Again,
CA is a specialized product for EV ,ebike DIY people not for average Joe. He need just bars displayed no subtracting, no multitude of electrical units which he does ot understand .
just get into skin of non tech person.
With good old Lead Acid it was relative easy simply because along with discharge voltage dropped so simply voltmeter was enough.
No so with Lithium where voltage drops little with discharge.
With lithium you need chip which can perform Columb count, which counts charge coming out of battery and charge put into battery.
sorry that is so specialized and electric tech stuff but it must be performed by chip if you want any meanenful results displayed.
here is Texsas Instrument chips who perform Columb count.http://www.ti.com/analog/docs/litabs...=1&familyId=64
those voltage based 3-light Chinese FULL-HALF-LOW indicators so popular on China brands are next to useless.