What to use between my 48vdc battery bank an the Sw4048

latinhawk

The more I read the more confused I get. I have a battery bank made of 4 12vdc marine batteries in series per string to make the 48 vdc.
At this time 3 have 3 strings of batteries soon to be 4. What to install at the end of the battery bank before the Schneider SW4048 is the question.
Some say just a switch other say a fuse of breaker. The bank is going to be wired with 1/0 welding wired terminated by crimped connectors. The wire to the inverter is also 1/0 welding wire with crimped connectors. Accurate help will be greatly appreciated. Thanks in advance.

Estragon

1/0 looks like 125-170a, depending on insulation:
http://www.armstrongssupply.com/wire_chart.htm

So it would be the lesser of the above wire max, or the max fuse/breaker in the inverter spec.

Not using a fuse or breaker to protect this wire is a really bad idea.  A short in the inverter DC or elsewhere in the circuit would potentially put huge overcurrent across it. 

A breaker provides a switch as well, so is preferable to a fuse on this wire IMO.

With three strings of batteries in parallel, there should also be a fuse/breaker on each string as well so a short in one string doesn't end up being fed by the combined current of the remaining two.  Fuses are often used for these connections.

latinhawk

Thanks. I understand what you say finding something to do the job is turning to be perplexing though.

Estragon

Maybe something like:
https://www.amazon.com/MIDNITE-SOLAR-125A-BREAKER-CENTER-MNDC125-LEFT/dp/B06Y99DJ3P/ref=mp_s_a_1_13?ie=UTF8&qid=1549033962&sr=8-13π=AC_SX236_SY340_FMwebp_QL65&keywords=125a+dc+breaker

For the batteries, maybe something like:
https://www.solar-electric.com/fb-110t.html

As above, size depends on inverter and wire specifics.  Just examples of what might work.