Cable and Fuse Sizing

[Flux]

Time for me to get serious and get the electrical system going. Haven't picked out which 4D AGM I will use yet. But here's a couple quicky things:

Will use Blue Sea 7622.

Have stock alternator 135amp I think? Will eventually upgrade to 200+ amp.


Thinking 2/0 cable between the batteries and the 7622. Too much?? Too Little?? Will I ever really see 200 Amps through there?? Obviously good for voltage drop considerations. I figure no more than a 22 ft run in total from battery to battery.

ANL fuses good?? I am confused on fuses. I will get it straight though on the Blue Sea Calculator with a bit of research.

Make me own grounding lug on the frame right?? and run the same size cable, 2/0.

Thanks in advance. Just want to start getting all this together ASAP. Found out there's a battery distributor near my work so I may go there to get the house battery, better for returns if I get a dud.

[larrie]

The Blue Sea circuit wizard will tell you the wire size and fuse size you need. Just plug in your values.

[Flux]

I put in 200 Amps nominally, but I just can't think if I would ever really pull 200 amps back to the house battery and/or loads.

200 amps is 2/0 for 25 feet with <3% drop. Rule of thumb is always oversize right?

thanks larrie!

[86Scotty]

22' of 2/0 wire is going to cost as much as your van. I ran 4 gauge with an 80 amp breaker and have no worries about it. It's working great so far.


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[Flux]

There's some pretty smokin deals on ebay if you poke around. Ancor marine grade too.

[winmag4582001]

I'm using 4 gauge wire (Ebay) for my set up. Running about 12' total going back to 2 AGM batteries and inverter. I'll do a video when I'm done.
Here's my purchase list:
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
4 Gauge Wire Red Amplifier Power/Ground 4 Ga Amp Wire 25 Feet Cable Roll | eBay
Going back to 2 of these batteries:
Duracell® AGM Deep Cycle Marine and RV Battery - Group Size 34M - Sam's Club

Personally I like going bigger but 4g will do, I consider that to be the minimum for the distance I'm running and what I'm doing.

[86Scotty]

Wow, that is a great deal on wire!

Looks like a good deal on that inverter too!

[boywonder]

I'm running 2ga (not 2/0) for most battery cables. If you need to start your van off of the house batteries you'll be pumping around 500+ amps through those cables. I haven't needed to do that yet, but if the voltage drop through the cables is too much to crank the motor over, I'm happy to sit for 15-20 minutes and let the house batteries charge the starting battery if needed....then the cables will need to deliver less amps.

Not sure what a 200A alternator gets you over stock, but I suppose that it depends on the power needs in the back of the van. My biggest load is a 1000W inverter running a small microwave. No house air conditioning or anything.

[Flux]

Tossed and turned on this last night. I would do as you do and simply combine and let the starter charge up off the house.

I doubt I will have more than 40 amps of house loads and there's no microwave.

I guess the question becomes how many amps does a 50% discharged AGM 4D battery pull?? That is where the voltage drop get's more critical.

But Wonder is right about the stock alternator.

[Scalf77]

I am running #2 also, I would think the real reason to move to the larger alternator would be the higher Idle output, not the total power.

-greg