Have had the SolarX 4K for a few months. Set it up with extensions and an extension on the communication cable into an outside cabinet, so it makes noise outside with its own cooling system, etc. Works fine, but every now and then I notice it is sunny (I am in California here in thee Spring of 2026) and I walk out into my patio where it is and no noise. This means it has not come on. I have two separate Bluetti set-ups with an inverter and stacks of batteries. My AC500 and batteries always comes on in the back of my house and runs. For some reason, the one with the SolarX 4K, which used to always run off of rooftop solar panels, will not turn on in the morning from time to time. There will be 2K worth of PV power being sent into it, and nothing. I have to turn off all the breakers coming and going from it, make sure my Apex 300 and 6 B300K batteries are all off, then cut everything on and it starts. This could be a problem if I left home for a few days and all my food went bad. Right now, it has not done so for about 10 days, which is good, but I would like to know if anyone else has this problem?
I have had this same issue. Usually it happens when the batteries get fully topped off and still have lots of solar coming in. Thought it was maybe and over voltage due to solar x turning off and not
liking the open circuit voltage, but I don’t think I’m that close to the max. Solar x did an update no issues since will see if that fixed it.
That is concerning intermittent startup issues like that definitely seem worth investigating further especially for reliability when you’re away.
Happened again charges battery 100% turns off then does not turn back on. Cannot turn solar on or off from the app when its in this state.
I experienced this as well with the Apex 300 + B500K combination. Interestingly, in this situation the LED on the device turns red, but there is no error indication in the mobile app, and if I try to switch Solar ON to OFF in the SolarX 4K settings, it gives an error.
What fixes it for me is disconnecting the solar input and unplugging the B500K, then reconnecting everything. In my case, this happens every 10–15 days, but I have not been able to link it to any specific parameter or condition.
After one of these incidents, a software update was released. After installing it, the fan no longer runs continuously at 100%, but the same fault still occurred.
I have three of the solar X units running into three Apex 300s with B 300 K batteries.
This happens almost every day with one of my units. Very random seems to only happen when the batteries are topped off to 100%.
Toggling this button on and off seems to help and it resets the units…
I wish this wasn’t an issue because it makes it difficult to go out of town. I power my entire house with the system. It’s so unreliable. I have to switch the shore power whenever I leave.
I hope Bluetti comes up with a fix for this.
Steve
Take a look at this → thread ← where a few of us have been working with Bluetti on this same issue of the SolarX 4K shutting down the charging process after getting to 100%. Bluetti does have updates that a few of us have confirmed does correct this issue (I posted my own update there just prior to finding this thread). A nice side benefit is that the cooling fans don’t run at max when the system is not hot.
My Solar X 4K is not at 100% when it happens. It is after charging all day, all the systems are working fine, we are using electricity all evening, the SOC gets down to about 83-85% overnight, then I wake up in the morning and find out it is not on. I have two complete set ups. One for the front end of my house and one for the back end. The back end (bedrooms, bathrooms) comes on with the sun. It does not have a SolarX. No problem. The SolarX system at the front of my house (Apex 300 + 6 B300Ks) is the one that does not turn on every 10 or so days. But it is always in the morning after a nighttime of use and nighttime of mild discharge. Therefore, it is not an issue where it reaches 100% then turns off. I guess I will have to get updates.
Regarding the cooling fans, I literally built a small cabinet for my SolarX 4K with large 3-inch holes on the sides and no bottom for air, with a 7" solar fan mounted on the front door of the cabinet that sucks the air through and out to keep it as cool as possible when the sun is out; although, the cabinet is in the shade and never gets direct sun.