System design

[r00t]

I think I can be of some help to you, having had to deal with trying to build an off-grid PV system in the desert of Northern Mexico. I have tried Lead acid batteries and frankly found them to be too sensitive and problematic for hot climates. As the temperatures go above 28 C the lead acid batteries lose 30 to 40% of their capacity, especially difficult at 35 to 40 C. That same problem of high temperatures affects the output of the solar panels, reducing their wattage by the same or similar amount. The alternative I chose was to use Nickel-Iron (NiFe) or Edison batteries. These batteries are available from China and India and shipped directly to your country. A check through Alibaba.com will give you a number of manufacturers. I chose Ciyi.com in Zhuhai, not far from Hong Kong. The Nife batteries I chose are 1.2 v/battery at 1200AH capacity. Thus a bank of 10 1.2 v batteries produces 14,400 watts at average 12v. The batteries are very safe, use distilled water to replenish the alkaline electrolyte, will last more than 50 years before replacing the electrolyte, and are very efficient at high temperatures. They are also large, very heavy, and very tolerant of inexperienced users. It is very hard to damage them. They cost about $528/battery. My shipping cost for 10 was $280 US to Mexico. The 10 batteries I bought have been in service for 1 year, 8 months, and have been flawless. They charge to about 16.1 volts and can be discharged to 0.0v and will come back time after time perfectly. Managing the NiFe batteries is different from Lead Acid or LI-iOn: They require adjustments in the Inverter to tolerate a higher voltage than from Lead acid or Li-ion batteries.

But going off-grid is much much more than just choosing the right equipment, Off-grid is a life-style change that necessitates thinking what it is that is important to you. Running two mini-splits, a refrigerator and a chest freezer is going to require about 10kwh/day of real power, and lighting and electronics, pumps, and power tools another 2 kwh/day. Switching to 12v lighting, eg. LED bulbs, upgrading to newer more efficient appliances, etc. Learning to manage power consumption, day and night is all a part of off-grid living.

Mod note. I disagree with several items (see msg #18 in this thread) and warn visitors to not put a lot of faith in the viewpoints of r00t

[max2k]

I think I can be of some help to you, having had to deal with trying to build an off-grid PV system in the desert of Northern Mexico. I have tried Lead acid batteries and frankly found them to be too sensitive and problematic for hot climates. As the temperatures go above 28 C the lead acid batteries lose 30 to 40% of their capacity, especially difficult at 35 to 40 C. That same problem of high temperatures affects the output of the solar panels, reducing their wattage by the same or similar amount. The alternative I chose was to use Nickel-Iron (NiFe) or Edison batteries. These batteries are available from China and India and shipped directly to your country. A check through Alibaba.com will give you a number of manufacturers. I chose Ciyi.com in Zhuhai, not far from Hong Kong. The Nife batteries I chose are 1.2 v/battery at 1200AH capacity. Thus a bank of 10 1.2 v batteries produces 14,400 watts at average 12v. The batteries are very safe, use distilled water to replenish the alkaline electrolyte, will last more than 50 years before replacing the electrolyte, and are very efficient at high temperatures. They are also large, very heavy, and very tolerant of inexperienced users. It is very hard to damage them. They cost about $528/battery. My shipping cost for 10 was $280 US to Mexico. The 10 batteries I bought have been in service for 1 year, 8 months, and have been flawless. They charge to about 16.1 volts and can be discharged to 0.0v and will come back time after time perfectly. Managing the NiFe batteries is different from Lead Acid or LI-iOn: They require adjustments in the Inverter to tolerate a higher voltage than from Lead acid or Li-ion batteries.

But going off-grid is much much more than just choosing the right equipment, Off-grid is a life-style change that necessitates thinking what it is that is important to you. Running two mini-splits, a refrigerator and a chest freezer is going to require about 10kwh/day of real power, and lighting and electronics, pumps, and power tools another 2 kwh/day. Switching to 12v lighting, eg. LED bulbs, upgrading to newer more efficient appliances, etc. Learning to manage power consumption, day and night is all a part of off-grid living.

switching to 12V loads is not a prerequisite- you could just use DC/AC inverter and convert battery voltage to standard AC, these inverters are pretty efficient. 12V is also poor choice at such power levels- to get say 1kW out of 12V battery would require almost 100 A current which leads to insanely thick wires and unnecessary losses. Otherwise thanks for the info.

[Mike90250]

I think I can be of some help to you, having had to deal with trying to build an off-grid PV system in the desert of Northern Mexico. I have tried Lead acid batteries and frankly found them to be too sensitive and problematic for hot climates. As the temperatures go above 28 C the lead acid batteries lose 30 to 40% of their capacity, especially difficult at 35 to 40 C. That same problem of high temperatures affects the output of the solar panels, reducing their wattage by the same or similar amount. The alternative I chose was to use Nickel-Iron (NiFe) or Edison batteries. These batteries are available from China and India and shipped directly to your country. A check through Alibaba.com will give you a number of manufacturers. I chose Ciyi.com in Zhuhai, not far from Hong Kong. The Nife batteries I chose are 1.2 v/battery at 1200AH capacity. Thus a bank of 10 1.2 v batteries produces 14,400 watts at average 12v. The batteries are very safe, use distilled water to replenish the alkaline electrolyte, will last more than 50 years before replacing the electrolyte, and are very efficient at high temperatures. They are also large, very heavy, and very tolerant of inexperienced users. It is very hard to damage them. They cost about $528/battery. My shipping cost for 10 was $280 US to Mexico. The 10 batteries I bought have been in service for 1 year, 8 months, and have been flawless. They charge to about 16.1 volts and can be discharged to 0.0v and will come back time after time perfectly. Managing the NiFe batteries is different from Lead Acid or LI-iOn: They require adjustments in the Inverter to tolerate a higher voltage than from Lead acid or Li-ion batteries.

But going off-grid is much much more than just choosing the right equipment, Off-grid is a life-style change that necessitates thinking what it is that is important to you. Running two mini-splits, a refrigerator and a chest freezer is going to require about 10kwh/day of real power, and lighting and electronics, pumps, and power tools another 2 kwh/day. Switching to 12v lighting, eg. LED bulbs, upgrading to newer more efficient appliances, etc. Learning to manage power consumption, day and night is all a part of off-grid living.

Hi r00t.
I'd be willing to let you correct yourself with many of your statements (highlighted in red) because I know them to be absolutely false. I don't know if you are here for sales leads or what,

[Diallodjeri]

This is interesting.

[Diallodjeri]

You ,r00t , didn't provide any rebuttal to Mike's response to your comment when he found some of your statements to be completely false. I will be really disgusted if you happen to be a sales man, because people like me who are new to solar energy come to this forum in order to seek some expert advices and yet we're being followed by a sales man who's trying to feed us some crap.

[sensij]

You ,max2k, didn't provide any rebuttal to Mike's response to your comment when he found some of your statements to be completely false. .

I think you got the wrong guy. max2k 's posts are fine (and welcome), r00t is who posted the problematic information.

[adoublee]

I think you got the wrong guy. max2k 's posts are fine (and welcome), r00t is who posted the problematic information.

He will also be 'really disgusted' if some information posted on an internet forum he paid nothing to access is not completely accurate. He is seeking expert advices on this internet forum.

[Amy@altE]

Schneider Electric says that you can set up your system to utilize they extra power generated by the solar panels to power your loads once the battery bank is full. Both the charge controller and SW inverter communicate with XANBUS, allowing you to use your solar power during the day for your loads. If you are interested in more details, I have a video where I discussed this with them. Search on YouTube for "The advantages of using Schneider's XANBUS enabled products in your solar system ".

[max2k]

He will also be 'really disgusted' if some information posted on an internet forum he paid nothing to access is not completely accurate. He is seeking expert advices on this internet forum.

you used wrong font

@Diallodjeri: if you were still waiting for response it would've helped if you accurately reviewed post #11 in this very thread instead of trying to attack anyone personally however wrong they might be. I'm not sure there will be a lot of takers after such outburst as the experts on this forum are not getting paid for answering questions so you might want to adjust your attitude accordingly and let mods monitor the content.

[J.P.M.]

you used wrong font

@Diallodjeri: if you were still waiting for response it would've helped if you accurately reviewed post #11 in this very thread instead of trying to attack anyone personally however wrong they might be. I'm not sure there will be a lot of takers after such outburst as the experts on this forum are not getting paid for answering questions so you might want to adjust your attitude accordingly and let mods monitor the content.

Hey Max: lighten up.
1.) It was mistaken identity.
2.) Mods got it covered.
3.) Besides, r00t looks like a crank.

[Diallodjeri]

@Max2k: I do apologize for the names mixed-up, otherwise my attitude is just fine. Like I said, we're here to seek an expert's advice not the advice from sales man.

Thanks.

[max2k]

Hey Max: lighten up.
1.) It was mistaken identity.
2.) Mods got it covered.
3.) Besides, r00t looks like a crank.

that's me lighten up Seriously I was unable to understand OP problem as stated and I think #11 post reflects that confusion as well. OP uses kW and kWh interchangeably and with money involved I guess no one wants to own his project outcome . If he still needs help he better clear up the problem and lower his expectations.

[J.P.M.]

@Max2k: I do apologize for the names mixed-up, otherwise my attitude is just fine. Like I said, we're here to seek an expert's advice not the advice from sales man.

Thanks.

Sensij has suggested this forum may be an example of the internet at it's best. While agreeing with him for the most part, I'd also suggest this forum, like most or all other forums can have examples of the net at its worst. It ain't all sweetness and light and enlightenment. That is, as well as a fair amount of anonymity which makes people more prone and enabled to exaggeration, lies, and just plain B.S., a lot of incorrect and possibly dangerous information can show up with no way to stop it except from moderators who perform the reviewer function as done in peer reviewed literature.

r00t seems to be one such bad actor. Mike seems to have called him out, but r00t did manage to get something posted.

As for looking for accurate information, I'm of the opinion that the more serious of us are considerate and professional enough to try to get it right, but I'd respectfully suggest you keep in mind that you usually get what you pay for or less, with no guarantees expressed or implied. Viewer discretion is advised. Or, P.E. consulting fees are running ~ $150 - $250/hr. there days.

Take what you what of the above. Scrap the rest.