MPPT Controller input

DIY
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1

I am slightly confused
All of the MPPT controllers need 5v above the battery voltage to turn on and start charging it.
For a 12v battery-
Most of the 12v panels (even 200w ones) have load voltages at best, perfect conditions- 17-19v.
So much of the time they will be too low output to turn on the charging.

I bought a victron- and now my 12V 165w panel is not putting out enough voltage.
Should I be looking at a 24v panel just to charge one 12v battery?
I can only find one 300w 12v with high enough volts for charging a battery-
But can find a less expensive 250W 24v panel that has a high enough output.

Confusing that most of the 12v panels do
Not have enough power to charge a 12v battery with the victron mppts.
Do other brands have a lower threshold difference for charging?
Every thing I read says a 200W 12v panel
Should be enough- but…
They don’t seem to be.

2

You either need panels with a higher Voc or you need to add two or more in series.
This is where the mppt calculator can really help.

3

Calling a panel a “12V panel” comes from PWM controller times. MPPT controllers can handle higher input voltages, so using a panel with a open circuit voltage Voc of 34V for example is no issue. The higher the PV voltage, the smaller the losses on the cables generally.

4

Remember that the 5 volt threshold is at a time when the panel is not producing any power so the open-circuit voltage of the panel applies. Once the MPPT has started the threshold is in the 1 volt range.

Usually a “12 volt” panel will produce the necessary open circuit voltage to start the MPPT.