Comparison

LEWDEN Connect vs StandbyCalc Battery Calculator

Price, ratings, monetisation and update history for both apps, side by side โ€” with what reviewers say about each.

Head to head
About

LEWDEN Connect

Features
Read full description

The LEWDEN Connect APP is a parameter setting tool provided for charging pile users, allowing users to conveniently use the APP to set and view parameters related to the charging pile.

About

StandbyCalc Battery Calculator

Features
Read full description

StandbyCalc works out the standby battery you need for UK fire and intruder alarm systems in seconds. Enter the quiescent and alarm currents, pick the fire alarm category or the intruder alarm grade, and get the minimum battery capacity in Ah plus the next standard SLA battery size. Add the fitted battery to see whether it's above or below the calculated minimum. Every battery calculation is free. No ads, no tracking, no sign-up and no subscription. FIRE ALARM BATTERY CALCULATION - Based on BS 5839-1 - Categories L, M and P - 24 h standby, or 6 h where a standby generator is fitted - Category P premises left unoccupied: standby periods up to 72 h INTRUDER ALARM STANDBY - Based on BS EN 50131 and BS 9263, Grades 1 to 4 - BS 4737 (legacy systems) for older installations - Standby battery sizing for control panels and remote power supplies PSU AND SLA BATTERY SIZING - Standalone 12 V and 24 V power supplies with your own standby and alarm periods - Minimum Ah with de-rating applied, rounded up to the next standard SLA battery HOW IT WORKS 1. Enter the panel and device currents for standby and alarm 2. Choose the system type, then the category or grade 3. Read off the minimum capacity and the SLA battery to fit 4. Optional: enter the fitted battery to see if it's above or below the calculated minimum The working is shown in full: C = 1.25 x (I1 x T1 + D x I2 x T2) NEW IN 1.0.5 - Fitted battery: enter the fitted Ah and battery date, see whether it's above or below the calculated minimum, and copy a one-line result for your service sheet (free) - Fitted battery line on PDF reports (Pro) - BS 4737 now labelled "BS 4737 (legacy systems)" STANDBYCALC PRO (one-off ยฃ9.99) - Redesigned branded PDF reports with your logo - Full formula working on every report - Save calculations against a site and come back to them later - A clear PDF record of each calculation for your job file Built for UK fire and security installers, engineers and maintainers who need a quick standby battery calculation on site. Always check results against the panel and battery manufacturer's data. From D4N LTD. Support: https://d4n.io/projects/standbycalc/ Independent app, not affiliated with or endorsed by BSI.

Screenshots

LEWDEN Connect4 screens
StandbyCalc Battery Calculator4 screens

Verdict

The call

The clearest difference is in-app purchases: LEWDEN Connect at none against StandbyCalc Battery Calculator's 1. LEWDEN Connect also leads on update cadence (fortnightly vs every 5 weeks) and iOS requirement (15.0 vs 17.0). On price, ads and device support there is nothing between them.

Scored on Price ยท Rating ยท Positive reviews ยท Number of ratings ยท Update frequency ยท Ads ยท In-app purchases ยท Monetization ยท Best chart rank ยท Devices ยท Requires iOS

CostPrice ยท In-app purchases ยท Ads ยท Monetization

Both are free to download. StandbyCalc Battery Calculator sells 1 one-off in-app purchase. LEWDEN Connect asks for nothing beyond the download.

UpkeepUpdate frequency

LEWDEN Connect ships an update fortnightly, StandbyCalc Battery Calculator every 5 weeks. The most recent releases landed on November 4, 2026 and November 5, 2026 respectively.

Scorecard3 real differences ยท 3 level
LEWDEN Connect versus StandbyCalc Battery Calculator: the parameters behind the verdict, then further details
ParameterLEWDEN ConnectStandbyCalc Battery Calculator
PriceFreeFree
Update frequencyFortnightly โ€” betterEvery 5 weeks
AdsNoNo
In-app purchasesNo โ€” betterYes
DevicesiPhone, iPodiPhone, iPad
Requires iOS15.0 โ€” better17.0
Further details โ€” not scored
Size20 MB3 MB
Age rating17+4+
DeveloperLewden LtdD4N LTD

In-app purchases

None

LEWDEN Connect

No in-app purchases

1 purchases

StandbyCalc Battery Calculator

One-time1
  • StandbyCalc Pro$9.99

Questions

Is LEWDEN Connect free?
LEWDEN Connect is free to download, with no in-app purchases.
Is StandbyCalc Battery Calculator free?
StandbyCalc Battery Calculator is free to download, with in-app purchases available.
Do LEWDEN Connect or StandbyCalc Battery Calculator have ads?
Neither LEWDEN Connect nor StandbyCalc Battery Calculator shows ads.
Which is updated more often, LEWDEN Connect or StandbyCalc Battery Calculator?
LEWDEN Connect ships an update fortnightly, and StandbyCalc Battery Calculator every 5 weeks. Most recently, LEWDEN Connect was updated on November 4, 2026 and StandbyCalc Battery Calculator on November 5, 2026.

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