Can a BLUETTI Apex 300 run a rooftop RV air conditioner?

Answered by RV Parts Giant · Upland, CA · October 15, 2026

Short answer: Yes on output: its 3,840W continuous clears the roughly 2,100W our calculator sizes for a 13,500 BTU rooftop unit. Capacity is the limit. The Apex 300 alone (2,764Wh) covers about two hours on a warm night plus the fridge; four warm hours needs one B300K added, and a warm eight-hour night needs two.

Two numbers decide it, and the Apex 300 only has a problem with one of them.

Output: not the problem

Our calculator counts a 13,500 BTU rooftop unit at about 1,400W while the compressor runs, and a 15,000 BTU unit at about 1,700W. It then sizes the inverter at one and a half times that running figure to leave room for the start, which comes to about 2,100W and 2,550W. The Apex 300 listing states 3,840W of rated output at 120V/240V, so either unit sits well inside it. Our listing does not give a surge figure, so check the locked-rotor or start current on your own AC's data plate, and fit a soft starter to the AC at install either way. We do not stock one.

Capacity: the real limit

How long it runs depends on how hot the night is, because the compressor cycles less as it gets hotter. The calculator uses three duty levels: mild nights in the 70s (on about 35% of the time), warm 80s (55%) and hot 90s and above (70%). Each figure below is the AC through the inverter plus the rest of a typical rig, a 12V fridge, lights, pump, phones and fans, which is about 550Wh a day.

AC hours, 13,500 BTU	Mild	Warm	Hot
2 hours	1,616Wh	2,224Wh	2,681Wh
4 hours	2,681Wh	3,898Wh	4,811Wh
6 hours	3,746Wh	5,572Wh	6,942Wh
8 hours, overnight	4,811Wh	7,246Wh	9,072Wh

Matched against the Apex 300 sizes we sell:

Apex 300 alone, 2,764Wh: up to 2 hours on a hot night, or 4 hours on a mild one.
Apex 300 + B300K, 5,529Wh: 4 hours on a warm or hot night, and a full mild overnight.
Apex 300 + 2x B300K, 8,294Wh: 6 hours on any night, and a warm overnight.
A hot overnight (about 9,100Wh): past two modules. One Apex 300 takes up to six B300K batteries, so a third module (about 11,000Wh) holds it; the calculator jumps to the two-unit 16,588Wh bundle.

A 15,000 BTU unit adds about a fifth to every AC figure. Four warm hours, for example, comes to about 4,600Wh, still inside one B300K.

Which battery versions and cables fit an Apex 300: BLUETTI expansion batteries: which fits which station.

Putting it back

This is where most AC-on-battery plans fall over. Replacing a warm overnight in one day of mixed sun (about five peak hours, 75% harvest) takes nearly 2,000W of panel, more than most trailer roofs hold. Four warm hours needs about 1,050W; two warm hours about 600W. The realistic refill is shore power or a generator: with BLUETTI's 50A fast-charging cable the Apex 300 takes up to 3,000W from a 30A outlet.

If the plan is cooling a bedroom rather than the whole rig, a 12V camping AC changes the sum. The calculator counts the Zero Breeze Mark 3 or Cybertake S2 Pro at about 300W running, and a warm eight-hour night with the fridge comes to about 1,870Wh, inside the Apex 300 alone with room to spare.

Run your own rig, hours and night temperature in our RV solar & battery calculator. How the station feeds the RV's own outlets is covered in which power station has a native 30 amp RV plug.