SYSTEM
I've been running an off-grid system with 24 x 450W panels connected in 3 strings to an EG4 18KPV inverter & storing in a rack of 4 x EG4 48V 100AH LifePower4 batteries in the home we are building in Puerto Rico since January 2024.
We only got internet at the site last week, so I was finally able to install the dongle & upgrade all the firmware (batteries & the inverter both) to the EG4 latest versions.
I've been monitoring (like an addict) this system remotely since our return to Minnesota.
ISSUE
I am curious about the step-wise charge and discharge profiles on the batteries. When the energy stored drops to the teens, it takes forever to charge up to 21% or so, then it jumps step-wise to 35%, followed by another jump to 55% or so, then it goes to full 100% nearly instantly. Same with the discharge - step function.
I anticipated that the charge and discharge plots would be smooth curves, not these giant steps/jumps. It should be a discrete curve, not a step function.
I read here in the forum that the monitor software updates every 5 minutes, but that still doesn't explain the observations.
In PR, we are lucky to have amazing sun power, so the system is fully charged before/right around noon. Throughout the morning, the photon muscle is strong after 7am, and we are pumping 5-7KW or so into the batteries after the house load of a 1KW to 2KW. So with pretty steady wattage charging the batteries, we are getting a stepwise charging behavior, and same with the discharge.
WHY DO I CARE?
I feel like I am missing something fundamental here, and it is important to figure this out because once the batteries drain, we are screwed until the next AM. That happened to me for a week when we only had 2 batteries, and it is not fun. I am trying to gauge the real KWh left in the charged batteries so that I can plan my power consumption after 4PM when the temps drop to reasonable outside. I am making kitchen cabinets with power tools that will suck up stored energy fast. I am talking about a cabinet saw, a planer + a bunch of smaller tools. I want to have enough juice left for the AC's to keep me cool through the night.
Thanks in advance for your thoughts.