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electrical:solar:sizing [2022/01/26 19:48] princess_fluffypants [Voltage] |
electrical:solar:sizing [2024/07/16 10:58] (current) frater_secessus [your reserve needs] |
==== calculators ==== | ==== calculators ==== |
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| * Unbound Solar [[https://unboundsolar.com/solar-information/offgrid-calculator|offgrid calculator]] |
| * AltE [[https://www.altestore.com/store/calculators/off_grid_calculator/|offgrid calculator]] |
* [[https://www.batterystuff.com/kb/tools/calculator-sizing-a-battery-to-a-load.html|BatteryStuff 12v load calculator]] | * [[https://www.batterystuff.com/kb/tools/calculator-sizing-a-battery-to-a-load.html|BatteryStuff 12v load calculator]] |
* [[http://gpelectric.com/tools/GoPowerCalculator.htm?state=RvDiv|GoPower calculator]] | * [[http://gpelectric.com/tools/GoPowerCalculator.htm?state=RvDiv|GoPower calculator]] |
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===== your reserve needs ===== | ===== your reserve needs ===== |
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| [see also [[electrical:autonomy|days of autonomy]]] |
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> ...one that really [effed] with me was running out of power or spending a few days in the dark cause the weather is bad. -- hellexual((https://www.reddit.com/r/vandwellers/comments/er4gf7/whered_you_get_your_van/ff1i66p/)) | > ...one that really [effed] with me was running out of power or spending a few days in the dark cause the weather is bad. -- hellexual((https://www.reddit.com/r/vandwellers/comments/er4gf7/whered_you_get_your_van/ff1i66p/)) |
Solar power is highly dependent on local conditions like weather, season, and latitude. One cannot assume getting a full charge every day in every condition. | Solar power is highly dependent on local conditions like weather, season, and latitude. One cannot assume getting a full charge every day in every condition. |
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To account for this decide how many reserve days of power((https://duckduckgo.com/?q=days+of+autonomy&t=ffab&ia=web)) you need if there is little [[https://www.wholesalesolar.com/solar-information/sun-hours-us-map|solar power available]]. You may need few in desert regions and many more in the Pacific Northwest. Long stretches of little solar charging may necessitate | To account for this decide how many reserve days of power(("days of autonomy")) you need if there is little [[https://www.wholesalesolar.com/solar-information/sun-hours-us-map|solar power available]]. You may need few in desert regions and many more in the Pacific Northwest. Long stretches of little solar charging may necessitate |
[[electrical:solar:rationing|rationing solar power]]. | [[electrical:solar:rationing|rationing solar power]]. |
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* Inversion from 24vdc to 110vac is more efficient than inversion from 12vdc. | * Inversion from 24vdc to 110vac is more efficient than inversion from 12vdc. |
* You have large, power-hungry appliances that can run natively off of 24v | * You have large, power-hungry appliances that can run natively off of 24v |
* Some [[food:refrigeration|DC refrigerators]] can run off of both 12v or 24v, and are slightly more efficient when running off of 24v | * Some [[food:refrigeration|DC refrigerators]] and induction cooktops can run off of both 12v or 24v, and are slightly more efficient when running off of 24v. |
| * [[hvac:solar_ac|Off-grid Air Conditioning]] can be slightly more efficient with 24v native systems, and will allow smaller wires to be used. |
* You have a lot of long, large cable runs | * You have a lot of long, large cable runs |
* 24v doesn't have as much voltage drop as 12v over a similar distance, and can use smaller/cheaper cables. | * 24v doesn't have as much voltage drop as 12v over a similar distance, and can use smaller/cheaper cables. |
===== solar panel array ===== | ===== solar panel array ===== |
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Pick a solar panel array output on battery bank capacity. A common **rule of thumb for matching panels to battery bank** is that there should be **at least** 1 panel watt per amp-hour of nominal bank capacity. | Pick a solar panel array output on daily power requirements and battery bank capacity. A common **rule of thumb for matching panels to battery bank** is that //at a minimum// there should be 1 panel watt per amp-hour of nominal bank capacity. |
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> "...the person draining their batteries to the 50% range regularly would do much better with a 2 watts to 1Ah ratio, or even 3 to 1." -- SternWake((http://www.cheaprvliving.com/forums/Thread-How-much-solar-do-I-need?pid=278438#pid278438)) | > "...the person draining their batteries to the 50% range regularly would do much better with a 2 watts to 1Ah ratio, or even 3 to 1." -- SternWake((http://www.cheaprvliving.com/forums/Thread-How-much-solar-do-I-need?pid=278438#pid278438)) |