Frequently asked questions

The Standard Mark on a registered charger shows an R-number such as R-12345678. In the BIS CARE app, use "Verify R-No under CRS" and enter it to see the registered manufacturer, standard and model list. One registration can cover a series of up to ten models, so check that the model number printed on your charger appears in that list. If it does not, the registration does not cover it.¹²³ More

BIS CARE is the Bureau of Indian Standards' official app, launched in July 2020. Under CRS it offers R-number verification and a search of registered manufacturers by category and model. Check that the brand matches, that the standard is IS 13252 (Part 1) or IS/IEC 62368-1, and that the model printed on the charger is listed. Note the registration's validity, which runs for two years before renewal.¹⁴⁵ More

A genuine registration has a number that anyone can check. Some listings in India state "BIS certified" without showing it. Ask the seller for the R-number and the exact model number, then verify them in BIS CARE. Check that the product in your hand carries the same mark and model. If the number is missing, invalid or does not list the model, choose another product.¹⁶⁷ More

Apple says iPhone can be charged with third-party adapters that comply with applicable safety standards, and warns that adapters which do not might pose a risk. In India, power adapters for IT equipment must be BIS registered under the Compulsory Registration Scheme. The danger lies mainly in counterfeit and unregistered chargers. Check the R-number and model in the BIS CARE app, and buy from the brand or an authorised seller.⁸⁵¹

Work through this order: check the battery percentage, since charging slows past 50–80%; feel the phone, as warm phones throttle; close navigation, games and hotspot; use a USB-C to USB-C or Apple/MFi USB-C to Lightning cable in good condition; confirm the adapter offers USB Power Delivery at 9V; clean lint from the port; and review Battery settings. A counterfeit adapter may only offer 5V.⁹¹⁰ More

Recent versions of iOS label low-powered charging as "Slow Charger" in the Battery screen. Common causes are a 5W or USB-A adapter, a cable that cannot carry USB Power Delivery, a loose connection, or a phone that can draw much more than the adapter offers. Apple has not published the exact wattage threshold, so we do not state one. Try a USB-C PD adapter and a compliant cable.¹¹ More

Three things pause charging at 80%. Optimized Battery Charging delays the last 20% to match your routine. On iPhone 15 and later, a Charge Limit of 80–95% stops charging near that level. And Apple says software may limit charging above 80% when recommended temperatures are exceeded. Check Settings, Battery, Charging. The charger is rarely the cause; a 20W adapter does not cap the percentage.¹⁰¹² More

Fast charging depends on the phone, cable and adapter all agreeing. Over time, Lightning and USB-C ports collect lint that prevents a firm connection, cables fray, and adapters can fail. Heat also suspends fast charging. Swap in a known-good cable first, then a different registered adapter, and check that the phone is cool and below about 50%. If nothing changes, contact Apple about the phone's port.⁹ More

Apple's fast-charge page states that iPhone 15 and earlier charge at up to 15W on a MagSafe Charger paired with a 20W or greater USB-C adapter. For iPhone 16, iPhone 17 and iPhone Air, Apple specifies a 30W or greater adapter to get the faster MagSafe rate. A 20W adapter still powers MagSafe on newer phones, just not at their highest wireless speed.⁹ More

The charger advertises a menu; the phone orders from it. A 65W charger offering 20V will not supply 20V unless the phone requests it, and iPhones request levels they support. Measurements show iPhone 16 Pro Max drawing about 30W even from 61W and 65W adapters. The safety question is compliance and registration, not wattage: choose a genuine, BIS-registered charger from a known seller.¹³¹⁴ More

Modern chargers are designed to sit in a socket. US and EU rules limit no-load consumption to 0.10W for this class, and ChargerLAB measured Apple's 20W at 0.021W at 220V. Leaving it plugged in costs almost nothing in electricity. Unplug it if the casing is cracked, the prongs are loose, it is warm with nothing attached, or the socket is damp, and use a surge protector where mains is unstable.¹⁵¹⁶ More

Our method follows published engineering practice: at least three production-intent samples; mains at 230V 50Hz plus 100V and 120V where relevant; loads at 10, 25, 50, 75 and 100%; efficiency and no-load draw on a calibrated power meter; ripple with AC coupling, 20MHz bandwidth limit and tip-and-barrel probing; one-hour thermal soak; and logged USB PD messages with real iPhones. Every result shows sample, date and conditions.^17181916

Samsung’s 25W charger (EP-T2510) offers standard USB Power Delivery levels of 5V 3A and 9V 2.77A, plus Programmable Power Supply (PPS) for Samsung’s own fast charging. An iPhone negotiates a standard fixed level and ignores PPS. Because the phone controls the current it draws, a higher-rated compliant charger is safe. Make sure it is a genuine, BIS-registered unit rather than a lookalike.²⁰