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Table of Contents
Q1: I want to size or oversize my PV array, how can I do this?
See the blogpost Matching solar modules to MPPT charge controllers.
Q2: 75/10, 75/15 and 100/15 cannot be controlled by a BMS, what now?
By default the RX pin is already used to control the battery life on/off selection with the jumper. Use VictronConnect to change the function of the RX pin to remote on/off to enable BMS control. See https://www.victronenergy.com/media/pg/Manual_SmartSolar_MPPT_100-30__100-50/en/configuration-and-settings.html#UUID-b6cabb55-8d14-4fc9-190f-c0856aab60d3 for details.
Q3: My MPPT is only showing voltage readings, not currents and also no Watts?
Make sure to *not* connect PV minus to the battery. See the manual.
Q4: Can the output of the MPPT be used as a power supply, thus without batteries?
The answer is; it depends on the type of load.
During low current situations the MPPT control bandwidth is too small to be able to maintain a stable voltage. The result is that loads that need to see a stable voltage before they can activate or loads that require a certain “under voltage” to active will not be able to run.
Loads where under voltage does not apply, like light globes, can be operated without any problems.
Q5: What about grounding one of the PV array poles?
The MPPT is non isolated, meaning that the minus of the PV input is at the same potential as the minus of the battery output.
Grounding is always done at one point only, to avoid ground currents. For a battery system, grounding must be done at the battery.
Q6: The Solar Charger is not working
1. Check that the PV voltage is high enough compared to the battery voltage. Either read it with a remote panel or VictronConnect.
Or measure the voltage with a Volt meter. Make sure to measure the voltage on the terminals on the charger. Not elsewhere, to rule out any faulty wires or fuses. The panel voltage needs to be at least 5V above the battery voltage for the charger to start power conversion; see the manual for more information.
2. For models with a Remote on/off switch (a green two pole connector, labelled Remote L H), check that the jumper is in. L and H need to be shorted for the unit to switch on. Only the large models have this connector, see datasheet for details.
3. Check that the battery voltage is set properly in the settings (12/24/48).
4. Check for error codes.
If all above is fine, and still the unit does not operate, contact a dealer to have the unit tested.
Q7: Can I use the MPPT Solar Charger as DC-DC charger?
For example to charge a 12 Volt battery from a 24V battery bank?
Q8: Can I connect different panels to the same charge controller?
No. Under no circumstances.
Q9: Can I use panels with optimisers?