Hi everyone,
I’m looking for advice on how to configure a Victron MPPT 75/15 for a specific use case. The usecase is needed for a university test.
I want to power a DC load directly from the solar array. The battery should only be charged , but not discharged to supply the load. In other words, the battery should act solely as a voltage reference and be protected from discharging, especially at night or during low sun conditions.
Background:
The goal is to use all the power provided by the solar panel directly in the load.
Is it possible to configure this behavior using the Load output and low voltage disconnect/reconnect settings or is there any other solution/workaround?
Have a look at the manual Section 5.2.2. You can set the load output to a user algorithm using settings of your choice so you could set something like load output on if Vbat>13.0V and off <12.9V. You can use the VictronConnect phone app in demo mode to test the setup.
Get the SmartSolar version as this is easier to configure via Bluetooth from a phone.
Yey, I have already tested this but with 14V and 12,5 V. The result is that it having a strange behaviour.
The input power is constant at 80W - until the first time reaching 14V it consumes the 80W and afterwards only ~40W.
I think this setting will always use the battery to power the load.
First problem, your load is listed as 180W but you only have a 100W solar panel. The solar panel will never produce enough power so you can not run your system as you plan because the load will always be trying to draw power from the battery. I will ignore that for the time being.
What you need to do in your case if you are keeping the battery full and never allowing discharge is to set the MPPT controller to only run at float settings, say 13.4V for both absorption and float. You may be able to run as low as 13.2V but you will need to check that out, this is a storage charge level. You only need to charge to 14.0V if you discharge the battery, if you keep it full you do not need to use 14.0V. You then set the load to stop at 12.8V which is just above the fully charged voltage of the battery so it never discharges. As soon as there is a small amount of solar the battery voltage will rise to 12.9V and you can turn the load on. Some testing may be required to develop the best settings for charging plus start and stop voltages for the load, but never go below 12.8V for load off.
