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lifestyle:faq_solar_generator

Words of wisdom: “These aren't aimed at people that know what they are doing.” – LastTreeStar

The self contained units are overpriced, underperforming “power for dummies”. – Somebodyelse1)

solar generators

images-na.ssl-images-amazon.com_images_i_51ug3iif-zl._ac_us218_.jpg “Solar Generators” (power stations, power packs) are self-contained devices that contain:

  • a battery pack, often lithium or AGM
  • USB outlet[s]
  • a pure sine wave inverter

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 "off_brand".2)

The overall proposition can be summed up by the title of a Bob Wells video, Should you Buy a Jackery Power Station? Super Easy but Super Expensive.

The terms solar generator and generator alternative are marketing terms with no real meaning: the units do not generate power.

Sometimes the term jump pack is used for portable battery packs in general, but it often means packs intended to jump start a vehicle. Battery pack usually means small, pocketable “bricks” for charging phones and other small devices.

best case scenario

The best use of these “generators” is

  • a person who camps on relatively short outings
  • who can charge from shore power when away from the camper
  • and who does not need to run devices in the camper when the owner is charging the unit elsewhere

A solar generator may also be useful for people who want to move the battery between different vehicles.

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.

Ah are often expressed as mAh. Which is more impressive, 33Ah or 33,000mAh? They are the same capacity expressed in different ways.

The 33Ah capacity lead-acid battery in the example above is stated as 400Wh. 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% depth of discharge, giving an actual usable capacity of 16.5Ah. In addition, lead-acid battery 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 peukert effect.

In typical units with lithium batteries, the DC output of the device will be somewhere between 9v-12.6v due to the voltage of li-ion chemistries and their 3S internal arrangement.3) Nefarious marketers sometimes multiply each cell's Ah rating times the number of cells, resulting in a 3x inflation of Ah rating.
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.

You could run run a load at the inverter's 300W normal rating for ~36 minutes.4) 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.

Pass-through charging is an important feature, as it allows you to run DC/USB/AC while charging the unit. While passing-through keep an eye on the unit's temperature and discontinue one or the other if it gets too warm.

charging

Using the Yeti above as our example again, the charging requirements are:

5 hours from a wall outlet with the included AC charger; in 13 hours with the available car charger*; or as fast as 8 hours from Goal Zero’s monocrystalline solar panels*

Things to consider:

Charging from solar panels

Charging these devices from solar panels will probably be slower than you might expect:

  • in the absence of an mppt controller5) panel output will be hamstrung by battery voltage. You may see a device listing 60w max input but specifying a 100w panel for use with it, and now you know why.
  • devices with 3S lithium cells will hamstring the panels even worse6)
  • long wire runs (as seen with portable panels set outside) result in voltage drops
  • sunlight is limited to a certain number of hours. Some units require more hours of charging than there are hours of sunlight in a day.

Poly panels will typically make slightly more power on normal (non-MPPT) devices due to poly's lower voltage / higher current. Devices with internal MPPT controllers will use both panels equally well because they decouple battery and panel voltages.

adding MPPT charging

goal zero optimizer

Goal Zero makes an optional MPPT controller that installs seamlessly into selected models. Will Prowse damns it with faint praise, noting the 22v solar input voltage limit and relatively modest yield improvements:

It does work better than the PWM on the goal zero… it's worth the money but not as good as a DIY system7) (see below)

Although the DIY mppt setup makes somewhat more than the Optimimizer, the sleek install of the GZ Optimizer may result in a better appearance and portability. The GZ display will not show the charge rate from external controllers.

standalone mppt

It may be possible to run the output of a standalone MPPT controller into a charging port of the device. Remember to configure the controller to put a max voltage in line with what the AC charging adapter puts out.

See this video by Will Prowse.

buck converter

It is possible to place a small DC-DC converter between the panel and input port to get the panel up near max power. Doing so will make it even more important to manually disconnect the panel when charging is complete.

Units that do not mention solar charging in their specs can likely still take solar charging through the DC charging port. Since there may be no controller, manually disconnect the panel when battery voltage creeps up too high. For lead this would be ~15v, and for lithium ~12.3v8). Another rule of thumb is that the cutoff voltage should be no higher than the voltage on the stock DC charger – read its label. Be certain not to exceed the maximum input charging voltage.9)

Another approach might be to place a shunt charge controller between the panel and DC input and limit the voltage automatically that way. This will not work if the DC port does not “show” the controller the battery voltage.

Charging from wall socket

Wall charging is typically fastest because the manufacturer gets total control over the adapter's voltage and current output. Note that they might not include a fast charger to reduce cost or heat stress on the battery.10)

Charging from car outlet

Car charging is typically slow because alternator voltage tends to be fairly low11) and ciggy outlet current limited to 10A. Unless one is on a road trip there is probably not enough time spent driving the vehicle to charge the device fully.

It's not *efficient* in the normal sense, but it can sometimes make sense to charge the device with the AC adapter running on an inverter rather than from the car charging adapter.

12v ciggy port → small inverter → AC adapter → device

Example: the Bluetti AC50S charges about 2x as fast from the inverter than from the car adapter, due to the AC adapter's higher 27.5v output.12)

internal AGM batteries

Some units use AGM batteries. This will greatly reduce cost and provide more normal voltage13) but requires diligent charging or the batteries will fail prematurely. All lead-chemistry batteries need to be fully charged then kept charged as much as possible.

manufacturers

The most common “premium” brands are Jackery and Goal Zero (Yeti). Bluetti is also gaining traction with a loyal following, and there are less-famous brands like Rockpals, ExpertPower, Aimtom, Nexpow, etc.14) They tend to be named after the watt-hours15) of battery capacity16), or sometimes by the inverter output rating.

The manufacturers often sell proprietary panels (Jackery Solar Saga, etc) which are needlessly expensive. Do the homework and find out which normal panels can work with your device;17) most will require an adapter. Will Prowse recommends devices with MPPT controllers.

Notes: inverter ratings below are the continuous rating, not peak/startup rating. Lithium packs are typically duty-cycle rated to 80% of capacity. Inverter runtime estimates are 100% of continuous rating at 80% DoD and 10% inversion losses.18) Inverters described below are pure sine wave (PSW) unless described as electrical:inverter#modified_sine_wave (MSW).

Jackery

  • Explorer 160 - 167Wh. 100w MSW inverter (~72 minutes practical runtime19) at full inverter load). 1x AC outlet. 2x USB. 1x USB-C outlet.20) 6mm DC output jack.21). PWM controller. 14.4v internal.
  • Explorer 240 - 240Wh. 200w inverter (~52 minutes). 1x AC outlet. 2x USB. Ciggy port. Some specs mention MPPT controller.22)
  • Explorer 300 - 293Wh. 300w inverter (~42 minutes). 2x AC outlet. 2x USB. 1x USB-C23). Covered ciggy port. Used by caratank24).
  • Explorer 440 - cannot use Solar Saga panels
  • Explorer 500 - 518Wh. 500w inverter (~45 minutes). 3x USB. 2x DC. ciggy port. Original version has a PWM controller; version 2 has MPPT.25)
  • Explorer 1000 - 1002Wh @ 21.6v(regulated). 1000w inverter (~43 minutes). 3x AC outlet. 2x USB. 1x USB-C26). Covered ciggy port. DC jack and Anderson27) inputs. MPPT controller. 1000 charge cycles to 80% DoD.

Goal Zero (GZ)

  • Yeti 200x - 187Wh @ 14.4v (regulated). 120w inverter (~67 minutes). 1x AC outlet. Ciggy outlet. DC jack outlet. 2x USB. 2x USB-C. MPPT controller. 500 cycles.
  • Yeti 400 - 428Wh @ 10.8v (regulated to 12v). 300w inverter (~62 minutes). 2x AC outlets. Ciggy outlet. 1x DC outlet port. 3x USB.
  • Yeti 500x - 505Wh @ 10.8v (regulated). 2x AC outlets. Ciggy outlet. 1x DC jack outlet. 2x USB. 2x USB-C28). 500 cycles.
  • Yeti 1500x - 1516Wh @ 10.8v (regulated). 2000w inverter (~33 minutes). 2x AC outlets. Ciggy outlet. 2x DC jack outlets. 1x DC Anderson outlet. 2x USB. 2x USB-C. 500 cycles. DC input jack and DC input Anderson jack.
  • Yeti 3000x - 2982Wh @ 10.8v (regulated). 2000w inverter (~64 minutes). 2x AC outlets. Ciggy outlet. 2x DC jack outlets. 1x DC Anderson outlet. 2x USB. 2x USB-C. DC input jack and DC input Anderson jack. 500 cycles.

Bluetti

Bluetti provides more information than usual about their specs, outlets, etc. [bravo! – secessus]

  • Maxoak AC20 - 200Wh. 120w inverter (~72 minutes). 1x AC outlet. 1x DC jack outlet. 2x USB. 1000 cycles. MPPT controller.29)
  • Maxoak AC100 - 1000Wh @ 14.8v (regulated to 13.4v). 600w inverter (~72 minutes). 2x AC outlets. Ciggy outlet.30) 4x usb. 1x USB-C. “Up to” 2500 cycles. MPPT controller.31)
  • AC200P - 2000Wh LiFePO4 @14.8v. 2000w inverter (~43 minutes). 6x AC outlets. Ciggy outlet. 3x DC jack outlets. 2x USB. 1x USB-C. MPPT controller.32)

Ecoflow

  • Ecoflow River Pro - 720Wh. 600w inverter (~52 minutes). 3x AC outlets. Ciggy outlet. 2x DC jack outlets. 3x USB. 1x USB-C. Specs do not list MPPT, but website does.33)

Some Ecoflow models have an inverter function they call “X-boost” that appears to drop voltage in order to increase current for heavy loads:

The X-Boost mode is not applicable for all electrical devices. Some devices with a rated power of 600W-1200W that have strict voltage requirements are still not compatible. Please conduct a full test to confirm before usage, so it will not to affect your work. It is recommended to use electrical equipment with heating elements and with a rated power between 600-1200W, such as hair dryers, electric kettles, coffee

Note that the loads mentioned are all resistance loads (heating coils).

quirks

The Jackery Explorer 1000 flashlight appears to activate one of the USB ports even when the USB panel is switched off.

The Jackery Explorer 500 solar charge controller is PWM34) while the 500 version 2 appears to be MPPT and capable of handling up to 30v.35)

Some units are tightly focused on inverter (AC) output, and don't have big DC outlets. The Bluetti EB150, for example, maxes out at 9A DC and that is through the ciggy outlet.

2)
COUGH inergy COUGH
3)
if LiFePO4 is eventually used in the devices then the voltage will be quite close to lead acid's voltage
4)
including 10% efficiency loss on inversion, but not including peukert effect
5)
sometimes present on higher-end devices
6)
3S Li voltage can be as low as 9v, and maxxes around 12.5v.
7)
ie, external charge controller. See https://www.youtube.com/watch?v=rqXscD69RvM
8)
assuming 3S
9)
typically 20-25v for built-in MPPT controllers. Standalone controllers typically can handle much higher input voltages – check the specs.
10)
particularly for Li
11)
particularly for charging lead
13)
compared to 3parallel_serial lithium
14)
Cheaper units may be high-value rebadged units, or they may be lacking features. Read and understand the specs so you know what you are buying.
15)
Wh
16)
at 100% DoD, unrealistic
17)
voltage and amps
18)
Jackery advises 15% inverter losses in the Amazon listings, but 10% is used here for consistency
19)
to 80% DoD
20)
discharge only
21)
no ciggy port but port-to-ciggy adapter included
22)
newer model?
23) , 26)
charge/discharge
25)
“You want the one that states 'Jackery' and underneath 'Explorer 500'.” - from an Amazon review
27)
for use with included parallel panel adapter
28)
one will also charge
29)
“Input Voltage must be 14V-40V”
30)
9A
31)
“working voltage is >16V,Open circuit voltage(OCV) <45V, the Max. output current is max.10A,Max. 170W”
32)
“Open Circuit Voltage between 35V-150V, Max.12A, Max.700W”, so at least 24v of nominal panel
33)
“You can connect 1 110W solar panel or 2 sets of 110W solar panels in parallel”
34)
maybe shunt
lifestyle/faq_solar_generator.txt · Last modified: 2021/07/05 11:17 by frater_secessus