Battery cables

[Eros]

Why do we have to size battery cables on the Ah of the bank dater than the Kw of the inverter and the ability to invert a limited amount of current and charge at a determined amount. The inverter can't draw 300amp from the battery and the CC is limited hits charging current. Just curious

 

[GoldDigger]

Why do we have to size battery cables on the Ah of the bank dater than the Kw of the inverter and the ability to invert a limited amount of current and charge at a determined amount. The inverter can't draw 300amp from the battery and the CC is limited hits charging current. Just curious

You don't have to, although it is good practice to allow for putting in a larger inverter later.
There is also a potential issue with short circuit current if you do not have fuses on the battery posts.

 

[iceworm]

Why do we have to size battery cables on the Ah of the bank dater than the Kw of the inverter and the ability to invert a limited amount of current and charge at a determined amount. The inverter can't draw 300amp from the battery and the CC is limited hits charging current. Just curious

I don't know - it's not NEC. Could it be the owner's spec? Cause if it is - that' a really good reason. Another reason for upsizing the cables is voltage drop. For me, that is more often the limiting factor than NEC ampacity.

As for upsizing for what might happen in the future, that wouldn't matter to me. If a larger inverter is being installed, there is a lot more to look at than just the battery cable size.

ice