Thinking about installing the Renogy 20 amp DC to DC charger

[Rob Culver]

Originally Posted by Wavery

That is exactly what you want. The controller is lowering the voltage from 32V (which is ~max output of the panel) to 14V which increases the panel amperage output from 6.7A to the maximum ~15A.

In order for a 30A controller to go past 15A, it would need higher voltage from the panel. Installing a 30A controller will not increase the amperage to the battery any higher unless you install a second panel.

The advantage that the MPPT controller gives you is that it will start charging your battery earlier and continue charging later in the day.

I have a 30A controller on my trailer with 640W of solar panels. I'll take a pic of the output of my setup when the Sun gets a little higher today.

Hi Wayne,
I agree that the MPPT controller, combined with the high voltage of the panel, and the high wattage, starts the battery charging earlier in the day and keeps it charging later in the day. With this 370 watt panel, I've already maxed out the 75/15 controller at 14.8 amps and 215 watts at 10:15 in the morning. And it stays maxed out all the way past 3:15 pm in the afternoon. So that's all good.

However, I have no doubt that my amperage in to the battery between 10:15 and 3:15 would go much higher than 15 and perhaps even 25 amps if the controller supported that and without having to add another panel.

What type of 30 amp controller are you using? Is it mounted in front of the sink? Does it require an extra ground wire for safety over and above the 4 positive and negative wires going to the panel and the battery? Thanks..