DC breaker for my Native DC air conditioner size?

[Deadeyecustoms]

I have a 13000w 28kwh 48v off grid solar system with two 6500w rich solar inverters in split phase & two 14kwh 48v big battery rhino power wall batteries. I have a native DC air conditioner that draws max 20amps & typical amp draw of 10amps. The manufacturer told me to connect the air conditioner direct to the battery busbars. My question is, since I'm drawing directly from the 48v busbars, and the only load off of this wire run is the efficient DC air conditioner that runs at 35w-10amps-20max. Do I size my wire for what the batteries put out or for the load my air conditioner will consume? If just the air conditioner load, will 6awg be sufficient & same question for putting a fuse or dc breaker in between the two. Does the breaker need to be 250amp which is the battery max or just 20amp which is the air conditioner max amp draw? My solar equipment has been installed inside an old Korean era Military Marine radio shelter. Which is designed to be a faraday cage itself with steel outer shell & mesh aluminum paneling inside. My run from the shelter to the air conditioner will be no more than 50'. My ac out loads will be in separate shielded conduit & exit in its own penetration. I was thinking of a DC breaker/disconnect right before the 48v wires penetrate the shelter. Any input would be greatly appreciated. Planning on hiring a solar professional once near completion to QC my work, but want to do most of the work myself to save cost.

 

[12VoltInstalls]

only load off of this wire run is the efficient DC air conditioner that runs at 35w-10amps-20max. Do I size my wire for what the batteries put out or for the load my air conditioner will consume?

The load of the air conditioner only.

Your air conditioner is what voltage?
35W doesn’t sound right to me. And that with the voltage of the a/c is the info needed for the question.

Does the breaker need to be 250amp which is the battery max or just 20amp which is the air conditioner max amp draw?

Just the air conditioner. 20A breaker might do nuisance tripping so 25A is what I’d use. But:
I’m assuming your a/c is 48V? And assuming you meant 350W? Which is ~7A straight up, but unknown startup amperage which one might assume is the 20A. If

If just the air conditioner load, will 6awg

Depending on length, 6ga is good for ~50A
10awg if not an excessively long run is 30A which - with if the assumptions above being correct - is sufficient.
I overcable a lot of big amp stuff. 20A isn’t that big but me? I’d use 8 ga if my above assumption are correct. I might go 10ga if the run was <6’

Others may have different opinions. YMMV

 

[Deadeyecustoms]

Sorry, not sure why I typed 35w, this is the label on the actual unit.

 

[Deadeyecustoms]

I actually bought 100' of direct burial 6/2 wire for the AC side but have decided to use 4/3 instead. So, I'll most likely be using 6awg for the 50' run to my split system. I have a fused disconnect right before my a/c lines head outside of my radio shelter/solar shelter with dual 30amp fuses. I don't plan on running a ton of appliances etc off the ac out. Other than lighting/fans/computers & the condenser fan for my geothermal floor heating. Which is a very efficient unit I had stored from my Refrigeration days. I don't want to completely bleed my system of energy by using too many power hungry devices. Would love to power my paint booth & cerakote oven, but thinking that will tie into my house ac.

 

[wdwtx2.0]

If you notice, the data tag shows minimum circuit ampacity is 7.2 amps, and MAXIMUM Fuse (or breaker) size is 15 amps.
That means do not exceed a 15 amp breaker, or fusible disconnect at the unit, or breaker at the battery, if you are not using a disconnect.
The 30 amp total input current includes the start amps, which a smaller wire will accept for the time it takes to start the compressor.
14 AWG wire will handle 15 amps, but obviously you would allow a safety margin, and for voltage drop.
6 AWG is expensive overkill unless you have a very long run. 4 AWG is a massive oversize.
I would feel perfectly safe using 10 AWG. I would use a 20 amp breaker or fuse at the battery, and a 15 amp fusible disconnect, or breaker disconnect at the condenser for maintenance ease.
Check your distance from the panel, and check an online voltage drop calculator, base your amp draw on the 20 amp breaker, it will save you a LOT of money.
As a note, I have never worked on a Chinese DC unit, but the data tag is just like the HVAC condenser data tags that I serviced and installed for decades.
If I am wrong, I am sure someone will correct me.

 

[12VoltInstalls]

6 AWG is expensive overkill unless you have a very long run. 4 AWG is a massive oversize.

^^^this

I overcable a lot of DC stuff on purpose but not frivolously. Inverter from battery I might be “frivolous” but that’s usually only a few feet and no big expense.

 

[Deadeyecustoms]

I have around a 6' run from my battery buss bars to my 20amp dc breaker & then from there another 60-70' to the unit.

The unit is actually from Kingston, Jamaica.

***Note... The 6awg was for the direct line from the 48v battery bank buss bar to the air conditioner 70' away. I bought it for my ac load at my shop but decided to go with 4awg because it's a 70' run & I'll likely be adding items to the load down the road, as I figure out what my system can handle. I cerakote firearms for a living & would love to use my paint booth, which is 120v, my cerakote oven which is 220v. I only use them for short durations at a time. That's the big reason I'm switching my ac lines to 4awg. The length of the run & the additional items I want to try & run.

These are the loads I'd likely be trying to run off the 4awg from my ac out from the inverters.

 

[Deadeyecustoms]

Just want to say thank you to everyone for your time & assistance, greatly appreciated!

 

[wdwtx2.0]

The 6awg was for the direct line from the 48v battery bank buss bar to the air conditioner 70' away. I bought it for my ac load at my shop but decided to go with 4awg because it's a 70' run & I'll likely be adding items to the load down the road, as I figure out what my system can handle.

Planning ahead. ?