I wanted to post this “Bluetti powerstation AC05S will not turn on” thread in an effort to help others .
I do see a lot of youtube videos with Bluetti powerstations that have various forms of not powering up…those videos have no conclusion.
My journey with the AC05S began with a craigslist ad for a free Blluetti AC05S. listing said she took it appart and could not get it to work. guessing she was looking for a fuse or loose connection. The listing owner said she contacted Bluetti and they would not service it.
drove 2 hours round trip to pick it up.
when I got home with the box of parts which looked complete I started with checking the battery pack.
battery pack was less than 7 volts with 1 bank at 2.5v at the lowest. The pack was a 3S setup.
I used a cell balancer to get the 2.5v bank to 4.1 volts…after getting to 3.9v I turned my attention to the other 2 banks and each were at 4.0V. so I balanced charged all the banks to 4.1V.
after balance charging the individual banks I chqarged the whole pack and it charged for about 15 minutes and the charger reported full charge.
thru all the above none of the cells or semiconductors where hot.
reassembled and power it up…the unit operated correctly and the first thing it did was a top off charge.
I did a few discharge test and got the correct number of hours based on the load.
so im using it for a cpap machine at night and it seems to be working correctly. all the features work.
dont know why 1 bank was so low and the others fair. dont know if that bank has a shorted battery or if the BMS has some semi conductor’s that have a reverse current leak in the circut of the bad bank.
I dont know how long the unit will keep its state of charge if unplugged and turned off. if there is a shorted cell or a leaking semiconductor it would drain back to a no start condition .
perhaps Ill do that test next.
dont know the BMS architecture in terms of the current rating of the cell balance aspect of the BMS…Im guessing its around 100 MA .
there are probably a few hundred Bluetti power stations out there with simple cell balance problems which prevent them form starting up.
all in all I spent about 10hrs on bringing this back to service…not economically a good use of my time but I wanted some hands on a bluetti powerstation to get a better understanding of the problems people were having.