my solar project, with Victron Energy equipment

[lepikut]

Hi,

I have a summer cottage with no grid electricity so I decided to go with off-grid solar system.
I'm kind a "do it yourself guy", so I decided to purchase the equipment and do the installation myself.
Partly because wanted to save some money and partly because I wanted to learn and really understand how the system works and why some things are needed. After watching lot of your videos on youtube I decided to go with Victron Energy equipment.
I purchased Blue Solar MPPT 150/70 charge controller and MultiPlus 24/3000/70-16 inverter-charger,
also 4 Naps Solar Saana 250W SP3 MAW solar panels.

My solar array installation will be ground based and charge controller, battery bank and inverter will be close together.
Distance between PV array and charge controller is max 8m, distance from charge controller and battery bank about 1m and
battery bank from inverter about 0,5m.
Battery bank will be in isolated and ventilated box, separated from charger and inverter.
I have decided to go with lead-acid batteries (regular truck batteries) because of the budget issues, I don't have finances to invest to battery bank this year. These are planned for next year.

Even though my equipment is close together I decided to go with bigger wire gauge because to minimize power loss in cabling and as I work for ABB I will get switch-disconnectors with good price. As the distance is not so big I don't need to buy so much wires, and if I want to upgrade in the future I have some redundancy in the system.

You can see from the picture my system layout and wires and switches I plan to use.
I plan to connect 2 solar panels in series and then in parallel because I read from MPPT charge controller manual that best charger efficiency is reached when PV input voltage is twice the battery voltage.
Grounding for the system is not in the layout, but will be done. I have not forgotten that.

I also would like to get professional opinion about my system layout and wiring connections.
Some questions I have
1. In professional opinion is my system layout optimal for the equipment I have?
2. Are my selected switches, fuses correct and optimal for the wiring I'm planning to use?
3. Have I overlooked something critical?

I attached also ABB catalogue for switches.
Just check from the file and copy-paste OTDCP32S21M(page4) , OTDC200E11(page4 and 8 ) and OTDC315E11( page4 and 9) to see the details about the switches.

I know you have lot of experience with Victron Energy equipment, so any general suggestions or ideas are most welcome.

Anyone please feel free to send your comments, will be greatly appreciated.

Thanks a lot in advance,
Toomas from Estonia.

[SeanB]

Nothing much to add other than a nice enough layout, though you might want to have a fused switch on the battery desuplphator as well, just to protect the wiring to it.

[MJLorton]

Nice setup, I would also have a look at these links regarding wiring battery banks:
http://www.reuk.co.uk/Interconnecting-Batteries-for-Battery-Bank.htm
http://www.solarray.com/TechGuides/WireDiagrams_T.php

They have some handy info on how to distribute the current load across the bank.

[lepikut]

Thank you for the comments.
Would this battery connection be better?
Using isolated positive and negative busbars.

[SeanB]

Remember the sense lines need fusing as well, like the main battery bus. This however is a lot easier, just use a 5A fuse in each line ( positive and negative) in a DIN housing ( those nice swing out DIN mount fuse holders and 5A ceramic fuses. Overkill but if a sense line shorts that will cause a fire fast, high current and limited capacity on the cable, so it will get very hot very fast) to match the disconnects, and housed next to them.

Otherwise still looks very nice. I like ABB equipment, I have a lot of old Brown Boveri and Asea Brown boveri equipment at work still in use after a few decades of service. Only reason I often do not but the replacements from ABB are the cost for what often is a low power use. High power I tend to replace with the modern ABB equivalent where possible. I just have to find a replacement sometime for an old 5 pole contactor, 16A rated without having to go the route of using a regular contactor and additional contact blocks. the original is 5 pole straight, and has done 40 years of service but is getting old.

[rayngohd]

Hi all. Am also looking to do a similar system with the following:

1. I don't have grid power yet, but would like to design and install an offgrid solar system.
2. Similar setup based on self consumption Hub 1.
3. Solar Victron energy SPP280 (2 in series/8 in parallel [4.5kwp]) feeding into a Blue Solar MPPT 150/70, which charges a battery bank (48v: 4 12v batteries in series [220A)h); This connected to a 5000kva Quattro instead of a Multiplus inverter.
4. The inverter to provide power to a single phase Grundfos submersible pump (0.75kW, 7.45A).
5. Since there is no grid power in the area, can the small power plant work just by first charging the batteries using solar without the Quattro inverter initially being connected to a grid source or generator. In other words, can it start just from the charged battery bank.

Thanks you all in advance for your responses... :-)
Ray from Zambia

[tillt]

Nice project, looking forward for progres.