Ep500 compatibility with expansion batteries

I have seen people inquiring about the compatibility of the expansion batteries (b230 and b300) with the regular (non pro version) of the ep500. Has anyone actually tried to use the expansion battery with the ep500 yet?
Having a single ep500 hooked up to an existing transfer switch and powering the whole house was not advertised but is possible without the fusion box or another ep500.
Is the compatibility between the ep500 and expansion batteries another non-advertised possibility?

I have not read about the expansion batteries with the EB500 (check the user booklet), but if you wish to power a whole house with the EB500, it can only supply 120 VAC. If your house needs 240 VAC (especially for large appliances) then you do need a second EB500 and the Fusion Box Pro. Some homeowners have reduced their emergency needs and only use one power station for the refrigerator, lighting, and small appliances. Check your house wiring and transfer switch (or get an electrician) to be sure.

I found the specs for the b230 expansion battery and the only DC output was a 12 volt port. I remember reading that the regular ep500 couldn’t be charged with a car (12 volt) unless you use an inverter. The DC input port for the ep500 is rated 55-145 VDC .

It seems that you’d need to increase the voltage using a voltage step up converter if possible. I don’t know if it’s worth it or not. I think that I saw this process being used (or alluded to) on Hobotech’s YouTube video.

Any thoughts on this?