question

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phom asked

MPPT 450/200 tracker output issue

Hi Community,

I have recently been installing a set up which eventually will enable me to fully offgrid.

I have 2 x 5kva multiplus 2 inverters and at present 4 x Pylontec US5000c batteries controler by cerbo GX.

Once installed I added a MPPT RS 450/200 pv unit and temporarily connected 4 x 550W panels to string 1 to allow me to power up the building where the install is sighted which is remote from the main property ( to be connected later)

I have to day connected in series to string 4 6 x 550w panels and to string 3 4 x 550w panels. Switching on string 4 gave an additional 2200w which I expected but then when switching on string 3 string four drops to 1450 ish watts. It would seem to me that my system is limiting the pv overall to somewhere around 4300 watts but i can't figure out why.

Can anyone advise why this would be happening.

MPPT Controllers
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3 Answers
phom avatar image
phom answered ·

Hi,


After further investigation and your prompts I found the batteries were set to 85A max charge.


Many thanks..

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mvas answered ·

Assuming ...
MPPT String #1 = 4 x 550 Watt Solar ( 2,220 Watts )
MPPT String #2 = Empty
MPPT String #3 = 4 x 550 Watt Solar ( 2,220 Watts )
MPPT String #4 = 6 x 550 Watt Solar ( 3,330 Watts )
Correct?
Was your Battery Bank in Bulk, Absorb or Float mode?
How many watts was the Load?
At that time, did your system actually require more than 4,300 Watts?
The MPPT's will only generate the watts needed, at that time.
Per the Cerbo how was the power being distributed between the Battery Bank and Loads?

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phom answered ·

Hi,

Yes your assumption on each string is correct.

The battery was in bulk as I discharged yesterday using a granny charger on an EV. The batteries tis morning were at about 12%

The system was drawing 2200w this morning with EV on charge and any excess would have gone to the batteries.

the cerbo was sending 2200w to the EV and the remaining fron the 4300W to the batteries.


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