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schindi77 avatar image
schindi77 asked

Virtual load output on mppt 100/30 seems unable to switch ssr

I´m using an mppt 100/30 solar charger and the digital load output cable.

The cable is connected to a ssr 25 dd solid state relay.

Unfortunately the load output seems unable to switch the ssr.

I´ve 2 of the ssr´s, both switch when applying 5V, the current is below what my ammeter is able to measure, so below 10mA.

The virtual load output has a voltage of 5V when switched on which is dropping to below 3V when the ssr is connected.

Any Idea what I can do?

MPPT Controllers
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1 Answer
wkirby avatar image
wkirby answered ·

You should be able to get 1mA out of it. Any more and the Voltage drops steeply. It's quite high impedance because it is connected to the UART of the microcontroller.

You'll need to use a transistor to drive the input of your SSR. The front end of an SSR is usualy and LED forming part of the isolation. That LED usually needs a few mA to get going.

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