I am building a off grid system using 2 EG4 6500EX-48 inverters in a 240vac split phase setup.
I have an EG4 battery bank 30kwh. I can not seem to find what size the AC input CB should be.
It says 4g or 6g wire but nothing on the size of the protective CB.
I'm also confused about the AC input function. Is it only to charge the battery bank or will it also feed power to the AC output section of the inverter ?
Finally my last question assuming it only is for charging the battery, in the setup menu is there a parameter that will limit the charging current to the batteries (and therefore the amount of AC input current) ? Thanks for any help.
You always size the circuit breaker to protect the wire (in accordance with NEC). The wire size is determined by factors such as max device current draw, length (voltage drop), etc...
The manufacturer, EG4 is recommending 4 AWG wire size on the AC input / output connections, which can handle 85a of current. So probably up to a 60a breaker could be used with 4 AWG wire no problem (within the 80% rule).
Ref:
Correct wire sizing is very important. Especially safety-wise. One of the most common questions we get about wiring is ‘what is the wire size for a 60 amp breaker?’. A lot of homeowners make this very common mistake: They use 6 AWG wire for a 60 amp breaker because 6 AWG gauge wire has 65A ...
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The EG4 manual also states in the specs that the max AC input draw is 60a, so that could be close to a 60a breaker rating. It may not be likely that it gets that close and ever trip a 60a breaker, but going to a larger breaker may require 3 AWG cable (to stay within the 80% rule). And also not sure how big the AC connection lugs are on the 6500EX, what is the largest gauge cable that the connector can receive.
Specs on Page 42 in the EG4 manual:
And on your last question, if it is like the MPP Solar LV6548, the AC battery charger would function only while in inverter 'bypass' mode (not sure if it's the same on the EG4 6500EX). But when in bypass, the AC input just feeds the AC output instead of running in inverter mode. You may have to check with EG4 to see if the 6500EX offers the ability to charge the battery bank while still running in inverter mode instead of having to put it into bypass mode to charge from AC input charger, like on the LV6548s.
I know the LV6548s and the 6500EX have many similarities, we have already seen they have several differences, especially with regards to the PV charger circuit design. So far, I do not know if there are other differences related to the inverter section, and handling of the AC inputs / outputs and the charger section, in relation to inverter mode vs bypass mode.
. My electrical contractor went crazy breaking every little thing out into it's own circuit.
