Freep wrote:
Keep in mind that Victron offers a lot more than just Bluetooth. Many of their components coordinate with each other, Victron also uses CAN bus, have developed the Venus Operating System for their monitoring and control features and opened it up for developers and DIYers. For example, a developer can run the Victron operating system on a Raspberry Pi and create their own custom monitoring and automation. And a lot of people do this.
So if you need that sort of interoperability and flexibility, it's hard to beat Victron. If you also don't mind paying the premium, then Victron is pretty much impossible to beat.
With all that said, it still looks like the claim that Victron uses some special lookup table for their Smart Shunt is false. It has a lot of great features, but that isn't one of them from what I can tell. And even if it is true, with most LiFePo4 packs you'll never be able to tell the difference between counting Coulombs and counting Coulombs plus using a lookup table.
There are a couple of features that make the Victron more accurate than many of the cheap-o monitors:
For lithium, an important feature is automatic syncing - you can program into the Victron what your fully charged voltage and tail current is, thus when you know the battery is full, the monitor automatically syncs SOC to 100%. This compensates for integral errors, which are always an issue with Ah meters/coulomb counters.
For lead acid, a big issue is charge efficiency - you need to put in more Ah to replace what you have used. The efficiency is typically around 90%. For example if you use 80 Ah from a 100 Ah battery, then charge it back up, the meter will show 100% full when you are still 8Ah short of full (actually 92% SOC), you do this for a week and the meter will be off by 50%. This is not a huge deal if the battery can sit on absorb for hours, but if you are trying to charge as quickly as you can, it is a big deal.
If you have a simple system and mostly camp with hook ups and maybe off the grid for a weekend, then the cheap meters are probably OK. If you have a more complex system and spend extended periods of the grid then you will appreciate the extra features of a better monitor. They are definitely not identical.
