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7caper avatar image
7caper asked

Quattro supplied by solar only... Bad?

I would like to power a Quattro 48/5000/70 via 50volts DC from a victron mppt 150-35 which is hooked to 1200 watts solar. There is now no battery in the system. Is this bad or will it damage the Quattro? I tried it a few times an what I observed was the Quattro's red low voltage light lit when the solar had no output (passing cloud) and then came on when the solar output rose to over 50 volts. I would like to leave the Quattro multicontroller switch on with a load (a dehumidifier) of 200 watts 120v always connected to the inverter output. The dehumidifier then would run when the sun shines. Are there any issues with this setup? A better way to do it? Thanks for any input.

MPPT ControllersMultiPlus Quattro Inverter Chargersolar
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Tom avatar image
Tom answered ·

Without a battery source to store energy and retrive from, your Multiplus is going to constantly turn on and off and power surge from your MPPT just to fill the caps in your Multiplus. I bet you burn up both your Multiplus and MPPT. Of course neither appliance is engineered to work without a battery bank.

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7caper avatar image
7caper answered ·

Hi Tom @Tom. Thank you for your quick answer! I'm curious where you found out that the solar controller and the inverter are engineered to require a battery. I looked through the manuals I have and could not find any reference to it.

I'm also curious if anyone has an idea how to make this work without the additional cost of a battery that would continuously cycle.

Thanks for any input.

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Tom avatar image Tom commented ·

The solar controller is infact a solar charger. A charger, charges batteries. It is not a stable source of power. An inverter takes a stable DC source of energy and inverts it to a stable source is AC power. Clearly the inverter installation manual has an inverter connected to storage energy source (a battery). Batteries and compasitors store energy. Batteries release that source slowly and compasitors release energy quickly.

An AC inverter can take a stable source of power 110VAC or 230VAC from the power grid and convert it to a stable source is DC with out a battery. The grid is the stable source.

A generator Dynamo can provide a stable source of DC power as it is engineered to do so. An alternator is not engineered to provide a stable source of DC power as it is a PWM charger.

You you may get away of connecting your PV to say a DC motor but it it will function erratically since the voltage will go up and down based on sun availability. You cant connect the inverter directly to the MPPT as the power will fluctuate as well and since there are not enough compasitors to even out the energy the unit will surge, fault, shut down and turn on as soon fail.

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kai avatar image
kai answered ·

Running a quattro constantly without a battery is not recommended, the manual certainly implies it (section 1 - product is used in combination with a permanent energy source (battery)...).

see also:

https://community.victronenergy.com/questions/25592/multiplus-operation-with-a-battery.html

Is there a better (read: lower cost) way of doing it? Suspect not.

I have no idea whether leaving the quattro exposed to the conditions suggested would create long term fault conditions or if it would be warrantied by Victron. Consider a no battery setup experimental territory.

If you didn't have the quattro already or willing to consider it a sunk cost, maybe...? Not going there though as it seems to be a hypothetical at this point.



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7caper avatar image 7caper commented ·

@kai, Thank you very much for that info. I decided to go the battery route. Makes sense.

Thanks!

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David Gould avatar image
David Gould answered ·

I have run similar when testing but did have a very small battery bank using 4 7ah lead acid batteries in series and you could turn the output on and off on battery SOC, very low cost.

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