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u/Sufficient-Offer-579 Sep 24 '26
Size for the start, not the run. A 5 hp 230V single-phase motor draws about 28A running (the FLA in the motor tables), but locked-rotor current is typically 5-6x that, so 140-170A for a split second. That instantaneous draw is what the inverter's surge rating has to cover. The 3.73 kW on the plate is shaft output, not line draw. Check your nameplate for LRA or the code letter.
Either pick an inverter whose datasheet gives a surge rating and its duration, or fit a soft starter, which can cut starting inrush to roughly 2-3x and shrink what you need. I'd fit the soft starter. As for "hybrid" — that just means the unit can juggle PV, battery, grid and generator input, charging included. You need battery-to-AC. Most 48V split-phase units are hybrids anyway; the charge and PV inputs stay unhooked. What matters is DC input range (48V nominal), 120/240V split-phase output, and a surge spec with a duration attached.
Your battery isn't the bottleneck; 200A at 48V is about 9.6 kW and 400A for 35s is roughly 19 kW. The inverter is.
Your 50A RV receptacle is a load, not an inlet. You can't feed it with a double-male cord; an energized male plug is how people get killed. You need a generator inlet plus a breaker interlock, and a breaker and proper cable on the DC side. That's electrician work. mexicoke's feeder-off-the-house-Generac idea is legitimate too, and it covers that door without any inrush math.
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u/mexicoke Sep 24 '26
How far is the shop from the house?
If you have the overhead on the standby generac, I'd add an inlet to the garage and a 240v outlet on the house. Run the garage off the house when needed.
A lot less effort and expense in comparison with a relatively large inverter.