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Electrical/Solar help needed

 
pollinator
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I am far from the energy industry, but circumstances force me to prepare for winter and the summer blackout showed that my old scheme for operating a gas boiler from a car battery and a UPS simply will not work since there is no time to charge the lead battery.  Therefore, a decision was made and a custom LifePo4 48 v 100 A 5 kW assembly and a 6.2 kW Powmr solar inverter were purchased.  Unfortunately, I am far from an electrician, but since there are currently no free installers, I will start with placement and gradually assemble the system.  I decided to place it in a small corridor at the entrance to the ground floor, there is a high ceiling and a stable temperature throughout the year, since the main panel is located on an unheated veranda, which is hot in summer and sub-zero in winter.
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Pieces of a solar system
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electrical panels
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bogdan smith
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I want to place it on the far wall, it will be convenient to run the cables from the main meter there, the wall is made of OSB, so I’ll remove the decorative boards and stick ceramic tiles so that the surface is non-flammable
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bogdan smith
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The first question that I am trying to solve is the protection between the solar inverter powmr 6.2 kW and lithium phosphate 48v 100A 5 kW, how to properly create the protection, install a 200 A circuit breaker and a 500 A fuse of a constant current closer to the battery on the cable + or on -?.  GP chat gave me the answer, is this correct or not?
 1. Positive Circuit Breaker (200A): Location: The circuit breaker is installed as close as possible to the positive terminal of the battery. Function: It protects the system from short circuit and overload.  In the event of excessive current (for example, a short circuit), the circuit breaker will operate and disconnect the circuit, preventing damage to components.2.  Positive Fuse (500 A): Location: The fuse is also located on the positive wire, but after the circuit breaker. Function: The fuse provides additional protection against extremely high currents that can damage equipment or cause a fire.  It is designed to operate at even higher currents than the automatic one.3.  Negative wire: Nothing installed: Usually no protection devices are installed on the negative wire, since all protection is usually concentrated on the positive wire.  The negative wire is usually connected directly to the inverter and battery.4.  The main advantages of this arrangement are: Safety: This configuration provides maximum protection for both the battery and the entire system. Compliance with standards: Installation of protection on the positive wire complies with electrical standards and recommendations. Reliability: The circuit breaker and fuse provide dual protection against overloads and short circuits.
 
pollinator
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I am not an electrician either.

But I think you might attract more help if you change the title of this thread to something like "Electrical/Solar help needed".

Good luck!
 
bogdan smith
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Thank you, how can I change the topic title?
 
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Let's do a little bit of math.  The max draw on the inverter is 6.2kW, or 6,200W.  Assuming the battery drops down to 48V, the maximal amp draw to make 6200W is 6200W/48V = 129A.  Looking at the wire included with the inverter, I am quite suspicious!  That looks like 4 gauge to me?  Can you please confirm the wire gauge before going further?

That is a cheap low-budget Chinese inverter, who can not be trusted to market safe and functional products.  I would look into upgrading the wire immediately.  Take a look at this ampicity chart.  The chart suggests to handle your amperage, you need at least 0 or better 00 gauge wire.

Remember, the breaker/fuse protects the wire, not the equipment.  To safely handle a 129A load, I think a 150A breaker/fuse is appropriate.  No way I would use a 500A part.

Now, that inverter is an AiO unit (all in one) that includes a MPPT charge controller?  Could you post the specs on the controller section?  Assuming it will charge your battery at up to 60-80A, and you want to de-rate output to 85% for real-world conditions, starting at 50V, that works out to be (60A X 50V)/85% = 3530W of panels.  With a 80A limit it's (80A X 50V)/85% = 4700W of panels.  We need to know the voltage limit of your controller to determine how many panels you can put in series.

Assuming your Voc limit is 150V, three 250W high-voltage residential panels in series would make a nice single string.  Four parallel strings of three panels each would be good for a 60A controller.

Don't buy 12V panels, and don't buy through the mail, because shipping is a killer.  Buy locally off of Craigslist with cash and carry panels.  Bring a volt meter with you if you question the quality.  Don't buy anything with a Voc more than 2-3V less than what's posted on the back of the panel.

The 100A battery bank you bought is very small.  Assuming you don't want to charge it all the way to 100%, and don't want to deplete it less than 20%, then you only have ~3300Wh of useable power.  That's not much.  I'm finding at my own cabin, just living a regular lifestyle with a refrigerator, lights, TV, and some computer time, I'm consuming about 4kWh of power per day.  I'd expect you to consume about the same.  That means one single cloudy/rainy day, and that battery is totally dead.

Adding more watts of solar can help with that.  With my system, I'm using virtual tracking to add watts to my system.  That means I have additional solar arrays facing East and West to complement my South facing arrays.  No single array orientation will overload my controller with too many amps, because not all the panels are at full output at the same time.  But, on cloudy days when the light is low but indirect, the extra panels help me make enough power, even in the rain.
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pollinator
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Chat GPT is not a good choice for electrical information. It cannot be relied upon for technical details that might cause a fire or injury.


You need to size your fuse to protect your wiring, and to size your wiring to suit the maximum current.

I personally do not install cheap chinese fuses, fuseholders, breakers, relays, etc.. I have had them melt/burn up far below their rated capacity, after working fine for months on end. I am not sure if I'd prefer a cheapo fuse/breaker to none at all.. but I wouldn't run either option in anything but a crisis.

With lithium of any sort you should consider the maximum interrupting current rating of protection devices; there are plenty of fuses and breakers that are rated high enough in terms of max amps, but they cannot all be relied upon not to short when faced with the massive potential current of a lithium battery.


A good source for info specific to this topic is Will Prowse's DIY solar forum; https://diysolarforum.com.
 
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D Nikolls wrote:Chat GPT is not a good choice for electrical information. It cannot be relied upon for technical details that might cause a fire or injury.


You need to size your fuse to protect your wiring, and to size your wiring to suit the maximum current.

I personally do not install cheap chinese fuses, fuseholders, breakers, relays, etc.. I have had them melt/burn up far below their rated capacity, after working fine for months on end. I am not sure if I'd prefer a cheapo fuse/breaker to none at all.. but I wouldn't run either option in anything but a crisis.

With lithium of any sort you should consider the maximum interrupting current rating of protection devices; there are plenty of fuses and breakers that are rated high enough in terms of max amps, but they cannot all be relied upon not to short when faced with the massive potential current of a lithium battery.


A good source for info specific to this topic is Will Prowse's DIY solar forum; https://diysolarforum.com.



listen to this advice it is bang on - cheap ANYTHING will put you in danger - as will incorrect information.

Will Prowse's site is great, another great tutorial site with diagrams is Nate @ explorist.life. here is a link to low res diagrams with fuse/breaker placements - start there:

https://explorist.life/solarwiringdiagrams/

you have not listed your input (solar, How much) and your battery cables seem a bit "thin" etc. breakers and fuses are tricky - to small and the trip all the time.. to big and you may have worse problems.

draw out a diagram end to end of what you plan and build piece by piece and buy quality components - most manufacturers have excellent install videos.

PLEASE be careful - this is one area of homesteading not to do on the cheap - good luck!

i see your location is Ukraine - that has to be tough, i am sorry - still, do what you can to protect your system accordingly - peace!


 
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Wiring diagram, adding manual circuit breakers will help you perform maintenance.
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bogdan smith
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D Nikolls wrote:Chat GPT is not a good choice for electrical information. It cannot be relied upon for technical details that might cause a fire or injury.


You need to size your fuse to protect your wiring, and to size your wiring to suit the maximum current.

I personally do not install cheap chinese fuses, fuseholders, breakers, relays, etc.. I have had them melt/burn up far below their rated capacity, after working fine for months on end. I am not sure if I'd prefer a cheapo fuse/breaker to none at all.. but I wouldn't run either option in anything but a crisis.

With lithium of any sort you should consider the maximum interrupting current rating of protection devices; there are plenty of fuses and breakers that are rated high enough in terms of max amps, but they cannot all be relied upon not to short when faced with the massive potential current of a lithium battery.


A good source for info specific to this topic is Will Prowse's DIY solar forum; https://diysolarforum.com.


https://amperok.com.ua/provid-pv-3-25-chervonyi-zzkm-15508?gclid=Cj0KCQjwiOy1BhDCARIsADGvQnDj39zCGLd1gIQnAjA-mqbSt5hJCb_cCzv-TWn7TylGYc436rxX_XYaAiEQEALw_wcB
cable marking (pv 3) 25, core cross-section 25 mm
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bogdan smith
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battery parameters and inverter label
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Michael Qulek
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Looking at your wire pic, you do NOT measure the thickness of the wire including the insulation.  You need to measure the thickness of the copper wire itself.  Your pic is a bit blurry, but it looks like the thickness with the insulation is ~7mm.  Assuming that the plastic is ~1mm thick, that means you are likely to have a copper wire that's maybe 5mm in diameter.  Referring back to the chart on wire gauge above, that looks like it's likely to be either 6 gauge, or 4 gauge (American scale).  I'd say thats totally inadequate for supplying your inverter with power.  Maybe it's OK to use it just to turn the inverter on, and check for power, but no way would I ever try to apply a full load to that inverter, with that wire.  Since the wire appears to be originally attached to the battery, instead of the inverter itself, I'm expecting that the battery selected was originally designed for a smaller application.  That goes along the lines of what I mentioned before, that this battery is too small for your application.

Looking at the MPPT section of your AiO, it appears that the operating voltage is between 90VDC and 500VDC.  That means my example above with three panels in series might not be appropriate for your electronics.  Having only three 30V panels in series might not guarranty that you supply >90VDC at all times.  It would be better to use at least four 30V panels to get at least 120VDC.  

I'm focusing on the 30V panels mostly because that is the common variety that appears most abundant right now, with many going for only 30-40$ right now.  Maybe higher in Ukraine?  It appears that your MPPT's optimal voltage is around 240VDC, so you could go with up to 8 of those panels in series to make that voltage.  I prefer ground mounts, rather than putting panels on the roof, and the most I've built now is an array frame that can hold 6 residential panels.  That would be ~180V (1500W), which would work well for you.  If you build rotating mounts like mine, you can rotate it East in morning, and West in the afternoon, resulting in more total power.

I'd consider building the array frame like I've pic below, though with such a small battery, the extra watts won't get you much.  You really need a bigger battery to take advantage of extra solar.
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bogdan smith
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Michael Qulek wrote:Looking at your wire pic, you do NOT measure the thickness of the wire including the insulation.  You need to measure the thickness of the copper wire itself.  Your pic is a bit blurry, but it looks like the thickness with the insulation is ~7mm.  Assuming that the plastic is ~1mm thick, that means you are likely to have a copper wire that's maybe 5mm in diameter.  Referring back to the chart on wire gauge above, that looks like it's likely to be either 6 gauge, or 4 gauge (American scale).  I'd say thats totally inadequate for supplying your inverter with power.  Maybe it's OK to use it just to turn the inverter on, and check for power, but no way would I ever try to apply a full load to that inverter, with that wire.  Since the wire appears to be originally attached to the battery, instead of the inverter itself, I'm expecting that the battery selected was originally designed for a smaller application.  That goes along the lines of what I mentioned before, that this battery is too small for your application.

Looking at the MPPT section of your AiO, it appears that the operating voltage is between 90VDC and 500VDC.  That means my example above with three panels in series might not be appropriate for your electronics.  Having only three 30V panels in series might not guarranty that you supply >90VDC at all times.  It would be better to use at least four 30V panels to get at least 120VDC.  

I'm focusing on the 30V panels mostly because that is the common variety that appears most abundant right now, with many going for only 30-40$ right now.  Maybe higher in Ukraine?  It appears that your MPPT's optimal voltage is around 240VDC, so you could go with up to 8 of those panels in series to make that voltage.  I prefer ground mounts, rather than putting panels on the roof, and the most I've built now is an array frame that can hold 6 residential panels.  That would be ~180V (1500W), which would work well for you.  If you build rotating mounts like mine, you can rotate it East in morning, and West in the afternoon, resulting in more total power.

I'd consider building the array frame like I've pic below, though with such a small battery, the extra watts won't get you much.  You really need a bigger battery to take advantage of extra solar.


10 мм
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bogdan smith
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wire length 1.3 m
 
Michael Qulek
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With a cross-section of 25mm2, it looks like it lays somewhere between 3 gauge, and 4 gauge, following American guidelines.  In the real-world, that looks like it is likely to handle 80A without getting too hot.  That works out to be about 4000W with a battery feeding the inverter at around 50V.  Most likely you are likely to get by as long as you never attempt to run the inverter flat out, at maximum wattage.  But, it's your call as how hot you are willing to push your wiring.

I can understand though that you are in a country at war right now, and you really have to make do with what you can find at the moment.  What I can suggest you do now is just attempt to run the unit supporting loads like the refrigerator, and lights, but not turn on any big-ticket items like an electric heater, or a microwave.  You can put a hand on the insulated part of the wire while running your loads to see just how hot it's actually getting.

You can control that a bit better by fusing it with a lower rating fuse, like 80A, even if you install it in front of a 150A breaker.  Some time in the future, when it becomes practical to upgrade your wiring, the 80A fuse can be dispensed with.

Have you started working on your solar input yet?  You haven't mentioned one word about panels yet?
 
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Here is a good site for DC wire sizing: https://www.bluesea.com/support/articles/Circuit_Protection/1437/Part_1:_Choosing_the_Correct_Wire_Size_for_a_DC_Circuit

Remember the length of the circuit is both your negative and positive wires.

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bogdan smith
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Michael Qulek wrote:With a cross-section of 25mm2, it looks like it lays somewhere between 3 gauge, and 4 gauge, following American guidelines.  In the real-world, that looks like it is likely to handle 80A without getting too hot.  That works out to be about 4000W with a battery feeding the inverter at around 50V.  Most likely you are likely to get by as long as you never attempt to run the inverter flat out, at maximum wattage.  But, it's your call as how hot you are willing to push your wiring.

I can understand though that you are in a country at war right now, and you really have to make do with what you can find at the moment.  What I can suggest you do now is just attempt to run the unit supporting loads like the refrigerator, and lights, but not turn on any big-ticket items like an electric heater, or a microwave.  You can put a hand on the insulated part of the wire while running your loads to see just how hot it's actually getting.

You can control that a bit better by fusing it with a lower rating fuse, like 80A, even if you install it in front of a 150A breaker.  Some time in the future, when it becomes practical to upgrade your wiring, the 80A fuse can be dispensed with.

Have you started working on your solar input yet?  You haven't mentioned one word about panels yet?


Tomorrow I will prepare the room for installing the inverter and battery, if the length of the wire is not enough for comfortable installation, I will put a 35 mm wire. If you think that this is critical, I will change the wire at the initial stage. I am sending a photo of the machine and fuse, there is an option to select a parameter. Should I put the machine on the + wire first, then the fuse? There are different opinions, the battery manufacturer recommends putting a 200 amp machine on the - wire. Others recommend putting a fuse on + and a two-pole machine on -, bifurcating the wire. They also do not recommend putting a fuse, citing the fact that the fuse is in the inverter itself. Regarding the panels, I have a problem, there is a shadow from the chimney pipe. Although now we have canceled the tax on the import of panels and I think that at the end of October you can buy panels very inexpensively.
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bogdan smith
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manual
Filename: POW-HVM6.2K-48V-LIP_User_Manual.pdf
File size: 4 megabytes
 
Michael Qulek
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At this point, I would not worry too much about the shading.  With your sized battery bank, you'd have nowhere to put all the watts.  With your house drawing, what's the direction of the drawing?  I'll guess that down is South?    As discussed above, you might want to consider six panel strings of 30V residential panels, 180V in series, making 1500W per string.  Right now, it looks like you could fit a 6-panel string at the lowest point of the roof, and then a second 6-panel string right up at the ridgetop.  Assuming you can get 3.0 sunhours per day in December, that's 9000Wh of power, about double what the battery could accept even at zero charge.

If you want to add another 6-panel string towards the middle section, you could position the panels in two rows of three panels, placed on the far-right side of the roof.  That would at least allow you for some extra power at noon?

Lastly, you can utilize virtual tracking to add even more arrays.  Maybe another 6 panels facing due West, or 6 facing due East, depending on the orientation.  The advantage of virtual tracking is that you can get additional power in the early morning, or the late afternoon when the main South-facing array is not putting out much.   With your roof, I'm guessing that the roof to the far left of the pics is facing West?

By breaking up the panel strings in to shorter 6-panel units, you decrease the very negative effects of shading to maybe only one string at a time.
 
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