AC300 with more then 4x B300, is it possible?

I have 2 full sets AC300 + 4xB300. Since the 3rd en 4th B300 is connected via the 1st end 2nd B300 to the AC300, the question pops up if it would be possible to connect more B300 units.

Although the AC300 will probably not recognize the extra units on the display, they might charge/discharge anyway. Did someone try this?

Since 3-4 are already connected via 1-2 to the AC300, this seems to be a parallel connection. So why not more in the existing connectors?


HI, could you try to take one of the batteries from one set you have and add to the other two batteries to see if it works?

I am also curious. Currently running an AC200Max, but looking at extension capabilities.

That is an excellent question and I believe that it needs a software update to see more than four B300 units. Probably a second battery status panel is the solution. I only have two B300 units so I cannot test it myself. But I expect Bluetti to modify its software and allow the AC300 and the EB500 power stations to manage up to eight B300 batteries some day.

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I have 1 AC300 and 5 B300s. I currently use my 5th B300 as my backup for my AC200 max and my AC200P. I plan to use my 5th B300 when my Ac300 gets low with the 4 batteries. I have 3 prime uses for it. Adding a 5th battery would be ok but not necessary in my case.

I do have enough B300 to try, but I brought it up since there might be issues known. Since these units cost real money I try to avoid harming them by doing something that they are not designed for.

@Raymondjram Where did you find the knowledge about an option to use up to 8x B300 on a single ac300?

The great thing about the AC series is the portability but this equipment is expensive. I would think that you would reach a point where the economics don’t make sense. With the AC 300 and 4 B 300’s you are approaching a point where you could purchase and install a fixed system for a similar cost. You would have to DIY it though. Having a company come in and install a system is still more expensive. Having 8 B300’s would require a lot of solar to keep it charged up and the portable panels that Bluetti sells aren’t really cost effective IMO so you would need a fixed panel system anyways. The major selling point of these systems IMO is the portability and the “plug and play” feature. But cost is a consideration as well and they are expensive.

I understand your considerations but mine a somewhat different. I require a flexible system off-grid and use standard solar panels to power them. At the moment I have about 6kW panels installed + 24 kW +4 kW storage. In spring-summer-autumn this is sufficient, however this turns out in winter I will find out.
It might turn out to be usefull to add some extra B300 units, we will have to see. But I would like to add them to the existing 2 AC300 I already have. Of course then there is always an option to use disconnected B300 units, but I do not prefer that.

It is not an option yet. I am analyzing the AC300 functions as an EE myself, and I see that the B300 units are all in parallel then each B300 unit has its identity, so the AC300 can sense, read, and charge each one. The battery status panel on the display only shows four batteries, so if the B300 architecture allows it, adding a second panel (pressing the “NEXT” indicator) may show the next four.

One detail I discovered is that the battery order on the panel is related to the order of its inital attachment. So if you disconnect B300 #1, that position will stay unoccupied until it is reconected, even at a different battery port on the AC300. You can do a simple test. Identify each B300 as it is attached from #1 on, then disconnect all and reattach them on different ports and order. The B300 unit lineup will return to the same order.

This is why I know by observation that each B300 is intelligent and the AC300 software is selecting the order by identity on the initial installation. And if you add a fifth battery, it will not harm the AC300 but will not be identified, either, unless the software is upgraded. And so it will not get charged or discharged.

Interesting observation, I have a unusual configuration from day 1 for my 1ste unit. I bought that one with only a single B300. Connected it at the 1ste port on the AC300 but it identiefied on the panel as the 3rd unit… No problem and with 4 units connected it works fine except the not logical numbering of ports identified on the panel.

So you expect a 5th unit not to charge/discharge? That is a bummer. How can we motivate Bluetti to do an update as you described? Do you have a contact within their organisation?

I can deduce is that the AC300 controls each B300, including the monitoring of its charge, through the extra pins on the battery cable . The charge status comes from inside the B300. If you add a fifth B300, it may not see it at all. The batteries charge and discharge through that common DC bus (the two large pins). I also deduct that each B300 has a relay at the DC pins that is controlled by the AC300, so when each B300 is fully charged by the AC300, it orders the relay to disconnect the DC bus pins until the charge is needed. But if you charge the B300 directly through its DC inputs on the front, the AC300 does not see that, only the total charge on the battery.

So all the intelligence of the setup is under the AC300 control, and each B300 is a slave.

@Raymondjram Today I have simply tried it. Result, 5th B300 not switching on but charge inducators were lighted. Nothing from the AC300.

I left it this way for a small hour, nothing changed. No charging/discharging to be noticed.

Now the question is, how do we motivate Bluetti to update the software…?

So it acted as expected. I knew that there is no harm adding a fifth or even up to eight B300 units to an AC300, but without the software change, nothing happens.

Let us hope that someone at Bluetti reads these posts and suggest the change to update the software.

They have made the long awaited update, but they called it AC500… Pitty for us, better for their business.

I expect someone to access that firmware, and find the code that allows six batteries to be accessed and monitored. The B300 has a dialogue with the AC300 through the four small contacts so just adding a plain 3 kW battery to the two 60 A contacts will not work. The battery must talk to the AC300. That dialogue may be easier to decipher.