Inverters that support high voltage (500v) storage batteries
- Thread starter Rational
- Start date
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.
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Well, we've got a typhoon about to hit us by Saturday. Took today off to prepare our and the in-laws house for it. Long day.
We also met again this morning with the solar installer we like the best. He's proactively created a new panel layout for us with 38 panels now as an option. So 445w x 38 = 16,910w total. Nice!
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?
Regardless, I asked him if he could check into installing the Solis S6 11.4k first and foremost. But since Solis doesn't have a Japanese certificate I am not so sure they will agree. In Japan they won't do things without the official certifications. So on our main house they are likely to refuse the Solis solution.
Hence why I also asked him about the SRNE HESP 12k inverter as that brand is widely sold on Amazon Japan and very popular within Japan I'm told. It's also certified for Japan and SRNE even makes their own Japanese marketing materials and support for it. So I tend to think this one will be much more likely to pass inspection by the local power company. But it's a 48v system. So for our main house this is proabaly more standard these days than HV is still yet. So he has hesitantly agreed to ask his company and the power company if either of these inverters can be used. So I will await that answer to come back before being able to decide on the main house decision. Sadly, he says that even if we commit to the system install this month, it will be next July before the system is put into service. So it takes a long time here to have solar installed.
As for my other shop location I am going to pay Sunpal for a Solis S6 11.4k tomorrow. He has been very professional and diligent in answering all my questions for a month and it's time to repay the effort he's shown with an order finally. Also, I've got our electrician engaged to install a manual transfer switch as well as a new 200v feed from the pole. He's provided the quotation today and it's very reasonable. This will allow me to connect the Solis at the shop and start testing it in person once it arrives. This will give me the experience with it I need to know what is the best path forward between HV and LV for our main house -- of course depending on local inspectors. I'm hoping HV is an option!
Lastly, Seplos has also been excellent in providing proof that their Hitens 409v battery stack work with the Solis S6 inverter. She sent lots of screenshots. That's refreshing to see. Communication has been good too with them. I've let them know that right now the Seplos Hitens are on my future buy list once I'm at that point if I can use the Solis on my main house. Fingers crossed! They're the only reasonably priced stacked battery solution I've found that has been proven to be compatible via real world testing. So for me, that's a big deal. The ones on the Solis approved list all seem to be very high priced in comparison sadly, so am not really considering them.
Well, that's the latest update.
We also met again this morning with the solar installer we like the best. He's proactively created a new panel layout for us with 38 panels now as an option. So 445w x 38 = 16,910w total. Nice!
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?
Regardless, I asked him if he could check into installing the Solis S6 11.4k first and foremost. But since Solis doesn't have a Japanese certificate I am not so sure they will agree. In Japan they won't do things without the official certifications. So on our main house they are likely to refuse the Solis solution.
Hence why I also asked him about the SRNE HESP 12k inverter as that brand is widely sold on Amazon Japan and very popular within Japan I'm told. It's also certified for Japan and SRNE even makes their own Japanese marketing materials and support for it. So I tend to think this one will be much more likely to pass inspection by the local power company. But it's a 48v system. So for our main house this is proabaly more standard these days than HV is still yet. So he has hesitantly agreed to ask his company and the power company if either of these inverters can be used. So I will await that answer to come back before being able to decide on the main house decision. Sadly, he says that even if we commit to the system install this month, it will be next July before the system is put into service. So it takes a long time here to have solar installed.
As for my other shop location I am going to pay Sunpal for a Solis S6 11.4k tomorrow. He has been very professional and diligent in answering all my questions for a month and it's time to repay the effort he's shown with an order finally. Also, I've got our electrician engaged to install a manual transfer switch as well as a new 200v feed from the pole. He's provided the quotation today and it's very reasonable. This will allow me to connect the Solis at the shop and start testing it in person once it arrives. This will give me the experience with it I need to know what is the best path forward between HV and LV for our main house -- of course depending on local inspectors. I'm hoping HV is an option!
Lastly, Seplos has also been excellent in providing proof that their Hitens 409v battery stack work with the Solis S6 inverter. She sent lots of screenshots. That's refreshing to see. Communication has been good too with them. I've let them know that right now the Seplos Hitens are on my future buy list once I'm at that point if I can use the Solis on my main house. Fingers crossed! They're the only reasonably priced stacked battery solution I've found that has been proven to be compatible via real world testing. So for me, that's a big deal. The ones on the Solis approved list all seem to be very high priced in comparison sadly, so am not really considering them.
Well, that's the latest update.
Brucey
Velcro Man
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.
Let's say you have a 6kW array. And for one peak hour it generates 5kWh. but the rest of the time maybe you get 3 or 4 kWh or less.
if you had say 8kw of panels, yes you may clip say for two hours, but your average capture/utilization will be better (I..e more amps of charge out of the day), because it will be closer to max charging versus just trickling in, for more hours of the day. I have a 7kW Rosie and currently about 8kw of panels, I'll prob need 20kWp or more for a successful winter. Because the goal is maximum capture during non ideal/overcast conditions. In the summer there'll be a huge amount of excess but that's fine. Using a Victron 450/100 and soon a Hawkes bay 90 SCC.
Apparently some AIOs can't handle this overpanelling so buyer beware.
teal95
Solar Wizard
I have 8400 W of panels feeding into a 7200 W inverter. It clips for a couple of hours on 3 days each spring and fall
"Free" battery packs from cars? I hope you didn't "free" any battery packs from anyone I know....
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.
With all the battery manufacturing ramping up, I suspect in the future batteries will go from being the most expensive component to the cheapest. Its already started with lots of price drops. Panels will become very pricy when silver goes up. They will come out with some copper panels that dont last as long and don't make as much power.
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
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
Thanks for that great detail. Very good to know.
Do you have a Solis S6 11.4k? How are you liking it?
I finally ordered one this week. All paid. Should be here in 42 days they said.
Our fourth solar company salesman visited yesterday and was saying that prior to three years ago they would always recommend that the inverter power and panel power should match 1:1. But in the last three years the new recommendation is to have a 5kw inverter with like 7+ kw of panels.
He was trying to say that the smaller inverters are more efficient at the lower and higher end of the bell curve. So even though it does clip a bit during peak sun each day, the lower and higher end is actually higher and adds up to more than the clipping losses during peak. Is that true? Is that what you were basicallly explaining?
I have one Solis S5 EH1P 6K (48V) and one 5K. S6 is not approved in Europe yet. These inverters work absolutely fine. Right now both have 6kW of panels, but before I installed the second inverter, the S5 6K had 9kW of panels. It was a bit too much, too close to the high voltage limit. 7.5-8kW would be ideal. The inverter has no issue using all the power from the panels as long as its battery charging power and grid output power are both within allowed limits, so no problem with 8kW input -> 4kW to batteries and 4kW to grid. When the battery is full through, it is limited to the maximum 6kW of the grid port, so it will clip.
Well it is likely that a lower power inverter will have lower idle losses, so it will be more efficient at low power.
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.
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.
Thanks again for all your high quality input. Where did you order your blade fuse holders and fuses from? I'm about to order and looking for specific suppliers and if you have the brand/model number on the ones you ordered to help me start off my search.
In searching for the Apator RKB00 models I'm only finding them on ebay out of Poland: https://www.ebay.com/itm/225263856281
Seems to be about $30 each but $40 in shipping. So $70 each really in total. A bit much. But I like the idea and ability to attach a string to them to keep hands away from HV during the disconnect if need be. Smart!
RBK 00 – horizontal fuse switch disconnector - Apator
RBK 00 – horizontal fuse switch disconnector (160 A, 690 V)
www.apator.com
Oh, I did find another brand. WOHNER QCB-NH00 FUSE HOLDER: https://www.ebay.com/itm/156412822774
And a third: Rittal SV 9344.010 NH Fuse-Switch Disconnector, Size 00, 160A, 690V, 3-Pole: https://www.ebay.com/itm/387021883773
Any others? These all acceptable?
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? These are a drop in replacement? Or are these used instead of standard DC breakers with T-fuses still inline somewhere close to the batteries? Or does having both increase risk points because of resistance and therefore potential heat and chances of runaway?
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?
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?
Hmmm.. Perhaps I need to order a specific 000 model fuse holder like this:
Wohner 3 Pole NH000 Fuse Holder and Off-Load Isolator up to 125A - Fuse Holders
Part No: 33217, Brand: Wöhner, Model: Wohner 3 Pole NH000 Fuse Holder and Off-Load Isolator up to 125A
Oh, I've found another good one I think here: https://new.abb.com/products/1SEP201428R0001/xlp000-6cc
I'm making my system design now so taking all input.
Also, I did give your feedback on using all isolated can bus (lilygo) modules and that input seems to have been taken well and is being considered in the future designs of their new devices. E.g. Stark board. So thank you for that.
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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.
Thank you. You are a great resource of information. I am learning some great stuff here.
I really like the ability to connect a string to these so I can pull the fuse from a distance. No hands next to the arc! SO SMART!
I could also close the fuse from a distance with a non-conductive pole as well for extra safety I suppose. Nice design.
It seems I was still updating my post above while you were answering. Hopefully some of what I added at the bottom makes sense.
Thinking I might go with a 000 size if I can find the PV version of the fuses you mentioned.
Yes
Not compatible, they're a different size.
That would be fine.
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.
This is actually really good scoop. Thank you.
I'm going to find a good 00 fuse disconnector but load it up with some 000 fuses as they go a bit lower on the amperage.
I could only find 00 fuses starting at 100A and I want 50A fuses for my setup's battery pack. As the Solis S6 11.4k is rated up to 50A.
I REALLY like the idea that I can put a tether on the handle and pull it quickly from afar should a short occur.
Especially during initial set up of the system and first turn on. Just for expediency of disconnection should something be amiss.
No hands near the arc that way. Seems the most logical and safest design of them all.
Also, I studied up a bit and only T-Fuses and these NH fuses are encased in sand they say which extinguishes arcs unlike all other fuse types.
Now just to find which 00 switch holder/disconnector to choose. Want to find a quality one but reasonably priced.
I like the siemens fuses but need to find a good source for them.
The Siemens part number for the NH000 50A part number is 3ND1820
Edit: https://mall.industry.siemens.com/mall/en/WW/Catalog/Product/3ND1820
https://datasheet.octopart.com/3ND1820-Siemens-datasheet-141211567.pdf
Seems octopart has the fuses for about $30 each.
Later edit: these seem to be 500vac/250vdc.
Need to find 500vdc - 1000vdc rated.
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If the inverter can output 50A, you need the fuse to be rated higher, say 70A, otherwise it will blow in normal use.
The role of the fuse is to protect against fire if there is a short inside the inverter, for example. That would draw much higher current than 50A.
Here's another style of fuse holder/disconnector that uses cartridge fuses, perhaps easier to find
The role of the fuse is to protect against fire if there is a short inside the inverter, for example. That would draw much higher current than 50A.
Here's another style of fuse holder/disconnector that uses cartridge fuses, perhaps easier to find
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.
www.mersen.co.uk
uk.misumi-ec.com
essandsolarsolutions.co.uk
IME, I'd look at Mersen, ABB, Eaton and Jean-Muller.
MERSEN | NH fuses and fusegear
Mersen is a leader in the protection of DIN systems. Our product encompasses a complete range of NH Switch Fuse Disconnector's and any class of NH power fuses : gG, aM, gTr. These devices must be handled by a qualified professional. Visit Electrical Power website
NH fuse-switch 3p box terminal from EATON | MISUMI
NH fuse-switch 3p box terminal from EATON ➤ Order in many variants in the MISUMI online shop ➤ Free CAD data ✓ Fast delivery ✓ Fair prices ✓ Select and configurate now.
Jean Muller combined KETO-00 fuse holder and battery disconnect
Jean Muller fuse switch disconnector KETO size 00 body (battery isolator)
essandsolarsolutions.co.uk
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!
One question to make sure though. You say, "regular expected usage". Shouldn't I put that at the max sustained rating of the inverter? E.g. 50A for the Solis S6 11.4k?
I will look up cable guage ratings now as my starting reference target point.
So basically:
1. For fuse, 50% over the inverter's peak sustained capability. E.g. in this case 50A. So the fuse needs to handle 75A.
2. For the cable, 25% over 75A = 93.75A. So I could just go with 100A rated cable.
Yeah, like she said 
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.
For cable ratings, it depends. Cables are usually rated quite conservatively because the ratings must take into account installation inside a conduit with very little airflow for cooling. Voltage drop is also an issue, which means thicker cables than strictly necessary to avoid overheating.
48V 100A battery cables are usually 25mm², and rated at about 115-125A. But they are very short and air cooled, so the rating can be relaxed a bit and a 125A fuse is adequate. In a conduit where the cables can cook, you'd need thicker ones.
For 50A and 63A fuse, the usual ratings for installation in conduit say 16mm² cable. Considering the high voltage of this battery, I would definitely run it in a conduit...
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.
For cable ratings, it depends. Cables are usually rated quite conservatively because the ratings must take into account installation inside a conduit with very little airflow for cooling. Voltage drop is also an issue, which means thicker cables than strictly necessary to avoid overheating.
48V 100A battery cables are usually 25mm², and rated at about 115-125A. But they are very short and air cooled, so the rating can be relaxed a bit and a 125A fuse is adequate. In a conduit where the cables can cook, you'd need thicker ones.
For 50A and 63A fuse, the usual ratings for installation in conduit say 16mm² cable. Considering the high voltage of this battery, I would definitely run it in a conduit...
Sounds good. Things are becoming clearer now based on this excellent input. Thank you guys.
So next question. Do I also use a breaker of equivalent rating in line in addition to the fuse?
E.g. the fuse goes very close to the battery to stop potential runaway voltage, right?
But placed in a location able to be reached so I can pull it if using a blade switch type.
But towards the other end, e.g. in a mini IP67 box would I also place a breaker? Or only ever a fuse between the battery and the inverter?
Or is it fine or even recommend to also have a breaker? If so, would that also be rated the same 63A?
There's another guy also setting up a Solis S6 11.4k-US right now on Dala's discord channel and he says, "I have the 20 amp on the solar strings a 63 amp between the battery and inverter and 60 amp on the AC out side in the breaker panel."
So it seems pretty simple and that 63A is what he used for between the battery and inverter. But I think he used a 2 pole breaker with arc suppression and not a fuse. Is that alright? Same in real world use between a fuse and a breaker?
So next question. Do I also use a breaker of equivalent rating in line in addition to the fuse?
E.g. the fuse goes very close to the battery to stop potential runaway voltage, right?
But placed in a location able to be reached so I can pull it if using a blade switch type.
But towards the other end, e.g. in a mini IP67 box would I also place a breaker? Or only ever a fuse between the battery and the inverter?
Or is it fine or even recommend to also have a breaker? If so, would that also be rated the same 63A?
There's another guy also setting up a Solis S6 11.4k-US right now on Dala's discord channel and he says, "I have the 20 amp on the solar strings a 63 amp between the battery and inverter and 60 amp on the AC out side in the breaker panel."
So it seems pretty simple and that 63A is what he used for between the battery and inverter. But I think he used a 2 pole breaker with arc suppression and not a fuse. Is that alright? Same in real world use between a fuse and a breaker?
Solar Guppy
Red Cobra Guppy
You are making this unnecessarily complex, the S6 has internally a fuse on the battery and all supported batteries for the S6 have circuit breakers on their output. No additional anything is needed.
If you are trying to connect an unknown battery from an EV, it won't work unless your using some home grown BMS solution that will require contactors and then a circuit break rated for DC would be fine, just like all the commercial options.
The is no need for breakers on the Solar as when Solar is shorted, it is close to zero volts at the ISC values ( typically 8 to 10 amps, near zero power, its not a battery with close in infinite amps when shorted ) the inverter has a DC disconnect as well.
If you are trying to connect an unknown battery from an EV, it won't work unless your using some home grown BMS solution that will require contactors and then a circuit break rated for DC would be fine, just like all the commercial options.
The is no need for breakers on the Solar as when Solar is shorted, it is close to zero volts at the ISC values ( typically 8 to 10 amps, near zero power, its not a battery with close in infinite amps when shorted ) the inverter has a DC disconnect as well.
Hedges
I See Electromagnetic Fields!
- Joined
- Mar 28, 2020
- Messages
- 23,279
How did you determine maximum current draw?
Circuit breakers on PV input serve two purposes:
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.
2) I got 600V DC breakers cheaper than 600V DC disconnects. So I used breakers as disconnects. But they will never trip, because they're 16A breakers, and the maximum current the strings can deliver is about 12A.
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.
2) I got 600V DC breakers cheaper than 600V DC disconnects. So I used breakers as disconnects. But they will never trip, because they're 16A breakers, and the maximum current the strings can deliver is about 12A.
From the inverter datasheet.
Solar Guppy
Red Cobra Guppy
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 )
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