I am updating my off-grid home and I would love some feedback on my wiring diagram.
I have an old 24V system (lead-acid) that runs on Solar + a Hydro Turbine (Pelton). The turbine is very valuable to me, especially in winter, so I don’t want to lose it. Also my father (the owner) likes to reuse everything.
I am installing a new main system with Victron gear (48V) and Pylontech lithium batteries, but I want to keep the old 24V system running to harvest the hydro power.
Left side (New) MultiPlus-II 48/5000, Cerbo GX, and Pylontech batteries. This will run the big loads in the house.
Right side (Old) My existing 24V bank with the Hydro Turbine and some old solar panels. This runs smaller loads.
The Connection: I added a Victron Orion-Tr Isolated DC-DC (24/48) between the two busbars.
My idea: I want to use the Orion-Tr to charge the new Lithium bank using the excess energy from the old 24V system (mainly from the turbine). I plan to control the Orion using a Relay on the Cerbo GX connected to the Orion. The logic would be: If 24V battery is full → Turn on Orion → Send power to 48V system.
My questions for you guys:
Does this schematic look safe?
Are the fuse sizes (red text) reasonable for these cable runs?
Will the Cerbo GX be able to control the Orion correctly with that relay connection?
I tried to make the drawing as clear as possible. Any advice or corrections are very welcome before I start buying everything!
Should be ok in general, though control of the power transfer will need some fine tuning.
Fuse sizes: These should be between 1.25 to 1.5 times tha max expected current, and the cables appropriately sized.
Thanks! Yes that was a struggle for me to understand, I don’t know if the picture in the diagram is correct, but I know it has to be a charger not a converter.
Orion-Tr Smart 24/48-8,5A (400W) Isolated DC-DC charger
That is the one I’m looking to buy, is that right?
Thanks a lot!
Yes, that’s the one. You can program it to turn on when the 24V system has a high voltage. I am pretty sure your batteries are 15S, so make sure you put in the correct voltage to charge them to.
I was thinking in connecting it with a rele to the cerbo so i can program it’s behavior, better than on the Orion it self, so I can take better care of the old batteries.
I’m not sure I understad the 15S claim that yo made, hare you talking about the lead ones or the litio ones?
EDIT: oh I see, you mean the litio one, yes, I will tell the orion to charge at the right voltage, thanks!
If you are using pylontech, they have 15s, not 16s, but not sure you will have to check. If you set the charger to a 16s 48v, you will overcharge them. There is literature from Victron to set up the battery with communication and DVCC, but adding a separate non-communications charger is not documented; you will have to figure that out.
Alright, I did a bit of research and that is my conclusion as of today. but I have some questions if I may. The fuses are always needed in the positive cable, never in the negative? Do I have to cut the original pylotech cable to put the fuse? Is the battery switch really necessary if the Plyotech batteries can be shutdown?
The orion charger I understand have to charge at 52V to 53.2V because the battery is 15s. is this the only thing I have to take care of?
The shunt from the 24V battery still needs to be integrated via VE Direct… but the Cerbo can only manage one battery… so that will have to be the Pylontech. You can certainly integrate the data into the system, BUT then it will probably be difficult to switch on the Orion WITHOUT additional programs such as NODE RED.
You can’t combine the batteries either… then the Cerbo will get confused.
The Orion can also automatically switch on the 48V output. You don’t need any control system for this. It simply has to operate in “power supply” mode and can be set to the pylontech voltage of approx. 52V. If the voltage on the 24V side is too low, the Orion simply switches itself off, so you don’t need a shunt on the 24V side.
Depending on the desired output, you will need several Orion units in parallel.
Please post the manufacturer’s website for the inverter. Google cannot find any information about the components.
Perhaps is it possible to use AC coupling
If you want to use the UC5000 at full load you need one battery cable per battery box with a separate fuse , max 100A per cable are allowed. Fuse 125A required
Hello! Thanks for your input, my idea is not that the cerbo controls the 24V batteries I only need it to read the charge from the 24v battery and activate or deactivate the Orion at a desire voltage. Can I do that? As far as I understand I can do that with out a mod. Maybe it is over kill? Maybe the Orion is the only one needed, but I’ll love if I can know the charge of the 24v battery and state in the cerbo.
You can, of course, insert the shunt into your system and then use the data, BUT the shunt will mess up all your “statistics.”
The shunt must not be used as a “battery monitor” BECAUSE your GX will then want to use it to evaluate the battery. It gets confusing somehow… So the shunt must be used as a “direct current meter” AND the additional input can also be used as a voltage measurement. Then the shunt will not mess up the battery measurement on the 48V side … AND you can make excellent use of the two data points from the shunt: current and voltage.
So I’ll need to find that setting, I’m still not familiar with the Venus os, this will be my first Victron system. But knowing it is posible and I can have the info is all I need
I have made this system like this because of my father and also because I don’t have any good ideas to integrate the turbine with Victron any other way. This was the best way I can think of, having the two systems working like this will give me a lot of flexibility. The old system is working just fine but it is lacking in power, and will eventually die, it is old.
We are always happy to help and welcome new challenges like this.