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--- lifestyle:faq_solar_generator [2023/09/24 23:36]
frater_secessus [solar charging limits]
+++ lifestyle:faq_solar_generator [2026/08/13 14:16] (current)
princess_fluffypants [The Downsides]
@@ Line 1: / Line 1: @@
+====== Solar generators ======
 Words of wisdom:  "These aren't aimed at people that know what they are doing." -- [[https://www.reddit.com/r/vandwellers/comments/dr387z/500w_aimtom_rockpals_500_solar_generator_review/f6jc7lz/|LastTreeStar]]
-**TL;DR - These things are //EXTREMELY// expensive for the capacity, however they do offer a lot of convenience.** For those with plenty of money who value ease and speed over capacity and run-time, an argument can be made for these if your power needs are small-to-medium and you are only taking short trips in your vehicle.
+===== 2026 Addendum =====
-====== Solar generators ======
+While these things were historically looked down as being too expensive for too little capacity, in the last few years these Power Stations/"Solar Generators" have gotten significantly less expensive. While building your own electrical system from scratch will still //usually// be cheaper, especially if you want a lot of capacity, these things have gotten to a point where the price difference between building your own vs getting a pre-made unit may pretty small.
-[[https://amzn.to/2MZhjzi|{{ https://images-na.ssl-images-amazon.com/images/I/51ug3IIF-zL._AC_US218_.jpg}}]]
+The smaller your power needs, the more sense these units can make, and they offer an //incredible// amount of convenience compared to building an entire system from scratch.
+===== Quick Overview =====
+{{ :lifestyle:screenshot_2026-08-12_002318.png?nolink&400|}}
 "Solar Generators" ([[https://amzn.to/2E7EG71|power stations]], power packs) are not actually generators. They are basically just a self-contained electrical system in a box, containing:
@@ Line 13: / Line 18: @@
   * A [[electrical:solar:charge_controller|solar charge controller]]
-These devices are packaged for convenience and are usually much more expensive than the components bought separately.  Sometimes manufacturers use non-standard panel connectors to keep customers in an expensive "walled garden", referring to normal, non-proprietary panels as [[https://inergytek.com/pages/support|"off_brand"]].((COUGH [[https://amzn.to/2SpgjbR|inergy]] COUGH))
+These devices are packaged for convenience and are //usually// more expensive than the components bought separately, but not always. For vandwellers with small-to-medium (And even potentially large) power needs, there's a lot of reasonable options on the market these days.
-Less expensive "solar generators" may cut corners by using more basic batteries (AGM vs Lithium), cheaper inverters (Modified sine wave instead of pure sine wave), or less efficient solar charge controllers (PWM instead of MPPT).
+As of the writing of this page (2026), the only use case where you probably //cannot// use one of these systems is if your power needs are EXTREMELY large, such as running a roof-mounted [[hvac:solar_ac|air conditioner]] or trying to do extensive cooking with electricity. For those use cases, you'll still need to build your own power system from scratch.
-The overall proposition can be summed up by the title of a Bob Wells video, [[https://www.youtube.com/watch?v=gFOZ6aetIPc|Should you Buy a Jackery Power Station? Super Easy but Super Expensive]].
+===== Common Brands =====
+This isn't an endorsement of any brand or specific model, but here's some links to a few manufacturers who offer systems that might have a lot of utility for the van dweller at reasonable prices and quality.
+  * [[https://www.pecron.com/collections/power-station|Pecron Portable Power Stations]]
+  * [[https://www.ecoflow.com/us/vanlife-roadtrips|Ecoflow Vanlife Solutions]]
+  * [[https://www.bluettipower.com/collections/power-stations|Bluetti Power Stations]]
+Some other common "premium" brands are [[https://amzn.to/318LNad|Jackery]] and [[https://amzn.to/3tx8hh4|Goal Zero (Yeti)]]. There are less-famous brands like [[https://amzn.to/3cDSGW0|Rockpals]], [[https://amzn.to/3sd001L|ExpertPower]], [[https://amzn.to/3s4j7L9|Aimtom]], [[https://amzn.to/3qZtYET|Nexpow]], etc.((Cheaper units may be high-value rebadged units, or they may be lacking features.  Read and understand [[lifestyle:faq_solar_generator#specifications|the specs]] so you know what you are buying.))  They tend to be named after the watt-hours((Wh)) of battery capacity((at 100% [[electrical:depth_of_discharge|DoD]], unrealistic)), or sometimes by the inverter output rating.
+Some manufacturers often sell proprietary panels ([[https://amzn.to/3ePyweB|Jackery Solar Saga]], etc) which are needlessly expensive.  Do the homework and find out which [[https://amzn.to/3cKgtnf|normal panels]] can work with your device;((voltage and amps)) most will require [[https://amzn.to/3tzzgbP|an adapter]]. [[https://www.youtube.com/watch?v=8k1URSZZ9uY|Will Prowse recommends devices with MPPT controllers]].
+===== The Upsides =====
+Again, it's about convenience and speed. These offer mostly complete systems right out of the box in a push-button-turn-on package.
+Historically they were limited by very small internal batteries, but these days most manufacturers offer add-on battery packs that can greatly expand the capacity (although typically with proprietary connectors between them, so you have to use the same family of power packs/power stations)
+===== The Downsides =====
+Weirdly, the most problematic part of these things is often the limited 12v power systems.
+=== 12v Charging ===
+{{ :lifestyle:screenshot_2026-08-12_002536.png?nolink&200|}}
+While these power stations can often charge pretty quickly (Within an hour or few) from a standard wall power outlet, or can input many hundred watts of solar at a time, their 12v charging is often limited to just a ciggarette lighter outlet which tops out around 120w. This could take //literal days// to charge some of the larger power banks.
+Different manufactuers offer various ways around this, usually with some kind of an "Alternator Charging" add-on which needs to be installed onto the vehicle battery system. Really what they are is high-current Buck/Boost converters that take the 12v power from the car's electrical system, upconvert it to 20-40v, and input it to the power station through the Solar inputs.
+It sounds kinda silly, but it actually works pretty well.
+  * https://www.pecron.com/products/pecron-500w-car-charger-dc1242-500-for-car-rv-van
+  * https://us.ecoflow.com/products/800w-alternator-charger?variant=41064248836169
+Another optional way around this is with a second cheap ~1500w inverter that is hooked up to the vehicle battery system and is only used while the engine is running, which is then used to charge the Power Station via the factory A/C power adapter.
+=== 12v Discharging ===
+Another problem is that many of these power stations can't actually output much 12v power, often offering just a single cigarette lighter outlet. Again, this is limited to 120w, which is not enough to power the startup/shutdown of things like a diesel heater.
+There's less options for how to fix this well. Some units like the [[https://www.pecron.com/collections/outdoor-recreation-protable-power-station/products/pecron-e1500lfp-expandable-power-station-2200w-1536wh?variant=42739059327164|Pecron E1500LFP]] offer an XT60 12v output connector, which can do up to 30amps (360w). This isn't much, but it's enough to power a small 12v house system with some lights, a small fridge, and a diesel heater.
+The assumption is that the high-draw loads (microwaves, electric tea kettles, larger laptops, etc) would be powered off of the power station directly.
+==== Other Gotchas ====
+Less expensive "solar generators" may cut corners by using more basic batteries (AGM vs Lithium), cheaper inverters (Modified sine wave instead of pure sine wave), or less efficient solar charge controllers (PWM instead of MPPT). The aformentioned problems with charging or supplying 12v power are also not a universally solved problem.
-The terms //solar generator// and //generator alternative// are marketing terms with no real meaning:  the units do not //generate// power.
 Sometimes the term [[https://amzn.to/2WZ9mP5|jump pack]] is used for portable battery packs in general, but it often means packs intended to jump start a vehicle.  [[https://amzn.to/2SvCHT3|Battery pack]] usually means small, pocketable "bricks" for charging phones and other small devices.
-----
+In the olden days manufacturers use non-standard panel connectors to keep customers in an expensive "walled garden", but post-2025 things have gotten very standardized and most manufacturers will be using standard 5.5mm barrel plugs for small loads, or XT60 connectors for larger loads.
-===== Best case scenario =====
+Connections between the "Power Bank" and any add-on battery packs is usually proprietary though, so it's a good idea to try and buy your entire expected capacity at once.
+----
+**From here below is some older info, back from the early 2020s when these things were ludicrously expensive and the market wasn't nearly as mature. We're leaving it here for historical reference and because there's some good info, but some of it might not actually make sense in the 2026+ world (For example, there's not a power station on the market these days that doesn't support simultaneous charging and discharging, while that was a very real problem with cheap units in the 2015 era)**
+----
+==== Best case scenario ====
 The best use of these "generators" is someone who:
   * Has little technical knowledge of electricity and battery chemistries, and no interest in obtaining any
-  * Is short on time and needs a solution very quickly
+  * Is short on time and needs a solution quickly
-  * **Has //plenty// of disposable income**
-  * Camps on relatively short outings
   * Has small to medium power needs, or does not need long run time.
   * Can charge from shore power when away from the camper
@@ Line 40: / Line 93: @@
 ----
+==== troubleshooting ====
+see [[12v:sg_troubleshooting|this article]]
 ===== Specifications =====
 Specs for these devices are often given in nonstandard or even misleading ways.  The following discussion will use the Yeti shown above, although their product description is better than most.
+==== TLDR ====
+We are most interested in
+  * how much capacity the bank has (typically in Watt-hours, Wh)
+  * charging limits
+    * by car adapter (typically ≤120w because of limitations of the ciggy port)
+    * by wall adapter (volts and amps, sometimes the stock wall charger makes lower power than is otherwise possible)
+    * by solar ([[electrical:solar:panels#specifications|Voc]] and input current, which will dictate which panels and how many are suitable)
+  * DC output (typically 10A at 12v)
+  * AC output (given as Watts, the biggest AC loads you can run)
 ==== capacity ====
-Ah are often expressed as mAh.  Which is more impressive, 33Ah or 33,000mAh?  They are the same capacity expressed in different ways.
+Capacity is most often listed in Wh (watt-hours), which makes comparison quite easy.  Some (especially lead cells) retain Ah ratings.  For lead batts, 12v x the Ah rating = Wh.  Sometimes Ah are expressed as mAh, or 1/000th of an Amp.  Which is more impressive, 33Ah or 33,000mAh?  They are the same capacity expressed in different ways.
+Nefarious marketers sometimes multiply each cell's Ah rating times the number of cells, resulting in a 3x inflation of Ah rating.
-The 33Ah **capacity** lead-acid battery in the example above is stated as 400Wh.((volts x Amp-hours = watt-hours))  This is technically correct but mixes units in a way that consumers may not understand.  Consumers may also not realize that lead-acid chemistries are usually only drawn down to 50% [[electrical:depth_of_discharge|depth of discharge]], giving an actual usable capacity of 16.5Ah.  In addition, lead-acid battery [[electrical:12v:battery_capacity|capacities]] are measured over 20hrs.  With our example this means a **10w** continuous DC load in this case, or 9w from the built-in inverter.  Loads greater than those will decrease usable capacity due to the [[https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=2ahUKEwjNo6ayjbXgAhXJwVQKHZ7xAmAQFjAAegQIChAB&url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FPeukert%2527s_law&usg=AOvVaw0guPoMgsy0smO6ISiV1t32|peukert effect]].
+=== usable capacity ===
-Nefarious marketers sometimes multiply each cell's Ah rating times the number of cells, resulting in a 3x inflation of Ah rating.  \\
+Most people know that only about 50% of lead batt capacity should be used in order to ensure a long life.  Lithium also has a recommended safety margin, 20%.  This means 80% of the rated capacity can be used and still hit the manufacturer's cycle life claims.  400Wh x 0.8 = 320Wh usable.
-On the upside, they have almost no peukert effect and therefore can support heavier loads (at the expense of running time).  Also, higher end units run 4S or higher voltages then downconvert them for a ~13v output much closer to what nominal 12v devices expect.
+With 320Wh usable we could run the a theoretical 400w inverter at max load for 48minutes.  (320Wh / 400W x 60 minutes)
-You could run run [[electrical:12v:loads|a load]] at the **inverter's 300W normal rating** for ~36 minutes.((including 10% efficiency loss on inversion, but not including peukert effect))  Some manufacturers will list the inverter's peak output (600w in this case) in the title as if it were the amount of power the unit could deliver over time.  New folk sometimes read this as "I can run 600w of appliances off the unit forever!", forgetting this is a //peak// load and that the unit has a finite capacity.
 ==== cell chemistry ====
@@ Line 85: / Line 153: @@
 === solar charging limits ===
+also see [[12v:sg_troubleshooting#must_i_use_the_ps_brand_s_proprietary_solar_panels|this article]] on choosing panels for a SG
 Many smaller units have quite restrictive solar input limits.
-  * **voltage** - 22Voc is a common voltage limit, effectively limiting one to [[electrical:solar:panels#panel_voltage|12v nominal]] panels.
+  * **voltage** - 24Voc is a common voltage limit, effectively limiting one to [[electrical:solar:panels#panel_voltage|12v nominal]] panels. **Input voltage limits must not be exceeded**.  Note:  some very large units have high input //minimums//, like 50v.
-  * **current** limit - 3A is a common input current limit on smaller, less-expensive units.  With PWM controllers the max power harvestable will be 3A x [internal battery voltage], which can be as low as 9v.  9v x 3A 27w.  MPPT controllers with the same limit might run the panels at 18v:  18v x 3A = 54w.((minus DC-DC conversion losses of ~5%))
+  * **current** limit - 3A is a common input current limit on smaller, less-expensive units.  8A is a common limit on larger units.
+    * With PWM controllers the max power harvestable will be 3A x [internal battery voltage], which can be as low as 9v.  9v x 3A 27w.  **PWM input current limits must not be exceeded**
+    * MPPT controllers with the same limit might run the panels at 18v, the Vmp:  18v x 3A = 54w((minus DC-DC conversion losses of ~5%))  MPPT  incoming current limits can usually be exceeded; the controller will throttle back incoming current to hold the limit. The allowable amount of overpanel is [[electrical:solar:overpaneling#vs_charge_controller|well-documented with most standalone MPPT controllers]] but "power stations" are usually black boxes with no published overpanel spec.  Proceed at your own peril.
+== the Amp bottleneck ==
+Because the Amp limit is usually the limiting factor for MPPT power production.  Selecting a panel with a Voc((//not// Vmp)) closer to the unit's input limit((with some headroom)) can make maximal power given the limitations.  This is because for a given rated output like 100w a higher Vmp (volts) means a lower Imp (amps).
+  * 22.5Voc panel - Vmp ~18v.((Vmp is typically 0.8 of Voc)) 18v x 8A limit = **144w**.
+  * 21Voc panel - Vmp ~16.8v.  16.8v x 8A limit = **134w**.
@@ Line 202: / Line 281: @@
 ===== manufacturers =====
+[note:  see [[https://www.reddit.com/r/vandwellers/comments/1cjab0x/popular_portable_power_stations_sorted_by_per/|this reddit post]] comparing larger units by Wh/$, etc. ]
 The most common "premium" brands are [[https://amzn.to/318LNad|Jackery]] and [[https://amzn.to/3tx8hh4|Goal Zero (Yeti)]].  [[https://amzn.to/3bVt6g9|Bluetti]] is also gaining traction with a loyal following, and there are less-famous brands like [[https://amzn.to/3cDSGW0|Rockpals]], [[https://amzn.to/3sd001L|ExpertPower]], [[https://amzn.to/3s4j7L9|Aimtom]], [[https://amzn.to/3qZtYET|Nexpow]], etc.((Cheaper units may be high-value rebadged units, or they may be lacking features.  Read and understand [[lifestyle:faq_solar_generator#specifications|the specs]] so you know what you are buying.))  They tend to be named after the watt-hours((Wh)) of battery capacity((at 100% [[electrical:depth_of_discharge|DoD]], unrealistic)), or sometimes by the inverter output rating.

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