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Hello,
this new 100/30 is set to "User defined" battery profile with 13.9V absorption for 1 minute and 13.4 V float (equalization not used but set to 14.0V) however every morning it brings the LFP batts from around 13.0V o 13.1V to 13.4V but never tries to get them to 13.9V as can be seen on the graph.
I read in a different post here that it needs a minimum drop of 0.1V for LFP before it rises to absorption. What is the required drop for this "user defined" profile then?
I’m no expert but maybe the Absorbtion Stage is not long enough. I think I’ve read on this community that absorbtion should be set to 30 minutes and you have it set to 1 minute.
But as I say, I’m no expert.
Thanks Steve, it was deliberately set to 1 minute to effectively turn the absorption phase off, since you don't want that with LFP batts.
I’ve misunderstood your question; i thought you were trying to get the MPPT to push absorbtion voltage :)
Hi, try increasing absorption time; and, measure at the mppt terminals. And check what the mppt itself is measuring; and what state it is in.
I really cant see a reason for it to go from bulk (which normally ends once the voltage has risen to absorption voltage) before it has done so.
I’m not sure what the 0.1V drop is referring to.
Lastly: check temperature compensation.
Thanks for the reply, the graph shows the voltage and current directly at the output of the MPPT terminals as that's where the producer controller is situated. That controller then send the data back to the database and web server.
I can try to increase the absorption time to see if it makes any difference, but if it does, it sounds like there is bug in the firmware, doesn't it?
I haven't touched the compensation setting, but will check that, too.
The 0.1V drop I mentioned was referred to in another thread: It suggests that the bus voltage has to drop by some value first before the MPPT changes from float to bulk mode. Can you confirm that?
Say the batts get fully charged by 11AM, MPPT goes to float, then comes a big load which draws the batts down to, say, 70% SOC by 1PM. At some stage, the MPPT should decide to go back in bulk mode rather than just trying to hold the float voltage, correct?
