Victron 100/20 mppt cuts out load when in float mode.

Hi all I love this forum it is excellent for knowledge and I am sure in the market for some.

I have a 190w panel on my Landcruiser, this goes to a victron mppt 100/20 controller and then to my 105amh deep cycle battery.
I run a 60lt ARB brand fridge with this.
The problem is when the fridge is wired to the load on the victron it will fault out when it is a float state. It works fine in absorption and bulk states but not in float.
To get around this I have the fridge wired direct to the battery but I really would like it wired to the mppt load.
If anyone has any idea about this I am all ears.
I have even thought of a NTC inline rush current limiter but I'm not sure.

Kind regards from gippsland Australia
Chip.

Hey, Chip.
I couldn't find the amps required to run the fridge, but what I'm guessing is that when the fridge cycles on, you're overloading the charger.

As a general guideline, most of us do not use the load output from the solar charger for just that reason, and wire any large load directly to the battery.

Rider said:

Hey, Chip.
I couldn't find the amps required to run the fridge, but what I'm guessing is that when the fridge cycles on, you're overloading the charger.

As a general guideline, most of us do not use the load output from the solar charger for just that reason, and wire any large load directly to the battery.

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Thank you for your reply, what I struggle to wrap my brain around is that it won't overload in bulk or absorption mode tho. The fridge draws 5 to 6amps when running so i must test the initial start up current, it could be a case that the inrush pushes over 20amps but then why would it not overload in the other modes.

Probably because when you are in bulk or absorption modes, the voltage is higher and drops when you go into float. When the fridge kicks on, you get a drop, or sag, in the voltage. In bulk/absorption the momentary sag doesn't drop below the threshold to trip the alarms. In float at a lower voltage, it does. You'd have to record voltage at each step to confirm. Not familiar with the Victron. Does it have a min/max voltage reading in the menu somewhere? My EPever does, and it has been very helpful in making sure my voltage sages are not a problem.

I concur with Rider. The inrush amperage for fridge compressors can be 5x or more the running amperage. If the fridge draws 5-6 amps running it may be pulling 30+ LRA.

The Victron controllers are very accurate when it comes to measuring current on their output and also swift to drop the load if the rating is exceeded. Someone I know was tripping the output on a 10 amp Victron just by hooking up a buck converter. The load from the converter's capacitors charging was > 10 amps momentarily.

Some camping fridges don't even have a compressor they use either peltier devices (ridiculously inefficient) or are ammonia based, where a heater drives the cycle. Multi-power fridges, DC / AC / gas, will be ammonia based.

I don't know the specifics of the ARB fridge but it may even use a switchmode power supply off the DC supply. As the voltage input goes down the power supply draws more current to maintain the output voltage. That could be another explanation for why the unit trips the Victron in float mode.

How about increase your float voltage setting and see if it goes away.

i think this is what is happening and this video may show a way around it. i'm not great with this but either way being a compressor motor i guess it is better to leave the fridge connected to the battery.

I had a similar problem with running an exhaust fan from my load output on my boat. I think the fan was only 3 amps, but my 75/15 would not turn it on. I assumed it was inrush, but never confirmed it. I originally got around this by using a bosch style auto relay from the load output to connect the fan to the battery. This worked as the mppt would cut power to the relay if the battery voltage dropped below threshold. The only down side was that I didn't get the historical usage vs generation data I wanted. After a few days later I came across a YT video of someone with a similar issue using the same controller. They built a soft starter to smooth out the inrush and got the load output working.
Building a soft starter was beyond me so i looked to see if I could buy one. I ended up finding a brushed dc motor speed controller with the function on amazon. It does use some extra juice, however, it allows me to adjust the speed of the fan if i want to reduce noise and the soft start function allows me to run the load from the load output of the controller.
I paid $14 for it:

Here is the YT video on inrush and building a soft starter:

Hope this helps.
-e

Excpta said:

i think this is what is happening and this video may show a way around it. i'm not great with this but either way being a compressor motor i guess it is better to leave the fridge connected to the battery.

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Aw man, beat me to the punch... Great minds and all of that good stuff...

Eduardo Kang said:

Aw man, beat me to the punch... Great minds and all of that good stuff...

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Oh man so close haha. Thanks for your reply it is very interesting. I will grab a amp clamp today and see if I can get the max inrush current reading.

b.james said:

How about increase your float voltage setting and see if it goes away.

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This I will give a shot and will be very interested to see what happens. When I get a result I will be sure to let you know.

You could install a relay on the battery triggered by the load terminal so the controller still protects the battery, yet isn’t loaded by the demand.

In past I had idea to connect to load output some optional loads, so they will be powered on after battery fully charged, so extra energy can be used somewhere else. But I assume fridge is a thing that should be always on. Just wondering, what benefits you going to get by connecting fridge to the load output instead of the battery? Maybe low voltage protection?
By the way this article about Victron 100/20 load output might be helpful https://community.victronenergy.com/articles/2992/load-output-of-mppt-charge-controllers.html

Low voltage protection is one of the things but also it allows the Victron to see the load so it can more accurately determine when the battery is charged by watching the charge current. If the Victron can't do that it will fall back to a maximum amount of time that it will leave a lead acid battery in absorption charging.

Supervstech said:

You could install a relay on the battery triggered by the load terminal so the controller still protects the battery, yet isn’t loaded by the demand.

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Bingo. That is the most fun way to do it :D Much easier than making a soft start