380 Amps of what?

[austingta]

My 2500 HD has two alternators with an advertised output of 380 Amps DC. My truck has a fuse that is rated at 30 A powering the 12VDC output wire on the trailer wiring plug.

If I want to utilize the full capacity or anywhere near it, I presume I have to run a very large wire back to the trailer 12VDC wire to power the breakaway charger (which doesn't need much) and/or charge my batteries at an efficient rate and all the electrical items I may need to power through the inverter.

Advice ?

[Turtle_n_Peeps]

Advice?

Ya, don't even get close to max output of those alternators.

They don't have the duty cycle and you will smoke them in short order.

Every single alternator I have replaced has came with a caution tag that said something like this:

WARRANTEE VOID if you do not fully charge the batteries on the vehicle you are installing the alternator on.

Any idea why they say this?

[theoldwizard1]

The best high amperage electrical connectors are Anderson PowerPole. Thta is what they use on electric hi-lows and floor machines.

[deltabravo]

deltabravo wrote:


Andersen connectors and 4AWG wiring.

This photo shows my original wiring, which was 6AWG.

6 months after I installed it, some critters got under my truck and chewed up a bunch of wiring, including the truck wiring harness, resulting in a repair bill of about $4500.

When I replaced the wiring, I went with 4 AWG

[horton333]

The wire does not know the difference between 60 Hz Ac and DC. The wire gauge for a given amperage is the same for either.
The wattage is higher given the higher voltage, but voltage only affects the insulation required around the wire.

[atreis]

Was just using a gauge calculator to see what popped out if one wanted to use all 380 amps at a distance of 5 meters. My guess was 4/0. The gauge calculator said 3/0 copper was sufficient.

[Grit_dog]

AC and DC is apples to oranges. AC is more efficient, hence the need for less "torque" to produce a given amount of work.
And no, it's not a marketing claim, but you're not going to charge your batteries at 200amps in the camper.
Either way it would be a worthwhile upgrade, IMO and at the same time you could wire in either an ignition triggered relay to disconnect the truck system from the camper when the truck is off but plugged in, or install a marine grade ACR in line that cuts the power automatically at a pre set voltage to keep from draining the truck batteries.
I'd totally do it, even with a single alternator if I used my camper more or relied on the truck to charge the batteries more.

[Bedlam]

It's 380A at 12VDC verses 200A at 120VAC that you are comparing above. Look at the wattage output between these two and you will see there is a big difference.

[OH48Lt]

Many trucks that have a snowplow mounted are equipped with dual alternators and dual batteries. The electric motor that powers the hydraulic cylinders on the plow pulls a LOT of juice. Add the regular load of headlights (many plowers work at night), and one alternator just can't keep up. 380 amps though is way overkill. Most modern houses have 200 amp service, and the supply lines coming in are usually 1/0. (I know, just had my house electric meter base and load center changed out 2 weeks ago). I wonder if Chevy put 1/0 or heavier wiring from the alternators to the battery then to the first load center.

The 380 amps is probably just another marketing claim.

[horton333]

Unless you have some huge and fully drained batteries the low voltage output from an alternator is going to realistically limit you to 10 or 15 amps charging. That's why the trailer fuses tend to be only 30 amp when even the smallest alternators are over 100 plus what the battery can supply. Thicker wires will help a bit by reducing voltage drop. Even with thick wire to the battery you just cannot force much current with 1.5 volt differential, and that goes down as charging progresses. You can alter the voltage fairly easy if you can read a schematic, but then you may boil the truck battery.
If you have some other purpose than battery charging in mind like running air conditioning the invertor may work better as suggested above, but I wonder what duty cycle those alternators are rated at, likely they are only rated for hundreds of amps for minutes not hours.

[RoyB]

I would use one of these two pin 4AWG rear connectors on the truck side mounted near your 7-pin receptacle.

The chassis mount uses standard lugs on the back for the 4AWG cables... These are rated for 200A DC CURRENT I think it is...

I have heard some folks have fitted 2AWG cables to this receptacle.


google image

Mating plug connector would look like this one... This looks very similar to the 7-pin plugs coming from the RV trailers except only has two large pins to use.

google image

The 4AWG version is available from ETRAILER.com being the PK12800 series...

This would fit very nicely with my plans for a external battery bank in the back of my truck big for my EMERGENCY RADIO OPS requirments and a receptacle to connect to my OFF-ROAD POPUP trailer to add to my trailer battery bank when in camping mode...

The external battery bank would be setup to be charged by the truck alternator when not connected to the trailer or charged by the trailer converter/charger unit when in camping mode.

Something like this perhaps...

Roy's Image

In my planning I would only need to protect the wiring for around 80AMPS DC Current... 380AMPS capacity is alot of power to only be used for a RV unit.

Roy Ken

[KD4UPL]

You will need very large wire to the rear of the truck, a very large connector (like the Anderson pictured), and very large wires on the RV side to the batteries.
What batteries do you have? It it's a fairly normal sized bank of around 200 AH then most current you could reasonably hope to put into them is probably about a C/5 or 40 amps. If you assume the truck wiring is 25' and the RV wiring is 10' then you need wiring to carry 40 amps that distance with minimal voltage drop. By my calculations something around 250 MCM would give you just over 1% of voltage drop.
This size wire is huge for RV work. So, basically, the biggest wire you can manage to afford and install.

[gbopp]

drittal wrote:

austingta wrote:
That is a funny notion...a government agency spec'ing a Denali ambulance!

A government agency spec'ing a Denali seems like a waste of tax payer money.

It's only tax dollars, there's plenty available. And, it's easy to raise more....:E

[drittal]

austingta wrote:
That is a funny notion...a government agency spec'ing a Denali ambulance!

A government agency spec'ing a Denali seems like a waste of tax payer money.

[Bedlam]

Ask this question again in the truck camper section. Many run a constant duty solenoid and heavier gauge wire to recharge their camper. The same is done in many Class B's. DB slipped in some photos before I finished responding.