Matching SOC between systems

[LilMT]

Hey All,

Just an off-hand question regarding SOC.

I have a Classic 250 for charging with solar and a Magnum 4448 inverter/charger that I use to charge with my generator.  My Batteries are Renogy Hybrid Gel

When I get good sun, the Midnite will show full charge (I use ending amps) and then go to float. When this happens my Magnum typically shows 98%, after another hour or so at float (I have not actually timed it) the Magnum will show 100%

When I need to charge using the generator (also using end amps), the magnum will show 100% and the classic will show around 98%.  If I over-run the generator for another hour or so at float, the classic will eventually hit 100%.

Typically, this is not an issue during spring, summer, and fall, as I get enough solar to get the "top-off" on the magnum BMK.  During the dark season though, when I use the generator every couple of days, the classic will hit 98%, then the next run it will hit 95%, then next run 92%, etc.  By then of the dark season, it gets pretty out of whack.  I have gotten to where I reset the SOC% every couple weeks just to make myself feel better. 

I can understand a one-way discrepancy as electronics are different, algorithms are different etc.  But with it occurring both ways, it makes me wonder if I have a setting wrong.

BTW, 1 shunt, wizbang Junior for the Classic and Magnum BMK.

Thanks all.

[ClassicCrazy]

You really won't ever know since you don't know how the Magnum calculates SOC.
The Classic takes efficiency and temperature into consideration when calculating SOC.
Larry