Does a MPPT Controller draw current at night?

[Wainui]

A friend stated that a Mppt controller will draw some current from the battery over night.
I have not heard of this.

[seandepagnier]

you can measure with an ammeter. It depends on the particular controller, nothing to do with mppt. Even solar panel directly will draw some current over night.

A well designed controller can reduce to microamps where even milliamps will not have significance in power consumption.

[thomm225]

Any controller will draw current but it's so low it's not worth thinking about...........

[rslifkin]

Most do draw a little power to keep the controller electronics running. For my Victron controllers, I think it's something like 20 milliamps. A more basic controller with less data logging, etc. abilities may draw less. The idle draw of the 2x MPPT controllers plus the battery monitor totals up to less than 0.1 amps, so I consider it insignificant for most purposes.

[HeywoodJ]

Short answer:Yes. Keeps the brains running. The Victron SmartSolar 75/10,75/15,100/15,100/20 family list their no-load "self consumption" at 10mA@12V, assuming a 16-hour 'night' from end of solar production to wake up the next morning that's 0.16Ah drawn from your battery. The next size up in the Victron family are listed at 20mA.

Morningstar lists their small units at "<1.2W". At 12V that could be as much as 100mA, so 10x what Victron claims but still not much. All depends on how much "less than" the less than is indicating.

[Madehn]

If there is a full bright moon I actually show a very small charge from my 1kw worth of panels and Outback controllers. 😀

[GILow]

Originally Posted by Wainui

A friend stated that a Mppt controller will draw some current from the battery over night.

I have not heard of this.

Some great answers already, yes they do, but unless your boat is powered by a small string of AA batteries it's nothing to lose sleep over.

[GILow]

Originally Posted by Madehn

If there is a full bright moon I actually show a very small charge from my 1kw worth of panels and Outback controllers. [emoji3]

I'm jealous. I've watched my 760 Watt array for any sign of power during a full moon and haven't found it yet. I've always felt there SHOULD be something.

[meirriba]

Also the inverter, if you have one, draws power constantly, even if nothing 220v is working.

[MJH]

Originally Posted by Wainui

A friend stated that a Mppt controller will draw some current from the battery over night.
I have not heard of this.

Yes but insignificant.

[goboatingnow]

It’s interesting to track the standby current when the boat is “ electrically idle “ , mines runs at about 120 mA in total

[noelex 77]

They do draw a small current in sleep mode. For my Victron 100/20 units it is around 0.02A @24v. As I have 3 solar controllers this amounts to 0.6 AHr @ 24v (equivalent to 1.2 Ahr for those with a 12v house bank) over a 10 hour night.

This is low, but not insignificant. To be successful when relying on solar power, especially in areas of poor solar insolation, means minimising parasitic loads that achieve nothing practical.

It is worth noting that this is when in sleep mode. This is the mode where the solar controller reduces its power to a minimum level. At the end of the solar day the consumption will be higher before the controller drops down to this lowest power mode. Also the controller needs to wake up at the start of the solar day and at this stage the controller will consume significantly more power. Finally these numbers vary from controller to controller. The Victron units have very low self consumption. Larger units tend to have a higher consumption.

[goboatingnow]

Generally with well designed switching supplies ( which is essentially what a mppt controller is ) standby current can be ignored as they are efficient when not generating power especially if the switching IC is modern

[Siberian Sea]

The panel meter shows mine is drawing a very very small amount, to put it in prospective my onboard Kenwood car type stereo when turned off is using more power to keep its digital clock face powered. Other onboard electronics also ghost draw power too.

[thomm225]

Originally Posted by goboatingnow

It’s interesting to track the standby current when the boat is “ electrically idle “ , mines runs at about 120 mA in total

Interesting?

Maybe if you are totally bored out of your mind.

Maybe you can monitor your CMOS Battery for your BIOS in your computer also is you really want some excitement.