Magnum BMK "Auto" Battery Efficiency

[Ron Swanson]

What are your thoughts about the Magnum BMK's Auto efficiency algorithm?  It seems like they want you to use it.  I would like to use it if it works as advertised.  But they don't tell you how it works.  They just tell you to trust them.

[Robin]

This is one feature I will need to learn about. I know how we could do it, but it would have to learn about your batteries over time. The goal here would be to tell you when it was time to think about replacing your batteries. We talked about doing this all the way back at Trace Engineering. We never did it because we didn't think people would believe it.
I will talk to the engineers and see what they think about this feature. Depending on the complexity, it may or may not get added. All the electrical engineer are pretty busy, but we do have a lot of them, so who knows?

[Ron Swanson]

SMA has been doing it for years.  In fact I think that is pretty much the only way they do it.  But SMA seems like a much more mature, thought out product than the aforementioned which looks like an overgrown RV setup. 

It does not seem like it would be that hard to do.  Track the AH flows in and out and calibrate when able whenever the battery reaches gassing voltage.  Apply a sanity filter/smoothing so isolated events don't throw it way out of whack.

The problem would be end users with destroyed battery banks, shunts not installed in the right place, etc.

Anyway I was hoping someone on here was using Magnum and could tell me if it is a good idea to turn it on or not.

[boB]

I remember 11 or so years ago when I was working at Magnum that Brian, the guy that did the GMK had
a way to do this and wanted to put that into the code. I remember that it would work just fine but can't
exactly remember how he did it.

I would think that having auto-capacity calculation would be more useful.  THEN, auto efficiency would make
even more sense to have I think.

boB

[FNG]

I would think if you have a complete system (IE inverter and charge controller) and you can assume it is properly programmed it gets a lot easier to learn capacity and efficiency as you have the raw data as well as the transition to float etc in the memory of the device. keep track of voltage vs load and the AH removed at that point etc