Judge My First Schematic - What am I missing? *Noob Alert*

[TheEngineer]

Attached is the first rough draft for an off-grid setup I'm working on. Please tell me if I'm completely off-base with the panel configuration etc. Other than details for the breaker box and generator connection, what else am I still missing?

Please go easy on me. I'm not a hobbyist. First time doing this, and it's out of necessity for an island home I'm building. There is no grid available where the property is located, so tying to a utility provider will never be an option. I have already purchased the batteries and Victron equipment, but have not yet ordered the solar panels.

*Updated Schematic with corrected MPPTs*

 

[Nobodybusiness]

Attached is the first rough draft for an off-grid setup I'm working on. Please tell me if I'm completely off-base with the panel configuration etc. Other than details for the breaker box and generator connection, what else am I still missing?

Please go easy on me. I'm not a hobbyist. First time doing this, and it's out of necessity for an island home I'm building. There is no grid available where the property is located, so tying to a utility provider will never be an option. I have already purchased the batteries and Victron equipment, but have not yet ordered the solar panels.

Block diagram looks fine.

How you implement it will be the thing most are interested in.

 

[pvgirl]

For the Victron MPPT 150/85 Charge controllers and the Bluesun BSM550M10-72HBD panels:

• Your panel config needs to 2s4p to be within voltage and current limit of that charge controller.
• You will need fusing on each of the 4 parallel strings, 25 amp recommended
• You will need a combiner box and runs form the combiner to charge controller, should be 2 AWG wire to handle current
• Your drawing shows 10 panels per array when there are only 8 in each array

If you want 4s2p, which will simplify wiring, you can use the Victron 250/85 charge controllers to handle the voltage of 4 panels in series, even with this config you will want to use 8 AWG wire from the panels to the charge controllers.

For each 85 amp charge controller the wiring should be fused where it leaves the bus bar with a 110 or 125 amp fuse, then run on at least 2 AWG wire.

With a max fuse size of 300 in the Lynx combining all 3 charge controllers will be too much for one fuse. Consider adding another Lynx distributor and running all 3 charge controllers to the distributors with 125 amp fuses.

If you have good conditions for bi facial gain you may want to consider the 250/100 charge controller.

 

[TheEngineer]

GG

For the Victron MPPT 150/85 Charge controllers and the Bluesun BSM550M10-72HBD panels:

• Your panel config needs to 2s4p to be within voltage and current limit of that charge controller.
• You will need fusing on each of the 4 parallel strings, 25 amp recommended
• You will need a combiner box and runs form the combiner to charge controller, should be 2 AWG wire to handle current
• Your drawing shows 10 panels per array when there are only 8 in each array

If you want 4s2p, which will simplify wiring, you can use the Victron 250/85 charge controllers to handle the voltage of 4 panels in series, even with this config you will want to use 8 AWG wire from the panels to the charge controllers.

For each 85 amp charge controller the wiring should be fused where it leaves the bus bar with a 110 or 125 amp fuse, then run on at least 2 AWG wire.

With a max fuse size of 300 in the Lynx combining all 3 charge controllers will be too much for one fuse. Consider adding another Lynx distributor and running all 3 charge controllers to the distributors with 125 amp fuses.

If you have good conditions for bi facial gain you may want to consider the 250/100 charge controller.

Good catch on the MPPTs. I used the wrong graphic, the Victron 250/85 is what I've already purchased. Updating schematic. Looking into the rest of your advice. Thank you very much!

 

[ghostwriter66]

So I always love these posts because you will be actually helping 100's of ppl design their projects without you even knowing it ... although all of them will use different nomenclatures of parts and pieces - the concept is the same ...

WITH that said ... it would be great also to show 2 PDF's ... one is the schematic that you already have -- and one is the excel spreadsheet (whatever) that shows all the parts and pieces being used ... with that said - what you have done in labeling each item is probably good enough for most although I always prefer to have a link to the product itself (yeah I'm that lazy - lol)

ALSO - if you don't mind -- if you could label the cables and wires with the AWG (or metric) you are using that will help everyone also ...

AND - when you make UPDATES (which you will) then do so in a timely manner and make sure you let people know that the latest posting is the updated one ... several times ppl here will spend time helping ppl and they will simply say Thx and then never post schematic updates ...

Thx

 

[pvgirl]

GG

Good catch on the MPPTs. I used the wrong graphic, the Victron 250/85 is what I've already purchased. Updating schematic. Looking into the rest of your advice. Thank you very much!

also with 4s2p you only need 1 branch connector per array

 

[ghostwriter66]

For the 300A Spartan manual non fused Switches - was there a reason you went that route instead of perhaps a 250A DUAL pole single throw BREAKER that could cut off both sides at the same time plus provide a breaker??

Also - coming off the main positive lead of each of the batteries you have a BLACK (typically NEG) and RED (typically Positive) running to your BMS. Should not the NEG wire (Black) be connected to the NEG terminal and not the Positive???