Classic 150 reports 87% capacity, but Rosie shuts off due to low battery

[qrper]

Everyone!

Last night the wife tells me that it's cold in the house. I get up and sure enough the furnace is off. It is being supplied juice from Rosie. Sure as @*#& stinks, Rosie has powered down. This time, there is an error saying low battery disconnect.

Lead acid batteries are reporting 48V.
Wizbang Jr reports 87% SOC (on the classic 150)

MN battery monitor reports 80% charge.

This morning, I checked the specific gravity of the acid, and whoa! The BATTERIES are sitting around 1.150SG, certainly a discharged state.


So, why am I seeing all these good numbers, yet the battery bank is clearly not at 87% SOC.

When Rosie shut down due to low battery, the SOC as reported from the whizbang jr says 87%

Clearly something is rotten and it's not in Denmark.

mike

[ClassicCrazy]

The SOC is always just an estimate.
I have found in the past that the Whizbang on the Classic is pretty accurate. That is unless you do a firmware update then it needs to cycle all the way to absorb and float  once to get back to being accurate again.
There are some settings on the Classic at least , that need to be set up correctly at the beginning for lead acid batteries to make it accurate. You need to watch it charge to full and check the electrolyte on flooded batteries to confirm that at 100% the sg is also showing 100%. There are also the efficiency and capacity numbers to adjust to make the SOC more accurate. For my system I would rather have it be a bit more conservative so I would know that I had plenty left so lower the capacity from what the manufacturer says . Also I would set ending amps which I want to terminate absorb and go to float at the 100% SOC point as confirmed with SG reading.
The temperature compensation has to be set right too.
Larry