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How close does the battery need to be to 12v fuse box?

OffRoadRN

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I am planning on building the classic 400w system. I have watched the Will's videos on the install. In the first video he talks about the importance of having the 12v fuse box, inverter, batteries, and charge controller all very close to each other. I am going to be putting this system in my 25 ft travel trailer. My question is, if the batteries, charge controller, and inverter are close to each other, how important is it that they are installed near my trailers 12v fuse box?

As it is, the stock batteries are already on the opposite of the OEM fuse box, can I install my other components in the front pass through storage, or under my bead up front, and then run a line to my 12v fuse box? Is this dangerous or really inefficient? I do have a space near the fuse box that I could use, but I already use if for storage and it would be tough to reorganize and find places for the equipment I store there.

Thanks!
 
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Distance is dictated by voltage, current, wire gage and distance. Those four factors determine your voltage drop:


% voltage drop equates to a % loss in power.
 
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Practically speaking, its non-optimal but totally fine to have components further apart. It just means you will have to spend more money on larger wire to achieve the same voltage drop. If your loads are small this is no big deal, if your loads are large this can be very costly.

Having your batteries + inverter + chargers near each other is the most important part.
 
What should I put for the load current? Would it be 30amps since I have 30 amp system? Or no because I will never be drawing that much at once?
 
What should I put for the load current?
This is something you would have to determine based on the loads. If you don't know what all they are, you could look for a max current rating on the fuse box itself, or add up the rating of all the individual fuses to get a conservative ballpark idea.
Would it be 30amps since I have 30 amp system? Or no because I will never be drawing that much at once?
No. Assuming your mean you have '30 Amp RV hookup?'
30A refers to your 120V AC (shorepower) hookup. This is totally separate and unrelated to your 12V DC fuse box which should only be used to power DC devices.
 
Oh ok. I'm just starting to learn about this as you can tell, it's my first RV and first foray into solar. I guess I'll probably go with the max of the fuse panel just in case I want to add more to it in the future (assuming it's not maxed out already). Thanks!
 
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Good points from Snoobler and Dzl. It's very rare that more than 40A is ever drawn from a fuse box. The slideout motors and furnace fan might be the biggest draws. The fusebox can be anywhere. Get under 2 or 3% loss (round trip) at 40 amps if you can. OEM probably is probably #6 wire. My initial calcs say that you should run #2. If you have no slideouts, #4 might be adequate.
Yet another quick voltage drop calculator: https://www.rapidtables.com/calc/wire/voltage-drop-calculator.html
 
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What should I put for the load current? Would it be 30amps since I have 30 amp system? Or no because I will never be drawing that much at once?
30A refers to the 120V AC current. The 12V DC system is a separate issue.
 
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