I'm not sure what the fuss is all about, my 12v and 24v systems are working great! You all trying to get to mars or somethin?
Generally it's pretty rare to reach max output of a panel, which is with ideal lab conditions, perhaps momentarily beyond rating with cloud edge effects in production. So thats why generally one would over panel, because you definitely won't be clipping all day.I also told him I wasn't happy with the 5.5kw Delta inverter he was choosing for us. I worry it will clip all the time with 8000w of panels per duplex house. We're splitting them into separate homes. So 8000kw each per house. He says he doesn't really believe it's a big problem. Anyone else think the inverter should match the panels power rating 1 to 1? Or am I mistaken here that they should?
"Free" battery packs from cars? I hope you didn't "free" any battery packs from anyone I know....Haha. Kinda. Trying to get free battery packs. With these inverters you can connect up reclaimed EV batteries from cars. Big packs. Without having to take the pack apart and reassemble it at all. Just leave it in it's housing as is and connect it up. Much safer and already tested and working when done this way. Waterproof too. BMS is already built for it as well. Like I have a free 24kWh pack from my Nissan Leaf that I just upgraded to 30kWh. And eventually when I upgrade that again I can move that over to my inverter too as a big, free ESS.
But also I'm told HV is much more efficient and less conversion losses. Supposed to run cooler and quieter too. So perhaps better longevity.
Thanks for that great detail. Very good to know.Hybrids have several power ratings. I will give numbers for Solis S5 EH1P 6K
1- Grid output power: 6kW, which is what it can output on the grid port to offset the house loads
2- Backup output power: 5kW, which is what it can output on the backup port
3- Battery power: 5kW, that's the charge/discharge power
3- MPPT power: "recommended" 8kW, maybe more
The last one means it can input 8kW (or more) on the PV side, and split that between grid and battery charging without exceeding the limits of each. I put 9kWp on mine, and with enough sun it has extracted 8kW from them. Since then I transferred some panels to the other inverters, because 24 panels was way too close to the overvoltage limit. But with the right combination of panel current and voltage, a cheaper 6kW inverter should have no trouble with 8kW panels, in fact it's absolutely fine.
Just pay attention to panel voltage tempco, you need to add some safety margin as voltage rises when the weather is cold. If that exceeds the voltage rating then you need panels with higher current and lower voltage.
Of course, when the battery is fully charged, then it is limited by its 6kW grid output.
Thus the idea is: when there is enough sun to reasonably expect the battery will be charged quite early, turn on your big consumers before it has finished charging to maximize utilization. This is especially true for an electric car which eats a huge amount of energy.
I don't know how other inverters will do, fortunately there are datasheets.
So basically it's fine to put 8kW panels on 6kW inverter. If you get 8-12kW inverter for 8kW panels you will pay more, and it will also have higher losses, so the final result will be less optimal for more money. For a 12kW inverter I'd put 16kW panels at least.
Notes:
- There is only one inverter in the box, so with the grid present the sum of output power on both ports cannot be more than 6kW.
- Battery power is specified when it is cold, if you want the S5 to deliver 5kW for a while, it needs an extra fan lol
Well it is likely that a lower power inverter will have lower idle losses, so it will be more efficient at low power.He was trying to say that the smaller inverters are more efficient at the lower and higher end of the bell curve.
It depends what you call "clipping". If the S5 or S6 inputs 8kW PV and splits it between battery charging and grid output, then it is using all the available power, so it is not really clipping. It would clip only when the battery is full, then it is limited to its rated power on the grid port. This would be a problem only if you intend to sell the power to the grid, or you have some very power hungry loads like an electric car charger. Otherwise, if you do not sell your production and do not have net metering, output power will not be limited by the inverter's maximum power (what it can output), but by what it needs to output to power the house and remain at zero export. In this case it isn't really clipping either, because the energy that is not produced is not really needed.So even though it does clip a bit during peak sun each day
Hey Perfu,Here's an industrial blade fuse holder. The fuses are in the handle, if you pull on the handle it will pull out the fuses, so it is able to interrupt pretty much anything without worrying about arcs. NH00 is rated to survive disconnection under full load (600V 160A) a few hundreds of times. It is not rotary, so you can pull on the handle with a string to keep fingers away from HVDC.
So it does double duty of fuse holder and heavy duty disconnector. You can use NH00 or NH000 size fuses and even get 500V DC rated fuses. NH000 (max 100A) would be more suitable because you don't need the 160A capability of NH00 fuses. (Yes 000 means "extra small" and "00" means small, it goes to way bigger sizes).
And the whole thing is pretty inexpensive too, I paid 30€ for this one, plus sand filled ceramic cartridge fuses, blast proof, about five euro each. It's normalized so fuses of any brand will fit into any brand of box as long as you get the right type.
There are many different connection options, many involving bus bars which you don't have, so it takes a bit of work to get the correct model.
![]()
It's an industry standard, there are many brands. I'm sure you can find the same in Japan/China or a local equivalent. I got the Polish one because it was cheap.Any others? These all acceptable?
I used Legrand 0 163 50 fuses which are rated for 500VAC and 48V DC. There are specific "PV" fuses in NH00 format that are rated for much higher DC voltages. You can try searching for "NH00 1000VDC fuse" or "1500VDC". There are some on aliexpress, but I don't like ordering safety equipment from aliexpress...Next I need to find the appropriate fuse size and source.
Another question I have is, how do these compare to the T-fuses all the 48v guys so highly recommend and use?
Since my inverter maxes out at 100A battery current, I used 125A fuses.Lastly, what is the best guide for sizing my fuses/breakers? I have a 360-400v Leaf battery pack I'll be connecting to the Solis S6.
It seems the above three examples are all 00 size at up to 690v. But should I use a 160A fuse? Wouldn't less would be more appropriate?
Thank you. You are a great resource of information. I am learning some great stuff here.It's an industry standard, there are many brands. I'm sure you can find the same in Japan/China or a local equivalent. I got the Polish one because it was cheap.
I used Legrand 0 163 50 fuses which are rated for 500VAC and 48V DC. There are specific "PV" fuses in NH00 format that are rated for much higher DC voltages. You can try searching for "NH00 1000VDC fuse" or "1500VDC". There are some on aliexpress, but I don't like ordering safety equipment from aliexpress...
Note AC fuses are not rated for high voltage DC. Most should work on 48VDC, but not 400VDC.
I'm not sure, they look similar in function. The advantage of a blade fuse holder is that it does double duty as fuse and disconnect, so it's convenient. But if you can't find one, then... it's not convenient lol.
Since my inverter maxes out at 100A battery current, I used 125A fuses.
In my case another reason to use NH00 fuses was trouble finding a bipolar battery disconnect rated for the high current of 48V batteries. But you don't have this high current problem, so another option would be hardware (disconnects and fuses) designed for PV strings, since your battery voltage and current are similar. Could be easier to find.
Note if you use ESP32 and Wifi to talk to the battery, well Wifi is isolated, the only problem is the ESP32's power supply. However the battery's BMS should have isolation between its CAN bus and the DC high voltage.
YesOh, in re-reading your reply above I see you recommend this, "NH000 (max 100A) would be more suitable because you don't need the 160A capability of NH00 fuses."
Not compatible, they're a different size.I will search for those. But do they fit in the 00 fuse holder or not at all?
Thinking I might go with a 000 size if I can find the PV version of the fuses you mentioned.
Oh, in re-reading your reply above I see you recommend this, "NH000 (max 100A) would be more suitable because you don't need the 160A capability of NH00 fuses."
I will search for those. But do they fit in the 00 fuse holder or not at all?
Not compatible, they're a different size.
This is actually really good scoop. Thank you.The body of the fuses themselves are different widths (28mm vs. 21mm), but the 00 and 000 have same length and height of blade (79mm x 53mm). So all the "00" disconnectors that I have seen will also take a "000" fuse. I upgraded the fuses in my Jean-Muller Keto Disconnector from 80A "000" to 125A "00" when I switched from my RH1 to EH1P Solis.
IME, I'd look at Mersen, ABB, Eaton and Jean-Muller.Now just to find which 00 switch holder/disconnector to choose. Want to find a quality one but reasonably priced.
There we go. Now that's the kind of formula that makes perfect sense and is simple to follow. Thank you. I wished someone had shared that earlier but glad you did for me. That's so simple!My rule of thumb is that the fuse should be rated 25% greater than your regular expected usage and the cable rated 25% above the fuse. Fuse must always be less than cable rating.
My inverter draws maximum 100A, so I added 25% and picked a 125A fuse.
If the inverter's max current is 50A, then 60-63A fuse would be adequate.
From the inverter datasheet.How did you determine maximum current draw?
The Solis S6 US has 4 mppt channels and in general don't have paralleled arrays additionally, with solar if there is a short, it is just the ISC current at near zero volts, there is no meaningful energy, even when you have a parallel array shorted. For example say it is 20 amps, but a short makes the volts 3 volts, that's only 60 watts, they same V drop all in the wiring as when operational ( draw it out )1) If you wire many strings in parallel, and one string shorts out, or a panel shorts out, it will take current from all other strings in parallel with itself and burn. In this case the breaker's role is to trip to prevent fire. This means the breaker has to be sized "just right". If strings are not paralleled, then this cannot happen, and the breaker or fuse is useless.