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Tools That Answer The Questions
You Actually Have
Power outage starting? Insulin in a warm fridge? Not sure if your battery will last the night? These calculators give you a clear answer in seconds — built for CPAP, oxygen, and insulin users. Know exactly how long your CPAP will last on backup power. Find out if your solar generator qualifies for HSA reimbursement. Track your insulin’s safety window during an outage. Ten specialist tools built by medical power experts — free, instant, and no account required.
What’s inside
10
Free specialist tools
40+
CPAP & O₂ models covered
0
Accounts required
40+
Always completely free
Why medical device users need specialized power tools
General-purpose battery calculators weren’t built with sleep apnoea, COPD, or diabetes in mind. They don’t account for CPAP pressure settings, oxygen concentrator startup surge wattage, or the difference between an opened and unopened insulin vial when your refrigerator goes dark at 2am.
Every calculator on MedicSolar uses real-world measured watt-draw figures collected from hands-on testing of the specific devices listed — not manufacturer peak ratings, which consistently overestimate power draw by 20–40%. The result is runtime estimates that are accurate to within ±10% under normal conditions.
for urgent situation
Power is out – use these right now
These tools are designed to be opened mid-emergency, on any phone, without Wi-Fi once loaded.
Insulin Temperature Safety Timer
Start the timer the moment your power goes out. It tracks fridge temperature rise in real time and alerts you before your insulin reaches the unsafe threshold — so you know exactly when to act.
Use when: your power goes out and you have insulin in the fridge.
Medical Outage Preparedness Checklist
A personalised step-by-step checklist for your specific devices. Covers what to do in the first 30 minutes, how to register with your utility as a medical priority customer, and when to evacuate.
Use when: a storm or outage is forecast, or you’re building your emergency plan.
Before you go to bed — or off-grid
Will my battery last the night?
Calculate exact runtime for your specific device and battery before you rely on it.
CPAP Battery Runtime Calculator
Select your exact CPAP model and pressure. See how many nights you get — and how much longer a DC cable adds. Covers ResMed, Philips, Fisher & Paykel, and 40+ other models.
Use when: you’re buying a backup battery, travelling, or a storm is coming.
Oxygen Concentrator Runtime Calculator
Home O₂ concentrators draw 10× more power than a CPAP. This calculator covers stationary and portable units and tells you exactly how many hours your battery provides at your flow rate.
Use when: you’re buying a backup generator or preparing for an outage
DC vs AC Runtime — How Much Does a DC Cable Add?
A DC cable can add 15–30% more runtime per charge on most CPAP machines. Enter your machine and battery, see exactly how many extra hours you gain — and which cable to buy.
Use when: you want to squeeze more nights out of your existing battery
before you buy anything
What size generator do I actually need?
Stop guessing at watt-hours. These tools tell you exactly what to buy — matched to your device, your outage risk, and your budget.
Medical Power Needs Wizard
Three questions. One clear recommendation. Tell us your device, how you’ll use backup power, and your budget — and we’ll match you to a specific, tested generator with exact runtime figures and pricing.
Use when: you’re not sure where to start and want one clear answer.
Solar Generator Size Recommender
Enter your devices and the number of hours you need coverage. Get the minimum watt-hours required, the exact generator models we’ve tested that hit that target, and what to avoid.
Use when: you already know your device and want to compare generator sizes.
Save money on your purchase
Can I get this paid for — or pay less tax?
Many patients don’t realize their generator may qualify for HSA/FSA reimbursement or solar tax credits.
HSA / FSA Eligibility Checker
IRS rules may allow you to pay for your solar generator tax-free through your HSA or FSA when it powers a prescribed medical device. This tool walks through the criteria and generates a printable summary for your doctor.
Use when: you have an HSA or FSA and want to know if you can use it
Solar Panel Size Calculator
How many panels do you need to recharge your generator fast enough to run your medical device indefinitely? Enter your location and generator — get panel count, positioning tips, and daily recharge estimates.
Use when: you want to go fully off-grid or solar-sustained
For refrigerated medications
Keeping medication cold safely
Beyond insulin — for anyone managing biologics, GLP-1 medications, or other refrigerated drugs.
Medication Cold Chain Timer
A broader temperature tracker for Ozempic, Mounjaro, biologics, immunosuppressants and other refrigerated drugs. Tracks cumulative temperature exposure across multiple excursions — not just one outage.
Use when: you’re managing GLP-1 medications, biosimilars, or other cold-chain drugs
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Managing a medical device that isn’t covered here? We build new tools based on what readers actually need. Tell us what calculation would help you most.
What makes a good CPAP battery runtime estimate?
Most CPAP runtime calculators online ask for your machine’s wattage and a battery capacity — and stop there. But real-world CPAP runtime depends on at least six variables:
Our CPAP Runtime Calculator accounts for all six. That’s why respiratory therapists, sleep clinics, and emergency managers have cited it as a reference in their patient materials.
Can a solar generator be HSA or FSA eligible?
Under IRS Publication 502, medical equipment and supplies required to treat or mitigate a medical condition qualify for HSA and FSA reimbursement. A portable power station or solar generator may qualify when it is specifically prescribed by a licensed physician to power a covered medical device — such as a CPAP machine, home oxygen concentrator, or insulin pump.
The key is documentation: you need a Letter of Medical Necessity (LMN) from your prescribing physician, and your claim should reference the specific device it powers. Our HSA/FSA Eligibility Checker walks you through the exact criteria and generates a pre-filled LMN template that you can take to your doctor’s office.
How long is insulin safe during a power outage?
This is one of the most urgent questions people type into Google during an active outage — often while standing in front of a warm fridge. According to FDA guidance and American Diabetes Association protocols:
Our Insulin Temperature Safety Timer was designed to be started during an outage, not in advance. It runs directly in your browser, stores no data, and works without wifi once loaded.
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Common questions
Frequently asked questions
The questions our readers ask most — answered clearly and without jargon.
Yes. Every tool on this page is 100% free with no account, subscription, or email required. We fund the site through affiliate commissions when you purchase a recommended product — at no extra cost to you. We are transparent about this in every recommendation.
A portable power station may qualify for HSA/FSA reimbursement when prescribed by a licensed physician specifically to power a medical device (such as a CPAP, oxygen concentrator, or insulin pump). Our HSA/FSA Eligibility Checker walks through the IRS Publication 502 requirements and generates a printable summary for your healthcare provider. Final eligibility depends on your plan administrator.
Our CPAP Runtime Calculator uses real-world measured watt-draw figures for over 40 CPAP and BiPAP models, cross-referenced against ResMed, Philips Respironics, and Fisher & Paykel specifications. Results are accurate to within ±10% under normal conditions. Altitude, cable type (DC vs AC), and humidifier heat settings all affect actual runtime and are factored into the calculation.
Unopened insulin vials stored below 77°F (25°C) remain stable for up to 28 days at room temperature per FDA guidelines. Once your refrigerator loses power, the interior temperature rises at approximately 3–5°F per hour. Our Insulin Temperature Safety Timer tracks this in real time and alerts you before your insulin approaches an unsafe temperature.
Home oxygen concentrators draw between 150W and 600W depending on the model and flow rate. For overnight coverage (8 hours), you need 1,200–4,800 Wh of usable capacity. Our Oxygen Concentrator Runtime Calculator identifies your specific model, accounts for startup surge wattage, and recommends the minimum generator size with specific tested units.
Running a CPAP via its DC cable bypasses the internal inverter, reducing energy waste by 15–30%. A CPAP drawing 50W on AC might draw only 35–42W on DC — significantly extending runtime. Our DC vs AC Runtime Calculator shows exactly how many extra hours you gain for your specific machine and battery combination.
A 200W panel in a region with 5 peak sun hours generates approximately 1,000 Wh per day. Our Solar Panel Size Calculator accounts for your location, generator capacity, and medical device usage to give you a precise panel count. Generally, a 1,000 Wh generator running a CPAP needs one 200W panel in most US climates to maintain indefinite off-grid operation.
Yes. Every tool on MedicSolar is fully responsive and tested on iOS Safari, Android Chrome, and all major desktop browsers. No app download is required. The Insulin Temperature Safety Timer is specifically designed to be started immediately on any phone during an active outage.
Yes. Most tools include a Print Summary button that generates a clean, PDF-ready output. This is particularly useful for the HSA/FSA Eligibility Checker (share with your physician for an LMN) and the Medical Outage Preparedness Checklist (share with your utility company to register as a medical priority customer).
MedicSolar tools are built by a team with deep expertise in portable power systems and medical device requirements. Runtime calculations are based on published manufacturer specifications verified through hands-on testing. We always recommend consulting your physician, respiratory therapist, or certified diabetes educator for medical decisions specific to your situation.
Not sure which tool to start with?
The 3-question wizard picks for you.
Tell us your device, how you’ll use backup power, and your budget. We’ll match you to the right generator — with exact products, runtime figures, and Amazon pricing. Takes under 60 seconds.
or browse our tested generator reviews →