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d-ferdi avatar image
d-ferdi asked

night/sunrise detection problem mppt 75/50 with firmware 1.59

hello,

i have a problem with one of my mppt 75/50 and this is the only with the newest firmware 1.59 all other have version 1.17 and one 1.19.

to get date in the night, i install a little circuit to get power to the mppt und this works fine with all mppt 75/50 only this with the newest firmware makes problem to detect the new day. i reduce the supply voltage to less then 15v in my 24V system, but this don't help, next i will try to reduce it to less then 10V.

why does the mppt don't detect a new day, if the pv-voltage is over 5v under the battery-voltage over more then 12 hours ?

i don't like it, if i must insert a circuit, which set the voltage for a short time to 0 V.

goodby

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klim8skeptic avatar image
klim8skeptic answered ·

why does the mppt don't detect a new day, if the pv-voltage is over 5v under the battery-voltage over more then 12 hours ?

It would seem that externally powering the PV input, even with a low voltage keeps the mppt awake and unable to detect a new day.

The 75-50 mppt appears to start operating at PV voltages of about 7v, YMMV.

75-50-start-up.png


75-50-start-up.png (42.7 KiB)
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d-ferdi avatar image d-ferdi commented ·
hello,

i have 7 mppt 75/50 installed and only on don't detect a new day. all other detect a new day and the pv-voltage is between 20 V and 25 V in my 24-volt-system and the mppt which doesn't detect a new day have a pv-voltage of 14V and it is the only mppt with firmware newer as 1.19 all other have 1.17 or 1.19 as firmware.

i will try to reduce the pv-input-voltage to the minimum which is needed, to get the mppt online.

i have the problem, that i lost the connection to cerbo-gx if the mppt have no power, so i install a diode and a resistor between the battery and the pv plus pole. and it works find, only the mppt with the newest firmware makes problems.

i try to sync the mppts with my software, but this mppt don't support that.

goodby

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