Simulating PV with power supply & battery to test functioning of solar charge controller.

[apctjb]

I have an all in one inverter with built in MPPT controller that I would like to test, but don't have a PV array available at the location where I am testing.

I do have a 30V, 10A power supply but my inverter is 48V and the minimum input voltage for the MPPT controller is 60V.

So could I connect my power supply in series with a 48V battery (not the one powering the inverter) and then use the combined voltage/current of the power supply/battery combo to test the controller? On paper it looks like that could work but anyone with real world experience know if this will work?

 

[gnubie]

The power supply would need to be spec'd for stacked operation. If it's not you run the risk of blowing transistors since you don't know if they are spec'd to handle the higher voltages and any increased spike voltages if things disconnect unexpectedly.

If its a run of the mill Chinese power supply, you can essentially take it as read that the transisotrs etc would not be up to the task.

 

[apctjb]

Yup; cheap power supply off of Amazon.

Thanks, Not doubting what you say but if the power supply is not grounded then isn't the voltage across the power the supply the same regardless if it has another voltage source in series so not understanding where the increase in voltage is occurring. I get increase in current as the battery can supply way more current than 10a.

 

[gnubie]

It depends on how the power supply is designed but suppose there is some sort of over voltage protection in the unit and instead of clamping it is designed to open the DC output with a transistor. If there is a problem and the transistor is turned off it will now have 48V across it. TBH that's not a likely design but it is an example of how you can get your higher voltage across components by stacking power supplies.

 

[efficientPV]

Typically bypass diodes are used on the output of the power supply when stacking in series to prevent reverse voltage. Run in constant current mode with a set limit on voltage. Include a little series resistance.