Arizona Battery Backup Sizing Calculator

How to Size Backup Power for Arizona Monsoon Outages

Sizing a portable power station is actually two problems in one. First you need enough continuous output power (watts) to run every load you plan to have on simultaneously. Then you need enough energy capacity (watt-hours) to sustain those loads for as long as the outage lasts. A unit can have plenty of stored energy but still be useless if the continuous output is too low to start your fridge compressor — and a unit can have enough output but run out of energy in two hours. Both numbers matter, and this calculator checks both.

The surge (startup) value is the third number that trips up most buyers. Motor-driven appliances — fridges, AC compressors, pool pumps, well pumps — spike briefly to 2-3x their running wattage when they first turn on. A power station rated for 1,500W continuous might handle a 1,500W load forever but still trip offline the instant a fridge compressor kicks in at 600W surge. Every product in our database has both a continuous and a surge rating, and the calculator matches your worst-case surge load against the unit's surge rating, not just the continuous.

Why Arizona Monsoon Outages Are Different

Arizona monsoon season runs roughly June through September. During that window, the Phoenix metro area sees frequent short outages from dust storms, lightning strikes on transformers, and extreme-heat load events that cause parts of the APS and SRP grid to trip. Most monsoon outages last between 1 and 12 hours, which is why our calculator defaults to 12 — that's the right target for "I want to keep my fridge and CPAP running through a summer thunderstorm outage" without overbuying.

Three things about Arizona that change the sizing math compared to temperate climates:

• Ambient temperature. Portable power stations derate in extreme heat. A unit rated for 50°C (122°F) discharge will still deliver full output on a 110°F day, but a unit rated for 40°C (104°F) discharge may cut output or refuse to charge inside a Phoenix garage in July. All of the Jackery and EcoFlow units in this calculator are LFP (LiFePO4) chemistry and rated for at least 113°F discharge — which is the minimum to be called an "Arizona-capable" power station in our view.
• The fridge is the baseline everyone forgets. In a cooler climate you might skip backup for the fridge and rely on ice. In Phoenix in July, a fridge left without power for 8 hours loses everything. The calculator treats the fridge as an essential and computes the realistic duty-cycled energy draw (about 1,200 Wh per full day, not the naive 3,600 Wh you get by multiplying 150W × 24).
• CPAP users can't skip a night. The medical category in this calculator exists because CPAP backup is one of the highest-intent sizing questions on the internet. A CPAP without humidifier draws 30-60W and runs about 8 hours — that's 320 Wh per night. The Jackery Explorer 300 Plus (288 Wh) can just barely do one night of CPAP with humidifier off. A Jackery 1000 v2 gives you CPAP plus fridge plus Wi-Fi plus phones for the whole night with comfortable margin.

How This Calculator Picks the Product

Our product database currently covers seven units across the two affiliates we work with: three Jackery power stations (Explorer 300 Plus, Explorer 1000 v2, Explorer 2000 Plus), one Jackery home-adjacent unit (Solar Generator HomePower 3000), and three EcoFlow units (DELTA 3 Plus, DELTA Pro 3, DELTA Pro Ultra). For each, we have the published capacity in Wh, the continuous AC output in watts, the surge capacity in watts, and the typical sale price — not the MSRP, because nobody who reads this site actually pays MSRP on power stations.

The picking algorithm is simple:

1. Filter to units where the surge capacity is at least as high as your peak surge load.
2. Filter further to units where the total capacity is at least as high as your energy need (including 15% losses).
3. Sort the remaining list by typical price.
4. If your energy need is under about 2,000 Wh, recommend the cheapest Jackery that fits. If it's 2,000 Wh or more, recommend the cheapest EcoFlow that fits. This is the brand-lane separation we use across the site: Jackery wins on the portable/critical-loads tier; EcoFlow wins on whole-essentials and whole-home. Both brands have strong products in the middle overlap, so the calculator surfaces an alternate pick from the other brand when one exists.
5. Also surface the next step up for readers who want headroom. If you plan to add loads later — a window AC for next summer, or a heated CPAP humidifier — the step-up pick avoids needing to buy twice.

When no unit in our lineup fits your scenario (typically because you selected central AC, or too many loads over a very long duration), the calculator tells you explicitly rather than forcing a bad recommendation. In those cases the honest answer is either a reduced load list, a shorter duration, the biggest unit with expansion batteries, or a permanent whole-home battery like Tesla Powerwall 3 — which is outside the scope of this particular tool.

Before You Buy

Three things worth knowing before clicking any affiliate link:

• Seasonal discounting is significant. Jackery and EcoFlow both run 30-65% off during Memorial Day, Father's Day, Prime Day, Labor Day, Amazon October Prime Day, and Black Friday. If your outage isn't imminent and you're within 4-6 weeks of one of those events, wait. Our Arizona power outage backup guide has the full seasonal calendar.
• Solar panels stretch runtime dramatically. Adding even a single 100W portable solar panel to any of these units can double or triple effective runtime during daytime hours in Phoenix sun. Jackery's Explorer 1000 v2 often bundles with a free 100W SolarSaga panel during sales — that's the single best-value entry into solar-capable backup in Arizona.
• Battery chemistry matters here specifically. All products in this calculator are LFP (lithium iron phosphate), which handles Arizona heat dramatically better than older NMC chemistry and has 3-4x the cycle life. If you see a power station recommended somewhere else that uses NMC, it's disqualified for AZ use in our view. (Relevant disclosure: Jackery still sells some older NMC units, including the Explorer 3000 Pro. We explicitly exclude those from this calculator and recommend against them for AZ customers.)

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Frequently Asked Questions

How big of a power station do I need for an Arizona outage?

For a typical Arizona critical-load kit (fridge + CPAP + Wi-Fi + phones + a few LED lights) running for 12 hours, you need about 1,520 Wh of battery capacity with at least 600W of surge. The Jackery Explorer 1000 v2 is the volume hero for exactly this scenario and usually sells for around $429-$449. Add a window AC or step up the duration and you'll need the Jackery Explorer 2000 Plus or EcoFlow DELTA Pro 3 tier instead — the calculator above shows you the exact threshold.

Can a portable power station run central air conditioning?

Only the very largest portable units can. A typical 3-ton central AC has a surge requirement around 7,000W — above any Jackery unit currently sold, and only comfortably within reach of the EcoFlow DELTA Pro Ultra (14,400W surge) in our lineup. For most Arizona homeowners, the better monsoon strategy is a single window AC unit in the bedroom or living room off a mid-tier portable. If you truly need central AC backup during outages, the conversation shifts to installed whole-home batteries — Tesla Powerwall 3 or the EcoFlow DELTA Pro Ultra with Smart Home Panel 2.

What's the difference between Jackery and EcoFlow for backup power?

Jackery dominates the 300-2,000 Wh portable tier — lighter weight, simpler app, stronger retail footprint (Best Buy, Home Depot, Costco, Amazon), deepest seasonal discounts. EcoFlow owns the 2,000+ Wh whole-essentials and whole-home backup tier with the DELTA Pro 3, DELTA Pro Ultra, Smart Home Panel 2 integration, and the WAVE 2 portable AC — the only portable AC rated for 115°F Arizona heat. Our calculator respects this split: for small kits we recommend Jackery first, for whole-essentials and whole-home we recommend EcoFlow first, and in the middle overlap we show both.

How long will a power station actually run my fridge?

A standard residential fridge pulls about 150W while running but cycles on only 33% of the time. Real-world average is about 50W per hour, or 1,200 Wh per full day. A Jackery Explorer 1000 v2 (1,070 Wh usable) runs a fridge alone for about 20 hours. A Jackery Explorer 2000 Plus (2,042 Wh) gets you close to 40 hours of fridge-only runtime. Layer on CPAP, Wi-Fi, and lights and you'll cut those numbers by about 25-30%.

Should I get a gas generator instead?

For pure cost-per-watt-hour a gas generator is cheaper. But in Arizona specifically, battery units have real practical advantages during monsoon season: no fuel storage in 115°F garages (gasoline degrades fast in extreme heat), no carbon monoxide risk, near-instant UPS-style switchover for fridges and medical devices, and zero maintenance between outages. For most Maricopa-area homes, battery wins on practicality even when it loses on raw $/Wh. This calculator assumes you've already chosen the battery path.