I am currently adding batteries, just bought 2 additional B300K batteries for a total of 4 B300K batteries. I use a AC500 and looking at the manual it seams they do not explain in detail how to connect 4 batteries and the various possibilities. I have connected it like this… not sure it is correct. I have only 1 cable that comes out of the AC500. Is this feasible? I did not turn it on yet as I would like some advice first. Thank you!
Hello, the AC500 can support a maximum of 6 batteries. You must connect 3 batteries per connection port.
In your case, connect 2 batteries per connection port
I don’t have the attachment to actually do that. The connector that attaches to the AC500-B300K is different from the one that connects the B300K to B300K. Unfortunately I only have 1 of those connectors. That’s Why I’m thinking if I could connect all 4 batteries to 1 port
@Mangaliliu
Connect one B300K to each of the two battery pack expansion ports on the AC500, and then connect another B300K to each of the B300Ks.
The AC500 requires a P090D to P150D adapter (optional) to connect to the B300K. The B300K + B300K is a P090A (standard).
Please refer to this video tutorial for your reference. 
Thanks for the reply, sorry but maybe I was not clear. I ONLY HAVE 1 of the P090D to P150D cables all the rest are P090A as you can see in the picture I sent. At the moment I have to work on this with what I have, I am on an island in the middle of the pacific! So I really need it to work as is. I was connecting 2 batteries with one P090D to P150D now I bough another 2 batteries. I only have one cable… can I connect all 4 batteries or only 3?? Please advise
I see so now I got to basically disconnect one of the 4 batteries… in the future by another P090D to P150D cable right?
I cannot do it because I am missing a P090D to P150D cable. I only have 1 of those cables…
There you can buy one. Then your problems are solved.