The EP500Pro strikes me as a standalone AC200Max with integrated B230 And B300 but no external battery connectors (which both charge and accepts charge from an attached battery).
The only official support for external batteries appears to be connecting to the solar panel cable (MC4). So you need a P090D to MC4 cable.
To charge the external battery you appear to need a charging brick (T500 AC Adapter). Possibly one each if you want to leave it charging at all times.
Seems an inconvenient kludge. It might be easier to sell the EP500Pro and buy an AC300 and one or 2 more B300 batteries.
Hi @Flyleaf , The combination of EP500PRO and B300 is not the official standard modular power system. Only the AC300+B300 combo is. The function you mentioned above refers to the modular function that only AC300+B300 has. In addition, our latest AC500+B300S is also 100% modular. Here is the list of battery pack compatibility you can refer to.
When EP500Pro and B300 are connected through P090D to MC4, only B300 can charge EP500Pro.
It is possible to charge the battery pack through the AC output port of EP500Pro, which is equivalent to wall charging. That is, the B300 connects to the T400 or T500 adapter plugged into the AC output port on the EP500Pro.
I see that the AC300 cannot communicate to the B300S, so I have to order just the original B300 to add storage to my two AC300 setup. Does the B300S use aditional pins in the battery cable? Or did the engineers change the protocol between the controller and the battery?
Edit: I read that the B300S uses a different battery cable, so the protocol can change. The new B300S cable is rated at 80 A since the AC500 has to pull more power. The original B300 cable is rated at 50 A.
As a quick refernce, the B300 uses 16 LFP cells in series. Each cell is rated at 3.2 VDC at 60 Ah. So 16 x 3.2 x 60 = 3072 Wh.
Here is an idea: If those 16 cells were divided as a 4 x 4 setup, where 4 cells in series gives 12.8 VDC, and four sets in parallel gives 240 Ah, you now have a 12.8 VDC and 240 Ah battery. Now you can replace the obsolete sealed lead-acid (SLA) auto battery with this, and have a lighter, longer lasting battery for your car.
But the cost is incredibly high! There are some LFP 300 Ah auto battery offers around that cost about $500 or less. It is less expensive but it will last over ten years, while a SLA can only last less than five years.
Hi @Flyleaf , Yes, up to two B300s are supported to be connected.
But the B300 will not automatically switch, can only manually open charging mode: long press the battery power button for about 5 seconds, the light flashes is to enter the charging mode.