I am looking to install 4 Northstar SMS AGM 480 batteries giving me 868 Ah of total capacity. I been reading a couple of article on sizing but thought I would ask this community to weigh in.
868 Ah
868Ah * 10% = 86.8Ah.
868Ah * 20% = 173.6Ah
Even though the 20% value is outside the MultiPlus 12/3000/120. I would like to get your opinion on whether one or two MultiPlus 12/2000/120 units are needed. I also have a Northern Lights 6K generator and no solar at this time.
Thank you in advance.
Consider a 48V system instead.
It all depends on how fast you want the batteries to recover. It would take the Multi 3000 about 4 hours to move the batteries from 50% to 100% (900/120).
If the Multi 3000 provides enough AC output, a less expensive way to add more charging capacity may be to add a just a charger.
I would agree with seb71 that a higher DC voltage should be considered. There is no 48 volt Multi 3000 for 120 volts. 24 cuts currents in half. You would also benefit from about 16% faster charging.
The rule of thumb says a lead/gel/AGM battery should be changed with a current that is 10-15% of the capacity.
So for your battery pack 86.8-130.2A. That means you are perfectly fine with one MultiPlus 12/3000/120.
