What size generator do I need for a 50 amp RV?

Many RVs with two roof ACs have 50 amp service. The 50 amp label sounds like you need a huge generator. You don't, as long as you size for what you'll run at the same time.

How much power can a 50 amp RV use?

A 50 amp RV has a 4-prong 14-50 plug. It carries two 120 V lines of up to 50 A each:

• 50 A × 120 V × 2 lines = 12,000 watts at most

That's the ceiling, not what your RV actually uses. Two ACs, a fridge and some lights use about half of it. For comparison, a 30 amp RV tops out at 3,600 W. See what size generator for a 30 amp RV.

What size generator for a 50 amp RV with 2 AC units?

This is the most common question. Using Champion's chart figures in our calculator (13,500 BTU AC: 1,500 running, 3,000 starting):

What's on	Running W	Starting W	With 20% headroom
1 AC (13,500 BTU) + fridge, microwave, lights, TV, chargers	3,230	4,730	about 3,900 / 5,700
2 ACs (13,500 BTU) + the same	4,730	6,230	about 5,700 / 7,500
2 ACs (15,000 BTU) + the same	5,730	7,230	about 6,900 / 8,700
3 ACs (13,500 BTU) + the same	6,230	7,730	about 7,500 / 9,300

The 15,000 BTU row uses 2,000 running and 3,500 starting watts, the low end of Champion's range. Champion also lists an RV electric water heater at 1,200–1,500 W. Add that if you'll run it on the generator.

A worked example: two ACs and the basics

The calculator above is set up for this:

• Running: 1,500 + 1,500 (two ACs) + 400 (fridge) + 1,000 (microwave) + 100 (lights) + 150 (TV) + 80 (chargers) = 4,730 W
• Biggest surge: one AC, 3,000 − 1,500 = 1,500 W
• Starting: 4,730 + 1,500 = 6,230 W
• With 20% headroom: about 5,700 running and 7,500 starting watts

We only add one AC's surge because the two ACs rarely start in the same second. You can make sure of it: turn one on, wait a minute, then turn on the other.

Which generator outlet do you need?

Generator outlet	What it gives a 50 amp RV
14-50R (50 A, 120/240 V)	The full hookup, up to 12,000 W or the generator's limit
L14-30R + 14-50 adapter	Up to 7,200 W (30 A × 240 V). Enough for two ACs and the basics
TT-30R + 50-to-30 adapter	Up to 3,600 W. One AC and a few small things

Some larger open-frame generators have both an L14-30R and a 14-50R. The Westinghouse WGen9500DFc is one example (9,500 running, 12,500 starting watts on gas). An adapter doesn't add power. It just lets the plugs fit.

One RV-specific catch: some big RVs have 240 V appliances. Those need a true 120/240 V source. A 120 V-only generator on an adapter feeds the same 120 V to both sides, so check your RV's manual first.

Can an inverter generator run a 50 amp RV?

Yes, with limits. Two inverter generators linked with a parallel kit act like one bigger unit, but the kit's outlet sets the ceiling. A 30 A kit (TT-30R and L5-30R, 120 V) feeds a 50 amp RV at most 3,600 W through an adapter: one AC and the basics. Some makers also sell 50 A kits with a 14-50R, for example WEN lists a 6,000 W 120 V kit and a 12,000 W 240 V kit for its 240 V-capable models. Check that the kit is approved for your exact generators. See how to run inverter generators in parallel.

If you want both ACs on a quiet setup, you'll need a generator with a 14-50R or L14-30R outlet, or soft start kits and careful load management.

Soft starts make a real difference

A soft start kit fitted to each AC cuts its start-up surge. That helps most when the generator is close to the limit. Micro-Air, which makes one, pitches it for starting an RV AC on a single small generator. Our 2,000 watt generator and 13,500 BTU AC guide covers how much it helps.

High altitude and heat

Generators make less power up high. Westinghouse's manual says power drops about 3.5% for each 1,000 feet above sea level, and about 1% for each 10°F above 60°F.

• Example: a generator rated 7,500 running watts at 5,000 feet: 7,500 × (1 − 0.175) ≈ 6,200 W

That's still enough for two 13,500 BTU ACs and the basics, but with less room to spare.

Quick checks before you buy

1. Count your ACs and their BTU. It's on the AC's label or in the RV's manual.
2. Decide what runs at once. Two ACs plus the microwave is the usual peak.
3. Match the outlet. A 14-50R, or an L14-30R with an adapter.
4. Cords matter. A 50 amp cord needs 6-gauge wire. See 30 amp vs 50 amp generator cords.

Safety: Run it outdoors only, 20+ feet from the RV and any buildings, away from windows, doors and vents. Read our carbon monoxide guide.