Hi All, new to the forum and trying to educate myself on off-grid solar. The family is purchasing some land without electrical service for a "camp" of sorts, and figure a combination of solar, propane, and generator power will be used. In short, I'm trying to size a solar power system to handle smaller electrical loads while we are visiting (NOT heating, cooling, or cooking), or anything that runs while we are not there (so the generator doesn't have to be running). Roughly looking for it to run a water pump, some lights, bug zapper, that sort of stuff. But before we get to that and ultimately a design, I have some (hopefully) basic questions:
1. Since power goes into banks of 12V batteries (generally speaking), is there an efficiency advantage to running 12 VDC lighting? I'm assuming that the voltage drop in a low volt DC system is a lot more of an issue than 115 VAC, which may mean any efficiency loss in the conversion from DC to AC is outweighed by the size of wiring that would be needed to run 12 VDC say, 100' or so. I'm not completely new to wiring in boats, so I do have a little bit of experience with 12 VDC. Asked differently, how efficient are good inverters at converting from DC to AC?
2. I'm 99% sure the answer to this next question is "yes", but just to confirm: the inverters will only pull enough power to match the load requirement at any given time, up to is rated capacity, right? In other words, just because you have, say, a 2000 watt inverter doesn't mean it's always drawing 2000 watts unless the demand is that high?
3. I'm planning on electricity for any "big" loads (air conditioner, power tools) being provided by a generator. I have seen some inverters with built-in transfer switches. Next question is: does the inverter rating still matter for the load being pulled if the generator is running and the inverter has a transfer switch? Explained differently, let's say I have a 2000 W inverter and a 5000 W generator hooked to the inverter's transfer switch. Would I be able to run a 3000 W load, or would that still overload/damage the inverter even with the generator running? Or is this a "it depends" answer depending on the manufacturer?
4. I've also seen battery protectors that shut off at a certain low voltage level. I'm planning to use lead-acid batteries due to cost, and think this would be a good way to help protect them considering the system will be unmonitored for long stretches. Question is: do these also turn back on once the voltage level rises from charging, or do they need to be manually reset like a circuit breaker? Or does it depend on the model/manufacturer?
5. Finally (for now), suggestions on manufacturers to use and/or avoid? This is all new to me so I don't have prior experience with any of the companies manufacturing this stuff. There's nothing life critical that will run off this solar, but it should be able to be left alone for a few weeks at a time without constant adjustments/fixes/resets. Looking for robust more so than feature-rich if that's a better way to put it. In case location matters for what's available in my market, this will be in Florida, USA.
Next step will be to determine my constant and transient load requirements, and try to work out a design that matches. Trying to get some of the basic questions answered on how the systems work first. Thanks in advance for your help!
1. Since power goes into banks of 12V batteries (generally speaking), is there an efficiency advantage to running 12 VDC lighting? I'm assuming that the voltage drop in a low volt DC system is a lot more of an issue than 115 VAC, which may mean any efficiency loss in the conversion from DC to AC is outweighed by the size of wiring that would be needed to run 12 VDC say, 100' or so. I'm not completely new to wiring in boats, so I do have a little bit of experience with 12 VDC. Asked differently, how efficient are good inverters at converting from DC to AC?
2. I'm 99% sure the answer to this next question is "yes", but just to confirm: the inverters will only pull enough power to match the load requirement at any given time, up to is rated capacity, right? In other words, just because you have, say, a 2000 watt inverter doesn't mean it's always drawing 2000 watts unless the demand is that high?
3. I'm planning on electricity for any "big" loads (air conditioner, power tools) being provided by a generator. I have seen some inverters with built-in transfer switches. Next question is: does the inverter rating still matter for the load being pulled if the generator is running and the inverter has a transfer switch? Explained differently, let's say I have a 2000 W inverter and a 5000 W generator hooked to the inverter's transfer switch. Would I be able to run a 3000 W load, or would that still overload/damage the inverter even with the generator running? Or is this a "it depends" answer depending on the manufacturer?
4. I've also seen battery protectors that shut off at a certain low voltage level. I'm planning to use lead-acid batteries due to cost, and think this would be a good way to help protect them considering the system will be unmonitored for long stretches. Question is: do these also turn back on once the voltage level rises from charging, or do they need to be manually reset like a circuit breaker? Or does it depend on the model/manufacturer?
5. Finally (for now), suggestions on manufacturers to use and/or avoid? This is all new to me so I don't have prior experience with any of the companies manufacturing this stuff. There's nothing life critical that will run off this solar, but it should be able to be left alone for a few weeks at a time without constant adjustments/fixes/resets. Looking for robust more so than feature-rich if that's a better way to put it. In case location matters for what's available in my market, this will be in Florida, USA.
Next step will be to determine my constant and transient load requirements, and try to work out a design that matches. Trying to get some of the basic questions answered on how the systems work first. Thanks in advance for your help!
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