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the-salmon avatar image
the-salmon asked

Off-grid system configuration Multiplus II + Pylontech battery

Hello folks!

I'm studying an Off-grid system to be installed in a mountain house, which will be mainly used during the weekends.

I'd like to ask you some advices on the equipment I selected:

Item Qty
MultiPlus II 3000VA 48V 2400W 1
2.4kWh 48V Pylontech US2000 Battery 1*
300W solar panels 4*
MPPT BlueSolar 150/35 1
Control Venus GX 1

* Qty may be expanded in the future

My questions is: will my system work? Is the selected equipment compatible?

Is there anything to correct / improve?

Thanks a lot! Any suggestion is welcome.

Matteo

Multiplus-IIMPPT ControllersPylontechVenus GX - VGXoffgrid
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3 Answers
ejrossouw avatar image
ejrossouw answered ·

@the_salmon The short answer is it should all work, but it may be worth consulting the below resources e.g. Pylontech recommends 2x batteries for your configuration. As for the panels, if you know exactly what you will be buying, run it through the configurator as there are many variables that apply such as temperatures etc. Take some time to make sure you get the details right and especially fuses etc. Not sure what loads you will be running off the inverter as that is typically what determines the size of your batteries. Don't forget lithium typically batteries don't charge at temperatures under 5 degrees or thereabouts,

Hope it helps.

https://www.victronenergy.com/live/battery_compatibility:pylontech_phantom

https://www.victronenergy.com/solar-charge-controllers



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the-salmon avatar image
the-salmon answered ·

Thanks a lot @ejrossouw! I will definitely follow your suggestion to use the configurator, I didn't know that. Regarding the battery I already had a look to the link you pointed out, but I'm forecasting an average consumption of 1500 - 2000 Wh per day, only 2 days per week. Therefore I think the choice of 1 Pylontech US2000 Battery module should be OK, then I can upgrade it in the next years. What do you think about? Do you suggest other kind of batteries? Another question, do you see any drawback in choosing the MultiPlus II instead of MultiPlus I for my use case? Thanks :-)

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ejrossouw avatar image ejrossouw commented ·

Only a pleasure @the_salmon. The Pylontech batteries are a great choice and if you can stretch to the us3000 it will be better. The only thing to take into account is the discharge rate as that is why two batteries are recommended for the larger inverter which matters if you run e.g. a dishwasher off it. Personally I cannot comment on other than BlueNova and LG Chem, but if you stick to the below and ensure it has built in BMS, it is only a matter of how deep your pockets are and the space you have to place or mount them.

https://www.victronenergy.com/live/battery_compatibility:start

The new MP II is smaller footprint with slightly lower power consumption and some added functionality, which won't matter to your application. Both versions are fine. There are also an earlier version MPII which has m6 battery connectors which is now m8 on the latest model. Just be wary, if you buy an old MP, the earlier versions are not ESS capable, but that is not relevant for off grid.


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the-salmon avatar image the-salmon ejrossouw commented ·

Thanks @ejrossouw for your advice, I think I will go for MP II.

To sum up my system design (1 US2000 battery module with 2kWh capacity - sorry I cannot afford US3000) is fine with my current power consumption during the weekends: only TV, LED bulbs, small fridge - no dishwasher neither washing machine.

If in the coming years I will add those appliance I will need to buy another battery module, may be adding also another solar panels string, but without the need to change my MP II.

Do you agree?

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Schalk van der Merwe avatar image
Schalk van der Merwe answered ·

Hi

I have a customer with a similar setup (all the same except for US3000) and it runs perfect!!

Note the discharge limit on Pylon US2000 is 25A/1200W, and US3000 is 37A/1776W (there is a 'max' value that is more as well as a 'peak', but i normally design my systems on 'recommend' value).

Make sure your requirement/load is less. As long as you keep these limitations of Pylon in check, it is a decent battery for a competitive price. Spending ZAR5000 more to upgrade to US3000 is definitely worth it.

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the-salmon avatar image the-salmon commented ·

Thank you @Schalk van der Merwe. For the installation did you follow the steps explained in the following link: https://www.victronenergy.com/live/battery_compatibility:pylontech_phantom ?

Did you experience any issue in configuring the MP II or the Control Venus GX?

Regarding the US3000 I will think about that, thanks for the suggestion, the point is I cannot easily find it in the online stores (at least the Italian ones...). Let's see if I can find it at good price in some international stores.

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Schalk van der Merwe avatar image Schalk van der Merwe the-salmon commented ·

Hi, I absolutely followed that page (lets call it the manual), but that manual has been updated since (restart V was changed and prob other things too - https://community.victronenergy.com/questions/27536/multiplus-displaying-low-battery-alarm-and-wont-st.html?childToView=27624#comment-27624 )

Also, I honestly do not remember the table advising me that 2x US3000 is minimum on a MPII3000 (see section 2 on the manual) the first time i opened that link. I only installed one and it works perfectly fine.

Regarding your question on issues configuring: no, not at all. Make sure to get the MK3 if you buy the older MPII, i understand the new MP GX models program differently (attending this training on Monday, cannot wait to see them in action). If you haven't bought your kit yet, see if you can get them. The GX is integrated in MPII, very cool!!

Venus setup is just as easy, BUT, make sure you get the right cables from Venus to Pylon, do not try to use the one in Pylon box (see section 3 on manual). And get correct cable from Venus to MPII, don't crimp it if you do not have a crimp tester, buy the cable instead.

Lastly, update firmware on all devices when you start, if you have comm issues between devices this normally resolves them. Again, MK3 required on prev MKII to do firmware updates.

I hope it works, send a pic when you are done!!

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the-salmon avatar image the-salmon Schalk van der Merwe commented ·

Hello @Schalk van der Merwe! Thank you, I'll look for what is more conveniente among MP II + Venus GX and the new MP GX.

Regarding the connections I identified the following ones:

  • VE.Direct from MPPT to Venus
  • VE.Can to CAN-bus BMS type B Cable from Venus to Pylontech module
  • RJ45 UTP Ethernet Cable from Venus to MP II

The latter one can be used together with MK3 to upgrade MP II firmware and to apply the initial configuration with VE Configure.

Do I miss something? Thanks!!

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Schalk van der Merwe avatar image Schalk van der Merwe the-salmon commented ·

Yeah, that looks perfect!!

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the-salmon avatar image the-salmon Schalk van der Merwe commented ·

Thanks @Schalk van der Merwe!! One last question: Did your CTM install the 4 panels in two 2 rows? And in each row 2 panels in series. I think it should be the best solution...

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Schalk van der Merwe avatar image Schalk van der Merwe the-salmon commented ·

Hi

CTM?

Yes, I installed it 2 strings of 2 panels each, joined with a 2-to-1 MC4 connector and 1 pair of cables into combiner box. Be sure to increase fuses to 25A or 30A!!

If i may add something: from above i cannot make out if you do this at your own place or if you are an installer, If you are not an installer, please allow me to suggest something on safety devices as they are often neglected:

  • For PV I use small DB, with 10x38 fuse holders and fuses (15A/30A depending on strings), 15A/30A MCB (to break it if you have to do maintenance later) and SPD on the MCB.
  • On battery side i normally use a NH00 Fuse Switch Disconnect and in most cases even a 275A disconnect (sometimes the lithium battery is hard to reach in order to switch off, or locked in a cabinet as it is with Pylon).
  • On DC DB board i break my inverter supply and return with correctly calculated MCB, with SPD on main MCB supply, just as additional protection for my customer's investment! You will prob only have a return MCB (AC1 out) as it is off-grid;

These may not be perfect for every type of install, but it outlines the safety i use in every install.

I hope any of this helped, to protect your new investment, property and family!!!

I included some pics: inside mounting was a struggle. Luckily i threw that piece of ply in before i left. Without it i would have had to drive all the way back to town as other than the NH00 Battery Disconnect, it is the only bit that actually hit the stud. Not my prettiest work, but i am happy with it and so was the customer.

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the-salmon avatar image the-salmon Schalk van der Merwe commented ·

Hello!

Nice picture, I like the orderly installation of cables and equipment.

Indeed I'm not an installer, I will install that system at my place (a mountain house we'll use during the weekends). So far I focused on choosing the main system blocks and on the logical connections, later on I will focus on the electrical and power connections.

Thanks for giving me your advice! Could you help me to understand the meaning of the acronyms you used (DB, MCB, SPD)?

Thanks!

Matteo

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Schalk van der Merwe avatar image Schalk van der Merwe the-salmon commented ·

sorry :)

MCB - Micro circuit breaker

DB - Distribution board

SPD - Surge protection device

Then other things to please take in consideration:

  • stay away from doors, windows, etc. The inverter builds up heat and cools down, naturally water forms. In open entry ways this will result in dust build up. Unfortunately it is not always possible, but please take in consideration (like in my install, not a big house, not many spaces to install, the door does not open often)
  • was reminded yesterday again by my Victron representative: you buy an expensive battery and install it outside of cabinet, like parking an expensive car in the street sideways. If at all possible, mount inside the appropriate 'Pylon cabinets', it protects the front cables. If not possible, please use 'pylon mounting bracket' on a shelve, but take care to mount properly (again, not always possible, but i should have at least put the battery on the floor position inside a 2 shelve cabinet, not exposed like that). You can find cabinets by searching 'pylontech cabinets', hopefully you can source one for a price in budget.

This is at least 2 things not ideal in my install, i'm sure there are others too. But my point was to help you with basics on top of the general system config you enquired about: battery fuses, PV fuses and disconnect and AC disconnect. The rest you do as neat and safe as you possibly can. Try to use as much trunking as possible with flex conduit between trunk and devices, stay away from entry ways (to avoid condensation and dust buildup), label everything it so it is safe for anyone to use.

Good luck, and let me know how it turned out!!

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ejrossouw avatar image ejrossouw the-salmon commented ·

Shipping may be an issue for lithium so you may find buying two us2000's local may work out a better value proposition. I struggled to locate stock but on "brexit bay"you will find £1200 will buy you one without shipping. Germany certainly is good for electronics too.

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the-salmon avatar image the-salmon ejrossouw commented ·

Thanks @ejrossouw. Why do you say the shipping may be an issue for lithium, is it just a matter of cost? Or are there some technical worries also? Have a good WE!

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ejrossouw avatar image ejrossouw the-salmon commented ·

@the_salmon Cost mainly as these are typically 25kg upwards and secondly fire risk as is the case with batteries in general.

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