Hi sorry if this is a silly question but its something i have seen and just need to understand/clear-up...
MPPT 450/100
SmartShunt
1300ah @ 48v AGM Batteries
So when my system goes to float (after Bulk then Absorption set as adaptive) after let say 2h can i assume my batteries are fully charged? why i ask is the SOC % reading is not @ 100%. This happens when its in the mid to high 80s% so do i have something se wrong or ?
Any help suggestions gratefully appreciated
Dave.
Hi @nesswill
That's a fair size battery. But you have all the necessary kit (& presuming VRM logging too), to never have to make assumptions at all.
One issue that stands out though with your mppt bar charts is that you rarely actually reach Float, which may be an issue.
Batteries are usually considered fully charged when they can't accept much current at the target V. AGM charge will taper off to a point where it won't go any lower (in a practical time), so considered full. This level varies with V, but at your 58.8V Absorb might be 2-3% of batt capacity, so 26-39 Amps. And maybe 10A or so at your set Float V. These are rough guesses, so please don't apply them as gospel, determine them for your own system.
The Adaptive charge profile is quite good, but given you have a Smartshunt and DVCC already enabled (SCS should be checked), you could use the Shunt Amps in the *mppt* to override Adaptive and drop to Float when you decide. You have 3.0A set there now, but you could use maybe 40A, and at that point your batts might be 99% done and can finish in Float.
The settings in your Smartshunt are such that it will never sync to 100%. So you're likely to be suffering drift, and the SOC can't be relied upon. Ignore it until you sort it out, maybe hit the manual in the meantime. Too much to add here.
