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Discussion Starter #1 (Edited)
I have a very basic digram made, mostly just to show fuse placement. Just want to make sure that the 3 150a fuses from the alternator to the battery are appropriate size and placement. I apologize for some missing info on the screen shot, was meant initially for my own eyes. But my alternator puts out 180amps and I'm using a 150amp batter doctor. The batteries are AGM, 125ah x 2 in parallel. Also would breakers work for the 3 150amps? or are inline fuses better?

Still very much a work in progress

Thank you in advance,
K
 

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First and foremost, you need to make sure your wire gauge is big enough for the expected current (amps) relative to the length of each wire. There are lots of tables/apps out there for doing that. BlueSea has some really good ones.

Sizing wire and fuses (or breakers) for 150A will be fine, if not slightly overkill. I run 150A fuses with my battery isolator with a 220A alternator. I have never seen over 120A, and that's just brief initial spikes. It quickly settles down to around 60-80A.

Also, be aware that 150A may be too little for jump-starting the engine off your coach batteries. If I ever need to do that, I will probably do it the "long way", just to be safe. That is, patiently let the coach bank slowly recharge the starter battery first. Go with breakers over fuses if you what to try jump-starting. I opted for fuses just because the battery fuse block accommodates them so nicely.

Obviously, your diagram still needs work on the battery, inverter, and monitor side of things. You need to size the inverter wiring and fuse based on the inverter's max amp draw. Check your inverter's documentation. Also check your monitor's documentation for the correct placement of the shunt.
 

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Discussion Starter #3 (Edited)
Thank you very much for your response! I believe I have the wire gauge situation panned out accordingly. The battery doctor manual suggests the 150A fuse so i'll just stick with that to be safe.
 

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To the Q about fuse vs breakers - convenience vs space vs cost. I like to be able to affirmatively disconnect things, so for high loads like this I went with fuses and a separate switch (instead of just a fuse). You can could do it with breakers, but they get expensive at this size.
 

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Discussion Starter #5
To the Q about fuse vs breakers - convenience vs space vs cost. I like to be able to affirmatively disconnect things, so for high loads like this I went with fuses and a separate switch (instead of just a fuse). You can could do it with breakers, but they get expensive at this size.

Thank you! We ended up running double 4 gauge wire, so I think we will use a breaker close to the alternator and inlines wherever else we can to save a few bucks.
 
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