So what is the deal with the Bluetti EB3A power station?

[David Hess]

I have been using a Bluetti EB3A power station for almost 2 years, and while it has some minor issues, it has worked well up until now.  The variable speed fan control is terrible.  The AC UPS function is unreliable.

Recently I accidentally mostly discharged the starter battery in my pickup, so I used the Bluetti EB3A along with a charger to recharge and recondition the starter battery over a couple of days.  In doing this, I fully discharged the EB3A at which point it should automatically shut down, and then I could recharge it from AC and start the process over.  Unfortunately, that is not what happened, and there are lots of reported incidents describing what did happen.

Instead of working as expected, the EB3A shut off like it was suppose to, but the battery management system disconnected the internal battery and refuses to reconnect it, so the EB3A shows that it is at 100% charge when the battery is empty, and cannot charge the battery.  The battery is not even that dead, and I manually charged it to 22 volts, but this did not restore any functionality.

Perusing various forums, including the Bluetti forum, shows that this is a common problem with no solution.  Did Bluetti really design a power bank which routinely fails and bricks itself if you discharge it to the point where it shuts down?

[edavid]

Well, at least it has a 2 year warranty, so you should be able to return it 

[thm_w]

This sounds really dumb, but, a lot of laptops seem to have the same issue. BMS's seem to be hard for people to get right, even though the concept is so simple.

I wonder if it was a bug were it didn't shut the output off early enough, causing more drain than expected?
Do you remember what the cell voltages were?

[David Hess]

I wonder if it was a bug were it didn't shut the output off early enough, causing more drain than expected?
Do you remember what the cell voltages were?

Total voltage for the 7 series cells was about 21.5 volts, and pretty even so about 3.07 volts per cell.  I charged it to 22.0 volts without effect.

[thm_w]

Someone here was able to charge by simultaneously using AC + DC: https://www.reddit.com/r/bluetti/comments/1818zgx/eb3a_not_charging_solution/
Easier than taking it apart.

[David Hess]

Someone here was able to charge by simultaneously using AC + DC: https://www.reddit.com/r/bluetti/comments/1818zgx/eb3a_not_charging_solution/
Easier than taking it apart.

I did that, and many other suggestions, none of which had any effect.

[David Hess]

The battery management system eventually reconnected the battery, but I do not think anything I did had any effect.

I have tried to replicate the problem by discharging it under the same conditions for the past few days, and the problem has not repeated.  My guess is that cell imbalance during the first discharge triggered the battery management system to disconnect, but my measurements at that time showed no imbalance.