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Discussion Starter #1 (Edited)
Wire gauge selection for ACR and fuse box

I am moving on to starting my electrical installation and have a blue sea ML ACR showing up in the mail today. Wondering if anyone could confirm that 4 gauge wire would be enough for my run or should I go 2. I have the 180 amp alternator up front and have 2 x 6v lifeline 220 amp batteries out back. Unfortunately my setup required them to be all the way out back so a rough estimate giving myself room for slop is 18ft run. If it was a full 180 amps flowing obviously 4 gauge would not work but my vehicle should suck up enough amperage that 4 gauge protected with a 50 amp fuse should work?

I also have 200W renogy solar setup. I am planning on running wire straight from the charge controller to my fuse box. I have a 12 fuse box but do not plan on using most of them but you never know. So far 7 led's, water pump, fridge. Renogy stated that 10 gauge would be fine does this seem adequate or should I go 6 or 8 just to be cautious? Should a fuse be placed between charge controller and fuse box?
 

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Mine is closer- total run about 6 ft as my ground is to the chassis. I am fused at 80 amps and am using 4 AGW. Same sized batteries but 220 amp alternator. Never blown the fuze BTW. I think you are fine.
 

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Discussion Starter #3
Mine is closer- total run about 6 ft as my ground is to the chassis. I am fused at 80 amps and am using 4 AGW. Same sized batteries but 220 amp alternator. Never blown the fuze BTW. I think you are fine.
Thanks once again for your input!!!
 

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Thanks once again for your input!!!
I'm running about 10 feet of wire to a 360 ah pack. I ran 1 awg with a 150 amp fuse. The most I've seen from the alternator according to my Victron BMV is 65 amps. I have the 220 amp alternator however so your results may vary.

One advantage of running larger wire is lower voltage drop which is helpful for charging batteries.

Sent from my Pixel 2 XL using Tapatalk
 

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I’d go with the 2/0 for such a long run. The extra cost is minimal. You only need to run one cable to connect the + terminals together and use the cahassis as the ground. I have a 160 amp fuse but that’s just because it was all I could find at the time, 80 amp should be fine.

I have the same fuse setup and just ran a # 8 wire tomit from the battery - no blown fuses ever. Wire is cheap!
 

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but my vehicle should suck up enough amperage that 4 gauge protected with a 50 amp fuse should work?
Your comment that 'my vehicle should suck up enough amperage' requires comment. What current your vehicle wants for its purposes is largely irrelevant to what is going to happen when you connect a large, mostly discharged second battery across your alternator with large (low resistance) wire. To take this point to the extreme, if you drop a wrench across your alternator, the fact that your Promaster wants to "suck up" energy for it's own use will all be ignored as your wrench melts.

Make your analysis based only on how much current you wish/expect to supply to the battery.

We went, incidentally, the opposite direction in our earlier CaRV where we had an 8D 245ah AGM battery in the trunk fed by 2 - 15' runs (positive and negative) of #10 . Our reasoning was that we wanted to use the resistance of the wire to limit the maximum charging current to the trunk mounted battery. At a charge rate of 30 amperes, this #10 wire would drop about 0.9 volts which was appropriate to limit the charge current on our house battery that was rarely discharged even as low as 50%. The resulting power consumption was less than 1 watt/foot which only perceptibly raised the temperature of the wire.

Thus, we think your #4 is more than enough.
 

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****- an answer based on science and reason. What is this forum coming to. Next thing you know we will be discussing stuff like NASA does in designing the next space mission!
 

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This is the one I bought [ame]https://www.amazon.com/gp/product/B000OTIPDQ/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1[/ame] and then I put one of these between the starting battery and it. [ame]https://www.amazon.com/gp/product/B00445KFZ2/ref=oh_aui_detailpage_o05_s00?ie=UTF8&psc=1[/ame]

About $100 total I see they now have an all in one unit but it’s close to $300! .https://www.bluesea.com/products/76...rging_Relay_with_Manual_Control_-_12V_DC_500A
 

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Discussion Starter #10
Wish model did you get? Did you go this route to be able to shut off the circuit when using solar?

Thx
I am planning on doing a lot of camping this winter in the PNW and BC before heading up to AK in march. Given the nature of those areas in winter I won't be able to rely on solar. I purchased most of my parts back in August when I bought the van. Originally I bought the Blue sea 7610 but I noticed that it is technically only rated for 120 amp alternators when I was getting ready to install it. After speaking with the reps at blue sea I decided to purchase the 7620 and install that. Others have used it with no problems but the last thing I want to do is fry my van driving through the Yukon in march. That being said I am about to post the 7610 for sale if you are interested. Paid $80 asking $50.
 

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They only real valid reason is the have more control over your system (IMHO) ;)
 

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Discussion Starter #12
Your comment that 'my vehicle should suck up enough amperage' requires comment. What current your vehicle wants for its purposes is largely irrelevant to what is going to happen when you connect a large, mostly discharged second battery across your alternator with large (low resistance) wire. To take this point to the extreme, if you drop a wrench across your alternator, the fact that your Promaster wants to "suck up" energy for it's own use will all be ignored as your wrench melts.

Make your analysis based only on how much current you wish/expect to supply to the battery.

We went, incidentally, the opposite direction in our earlier CaRV where we had an 8D 245ah AGM battery in the trunk fed by 2 - 15' runs (positive and negative) of #10 . Our reasoning was that we wanted to use the resistance of the wire to limit the maximum charging current to the trunk mounted battery. At a charge rate of 30 amperes, this #10 wire would drop about 0.9 volts which was appropriate to limit the charge current on our house battery that was rarely discharged even as low as 50%. The resulting power consumption was less than 1 watt/foot which only perceptibly raised the temperature of the wire.

Thus, we think your #4 is more than enough.
Thank you very much this is very informative. I am definitely an electrical novice and probably in over my head but have been doing tons of research before installs. Limiting currents with wire gauge is out of my pay grade and I would be too scared of frying the wire. But like I said I am a novice. So far my motto has been a little bigger wire than I need with a smaller fuse and I should be safe (I hope and please correct me if I am wrong). That being said I installed the ACR yesterday and it works perfectly! Thanks again for your detailed explanation.
 

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I am planning on doing a lot of camping this winter in the PNW and BC before heading up to AK in march. Given the nature of those areas in winter I won't be able to rely on solar. I purchased most of my parts back in August when I bought the van. Originally I bought the Blue sea 7610 but I noticed that it is technically only rated for 120 amp alternators when I was getting ready to install it. After speaking with the reps at blue sea I decided to purchase the 7620 and install that. Others have used it with no problems but the last thing I want to do is fry my van driving through the Yukon in march. That being said I am about to post the 7610 for sale if you are interested. Paid $80 asking $50.
Thx for the reply and offer. Not sure what I am going to use yet. Will keep that in mind though.
 
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