Batteries vary quite a bit in regards to cycle life, which in turn are heavily correlated to what routine DOD you use. I am wondering if it is possible to add a feature to the Classic and the local app in which you can readily see how many cycles are on your bank. Much akin to laptops showing such information in their battery status menus. Due to differences in chemistry the end user would have to add in parameters such as battery chemistry to know what its ball park cycle life is. Such as : LiFePo4 being 2-3000 cycles at 80%DOD.
Also, I wonder if there is a way to gauge health of your bank as there is on my macbook air. Is there a way that a new software feature in the classic could accomplish this without actually having to fully charge a bank and then fully discharge it to determine actual aH taken out?
Just a thought.
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So it would be like a ticking down (doom) counter to constantly remind you when a BIG bill is looming to buy a new battery bank. :o
Personally I'd rather live in ignorant bliss and let that event happen when it needs to.
My trusty voltmeter would give me all the advance notice I need.
dgd
Notebooks can do that because they know quite a lot about their own batteries, and to some extent lithium battery capacity/life is more highly modelled/ modellable.
For off grid RE, it would be a nightmare to attempt to indicate much at all about battery health. However there are token metrics that might be doable, assuming they ever made it to the top of a long todo list.
As you said: 'average cycle depth', ought be simple enough.
Number of cycles, bit complicated by reboots, accurate time of day tracking (lites) etc.
Morning 'rest' voltage: fairly easy: take the highest voltage in teh half hour prior to solar production commencing.
Rest voltage v SOC, track changes over time: maybe...
Internal resistance: ought to be able to do something there using dV/dI (cant really at present because of too much rounding). Actually pretty tricky on a live bank, that is charging and discharging.
good logic ZB.
However, as a rough(ish) guide of battery cycles the SOC% max and min figures can be extracted from the ongoing SOC data from the WBjr
I decided to graph this as an option in the Arduino web server then at least I get a useable picture of daily battery cycles.
The column chart below shows how SOC went over a few days, 10% average Depth of Discharge with that clouded over couple of days taking it to 20% DoD.
This has me thinking that I may need to use that feature that delays an Absorb cycle for a couple of days every so often. AFter a 20% or up to 25% DoD then a full abs/float cycle the bank really wakens up and holds higher voltage longer.
I was thinking on how to improve this reporting and a dual column chart with SOC max/min and the resting voltage at max or near to it plus the battery voltage at the min SOC would, imo, tell more about the bank health.
dgd
That graph is certainly informative all right. Be interesting to see if 2050 improves the stability of my SOC.