Bluetti AC50S 500Wh Solar Generator Review

Maxoak Bluetti AC50s 500Wh Solar Generator

Last November I reviewed the Jackery Explorer 1000 solar generator on this web site: www.californiaskys.com/blog/archives/11-2020 (scroll down below the solar panel review) The Explorer 1000 packs almost 1000Wh of power into a compact and rugged design weighing only 22lbs making it well suited to multiple nights of astro-imaging without the need to recharge.  But not everyone needs that much power or cannot afford to pay $1000 ($880 on sale) for their power supply.  So, I got hold of Maxoak's Bluetti AC50s which is a 500Wh model costing only $400 ($380 on sale) to run through the same set of tests to evaluate its usefulness as an astronomy power supply in the field.  In short, the AC50s worked well over multiple nights in the field.

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Let's first start with a run down of the AC50s' included accessories and then its features.  The generator comes with an AC charger, a car charging cable, an MC4 cable to use when charging with a solar panel, a USB Type C extension cable, a decent user manual and a 24 month warranty.  Unlike the Jackery, a carrying case for the accessories is not included.  The AC50s is well built with a rigid ABS plastic casing, very compact at 11.6 x 7.7 x 7.5 in. (L x W x D) and extremely light weight at 13.6lbs.   It has fold down handles which makes it easy to carry around and store.  Most everything one needs to access is conveniently located on the front of the generator including:

1)  a regulated 10A DC cigarette adapter socket with dust cap
2)  two unregulated 3A DC 5.5mm x 2.1mm ports
3)  a 45W PD type C charging port
3)  four USB A 5V/3A ports
4)  two 110V AC outputs from the internal 300w pure sine wave inverter
5) an LCD display showing DC/AC power output, charging input power and battery State of Charge (SOC) in 20% increments
6)  On/Off buttons for the power outputs and the display

This generator also has a 10W magnetic charging port for phones equipped with magnetic charging capability located on its flat top.  On the backside you will find an 8mm port for the internal MPPT charge controller used to re-charge the generator either with the included AC charger or an optional solar panel.  There you will also find a large white LED light.  This light is much more useful than the small LED spotlight on the Jackery for illuminating a large area.

As noted above, a major convenience of solar generators is the inclusion of a pure sine wave inverter to supply AC power for any devices being powered with an AC wall charger like a laptop.  At 300W the AC50s' inverter will easily power all of our astronomy equipment if we so choose.  Also, the internal MPPT charge controller eliminates the need for an external charge controller when recharging the generator.  Simply connect the solar panel output with the appropriate cables to the 8mm charging input of the solar generator.  Always keep any lithium battery shielded from the sun when charging with a solar panel.  I like to use the panel itself to shade the lithium power supply.​

Just like with the Jackery Explorer 1000, I ran a series of tests of the AC50s both at home and in the field powering my Software Bisque MyT mount, Celestron C11 OTA, Celestron focuser, ASI1600MC camera, ASI224MC guide camera, TEMP-est cooling fans, mini-PC and a Pegasus Power Box Advanced (PPBA).   I used a cigarette adapter to 5.5mm x 2.1mm cable to supply power from the AC50s to the PPBA which in turn distributed power to the MyT.  The cameras, focuser and fans drew their power from the MyT.  Since the MyT requires 48V I used  a DC-DC up converter on the output of the PPBA to transform 12V to  48V rather than using the less efficient AC adapter.  I use The Sky X (TSX) to control everything except the PPBA which is controlled by its own application. 

First, I measured the total energy capacity of the AC50s by running the generator from 100% to 0% SOC multiple times.  Yes, with lithium based power supplies you can safely run them down to 0% SOC quite unlike a lead acid battery which should never be drained below 50% SOC to avoid permanent damage.  In the case of lithium batteries, an internal battery management system (BMS) functions to protect the battery from all manner of unsafe operating conditions.  This includes over-voltage, shorts, charging below freezing, charging/discharging above 104 degrees F, over-charging and over-discharging the individual lithium cells inside.  All lithium batteries with an internal BMS, this includes solar generators, are designed to be discharged to the point where the BMS shuts the output down to avoid dropping the voltage of the internal lithium cells below the voltage where permanent damage may occur.  Thus, these solar generators can use 100% of their SOC without damage to the internal cells while maintaining the manufacturer's full discharge cycle spec.  In the case of the AC50s, it is spec'd to 1000+ full discharge cycles at which point it's capacity will be reduced to ~ 70 to 80% of the original capacity.  That will provide energy to run a setup more than 100 nights a year over the 10 year expected lifetime of the generator.  The results of my capacity measurements produced an average of 461Wh or 92% of the rated capacity, which is in agreement with another on line review I have seen, and is similar to what I found for the Jackery Exporer 1000.  Not surprisingly, some power is lost in the regulation circuit, etc.

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After each full discharge test I was able to make measurements of the recharge times using both the supplied AC charger and a 100W solar panel.  I made repeated tests for each method.  It took between 7 and 7.5 hours to recharge the generator using the AC charger while it took only 6 to 6.5 hours to recharge using the 100W solar panel.  The faster charging rate with the solar panel occurs because the AC charger supplies ~ 82W while the solar panel supplied 95W of input power, hence the faster charge time with the solar panel. 

Now the most important question is "How long with the AC50s be able to power your astro rig?".  That, of course, depends upon what is included in your particular rig.  After verifying that the AC50s powered all of my equipment over many nights in my home observatory without any issues, I took it into the field for 3 nights under the stars with the setup described above:

1.  Software Bisque MyT mount
2.  ASI1600 MC uncooled camera
3.  ASI224MC guide camera
4.  Beelink Mini-PC
5.  Pegasus Astro PowerBox Advanced
6. TEMP-est cooling fans
7. Celestron Focuser

The cameras, cooler fans and focuser all drew power from the MyT Versa-Plate power connections.  The mount and mini-PC were connected directly to the PowerBox which was itself powered directly from the AC50s through the 10A regulated cigarette port.

The first night using the guider, my setup drew an average of 35W per hour over 6hrs for a total of 210Wh leaving the AC50s with 60% SOC at the end of the night.  During the next day, I used a 100W solar panel to re-charge the generator to 100% SOC in just a few hours.  Over the next 2 nights I ran without guiding, averaging 29W of power for 7 hours the first night and 5 more hours the second night without re-charging in between.  Thus, after 12 hours I had used 352Wh, or 76% of the measured total capacity, leaving me with 3.75 hrs more run time at 29W.  Overall, the Bluetti AC50s performed flawlessly as expected.  

Now, there are setups which require more than ~30W of power.  From my own measurements here www.californiaskys.com/blog/archives/11-2020, adding a dew heater for the C11 at full power requires 20W additional power and Peltier cooling for a camera will also add ~20W at maximum power.  That would push the power requirements of the above setup to ~70W.  At that consumption, expect the AC50s to last for 6.6hrs.  You can estimate your power consumption by scaling my numbers to your typical use conditions.  I believe typical power consumption falls into one of 3 ranges:  1) 20-30W;  2) 30 - 60W;  3) 60 - 90W.  Likely most fall into either range 1 or 2 and only those using a laptop to control their setup along with significant dew control and camera cooling will require as much power as indicated for range 3.  If we divide the measured maximum capacity of 461Wh by 30W, 60W and 90W we can estimate run times of 15.3hrs, 7.7hrs and 3.8hrs.  If your needs fall within category 1 the Bluetti AC50s will likely support 2 nights of imaging without a recharge, but if you fall within category 2 you will need some way to recharge during the day to obtain multiple nights in the field.  If your needs fall into category 3, you will need a solar generator rated with a much higher capacity like the Jackery Exporer 1000.

In summary, the Maxoak Bluetti AC50s 500Wh solar generator is well designed, simple to use and easy to carry about.  It sure beats lugging a 64lb 100Ah lead acid battery to provide the same amount of energy and comes with all of the power connections and additional features designed in. 

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The AC50S is no longer available and has been replaced with their 716Wh model for just $399.  Even better this one use LiFePO4 cells inside.  Amazon links are associate links from which I can earn a commission.