Hello,
with a Multigrid-II running in an AC coupled on-grid ESS configuration, is/would it be possible to make a battery capacity test by
- asking the multi to stop doing the normal ESS work and
- asking the multi do e.g. a "charge => {0.1C / 0.2C} discharge => charge cycle"?
Thanks & Groeten - tullsta
Interesting concept and useful, I wouldn't have a clue do to deploy this through a Multi though.
It sort of relies on there being a dump load.
In practice, I have seen people use huge banks of electric fire elements, but direct on the batteries.
This raises some other interesting control questions.
But to your core question, the current sensor in the multi is not test equipment accurate. It is perfectly functional, but it is not precise enough.
If you had a BMV....then maybe we get onto the questions of how to make it dump the battery capacity to the grid.
Hello Guy,
thanks for the fast reply. I know that the Multi is not (calibrated) equipment, but I thought that for most sanity checks this would be accurate enough.
In case one had a BMV :) would it then be possible to make a battery-dump / battery charge (i.e. control for const current/power discharge) or would this be a feature request for the Multi's FW? => just ordered a BMV700 anyhow
Thanks & kind regards - tullsta
In case of a BMV and Peukert correction over there is no need for a calibratete constant Check.. just disload and compare SOC to realstate
Hello Peter,
do I understand it right that the BMV then does the Peukert correction on the fly while integrating power? Guess this would be needed since there is not a constant load discharge guaranteed and all discharge would be related back to C20 then.
Sorry - new in this domain...
Thanks - tullsta
I do this with a BMV and use the grid setpoint to discharge the batteries.
without a BMV a rough calculation will work, just count the time and current in VRM
