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I second Bentley’s congratulations for planning before you buy, and I also think 48volts is the only way to go. I encourage you to do some modeling of solar photovoltaic production instead of relying on the too simplistic hours per day stuff. Look at PV Watts, and see what your 6500 watts of...

No. 4 cable is way too small for a spectacular amount of current like that. You’ll need 1/0 as a minimum, probably larger as you de-rate for more than 3 conductors, etc. What kind of monster are you building? It would be fun if you post the details, especially which charge controller handles...

Six hundredths of oF a volt isn’t much. Many pieces of equipment -and voltmeters- are off by more than that. Don’t worry about it.

Wire and fuse sizes should be determined by the current your devices will draw, not the current a device is capable of delivering. That kind of defeats the purpose of a fuse.

It's normal for the current to slowly decline as the batteries approach the fully charged voltage. My five LiFePO4s only draw a few watts each after they're charged to 55.9 then go to float at 53.9. I've never seen the draw spike after that point. I don't believe that it's a good idea to...

I don't think that the batteries should really draw a few thousand watts when they're fully charged. I've never seen mine draw more than a few watts each. So unless something like a cell overvoltage protection is shutting off the charge to a battery long before it reaches full charge and then...

An M4 screw is 4mm in diameter, and the standard clearance would need a 4.8mm hole. But through a thin aluminum panel I think you could easily get a screw through a 4mm hole. A little screwing action, or tappy-tap-tap. edited to add: most screws are a few thousandths smaller than nominal, too.

Go to the website of the cable manufacturer. It will give you all the certifications, etc. For examplehere's the southwire I mentioned earlier

The DLO number 10 doesn’t have hundreds of strands, only 27

I don’t think the connector victron uses is robust enough to properly grip solid or low strand count wires. South wire makes many #10 wires with 105 strands and high temp insulation. You will pay a lot for them. Wireandcableyourway has diesel locomotive cable for about a buck a foot, for sale...

I’ve never heard anyone claim that LiFePO4 batteries need a high charge rate, and that a slow charge will harm them. I believe that may be true of lead batteries.

The size of your array depends on your energy needs, not just battery size. Lithium batteries work well at low charge rates, so any charge rate below the maximum is fine.

And don't forget the overpotential voltage. It's way larger than the voltage drop internal resistance and the resistance of connections and cables causes unless you have done something really, really bad. And it tends to equalize the current flow to and from batteries. A battery sourcing...

Many people think that. It’s a shame that that chart is so often replicated without titles clarifying what it is. As soon as voltage drop is expressed as a percentage you know that the chart is voltage specific. Of course higher voltages and lower current leading to less loss doesn’t depend on...

i just ran 13.3 amps, 72 volts for a 65 foot circuit using #10 and got 2.5% voltage drop. Are we talking about the same thing? Again, that chart is for 12 volt wires exposed in engine rooms. It is useless for anything else.

That chart is wrong. It’s for 12 volts. Go to the south wire (or any other calculator) and run it using the actual voltage.

As I understand it, everything inside the house has to be in metal conduit. Flexible is ok too, not just emt.

6% difference in estimated SOC isn’t significant. Heck, it’s probably a rarity that they’re that close.. I’ve been open loop with my 12 k for two years, and for the first year and a half the SolArk was great at estimating SOC. Then it started being really bad, but it’s not a supported...

Traditional solution is to start with bonding and shielding and grounding. Wider conductors offer lower impedance to rf-that’s why you see those wide copper straps bonding cabinets together. The shield from big,old coax works well. Put as much as you can in steel conduit. It adds a ton of...

I think you may be shooting yourself in the foot. I've noticed that on bad solar days (when you want to be overpaneled) the mppt runs at a lower voltage. So you'd be giving up production when you need it most. For example, when I was producing 7kW two days ago my strings were at 275v and...

No problem shutting off your solar arrays. In fact I’d recommend it, and keep it off until you are sure you are running with the proper settings. Why don’t you post your settings here? You’ll get lots of advice.

How much work do you want to do? You could install a small panel at the same angle as your current array and run the output to a resistor calculated to provide a load near the best power point for the panel. Monitor the current and it will predict quite nicely the potential power of your array...

It’s been a while since I’ve used PVWatts, but don’t they express angles as tilt from horizontal? So wouldn’t you expect the 35 degree (closer to vertical) panel to produce more when the sun is at a low angle?

I too have installed pairs of interlocked breakers to allow the panels to be fed from either the utility or inverter, I just didn’t think of those as “main” breakers.

To clarify, mine are distribution panels so there is no main breaker in the panel.

30 amps at 13 volts is 390 watts. How often do you expect those three panels to produce that much power? I suspect it would be a rare event.

It’s ok to invert some square D, I think probably all are ok, but don’t know for sure. I inverted three and passed a thorough inspection.

The clipping you’re worried about won’t happen too often. You’ll be well below the rated output with your panels baking in the Texas sun most days. And the rest of the time those extra panels will be providing more power. Do you look for a #13 wire if a #12 has 1% too much ampacity ? No...

THHN/THWN is the most commonly used wire. It’s affordable too. Don’t forget to de-rate the wire for the number of conductors in your conduit. I think you should at least calculate the voltage drops. So you know what you’re getting into. If you go to a good online calculator, like Southwire’s...

This is from a Victron document: The MultiPlus switches to inverter operation when no AC source is available. The inverter output is also 120V single phase. In inverter mode, the MultiPlus-II 2x120V internally connects both lines L1 and L2 together to provide 120VAC to loads on either output...

Just to clarify, I have the problem whether I’m connected to the grid or not. It’s Never off as much as .5 volts, usually just .2 or .3 I updated the firmware yesterday, and saw no change. The gentleman I talked to said that they’re all off some and not to worry about it.

Sunshine Eggo is far from normal. You are using about four time the power an “average” household uses.

I don’t think they confirm it unless you’re audited. But you should keep documents to support your claim, like your inspections.

Yes, as I understand it. As long as you otherwise qualify. You can’t take the credit until the system is in service, is correct.

Since you already have the top off, why don't you measure the individual cell voltages before you do anything else? That will tell you if you have any outliers. And it will only take a minute. Then put the charger on, for what it's worth.