Hi everyone! I had an all in one off grid solar kit I bought when I first moved on my property. It was cheap and easy but it started showing signs of weakness so I am upgrading and really trying to understand all this off grid electric system thing. I bought the Victron MPPT 150/60 smart solar and also a good 500W solar panel. I thought putting two of them eventually but I am told that I cannot do that with the MPPT I have now… Is this a thing, like will it damage the system or the MPPT will just not exploit all the power of the solar panels? Also, I really want to get rid of my DC converter (taking so much power out of the batteries) and build a system to charge my laptop, phone and plug some lights on but I feel very intimidated and don’t really know how to set this up… Any help will be greatly appreciated!
Use MPPT Calculator - Victron Energy to find out compatability
Please describe your use case and situation more detailed so we can give hints:
- location (for weather)
- Appliances DC/AC
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- heat pump
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- water heating
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- EV
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- fridge
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- cooking
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- pool…
- Usage profile (temporary/weekend, permanent)
- possible direction, elevation and space for PV
- Grid ties or off grid
- If grid ties, need for offgrid due to land lines
For a laptop, fridge and some LEDs 1-2 panels on 12V is enough
For living a 48V system is better
@BjoernK is spot on. For a fridge, laptop and lights, you may also need an inverter as you are likely to have AC power thrown in. Also describe your existing kit if you hope to keep it.
Hi, thanks for this! I live in the south of France, we get pretty rainy and cloudy winters with hot and dry summers. I live there permanently and am totally off the grid. I currently have a kit I bought when I first moved in with 200w of solar power, a charge controller, a 600w inverter and two 100Ah lithium batteries. I have pretty basic appliances, low consommation lights I have to run on the inverter, a 12v fridge that is directly connected to the batteries, and I need to charge my regular appliances also via the inverter (laptop, phone, plunger mixer etc…). With this current set up I have enough power to run everything in the summer but not in the fall/winter. I also started to have issues with my charge controller (cheaply made) and had to replace it. I bought a Victron smart solar MPPT 150/60. Having now the app to track the power I also realized that my solar panels were defective (giving only 95w at their pic), so I bought a new 500w solar panel hoping it would be enough to run everything during the winter months but I would like to also install a water pump in the near future for the next project aka outdoor hot shower. So I thought to order a second 500w solar panel. Thing is I’m not sure I can do that with my new MPPT (they say max 880w). I read that it would be fine as in the winter I would rarely get the 1000w of solar power but I wouldn’t want to over power and damage the system during the summer months, is that even a thing or can the MPPT just regulate the power? Also I saw someone removing the inverter all together for charging phone and laptop for exemple, installing busbars etc but it seems pretty complicated to me as a beginner. Thank you so much for the help!
The 860w is nominal power, this is the max the mppt can use & convert at a given voltage, is is not the max pv power allowed.
If you go over the nominal, no harm will occur as long as compliance with other given specifications is adhered to.
If you simply use the link above to victron mppt calculator( provided free of charge for this tyoe of question) you will see if your mppt is compatible with proposed panels.
That’s the limiting factor: MPPT 150/60. The second figure always indicates the current, while the first indicates the voltage. At 48 V, the unit can deliver 2,880 watts, provided the panels can supply that much. However, not every Victron charge controller can handle 48 V, and the panel voltage must also be at least 5 V above the charge termination voltage (battery full). I have an MPPT 150/35 and will probably expand it with a second one. This simply charges my battery system.
To reach currents of 60 A at all, you would have to connect identical panels in parallel.
Hello, the Victron calculator isn’t very accurate for low power ratings. Just add a 20% margin to the open-circuit voltage (VOC) (for the first MPPT figure, 150 here), or less if the panels aren’t optimally oriented.
Bonjour @Louoffgrid
it seems your are not consuming much energy.
Victron’s MPPT Calculator shows a facto 1:3 between December and August. With one 500Wp panel you can expect 1 kWh/d in December and 3 kWh/d in August.
For very small systems e.g. caravan 12V is good. If you have bigger power demands like a “normal” house, 48V is better suited.
Most Smart MPPTs like your 150/60 support 12-48V, though can be reused when upgrading.
The first number of a MPPT is the maximum PV string voltage (panels in series). The second number is the maximum battery charge current.
As power is (battery) voltage multiplied by (battery) current, with a 48V system the same MPPT delivers 4 times the power compared to a 12V system.
The inverter/charger MultiPlus2 (MP2) or Multi RS do support either 12V OR 48V but not both.
I recommend you first thing twice how much power do you need in future.
Will you add an air condition (air air heat pump) for cooling in August (4-8kWh/d) and heating in April.
Will you add a hot water heat pump (500W, 2kWh/d).
Will you add StarLink (70-120W, 2,5kWh/d).
Will you add a wine fridge 
(0,5-1,0 kWh/d)
Laundry and dish washing machines each take some 1-3kWh per run.
If you have capable PV system, comfort and usage will increase.
In Germany we like energy saving appliances and calculate without air condition, heating and hot water:
1 person: 1.500 kWh/pa (4,1 kWh/d)
2 persons: 2.500 kWh/pa (6,8 kWh/d)
3 persons: 3.500 kWh/pa (9,6 kWh/d)
If you calculate 1.500 kWh/pa or 4,1kWh/d you would need 8 of your panels for winter time.
With a 48V system, you could reuse your MPPT 150/60 and create 4 parallel string each with 2 panels in series.
With an MP2 3000 you can supply normal house hold appliance up to 2400W, e.g. a laundry machine or water boiler.
On AC_in of MP2 you could connect a small generator if you run out of battery.
In any case I would go for a Lithium Ion Phosphate (LFP) battery.
I have a house boat located in Hamburg/Germany in my VRM with appr this setup incl 8kWh LFP battery. The boat is mainly used during weekend. During summer, the battery rarely supplies the weekend. During winter the battery never reaches 100% SOC due to base consumption from IT. Base load is 2,8 kWh/d. When people are on the boat, consumption is appr 10 kWh/d. They use electricity for heating water.
Use the MPPT Calculator with your panel to calculate your rough daily PV production. If you do not find your panel, use custom panel with the parameters from your panels data sheet.
If you invite me, I will help you build the system while my family is enjoying vacation in south France
I hope this helps a little…
Pls find a link to Victron Opportunity Loads.
It’s working in conjunction with a MP2 only.
If this of interest for you, pls ask if 12V MP2 is supported. Pls mind there is also a MP(1), which might not support the feature.
Let the thread owner confirm before buying.
I’d like to clarify: For Opportunity Loads, there is no restriction to a MultiPlus-II. Any Victron inverter/charger is supported.
@ptrenz
Are the Multi RS also supported? This was an open wuestion some days back.
Yes, they are. See the manual at https://ve4.nl/ol-manual