Independent portable-power decision support
Find the right backup power system for your situation.
Start with what you need to keep running, for how long, and under what recharge constraints. Before the Battery helps you size the system before comparing products.
The editorial method is live. The interactive sizing engine and dated product catalog are still in validation.
Start here
What are you trying to keep running?
- UC-01Home outageA few hours to a full night, mixed household loads.
- UC-0272-hour family readinessMulti-day plan with a realistic recharge window.
- UC-03Fridge & freezerCycling compressor loads with a hard startup peak.
- UC-04Router, laptop & PCSmall continuous loads, long duration, work continuity.
- UC-05CPAP & medical-adjacentOvernight continuity with a conservative reserve.
- UC-06Van & RVWeight, charging while driving, indoor-safe operation.
- UC-07JobsiteTool inrush, duty cycles, rough handling, noise limits.
- UC-08Outdoor & campingPortability first, solar-only recharge realities.
What happens next
Today, recognizing your situation leads to the published sizing method: how loads, peaks, losses, reserve and recharge are computed for that context. Personalized sizing is not live yet — the interactive engine and dated catalog are still in validation.
Editorial standard
What this publication refuses to do
- Rank by brand popularity or by commission.
- Convert nominal watt-hours into a runtime promise.
- Hide a blocking peak or recharge failure behind a big capacity number.
- Produce a recommendation when the honest answer is abstention.
How figures are handled
Every figure is sourced, computed from stated assumptions, or marked unknown. Volatile data carries a date. Corrections are logged with the date they were made.
Two affiliate programs have accepted the publisher: BLUETTI US and ALLPOWERS US & CA. No affiliate link is live on this site, and no merchant influences rankings or editorial conclusions.
Step 02 & 03 — Loads and energy need
Why nominal watt-hours are not enough
Conceptual worked example
Arithmetic only. No product is named, and no figure below describes a real unit.
- Nominal capacity on the label
- 1,000 Wh
- Minus inverter and conversion losses
- ≈ 850 Wh delivered
- Minus a conservative safety reserve
- ≈ 765 Wh usable
- Continuous load declared by the user
- 150 W
- Naive runtime from the label
- 6 h 40 min
- Conservative planning runtime
- ≈ 5 h 06 min
The gap between those last two lines is where most bad purchases are decided.
The startup peak is a separate test
A compressor or a power tool can demand several times its running wattage for a fraction of a second. A unit with plenty of stored energy can still refuse to start it. Peak output is a pass/fail gate, not a bonus feature.
Simultaneity changes the answer
Three devices that each fit individually may exceed continuous output together. The engine asks what runs at the same time, and what you would sacrifice first.
Duration is meaningless without recharge
A unit that covers the outage but cannot be refilled inside the available window fails a 72-hour scenario, no matter how large it is.
Priority beats capacity
The engine protects what you declared as critical. A larger unit that misses a priority condition loses to a smaller one that meets it.
Architecture
How the Decision Engine works
Feedback loop — asynchronous
Catalog changes (specs, availability, dated pricing) and post-click outcomes feed back into the catalog and the decision rules. A changed input can invalidate an earlier verdict, which is what the planned Power Match Update loop is for.
Deterministic
The same declared inputs always produce the same verdict. No model guesswork in the sizing path.
Explainable
Each verdict lists the reasons that produced it and the limits that constrain it.
Conservative
Losses and reserves are applied against the user, not in favor of a bigger sale.
Step 07 — Outputs
What a verdict set looks like
- Best fit
Covers every priority load for the declared duration with reserve left, and can recharge inside the available window.
Limit: heavier than the constraint the user set as 'preferred'.
- Lower cost
Covers priority loads only if the user accepts dropping one non-critical device from the simultaneity set.
Limit: no headroom if a second peak lands at the same moment.
- Lighter
Meets the portability constraint and the peak requirement, at a shorter duration than requested.
Limit: requires a mid-cycle recharge that the declared conditions may not allow.
- No fit — abstention
When the declared peak, duration and recharge window cannot be satisfied together, the correct output is that none of the current options fits.
The system says so instead of ranking the least-bad unit.
Two layers, two jobs
Decision Engine vs Power Match Update
Synchronous reasoning layer
Decision Engine
The reasoning layer. It turns one declared situation into an explainable verdict using deterministic rules and the dated catalog.
- Runs at the moment you ask
- Inputs: your loads, duration, recharge window, constraints
- Outputs: 3–5 verdicts with reasons and limits, or abstention
- No email required to see the result
Future capability — asynchronous
Power Match Update
The optional owner email and update loop that would run after a decision: price and stock moves, lineup changes, compatibility changes, expansion-path changes, dated catalog updates, and a re-check of whether the verdict still holds.
No signup and no alerts are active. Nothing is collected or sent.
Independence
Ranking happens before commission
No paid placement
A merchant cannot buy a position, a badge, or an inclusion in a verdict set.
No live link
Two affiliate programs have accepted the publisher: BLUETTI US and ALLPOWERS US & CA. No affiliate link is live on this site, and no merchant influences rankings or editorial conclusions.
Attribution, not influence
Future deep links and SubIDs will record source, scenario and verdict for measurement — never as a ranking input.
Method
Methodology and dated catalog policy
Catalog structure
- Stable specifications: estimated usable capacity, continuous and peak watts, wall and solar recharge, UPS / pass-through behavior, expansion options, weight, warranty.
- Volatile fields: price and stock, always time-stamped and stored separately from the specification record.
- Every entry carries a source reference and an evidence-quality note.
- Values that cannot be verified are marked unknown rather than estimated silently.
Calculation policy
- Usable energy, not nominal energy, drives every duration figure.
- Conversion losses and a safety reserve are applied before any runtime is shown.
- Peak output is treated as a pass/fail gate, evaluated independently of capacity.
- A full use-and-recharge cycle must close, or the architecture is eliminated.
- Missing, unknown and not-applicable are distinct states and are displayed as such.
Scope
What you can use today
Situation map
Eight declared use cases that decide which loads and blocking conditions matter.
Conservative sizing method
Usable energy, conversion losses, safety reserve, peak as a pass/fail gate.
Worked example
The arithmetic that separates a label runtime from a planning runtime.
Independence rules
Ranking before commission, no paid placement, disclosure in full.
Dated methodology
Published rules with a date, open to challenge and correction.
Revision log
Every rule change and correction recorded with its date.
In validation: the interactive sizing engine and the dated product catalog. Until they are published, this site carries no live product recommendation, no current price and no affiliate link.
Publisher and editorial standards
Alexis Marchais
Engineer based in France, publishing independently for a US audience, with experience in high-stakes operational environments. The same discipline applies here: declare the constraints, compute conservatively, show the reasoning, and accept that the correct answer is sometimes “none of these”.
Editorial commitments
- Situation before brand, in every piece of analysis.
- Every published figure is either sourced, computed from stated assumptions, or marked unknown.
- Volatile data is dated; ranking is decided before commission.
- Corrections and rule changes are logged with a date.