. When to stop my generator?

battery charging
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3 Answers
kai avatar image
kai answered ·

This is suggestive of the SOC meter being not accurately dialled in / configured. Did you old battery set have the same total AH capacity?


edit: looked up the other thread. If your old bank was 660AH, you will need to tell your BMV that the battery is now 6 * 145 = 870AH. If the BMV is left at 660AH, you can get into the situation where it thinks the battery is charged (100% SOC) when its not - which is probably what you are seeing. Change your BMV setting to 870AH, and charge until it resyncs (which should be around Vbat =13.X. X being dependent on your battery specs.)

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JohnC avatar image
JohnC answered ·

Yes, Tom. Perhaps you could revive that other question to see if you can sort that BMV.

To answer what you're asking here, and trying to convert from my own figures, perhaps 15 to 20A might be where genny run time isn't giving you much of a return on your fuel cost. Certainly if the Centaur has reached 'Float' status then you're there already.

What you do is dependent on a number of things, including your load habits, but watch that V. If you can keep it above 12.3 (with little or no load on) then you should be ok.

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tom-bell avatar image
tom-bell answered ·

Thanks for the replies, FYI I had already corrected to 870 Ah and then sync"ed. Thus I will go with the flotation and turn off Gen at that point which has shown 100% SOC

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