Unequal charging AC200L + B300

Product Discussion BLUETTI AC Series
1

Hi all,
For those with an AC200L and a B300 battery, how is the charging behaviour when the B300 is connected as an expansion battery? I am finding that when I set an SOC limit of 85% (where it will stop charging and go to passthrough mode), there are situations where my AC200L can be at 90% and the B300 can be at 80% when it stops charging because the AC200L reports an average SOC of itself and the B300. The only way to get the same SOC level for both AC200L and B300 is to set the SOC limit to 100%, but I don’t want it to be charged fully every day, but want to keep it at 85% to reduce any battery wear.

In the above example of an SOC limit of 85%, it would be good if the firmware would charge the AC200L up to 85%, stop there, but continue to let the B300 charge until it too reaches 85%.

Similarly, it would also be good in a discharge situation to let the AC200L drain down until a predetermined lower limit, stop and instead continue to draw from the B300. The current situation is that the AC200L can drain down to 0% and shut off, while the B300 may still have 20-30% of charge remaining.

I have not yet seen the B300 top up the AC200L when it is connected in parallel (expansion), so I have come across AC200L at 5% and B300 at 35% in extreme cases, yet the B300 does not slowly top up the AC200L, which I thought would be the case since the batteries are connected in parallel.

1 Like
2

Here is a screenshot of the unequal discharge.

Screenshot_20240707_180007_BLUETTI
Screenshot_20240707_180007_BLUETTI1440×3088 189 KB

3

Hi @aaron33, Could you please provide the BMS versions of both the AC200L and the B300? We want to ensure you have the latest versions.
If not, please upgrade first and then calibrate the battery. This should effectively resolve the issue.
Please follow the steps below:

  1. Please discharge all the power (charge AC & DC appliances with the power station till it is out of power and turns off automatically);
  2. Please charge it again, please do not load any device when charging it, and do not interrupt it while in charge.
  3. Once the power is 100% fully charged, turn off the machine, and leave it the whole day.
    Please let us know if it does help.
4

Hi @BLUETTI_CARE,
My BMS versions are:
AC200L - v1043.11
B300 - v1021.10

When I initially updated my B300 to this version, I had an error message that the update was cancelled about halfway through the update on the app. But when I restarted my AC200L and B300, the B300 was then updated before having a connection issue. The connection issue was fixed by Bluetti sending me a new expansion cable.

So I am not sure if my current v1021.10 on my B300 is good or if it has issues. Is it possible to push v1021.10 or newer to my B300 again?

5

I am having this same issue with the AC200l and 2 B300 batteries. Currently the AC200l is at 100%
and the batteies are at 85% and 90%
the BMS is v1043.1 on the AC200l
and 1014.1 on both batteries. but it shows the BMS is up to date.