AC300 2xB300: How far down do you discharge every 6 months?

Product Discussion BLUETTI AC Series
1

Yesterday I AC charged the B300’s to 100% (they were at 65).
I am currently discharging them now for the first time since purchase in March. Manual says to do that every 6 months. Do I discharge to zero? Or will the AC300 shut itself down at the correct point and then I can connect the AC charging cable and charge them back to 100%?
Additional info a few hours later: the AC300 is at 5% so I shut off the space heater I was using pending the answer to my question. I found section 9.3 in the user manual say the following: To extend battery life, the power station set the “depth of discharge (DoD) 90%, which means that only 90% of the battery capacity can be discharged. 10% of the energy is reserved to avoid damage to the battery due to over-discharge.”

So, the app & the LCD display on the AC 300 say the batts are at 5%. The “Battery Pack” screen on the app says one batt is 6% and another 4%. I hope the 5% remaining power is actually 5% of the 90% DoD allowed in the programming of the BMS. Can anyone clarify and confirm from experience that the AC300 AUTOMATICALLY stops discharge when it reaches 10% remaining, thereby protecting the battery from over discharge AND, at that 10% point, the LCD screen will read 0%, meaning 0% of the allowed 90%.
Inquiring minds need to know.
TIA,
Kent
Bluetti Newby

2

HI @kmackva ,

  1. Yes, discharge to 0% then charge to 100% and do not carry the device during charging. This will calibrate the SOC.
  2. DOD is already set before leaving the factory. No need to worry, you charge and discharge to 0% will not affect the machine.
3

Thank you very much!!
Kent

4

Sorry, what does this mean?

5

It means that when the machine is charging, do not carry computers, kettles or other devices that cause the machine to discharge.

6

I think you mean “connect” when you say “carry”. Thanks BlueTTI.

7

That is good to know that the Bluetti batteries DOD has been calibrated so as not to allow a real discharge of 100%.
But I’m not sure if this is relevant for Bluetti batteries but normal charging and storage practices recommend not to charge to 100% if you plan on leaving the battery for many months unused but to rather only charge to around 65% total charge for long term storage. Also store and use the battery within temperature range between 0(C) - 30(C) or in Fahrenheit 32(F) and 86(F)

8

Your understanding is completely correct :)