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Upgrading from 12v to 240v wired off grid

agnexus

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Jun 6, 2022
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Hi all,

New to the site and hope I can get some advise.

I have an off grid weekended running a 12v power system. 2x250w 12v panels + 20amp MPPT and a single 12v 200ah LiPo battery. I also have good wifi in tue shed.

I was given 16 x 36v x 190w panels second hand and in the process of upgrading to 240v. The weekender is fully wired which can be run off a generator when needed, mostly use 12v for lights, fridges x 2, water pump etc.

I have purchased and additional matching 400ah battery - the BMS can run up to 3.

I have also ordered a Victron 12/3000-16 charger/inverter as will cover my needs and also has the seperate direct generator circuit output for the high amp workshop tools.

My question about settting up the panels.

1. Do use a single MPPT controller or multiple - I an considering the Victron 150/100
2. What is the best configuration to connect the panels - 4x4, 2x8 1x16. I was told banks are best incase 1 panel drops out you dont lose the whole array?
3. Are there junction boxes I can use to connect the configuration.
4. In would like to remotely monitor the system and seems the only option is the Cerbo GX - happy to consider another controller if they have wifi

thanks Scott
 

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That’s a lot of basic questions.

I have some:

Are you not in North America (why 240V?)

Did you know you’re way undersized on batteries for that many panels? Plus the 18S you mention will be over 800VDC and that is super-killer voltage. 6S3P is 270VDC. Still high voltage.

You have two fridges In a weekend cabin? So you want them on 24/7/365.

Are you keeping the 12V system?
 
No not in Nth America - correct.

Yes basic questions hence posting in Beginners Corner - hope that make sense?

I am not sure what what 18S is however assume the panels are wire in parrallel so would be putting out 36v at about 80amp max into the MPPT which steps down to 12v. Just not sure they should be baksnpf parallel into seperate controllers or all parallel together into 1 large one?

The two 12v fridges both Engels are happily run on the single battery at the moment. I will keep the 12v system and take the circuit from the batteries prior to going into the Victron 240v inverter.
 
am not sure what what 18S
18 Series. Lotsa volts
is however assume the panels are wire in parrallel so would be putting out 36v at about 80amp max into the MPPT
That isn’t in your best interest for two cable reasons: lots of them, and heavy cables; and one practicality: the mppt will do better with some series panels on cloudy days.
which steps down to 12v. Just not sure they should be baksnpf parallel into seperate controllers or all parallel together into 1 large one?
I would pick a controller that could handle the volts and do 4S4P (four series four parallel), leaving two panels you could put on a separate controller. The issue is 6S is 270V… 4S is 180VOC and under the 250V max (?) of the bigger victrons I think. Or do they all max at 150V?
will keep the 12v system and take the circuit from the batteries prior to going into the Victron 240v inverter.
So you are doing 3000W on 12V? At 240 that’s more doable.
 
Thanks that is great and makes sense 4S4P configuration will work and the Victron will handle that according to their specs.

Appreciate you help thanks
 
The "not in Nth America" and 240V inverter statements are quite confusing for me. Are you trying to match with the European standard of 230V at 50Hz? At power levels this high, you really should consider going with a higher system voltage, me thinking 48V.

I'm not a fan of DC appliances. Do you really want to keep the 12 refrigerators? My personal choice was to go with a standard AC frig, and I've been very happy. Are you actually shopping for a 12V to 230VAC inverter?
 
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