I have an AC300 with 2 B300 batteries connected. I run into an interesting problem with my AC300+B300 combo and I could see the problem as being at the AC300 or one of the batteries. The AC300 seems to prefer to discharge one battery and charge the other. This happens whether or not the AC or DC power is turned on and when being charged via PV. Right now, for instance, the B300 that the AC300 has assigned battery pack 1 is at 63% charge. The B300 that the AC300 has assigned battery pack 2 is at 10% charge. Also, when there is a small amount of solar coming in, “battery pack 1” indicates it’s charging even though it has an indicated charge that is far greater. I already tried discharging to 0% and charging together with no load and it didn’t fix the problem of one battery being used more heavily and not getting charged first. Bluetti like to promote being a viable option for off grid but if this scenario continues one battery will spend it’s life between 10% and 40% which will would result in fewer overall cycles. That’s not really a feature. If it’s a case of the SOC being inaccurate and the two batteries are in reality at a similar state of charge, why have a state of charge indicator at all if it’s off by 50% or more? The SOC indicator would be approaching meaninglessness. If the indicator is not wrong and is ballpark accurate, there must be something wrong with the AC300s ability to ballance the batteries which would indicate to me that it is defective. If the solution is to simply plug the combo into the grid, how can Bluetti promote their product as a viable option for off-grid?
I have two AC300 and six B300 units, yet I have never seen that issue. The only steps I can recommend is to first swap the D090A expansion cables between the two B300 and see if the issue remains (the B300 with the lower charge has a problem), or moves to the other B300 (the cable or the AC300 expansion ports) . The second step is to move the weak B300 to a different AC300 expansion port and see if the issue remains or changes.
Some one may also recommend discharging both B300 batteries down to zero ( it will not harm the B300), then recharge them up to 100%. If nothing helps, contact Bluetti service for a replacement.
I’ll swap cables and see what comes of it. Thanks for the advice.
Just as an update. Bluetti emailed me with trouble shooting instructions and I’ll let everyone know what comes of it.
Charge to 100%, discharge to 0%, charge to 100% leave it sitting for a day turned off…switch cables, use one battery with the AC300 then switch to the other battery and use it (to see if the B300 batteries work normally individually) which would indicate a defect in the AC300.
I’m not complaining, but I will make an observation for those who are planning on using a unit or combination of units (I have an AC300 plus batteries and an AC200max). Thses units probably should not be used as a main power source off grid unless you have a back up because the situation will arise where you have to do calibration or trouble shoot a problem.
I like my Bluetti units, I will just say, there are some issues that will come up that should have been addressed or should have come to light during a beta test. If you’re OK with that, then Bluetti is for you. If you are not OK with that, you need to look at a DIY system or a different all-in-one system.