MPPT output voltage too high

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thtruck asked Apr 12, '23

MPPT output voltage too high

I have 2 mppt's, a 100/30 and a 100/50 both smartsolar. I have set them up with the usual parameters for a 24 volt AGM battery. 28,8 absorption and 27,6 float. But every time the mppts absorp at 29,14 and float 27.9 which i don't want.

I changed the floatvoltage to 27 volts but then the mppts float at 27,3.

I have reset both mppts but nothing seem to change this behaviour. What can be wrong?

In a couple of months i will change my batteries to LiFePo4 so i dont want my mppt's too charge higher then i want to.

The mppts were in a network but i removed that. Nothing changed.

MPPT SmartSolar

screenshot-20230412-161549.jpg (300.6 KiB)

screenshot-20230412-161644.jpg (289.0 KiB)

screenshot-20230412-161652.jpg (308.4 KiB)

vrm-voltage-absorption.png (336.3 KiB)

vrm-voltage-float.png (332.9 KiB)

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Answer 1 · 2023-04-12T15:31:11Z

nickdb answered · Apr 12, 2023 at 03:31 PM

Sounds like it is the temperature compensation adjusting the voltages.

32.4mV/C above/below 25C. At 15C (as per screenshots) that would equate to 0.32V, give or take.

As long as the compensation specs match the battery specs, compensating for temp is perfectly ok.

Else, disable it.

4

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thtruck commented · Apr 12, 2023 at 03:37 PM

But can i switch the temp adjusting off or modify it so the mppts will charge exactly to the volts i want them to charge? I've used the AGM standard user preset and then changed the floatvoltage only.

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nickdb ♦♦ thtruck commented · Apr 12, 2023 at 04:04 PM

Yes, just select the limit, it will provide an option to disable it.

You will need to change to “user defined” settings and expert mode first.

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thtruck nickdb ♦♦ commented · Apr 12, 2023 at 04:06 PM

Ok i will try that. Thanks.

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thtruck thtruck commented · Apr 13, 2023 at 11:54 AM

@nickdb That did the trick. Thanks again.

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float.png (353.9 KiB)

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