Victron MPPT Load Output will Not Run My Fridge :-(

Victron MPPT Load Output will Not Run My Fridge :-( main image Victron MPPT Load Output will Not Run My Fridge :-( image

PROBLEM:  The Victron MPPT load output will not run my fridge/water pump/inverter/heat lamps etc

A common complaint is that the load output will not run a fridge.  The load output is designed to run small resistive loads; a small fridge may have as much as ten times the surge current as the manufacturer's suggested: "run current".  The overload protection circuit sees large surge loads as a potential short circuit and trips to protect the MPPT, therefore, disconnecting the load output.

Victron's advice re MPPT load output operation is that the MPPT sees surge loads as a short circuit and engages the short circuit protection.  The only thing to be done is to work around it: power the fridge etc., directly from the battery.

SUMMARY ON LOAD OUTPUT DETAILS AND LIMITATIONS:

In summary, the load output is designed for resistive loads and is short-circuit protected.  Because of that, it is not possible to power (sizable) halogen lamps from it, even though you might expect so when looking at the amp-rating of the lamp.  Halogen lamps draw a multitude of their rated continuous amperage for a relatively long time; tripping the short circuit protection (with reason; without it, the MPPT could suffer damage)

  • Same for fridges and also inverters (capacitive loads).
  • See the Solar Charger manual (refer PDFs & Downloads on each product) for how to wire an inverter directly to the battery and still switch it on/off with the load output
  • Same applies to other loads with surge current on startup
  • The disadvantage of wiring loads directly to the battery is that you can't see their current draw in the VictronConnect app; or other visualisation.  To work around that, install a BMV battery monitor or smart shunt.
  • Some have asked if it's possible to disable the short circuit protection: the answer is no; that's not possible.  The design is nice for most systems but has limitations, and that's just the way it is.
  • After switching the load off, when a real or imaginary short-circuit is detected, the MPPT will retry within a few seconds.  So when you have a big load (halogen lamp, fridge, inverter, or anything else) that is being switched off and on every few seconds, disconnect it and wire it differently.

Sunergy recommends that fridges, water pumps, and inverters NOT be run directly from any Victron MPPT's load outputs.  Such loads should only be run directly from the battery.

As mentioned above, you could use a relay on the load output; these are cheap and readily available (some basic electronic knowledge required).  This won't allow the load of the fridge to be seen via the MPPT but will give you load disconnect functionality, and this will be settable via the Free Victron Connect app.

If you take this approach you can see the load of the fridge via a battery monitor (BMV) or SmartShunt.

If you need any further information, please contact us.