Wire size sanity check

[Pr3dict]

Im doing a conversion from 12v to 24v on my RV. All the previous wiring was 1/0 for all the 12v components - All battery connections, etc, going to a 2000watt inverter....

Well now Im upgrading to 24v going to a multiplus 2 24/3000w and for the 12v stuff I'm using an orion TR 24/12-70A. The Orion is 70A on the 12v side so 35-40A on the 24V side. When I do that math I get to ~165A. Do you think I can pull off reusing the 1/0 wire instead of making all new connections with the 2/0. For what its worth I have the 2/0 already but its THHN2 and the 1/0 is welding cable so a lot easier to work with lol.

Thoughts?

 

[sunshine_eggo]

Is the 1/0 wire rated for 165A?

 

[740GLE]

Edit: I didn’t know the Orion was a DC to DC converter.

The SCC down rates the current for higher Voltage? I thought charging current stayed the same for different voltages, maybe it’s an Orion thing.

Also 2/0 THHN2, that’s gotta be a bear to manipulate, lol!!!

 

[chrisski]

I have a 3000 watt inverter, and I use 4/0 wire.

Where do you get 175 amps from? The multiplus is 3000 VA, or 2400 watts. Also, did you use low voltage cutoff when doing amps, or what specifically?

 

[Pr3dict]

Is the 1/0 wire rated for 165A?

Yeah 170A. Now that I think about it ....

Edit: I didn’t know the Orion was a DC to DC converter.

The SCC down rates the current for higher Voltage? I thought charging current stayed the same for different voltages, maybe it’s an Orion thing.

Also 2/0 THHN2, that’s gotta be a bear to manipulate, lol!!!

Unless this thing is 50% efficient then its output would have to relative to the input voltage. So 70A @ 12V 100% efficient would be 35A @ 24V. I added 15% A to account for the loss.

I have a 3000 watt inverter, and I use 4/0 wire.

Where do you get 175 amps from? The multiplus is 3000 VA, or 2400 watts. Also, did you use low voltage cutoff when doing amps, or what specifically?

What 300W at what voltage? Also what kind of wire?

Goooood point about the multiplus. Jeez I need to take a step back and think about what I'm doing lol. For the amp calc I just added up the different loads .

 

[chrisski]

What 300W at what voltage? Also what kind of wire?

I have a 24 volt 3000 watt Samlex inverter. The wire is 4/0 TEMCO welding wire.

 

[sparkness]

3000W/24v = 125A
125A/.85 85% efficiency= 147A draw at full load
Cable Length ? Wire temp rating?
if the cables are 4' long each 1/0 cable, your cables will dissipate 18W at full load, not sure how warm that will be (R x I^2)
1/0 welding cable is rated to 105 degrees C
1/0 cable at 90 degrees C is rated at 170A from wiki AWG chart

 

[chrisski]

With a 20 volt low voltage cutoff and a 1.25 safety factor, this becomes

3000/20/.85*1.25=

221 amps

I use wire thickness for 60c rating off an NEC chart.

 

[Pr3dict]

With a 20 volt low voltage cutoff and a 1.25 safety factor, this becomes

3000/20/.85*1.25=

221 amps

I use wire thickness for 60c rating off an NEC chart.

Gotcha.. I'm using the 90c rating as all the connectors and components are rated for that or higher.

Also the largest runs are going to be 1 to 3ft max per cable. Its mostly the parallels cables for the batteries and then going to the fuse -> Lynx distributor/ battery shunt. From there the loads will drop off where 1/0 or lower will 100% be fine.

Thx everyone for the thoughts.