John Frum
Tell me your problems
- Joined
- Nov 30, 2019
- Messages
- 15,230
That table is silly.Hello Everyone! Hope someone from this thread will still be able to patiently have a look at my updated schematics, wire sizes, fuse sizes and dc breakers please.
I have re-read @smoothJoey 's initial post many times with wire and fuse sizes, then have read again the manuals for the Multiplus II and SmartSolars.
Here is an updated version of my schematics. I have oversized some of the wires but kept to the fuses as per Joey's recommendation and the manuals. Following the schematics you can find the screenshots from the manuals regarding fuses and wires.
View attachment 93133
The following is from the Multiplus II manual (shorturl.at/ayIT0), page 13.:
View attachment 93131
The following was taken from the MPPT 150\45 manual (shorturl.at/uCD17), page 9.
View attachment 93132
For the DC breakers between the solar panels and MPPTs, which of the two would you recommend? I suspect the thermal one has an extra layer of protection.
For that Class-T 300 A fuse, between the battery and the inverter, could I not use a DC breaker instead?
Similarly, would it not be better to have a DC breaker between the inverter and the busbar, rather than the 250A megafuse?
I know DC breakers are more expensive, but looking at doing the best option in the end even if it is going to cost more.
Thank you.
The solar charge controller has built in protection circuits so you fuse for the wire.
The manual says the solar charge controller has output short circuit protection.
The solar charge controller protects the branch circuit not the other way round.
The branch circuit fuse protects the wire not the solar charge controller.
But if you ever need Victron support doing it there way means one less thing to argue about.
The multiplus 2 manual includes some silliness as well.
They spec 2x 50mm2 with a single 300 amp fuse.
Double wires should get double fuses.
I suggest you do 2x 250 amp fuses one for each parallel circuit.
Its just safer.
Alternatively use the same 1x 120mm2 cable that you used for the battery circuit with this fuse.
MEGA fuse 300A/58V80 mV0, 17 mΩ
Which is the highest ampacity fuse that Victron makes.
Just because the device has double lugs does not mean you have to use them.
Most of the good installs I've seen use a thicker single wire.