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electrical:inverter [2021/06/17 11:25]
frater_secessus [the case for multiple inverters]
electrical:inverter [2023/11/22 14:34] (current)
frater_secessus [Inverters]
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 AC-only items will require an inverter.  [[electrical:12v:wallwart|Devices that run off a "wall wart" adapter]] almost never require an inverter.   AC-only items will require an inverter.  [[electrical:12v:wallwart|Devices that run off a "wall wart" adapter]] almost never require an inverter.  
 +
 +===== efficiency =====
 +
 +Inverting from DC to your local shore power spec will necessarily incur losses.  These might be 10-30%, depending on the inverter, the inverter's efficiency spec, etc.  In the absence of hard information you might use 20% losses as a rule of thumb.  This means it will require 20% more power to run your load than the rating spec.
 +
 +50w * 0.8 efficiency = 60w demanded from the system
  
  
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   * widely available   * widely available
   * works for many/most AC items   * works for many/most AC items
-  * generally more efficient under no load (?)+
  
 Con:  Con: 
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 ==== MSW and electronics ==== ==== MSW and electronics ====
  
-there is anecdotal evidence that MSW can damage some electronics.  The most commonly repeated stories are Dewalt cordless tool battery chargers and laptop chargers.+> In the end, probably 80% of the stuff you plug in will work fine [on MSW], 10% will fail pretty quickly, and the other 10% it will be difficult to tell.  -- BB((https://forum.solar-electric.com/discussion/comment/191612#Comment_191612))
  
-> Rule of thumb: Everything that has electronics and use a power supply or an integrated power supply to lower voltage will be fine [on MSW]. (Radio, charger, Screens etc.) Everything that uses a power motor (often without electronics) will not (hairdryer kitchen appliances etc.)  - WombatCombat2020((https://www.reddit.com/r/vandwellers/comments/i2fs18/power_inverter_wave_question/g04fz04/))+While MSW powers resistive loads like crockpots and coil heaters perfectly, there is anecdotal evidence that MSW can damage some electronics.  The most commonly repeated stories are Dewalt cordless tool battery chargers and [[electrical:12v:laptop|laptop chargers]].  Milwaukee battery chargers may also require PSW.((https://www.electriciantalk.com/threads/cordless-chargers-and-inverters.40405/post-754431)) 
 + 
 +Laptop chargers that work on MSW will usually run somewhat warmer and may buzz.  Laptop chargers that will not work on MSW tend to get hot, not power on at all (no light), or cycle on/off. Laptop chargers and other power supplies might be tested thusly: 
 + 
 +One way that I used to check computer/electronic power supplies... take a [[https://amzn.to/2XKSFfp|Kill-a-Watt meter]] and measure the power factor. If it was >0.9, it probably would work fine -- BB((https://forum.solar-electric.com/discussion/comment/191612#Comment_191612))((power factor is the PF button on the kill-a-watt)) 
 + 
 + 
 +------ 
 + 
 +Rule of thumb: 
 + 
 +Everything that has electronics and use a power supply or an integrated power supply to lower voltage will be fine [on MSW]. (Radio, charger, Screens etc.) Everything that uses a power motor (often without electronics) will not (hairdryer kitchen appliances etc.)  - WombatCombat2020((https://www.reddit.com/r/vandwellers/comments/i2fs18/power_inverter_wave_question/g04fz04/))
  
 Other devices which do not like MSW: Other devices which do not like MSW:
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   * 433MHz remote radio controlled plugs((https://diysolarforum.com/threads/what-really-requires-a-pure-sine-inverter.22574/post-266515))   * 433MHz remote radio controlled plugs((https://diysolarforum.com/threads/what-really-requires-a-pure-sine-inverter.22574/post-266515))
   * asynchronous motors with a capacitor to build up the 90° phase do not run well on MSW((https://diysolarforum.com/threads/what-really-requires-a-pure-sine-inverter.22574/post-266767))   * asynchronous motors with a capacitor to build up the 90° phase do not run well on MSW((https://diysolarforum.com/threads/what-really-requires-a-pure-sine-inverter.22574/post-266767))
 +  * hair clippers
 +  * In [[https://www.youtube.com/watch?v=wimTJw_Gpgk|an apples-to-apples comparison]] knurlgnar24 found a microwave to run 10% less efficiently and at 20% less power on MSW.
 +
  
  
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   * Not as widely available as MSW; you may not find them at truck stops, big box stores, etc.   * Not as widely available as MSW; you may not find them at truck stops, big box stores, etc.
  
 +Not all PSW are prohibitively expensive.  Bestek makes [[https://amzn.to/3N4YE3S|a 300w PSW for about $50]].  See [[https://www.amazon.com/gp/customer-reviews/R3UKQ7A0GQ196N/ref=cm_cr_dp_d_rvw_ttl?ie=UTF8&ASIN=B07KQ4Q2L5|the top-rated review]] for oscilloscope testing and limitations.
 ===== inverter chargers ===== ===== inverter chargers =====
 +
 {{ https://m.media-amazon.com/images/I/61wb7PGYPNL._AC_UL320_.jpg?150}} \\ {{ https://m.media-amazon.com/images/I/61wb7PGYPNL._AC_UL320_.jpg?150}} \\
-An //inverter charger// performs several functions:+ 
 +//Inverter/chargers// are most often found on rigs that are on shore power much of the time and run heavy AC loads  
 + 
 + 
 +It provides several functions:
   - invert 12v battery power to 120vac   - invert 12v battery power to 120vac
-  - pass-through shore power when available+  - pass-through shore power when available, with auto-switching
   - some can bond shore and battery power to support heavy 120vac loads   - some can bond shore and battery power to support heavy 120vac loads
   - charge battery banks like a [[electrical:converter|converter]]   - charge battery banks like a [[electrical:converter|converter]]
 +  - some also handle solar charging
  
 They tend to be [[https://amzn.to/2KMcImw|expensive]], some over $1000. They tend to be [[https://amzn.to/2KMcImw|expensive]], some over $1000.
  
 +Note:  the Victron Multiplus line has outputs for maintaining the starter battery:
 +
 +
 +>> The main DC terminal can supply the full output current. The second output, intended for charging  starter battery, is limited to 4A and has a slightly lower output voltage.((https://www.victronenergy.com/upload/documents/Manual-MultiPlus-3k-120V-(firmware-xxxx4xx)-EN.pdf))
 ===== Sizing your inverter ===== ===== Sizing your inverter =====
  
 Once you have made your MSW vs. PSW decision the next step is **sizing the inverter** (picking the right capacity). Once you have made your MSW vs. PSW decision the next step is **sizing the inverter** (picking the right capacity).
  
-Note that to **actually power the inverter** you will need something like a 1:1 ratio of panel:inverter on flooded lead and 1:2 on AGM or lithium.((https://www.solarpaneltalk.com/forum/off-grid-solar/solar-living/15554-how-to-increase-solar-panel-output-amps?p=181738#post181738))  This would mean 400w of solar to run a 400w inverter (dipping into the battery as needed) or 400w of solar for 800w of inverter on AGM/Lithium, which have greater throughput.  
  
 ==== estimating your needs ==== ==== estimating your needs ====
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 You will need to know the largest draws you will need to meet **at the same time**.  If your TV is 40w, and your your laptop is 100w you would need (40w + 100w) * 1.10((inverter losses)), or an inverter that can power at least **154w**. You will need to know the largest draws you will need to meet **at the same time**.  If your TV is 40w, and your your laptop is 100w you would need (40w + 100w) * 1.10((inverter losses)), or an inverter that can power at least **154w**.
  
-Note that motorized equipment like drills likely have **greater current requirements for startup and for running**.  Be sure to meausure both startup and running (see below).    There are tricks you can use to minimize the start load, like starting a sewing machine at a low-load position((http://www.cheaprvliving.com/forums/Thread-Is-it-possible-to-Boondock-with-an-electric-sewing-machine?pid=165956#pid165956)), or //easing// into the trigger of a variable-speed power tool.+Motorized equipment like drills likely have **greater current requirements for startup and for running**.  Be sure to measure both startup and running (see below).    There are tricks you can use to minimize the start load, like starting a sewing machine at a low-load position((http://www.cheaprvliving.com/forums/Thread-Is-it-possible-to-Boondock-with-an-electric-sewing-machine?pid=165956#pid165956)), or //easing// into the trigger of a variable-speed power tool
 + 
 +Note that to **actually power the inverter** without voltage sag or dipping so much into battery capacity you may want need something like a 1:1 ratio of panel:inverter on flooded lead and 1:2 on AGM or lithium.((https://www.solarpaneltalk.com/forum/off-grid-solar/solar-living/15554-how-to-increase-solar-panel-output-amps?p=181738#post181738))  This would mean 400w of solar to run a 400w inverter (dipping into the battery as needed) or 400w of solar for 800w of inverter on AGM/Lithium, which have greater throughput
  
  
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 [[https://amzn.to/3ptHIbX|{{ https://m.media-amazon.com/images/I/61FOAk4UA5L._AC_UL320_.jpg?75}}]] [[https://amzn.to/3ptHIbX|{{ https://m.media-amazon.com/images/I/61FOAk4UA5L._AC_UL320_.jpg?75}}]]
-The best way to understand how much your 110v equipment needs during startup/running is to use a **power monitor** like the [[https://amzn.to/3ptHIbX|Kill A Watt]]. You may be pleased to find that some appliances run at much lower power than their labeling would suggest.((the label likely has to list the highest-possible wattage draw under any conditions))  It is rare to find a device that pulls more than the label states.+The best way to understand how much your 120vac equipment needs during startup/running is to use a **power monitor** like the [[https://amzn.to/3ptHIbX|Kill A Watt]]. You may be pleased to find that some appliances run at much lower power than their labeling would suggest.((the label likely has to list the highest-possible wattage draw under any conditions))  It is rare to find a device that pulls more than the label states.
  
  
-Kill A Watts may be available for loan from your public library.((http://www.cheaprvliving.com/forums/showthread.php?tid=26835&pid=337451#pid337451))+Kill A Watts may be available for loan from your public library((http://www.cheaprvliving.com/forums/showthread.php?tid=26835&pid=337451#pid337451)), and sometimes used at thrift stores.  
  
 The buttons on the traditional Kill-a-Watt have two functions each.  You press the button repeatedly to see the information: The buttons on the traditional Kill-a-Watt have two functions each.  You press the button repeatedly to see the information:
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   * **Watt / VA**     * **Watt / VA**  
     * **Watt** - this reading is the most important thing for load assessment. Add 10%-20%((depending on your inverter's efficiency)) to tell how much power the appliance will actually consume.      * **Watt** - this reading is the most important thing for load assessment. Add 10%-20%((depending on your inverter's efficiency)) to tell how much power the appliance will actually consume. 
-    * Volt-Amperes is //apparent power//, not directly useful.+    * Volt-Amperes is //apparent power//, normally not directly useful. If you have a device that is unexpectedly tripping an inverter (200w load tripping 300w inverter when powering on) you might watch VA to see if apparent power is >300w;  this can happen with some loads.  For this reason some inverters are rated in VA rather than W.  See Power Factor below
   * **Hz / PF**   * **Hz / PF**
     * Hertz - as with Volts, you can check your inverters AC frequency with this. In the US it is 60Hz.     * Hertz - as with Volts, you can check your inverters AC frequency with this. In the US it is 60Hz.
-    * **Power Factor**  - this reading can be indirectly useful.  One rule of thumb is that [[https://forum.solar-electric.com/discussion/comment/191612#Comment_191612|devices with a PF of >=.90 are good candidates for MSW inverters]].  A resistance heater may have a perfect 1.0 power factor and works great on MSW.  A laptop charger or other wall wart might have a PF of .040 - .60, which suggests it might overheat on MSW.+    * **Power Factor**  - this reading can be indirectly useful.  It is a relationship between Watts and VA (see above).  One rule of thumb is that [[https://forum.solar-electric.com/discussion/comment/191612#Comment_191612|devices with a PF of >=.90 are good candidates for MSW inverters]].  A resistance heater may have a perfect 1.0 power factor and works great on MSW.  A laptop charger or other wall wart might have a PF of .040 - .60, which suggests it might overheat on MSW.  Also see [[https://www.youtube.com/watch?v=Tv_7XWf96gg|this video]] about power factor.
   * **kWh / Hours**   * **kWh / Hours**
     * **kWh** are 1,000w-hours.  This is the actual amount of power used over time     * **kWh** are 1,000w-hours.  This is the actual amount of power used over time
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 ==== understanding the specs ==== ==== understanding the specs ====
  
-Inverters are generally **rated in watts**.+Inverters are generally **rated in watts** in terms of continuous resistive loads (heatihg elements, etc).  Inductive loads (things with motors, some electric blankets, etc) can draw more than their rated wattage and overpower the inverter.  Plan accordingly
  
 While there are both **peak** and **continuous duty** ratings it is common for marketers to advertize only the peak rating.((http://www.cheaprvliving.com/forums/Thread-PROBLEM-Dorm-fridge-won-t-run-on-1000-watt-inverter?pid=86851#pid86851))  The peak rating is only for short bursts of heavy draw. While there are both **peak** and **continuous duty** ratings it is common for marketers to advertize only the peak rating.((http://www.cheaprvliving.com/forums/Thread-PROBLEM-Dorm-fridge-won-t-run-on-1000-watt-inverter?pid=86851#pid86851))  The peak rating is only for short bursts of heavy draw.
  
 +Stand-by power ((parasitic draw when no loads are present)) may be a factor when an inverter is run for many hours.  The inverter drops to a power-saving mode then checks regularly to see if any load has been added.    
 +
 +  * [[https://diysolarforum.com/threads/victron-power-save-modes-a-short-explanation.33621/|an explanation]] of Victron inverter power save modes
 +  * Renogy inverters >700w appear to have a power saving mode
  
  
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 Most inverters will shut off if they get too hot, or if the input voltage is beyond certain points. Most inverters will shut off if they get too hot, or if the input voltage is beyond certain points.
  
-The low voltage cutoff is to protect your batteries from [[electrical:depth of discharge|over-discharge]].  The high voltage cutoff is to protect the inverter itself.  +The low voltage cutoff is to protect your batteries from [[electrical:depth of discharge|over-discharge]].  The high voltage cutoff is to protect the inverter itself.  In addition, [[https://forum.solar-electric.com/discussion/comment/419096#Comment_419096|the current consumed by the inverter may increase]] as bank voltage drops.
  
 HandyBob((https://handybobsolar.wordpress.com/)) reminds us that //"Properly adjusted solar systems with temperature compensation will regularly exceed the 15 volts many inverters use as a high voltage shut down."//((https://handybobsolar.wordpress.com/the-rv-battery-charging-puzzle-2/)) HandyBob((https://handybobsolar.wordpress.com/)) reminds us that //"Properly adjusted solar systems with temperature compensation will regularly exceed the 15 volts many inverters use as a high voltage shut down."//((https://handybobsolar.wordpress.com/the-rv-battery-charging-puzzle-2/))
electrical/inverter.1623943539.txt.gz · Last modified: 2021/06/17 11:25 by frater_secessus