Starting solar setup for Micro Minnie 2108DS

[bobsh]

I am finalizing my plans for a small solar system for my 2108DS Micro Minnie. I've got 2 220 watt panels and a 230Ah lithium battery. I will wire the battery to positive and negative busbars. The battery has a 200W BMS and the mfr says a 250W fuse is what they recommend. I like the idea of a MRBF because it is simple and small. The wire to the busbars will be short; positive lead under 1.5' and the neg lead 2.5'. I am nervous about running wire and fuses that will stand up to 200a. The DC wire sizing calculators say awg 3/0.
The MRBF has a 3/8" (10mm) hole, and the battery has an 8mm or 5/16" screw. Is that going to make good enough contact? Should I get some copper washers to help the contact?

What kind of busbars would you recommend for this application?

[creativepart]

Some questions… you mention your battery’s capacity and its output and your fusing and wiring sizes but not a word about what those batteries and wires will be powering.

440 watts of solar panels outputs less than 30amps. So you only need 10ga wire for that.

You only need 200 amp scaled wiring if you plan on wiring the batteries to a 2000-3000 watt inverter to power larger amperage 110vac appliances. Otherwise when would those big batteries be outputting loads big enough to need that kind of wire size? And the only concern for high gauge wiring would be between the batteries and the 12vdc input on the inverter. 110vac wire needs to be no more robust than household romex.

Large draw 110vac appliances would include air conditioning, microwave ovens, coffee makers, etc.

So fill in the blanks here. Otherwise it sounds like you spec’d this project from folks running 110v A/C from their 12v batteries with large wattage inverters.

It’s what you plan to power with those batteries that matters most.

[Marine359]

First. Your wire size can be sized to accommodate the largest possible load on the bus, such as an inverter. An ANL fuse of 250 amps will protect the battery to bus bar connection and inverter connection (with up to 3,000w surge) just fine using 2/0 ANL wire. I recommend using MRSB for use between solar array and charge controller. This allows you to easily disconnect the always hot array from the bus when you’re working on your system. With 2x 220w panels and 10awg cable from the panels, an 30 amp MSRB is the right size. There are photos of battery and solar wiring in my 2108DS upgrades and mods photo album.