deangi avatar image

ESS - MPPT not reducing demand on batteries

I have setup an ESS system with a battery and MPPT controller. Grid is turned off.

If I turn off the MPPT, the output of the battery does not change. Surely it should be discharging at a lesser ampage when the MPPT is producing power?



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What batteries do you have?

What other components are in the system?

deangi avatar image deangi Matthias Lange - DE ♦ ·
Currently, for testing, it is a 100ah AGM. Waiting for Lithium to turn up. Thanks.
deangi avatar image deangi Matthias Lange - DE ♦ ·
Sorry, further detail:

Multiplus 12/1600

100ah AGM

75/15 MPPT with 120W input

Cerbo OS on PI

Thats all. It is a trial system before designing a much larger one.


Is the mppt on the battery side of the shunt?
No shunt in system at the moment. I understood this was not a requirement. Am I incorrect?


From my understanding many of those values will be "Calculated" and not exact, especially without a shunt or BMS communicating with your GX device or inverter. If you can see watts coming into your system from the MPPT, I would not be too worried.
deangi avatar image deangi basil katakuzinos ·
Thanks for that.

I will get a shunt put into the system anyway and wait for the lithium battery to turn up before further testing.

All the best.

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