Testing MPP Charge controller function with bench power supply?

[apctjb]

Anyone know if you can use a 5A-60V DC power supply to test functioning of a MPP charge controller. I have a all in one inverter with charge controller that I am testing in my shop before shipping to where it will be installed in MX. Everything is working great but don't have PV panels here and would like to at least test that MPP controller is working. My inverter is 48V and has a MPP voltage range of 60-115VDC.

 

[snoobler]

I would expect it to work.

 

[tictag]

I would not connect a regulated DC supply to an MPPT charge controller. MPPT charge controller are sophisticated devices that modify their apparent load to the supply (in this case a regulated supply) in order to identify the maximum point of the supply (in this case there isn't one - maximum power is delivered on all loads, hence regulated). It probably will work, as @snoobler, says but would I risk a test damaging a product that I would then be selling on? Probably not.

If this is a one-off, maybe give it a try and hope for the best. If this is regular, buy a PV array. You can pick up 400W or so for $100 these days, second hand.

Edit: corrected typo.

 

[Robin Gudgel]

It will not test the tracking feature, but you can use a power supply on the PV input as well as the battery output. We do it all the time.

 

[Forbisher]

Will Prowse emulates solar panels with a power supply on his video's.

 

[gnubie]

The MPPs seem to be fine with it, only thing to watch for is that the MPP doesn't attempt to draw more current from the power supply than it will provide. With a lab power supply that's fine because you can set a current limit, the voltage will reduce if that current limit is exceeded. A regular power supply will go into protection and drop its output to 0 etc... or if it's a cheapie it might let the magic smoke out. Under normal operation the MPP will try to satisfy the load's demand, be it the battery or the inverter so unless care is taken that might well result in protection or smoke.

 

[apctjb]

It will not test the tracking feature, but you can use a power supply on the PV input as well as the battery output. We do it all the time.

Thanks...curious are you "the" Robin Gudgel (Trace, Xantrex, Outback, Mid Night Solar)?

 

[Symbioquine]

In case other folks run into this question, I'll share what I ended up doing that seems to work okay;

It seemed unwise to use the same bench power supply for both the battery and PV inputs since it's not hard to imagine some sort of feedback loop occurring. Instead, since I don't have two bench power supplies, I used a cheap 12/24v power brick for the battery input and used my bench power supply for the PV input. As already mentioned in this thread, this means I can limit the current with the bench power supply and also more easily simulate different scenarios. All this is at pretty low total amounts of power - not sure what might break if I pushed the amps up very much...

 

[Tecnodave]

Thanks...curious are you "the" Robin Gudgel (Trace, Xantrex, Outback, Mid Night Solar)?

Yes, Robin Gudgel is “the Robin”......

 

[Short_Shot]

Reporting in to say I just did this yesterday without issue, though I didn't spend much time on checking it to the current limit of the power supply to see how it behaves. Just verified the charging voltage stayed constant across a few volt range up to 20v (75v mppt) and called it good.

 

[Short_Shot]

In case other folks run into this question, I'll share what I ended up doing that seems to work okay;

It seemed unwise to use the same bench power supply for both the battery and PV inputs since it's not hard to imagine some sort of feedback loop occurring. Instead, since I don't have two bench power supplies, I used a cheap 12/24v power brick for the battery input and used my bench power supply for the PV input. As already mentioned in this thread, this means I can limit the current with the bench power supply and also more easily simulate different scenarios. All this is at pretty low total amounts of power - not sure what might break if I pushed the amps up very much...

Why would you hook up a power supply to the battery output in the first place?

If anything you'd attach a load tester of some sort but not additional power.

 

[Symbioquine]

Why would you hook up a power supply to the battery output in the first place?

Many solar charge controllers require that battery input is provided before PV input - of those, at least some will not operate correctly otherwise.

 

[Short_Shot]

Many solar charge controllers require that battery input is provided before PV input - of those, at least some will not operate correctly otherwise.

Interesting.

Sounds like a good application for an old battery lol

 

[rin67630]

I am using a power supply with an old film projector bulb in series.
This will emulate the internal resistance.

On a long time planning I want to build a solar panel emulator that has a clear mppt and will have daily cycles.
Drok-Juntek-on-steroids I know i can program it, but i have to finish other tasks before...

 

[rin67630]

If this is a one-off, maybe give it a try and hope for the best. If this is regular, buy a PV array. You can pick up 400W or so for $100 these days, second hand.

Hmm: a PV-Array of 400W panels and their corresponding artifical irradiance ist somewhat inconvenient on an electronic test bench...

 

[Tecnodave]

A bench power supply is rather “stiff”, It does not drop voltage much when loaded like a solar panel does, so it cannot test the “sweep” function of the MPPT controller. One simple way is to use a bank of incandescent lamps as a variable resistor between the bench supply and the input of the MPPT controller. When the MPPT controller does it’s sweep function the incan lamps will vary their resistance with the varying voltage/current thus varying the voltage input to the MPPT controller thus allowing the maximum power point tracking function to work. This is only a rudimentary test but it will verify that the “sweep function” of the MPPT controller does indeed work. I use some 500 watt and 1000 watt lamps to provide this “variable resistor” which does drop the voltage when current increases much like a solar panel does.

 

[rin67630]

A bench power supply is rather “stiff”, It does not drop voltage much when loaded like a solar panel does, so it cannot test the “sweep” function of the MPPT controller. One simple way is to use a bank of incandescent lamps as a variable resistor between the bench supply and the input of the MPPT controller. When the MPPT controller does it’s sweep function the incan lamps will vary their resistance with the varying voltage/current thus varying the voltage input to the MPPT controller thus allowing the maximum power point tracking function to work. This is only a rudimentary test but it will verify that the “sweep function” of the MPPT controller does indeed work. I use some 500 watt and 1000 watt lamps to provide this “variable resistor” which does drop the voltage when current increases much like a solar panel does.

The lamps are only a rudimentary method: I use old 1000W Dia projector lamps too. But adding constant current is better.

 

[Tecnodave]

The solar panels do not exhibit constant current, I am attempting to somewhat “mimic” the charistics of the solar panels.

I would grab an old projector lamp if I saw one, very handy as a precharge resistor as well...

 

[rin67630]

The solar panels do not exhibit constant current, I am attempting to somewhat “mimic” the charistics of the solar panels.

In fact, the best simulation is constant current into a shaded panel.
Second-best is constant current into 2x18 silicon power diodes plus 2x by pass schottky.