How Much Power Does Parking AC Use?

• Table of Contents

1. Power draw by model and ambient temperature
2. Hourly Ah budget — overnight planning
3. Pull-down vs steady-state — peak amps differ
4. Solar replenishment math
5. Sizing help — talk to engineering

Battery-powered parking AC power consumption is the single most important number for sizing the auxiliary battery, the recharge alternator and the solar array. This guide gives real measured amp-draw values for the Vethy lineup across typical operating ambient temperatures, plus simple worked examples for sleeper cab, camper van and motorhome applications.

Power draw by model and ambient temperature

Measured continuous draw (steady-state, after pull-down): VS02 PRO 24V at 35°C ambient = 24–28A; at 45°C ambient = 30–34A. ZH 1000 12V at 35°C = 26–30A; at 45°C = 32–36A. VC 1000 24V at 35°C = 26–30A; at 45°C = 32–36A. VC 2000 24V at 35°C = 30–34A; at 45°C = 36–42A. Inverter (variable-speed) variants run approximately 25–30% lower at the same conditions. All four VS02 PRO / ZH 1000 / VC 1000 / VC 2000 models documented.

Hourly Ah budget — overnight planning

Sleeper cab VS02 PRO 24V × 8 hours × 28A = 224 Ah consumed per 8-hour overnight at 35°C. Camper van ZH 1000 12V × 6 hours × 28A = 168 Ah. Motorhome VS02 PRO 24V × 10 hours × 28A = 280 Ah. These are usable Ah requirements; size LiFePO4 battery to 1.0x usable (LiFePO4 supports 90% discharge), AGM to 2.0x (50% safe DoD).

Pull-down vs steady-state — peak amps differ

Initial cab pull-down (cooling from 50°C to 22°C setpoint) draws maximum compressor current for 10–15 minutes — typically 35–45A peak. Once setpoint is reached, the compressor modulates (inverter) or cycles (fixed-speed) at lower average draw. Auxiliary battery and DC-DC charger sizing must accommodate peak current at startup, not just average steady-state.

Solar replenishment math

Rough rule: 1W of nameplate solar produces ~3.5–5 Wh/day in moderate climates (4–6 hours equivalent peak sun). To replenish 224 Ah at 24V = 5,400 Wh consumption, plan ~1,100–1,500W of rooftop solar OR 300–500W solar + alternator recharge during driving day. Hot-climate fleets (US Sun Belt, Australia, GCC) often achieve indefinite autonomy with 400W solar + driving recharge.

Sizing help — talk to engineering

Email sales@vethy.com or call +86-532-87729918 for spec sheets, ROI worksheets and CIF pricing within 24 hours. Provide vehicle type, voltage, target overnight hours, climate ambient — we return battery + alternator + (optional) solar specifications.

Frequently asked questions

Is the power draw the same in heating mode?

Heat pump heating typically draws 20–25% less power than cooling for equivalent comfort. Battery overnight runtime in heat-pump mode is therefore longer than in cooling mode from the same battery.

Does the fan speed change power draw a lot?

Modestly — fan accounts for 2–4A of the total. High fan speed adds about 2A vs low; main current is compressor.

What if I run the AC continuously for 24 hours?

Possible with appropriate battery + solar sizing. Many full-time RVers and expedition vehicles run continuous cab cooling with 600W solar + 300Ah LiFePO4. Alternator recharge during drive days adds buffer.

How much power does standby (AC off) draw?

Negligible — under 0.5A standby for controller and LCD. Does not meaningfully drain battery overnight when AC is off.