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Discussion Starter #1
Does any one know the positive battery wire gauge size?

I could not locate any AWG or Euro markings on the red/positive conductor. I looked in the battery and engine compartments, but it looks like its not marked.

I have a 220amp alternator. Do you think I can assume the conductor would be specked for the maximum out put of the alternator?

Thank you,

Dave
 

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The wire is specified for the starter motor usually. The current draw for a starter can greatly exceed the alternator output albeit for a short amount of time. Short runs of wire (say 4 feet) can carry huge current. Example 4' of 8AGW can carry 200 amps! I'll bet the cables are 4AGW or 2AGW stranded. You don't say why you want to know?
 

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Discussion Starter #3
Battery wire gauge

The wire is specified for the starter motor usually. The current draw for a starter can greatly exceed the alternator output albeit for a short amount of time. Short runs of wire (say 4 feet) can carry huge current. Example 4' of 8AGW can carry 200 amps! I'll bet the cables are 4AGW or 2AGW stranded. You don't say why you want to know?
RD,

Thanks for the info, its super helpful!

I will not be doing the electrical on my camper build and have contacted a local contractor specializing in marine installations. The contractor asked for the conductor size.

It looks like a 6mm conductor. When I measured the total diameter including insulation it came to aprox 10mm(3/8"). I have no idea what this would correspond to in AWG.

I researched the electrical systems of camper vans/RV, I read countless posts from multiple sources to get myself up to speed on the electrical system required for my build.

I've calculated my average daily consumption (Whrs). I have gained a reasonable grasp of whats involved and the components required, but at the end of the day I still can't get motivated enough to do this part of the build myself. The learning curve is steep for me and the mistakes I would invariably make would be costly in time.

My consumption is high as I am going all electric with a 12v roof top ac, two burner conduction stove, 12v compressor fridge, 12v compressor cooler and in floor radiant heat consuming the lions share of energy.

I have a 9kw lithium energy storage system to deal with the high demand. The large lithium battery can accept as much as the alternator can push out so the question of the conductor size came up in the conversation with the electrician. I guess he wanted to make sure it was sized large enough.

In addition I had Outback Power build me a 12v version of their Flexpower One. The Flexpower One is intended to be a plug and play integrated pre-assembled and pre-wired power system. The system has all the components built into one unit preinstalled on one mounting board. In theory I just need to add a battery isolator.

I plan to install approximately 400 watts of solar and shore power to add to the alternator charging.

I will do all the simple stuff, wire runs, mounting lights etc.

It remains to be seen how well my plan will work out; I've taken a bit of a risk given my limited Knowledge of electricaltricity;)

Thank you for your help RD

Cheers,

Dave
 

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Wow! I now recall some of this being discussed earlier. What an awesome undertaking. I want to hear how this all works and what you learn from it. I would not be doing the electrical design and I do have modest experience. I'd want a really good marine electrician on this one. Share.

BTW the wire is a metric size and probably between 4AGW and 2AGW.

See: https://www.tedpella.com/company_html/wire-gauge-vs-dia.htm
 

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Discussion Starter #5
Battery wire gauge Size

Wow! I now recall some of this being discussed earlier. What an awesome undertaking. I want to hear how this all works and what you learn from it. I would not be doing the electrical design and I do have modest experience. I'd want a really good marine electrician on this one. Share.

BTW the wire is a metric size and probably between 4AGW and 2AGW.

See: https://www.tedpella.com/company_html/wire-gauge-vs-dia.htm
RD,

Again thank you, the link was super helpful.

I will soon start my build thread, probably next week some time after I finish poking the last hole in the roof for my ac unit. I've Benefitted from and enjoyed reading about yours and the rest of the gangs build threads so I need to reciprocate.

I think I do have a good progressive marine contractor to guide me through what for me feels cryptic and unfamiliar ground. I think I'd rather stick a drill in my eye rather than tackle the electrical head on;)

Strangely I made all the main design decisions and purchases before ever contacting an electrical contractor. For a time I thought I had my head wrapped around doing all the work myself, but then got cold feet and rationalized that it would free my time up for work on the other aspects of the build. I will be very happy if it turns out that I got evan a fraction of my plan for the electrical right.

Cheers,

Dave
 

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No. I meant 4 AGW. 4/0 would be ridiculous huge. 4 AGW is about 1/4 inch, 4/0 is about 1/2 inch. I don't know which the poster is referring to. The positive battery cable is smaller than 1/2 inch IIRC.
 

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I'm only on my second cuppa joe, but for what it's worth this is how I connected my house batteries to the starting battery (pos side only)
I used 4/0 stranded welding cable with a 175 amp fuse on each end at the batteries. As I recall it only cost about $35 online. I just grounded the house batteries to the body with a ground cable. The red cable with the black insulation is the one that goes to the house batteries.
 

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What is really needed and what we might do are two different things. KOV has a +++++ positive cable and fuse. No problems as long as it is also fused at the other ends. But is that 4/0 really needed? I ran my refrigerator overnight and the next morning I started the van and connected the battery to battery interconnect, I have a 50 amp breaker at the vehicle battery and 4 AGW wire. I did not throw the 50 amp breaker and the 4 AGW for 4 feet can carry well over 200 amps safely (in fact it can carry 200 amps for 15 feet.) my take is: a 50-80 amp fuse is enough and 4 AGW (or 6 or even 8) is enough with safety and low loss. I plan to go to an 80 amp fuse at the battery in response to another poster who blew an 50 amp fuse to give me a bit of margin. Copper stranded 4 AGW is available at H-D in TWWN sheathing cheaply which should be protected in flex conduit which I did. Crimp AND solder the ends, fuse both ends, and use a chassis ground for the negative side knowing you are pulling current through the vehicle's negative cable which is sized to turn the 5 hp (or so) starter motor which might draw 400 amps or more. I have an isolator rated at 80 amps and which engages when the key is on. I have a switch to turn off the solenoid of the isolator whenever I want to just stay on solar.
 

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The max current is going to depend on the battery type, size, and state of charge. I've measured up to 100 amps with 150ah AGM. It didn''t stay that high very long tho. I agree, #4 for 4 ft is fine. I have 1/0, but longer run. The main thing to consider for anything longer is voltage drop. Charging at lower than recommended voltage is not good for the battery.
 

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This thread is very interesting as I'm trying to figure out what I should do for my alternator connection. I'm glad to hear some clues as to what the range of actual amperage flow may be under various conditions. If any of you have dc tongs you can get a real time display. Or perhaps install a Hall effect sensor and meter.

As I will have 654 watts of solar it will often not be necessary to have an alternator connection. I would ideally like to be able to manually decide when the connection is made, engine running or not, and have a highly visible indicator light for status. I realize there is some risk in not having it more automatic but I suffered for years in my Navion with a temperamental connecting relay (burned out twice). Not exactly sure how to wire the indicator light since both sides of the switch are hot.

My thought is to use a simple Blue sea battery switch, #2 wire, and 150 amp fuse at each end:
http://shop.pkys.com/Blue-Sea-9003e-ON-OFF-Battery-Switch_p_1694.html

Or better yet just use one of these breakers at each end, also with #2 wire?
[ame]http://www.amazon.com/Bussmann-Hi-Amp-Circuit-Breaker-Amps/dp/B0024JOKM4[/ame]
 

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This thread is very interesting as I'm trying to figure out what I should do for my alternator connection. I'm glad to hear some clues as to what the range of actual amperage flow may be under various conditions. If any of you have dc tongs you can get a real time display. Or perhaps install a Hall effect sensor and meter.

As I will have 654 watts of solar it will often not be necessary to have an alternator connection. I would ideally like to be able to manually decide when the connection is made, engine running or not, and have a highly visible indicator light for status. I realize there is some risk in not having it more automatic but I suffered for years in my Navion with a temperamental connecting relay (burned out twice). Not exactly sure how to wire the indicator light since both sides of the switch are hot.

My thought is to use a simple Blue sea battery switch, #2 wire, and 150 amp fuse at each end:
http://shop.pkys.com/Blue-Sea-9003e-ON-OFF-Battery-Switch_p_1694.html

Or better yet just use one of these breakers at each end, also with #2 wire?
http://www.amazon.com/Bussmann-Hi-Amp-Circuit-Breaker-Amps/dp/B0024JOKM4
actually I have the Blue Seas switch that I use to manually disconnect both batteries before the combiner switch. I keep it in the off position normally but sometimes in the morning if I'm camping I'll connect the two and start the van to give the batteries a little boost if the panels didn't do their job (very rarely, however)!
 

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I'm only on my second cuppa joe, but for what it's worth this is how I connected my house batteries to the starting battery (pos side only)
I used 4/0 stranded welding cable with a 175 amp fuse on each end at the batteries. As I recall it only cost about $35 online. I just grounded the house batteries to the body with a ground cable. The red cable with the black insulation is the one that goes to the house batteries.
That is a good comparison of your 4/0 wire next to the Promaster wire, which is at least comparable to 3/0.

Why not use 4/0? Other than the extra cost, it is more efficient at transferring the power to the house battery.

I am using 4/0 cable running from the front to the house, with 200 amp fuses on each end. I have a Sure Power isolator that automatically closes the circuit when it sees 13.2 volts. Then I have a 400 amp fuse coming off the house going to the inverter.
 

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Why? The efficiency difference between 4/0 and 4AGW will never be noticed, the 4AGW is cheaper, easier to install, rated for the load, available at any H-D, in appropriate colors for both + and -. Thats why. However the 4/0 is great. Use it if you want. I think KOV bought a kit with the ends attached and some other stuff???

One of our tendencies on this forum is we see someone go way overkill on a product and often represent it as better somehow when it really is not or not much. Wire size, Watts of solar, battery technology, refrigerator options, Vent fan options, speakers and amps, suspension, radios in general, tires, etc. I love to hear about other folks options and how they are working out and encourage you all to participate BUT keep in mind those are options and other solutions may be equally good or so near we don't really need to do them. Flame me for my FLA batteries, Dometic refrigerator, Fantastic Vent, 4AGW feed wire, stock tires, Kinro windows, UnConnect 3 radio, etc. I can take it! Oh I did do an Espar diesel airtronic d2, yea I know way overkill for heat!
 
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Why, because 23% of all car fires are caused by electrical failure or malfunction. If the 12volt 230amp alternator and 100ah battery could use a smaller gauge than what the Promaster has now Fca would have used it.
And the QUESTION STILL REMAINS UNANSWERED WHAT GAUGE WIRE IS ON THE PROMASTER
 

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Why? The efficiency difference between 4/0 and 4AGW will never be noticed, the 4AGW is cheaper, easier to install, rated for the load, available at any H-D, in appropriate colors for both + and -. Thats why. However the 4/0 is great. Use it if you want. I think KOV bought a kit with the ends attached and some other stuff???

One of our tendencies on this forum is we see someone go way overkill on a product and often represent it as better somehow when it really is not or not much. Wire size, Watts of solar, battery technology, refrigerator options, Vent fan options, speakers and amps, suspension, radios in general, tires, etc. I love to hear about other folks options and how they are working out and encourage you all to participate BUT keep in mind those are options and other solutions may be equally good or so near we don't really need to do them. Flame me for my FLA batteries, Dometic refrigerator, Fantastic Vent, 4AGW feed wire, stock tires, Kinro windows, UnConnect 3 radio, etc. I can take it! Oh I did do an Espar diesel airtronic d2, yea I know way overkill for heat!
RD,

I posted because you kept insisting the stock cable was 2 or 4 AWG. It is clearly much larger.

For years I used 10AWG wire to run from the front battery to the house. My thinking was that I didn't need it to be under heavy load, so I didn't need heavy wire. I have learned a LOT about charging off of an alternator since joining this board. I didn't understand how voltage drop effected charging efficiency. Preventing voltage drop is where the heavier gauge wire really shines. I was schooled on this by papab. Small increases on voltage can make a big difference in charging efficiency.

Here is a calculator that papab posted in amother thread.
Http:// www.calculator.net/voltage-drop-cal...tance=15&distanceunit=feet&amperes=50&x=0&y=0
 

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Why, because 23% of all car fires are caused by electrical failure or malfunction. If the 12volt 230amp alternator and 100ah battery could use a smaller gauge than what the Promaster has now Fca would have used it.
And the QUESTION STILL REMAINS UNANSWERED WHAT GAUGE WIRE IS ON THE PROMASTER
Look at the picture that was posted showing the Promaster wire next to the 4/0 wire. The Promaster is whatever is closest to 3/0 wire in the mm equivalent.
 

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Why, because 23% of all car fires are caused by electrical failure or malfunction. If the 12volt 230amp alternator and 100ah battery could use a smaller gauge than what the Promaster has now Fca would have used it.
And the QUESTION STILL REMAINS UNANSWERED WHAT GAUGE WIRE IS ON THE PROMASTER
I think it is 95mm
 

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from Taylor......
"RD
I posted because you kept insisting the stock cable was 2 or 4 AWG. It is clearly much larger. "
cut......

No! I said 4AGW or 2AGW is large enough to connect the starter and house batteries together. I know the starter may draw 400 or 500 amps and that would require at least 4/0 wire although recent vehicles I have owned seem smaller. If you go back (I didn't) and find I said 4AGW is large enough for the starter battery to the starter I'll post up a picture of me eating the 4AGW. Be clear: 4AGW ok to connect the house battery, 4/0 OK to connect starter battery to starter.
This is important because the fire hazard mentioned is real.
 
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