If you go look at the product info for the B230 you will see it also has it’s own charging options, so i suspect you would charge the EB150+B230 through the charging ports of the B230?
A quick question to m.briney, is it possible to get that PO900 to DC7909 battery expansion cable outside of the USA? I looked on the EU/UK site but it did not appear in the ‘Accessory’ sections. And is there info on how many B230’s can be linked to the older EB series?
So to charge the B230 you can do it 2 ways… 1.) via the ac charging brick or 2.) via the D050S (charge enhancer) unit.
I personally love my D050S charge enhancer as it allows me to use a single panel to charge up my AC200, which normally requires a higher voltage input or AT LEAST 2 panels in series. And better yet, it allows you to charge up your EB150 from a normal 12v cig port in your car. The Enhancer pretty much is a boost controller/mppt charge controller, that will take a lower voltage(12-60vdc) and will increase it to 16-58.8vdc by lowering the amperage. Pretty genius tech in my opinion.
I believe the most efficient way you’re going to be able use the B230 to add storage to the EB150 would be to purchase the D050S, run your solar into it, which will then charge your B230, then use the P090D-7909 expansion cable to charge your EB150.
Note: I don’t believe the B230 will come with the P090D-7909 cable. You could possible request bluetti to ship that cable rather then the P090A Fusion Cable (which connects the expansion batter to the AC200Max) that comes with it tho since you wouldn’t be needing that one? Can’t hurt to ask and not sure why they wouldn’t?? Probably cheaper to produce anyways, but you’ll have to ask them. Otherwise the P090D-7909 will need to be purchased separately from bluettipower.com