Buying a used iPhone: battery health and locks to check before you pay

Buying a used iPhone: battery health and locks to check before you pay

If battery or locks fail the check, do not rush to pay — even if the price looks good.
Clearing these two checks beats fighting it out later.
This is anti-scam guide Issue 03 — battery and locks in depth — not a push to check out.

Two regrets buyers see most often after paying

1. A battery that dies by lunch
2. A phone that will not unlock

Issue 01 covered the checklist and local prices; Issue 02 added screen, camera, and function checks. This issue (Issue 03) zooms in on two of those checks — battery health and locks / accounts. Whether you buy on Carousell, from a stall, or through a friend, both can be verified in person or on video before you pay. This is not scare tactics — it helps you avoid the most expensive traps.

1. Battery health: how to check, what to look for

Scratches are negotiable. A weak battery that needs constant charging turns the “saving” into daily frustration. In person or on video, ask them to open:

Path (typical iOS)

Open Settings → Battery → Battery Health & Charging, show Maximum Capacity, and screenshot it. Menu names can vary slightly by iOS version — Maximum Capacity is the line that matters.

How to read the percentage

Closer to 100% means closer to factory condition. Reputable sellers often state a floor (e.g. battery health ≥85%) — not a universal law, but a useful reference: below that band, runtime usually drops more noticeably. Grades A+ / A / B / C describe looks mainly; battery health is separate — a nicer grade does not guarantee a full day of use.

Watch out for these

• Refuses to open the battery screen, or only shows someone else’s screenshot
• Claims a “new battery” with nothing you can verify, and will not show current Maximum Capacity
• Sudden drops or unexpected shutdowns right after power-on — do not pay until runtime is clear
• About shows battery as Unknown Part — a replacement is not always bad, but “new battery” with no source and no Maximum Capacity is blind buying. Proper swaps should come with paperwork

Quick look at About This iPhone

Issue 02 showed how to use Settings → General → About for Parts and Service History. Same idea here: a replaced battery may be flagged. A flag is not scary — what is scary is they refuse to open it. Pair that with Maximum Capacity; two data points beat a verbal “just replaced.”

2. Locks and accounts: confirm it works before you pay

Discovering a lock after money changes hands usually costs more than the discount. In person, confirm:

1. Reach the Home Screen — not stuck on activation, a passcode screen, or “Unable to Activate.” If they say “activate at your place” or “password later” — do not pay yet.
2. Apple ID / iCloud and Find My — no one else’s Apple ID signed in. Find My still on often becomes Activation Lock. Ask them to sign out and turn Find My off, or confirm clean activation. Do not take verbal promises alone.
3. Carrier lock (SIM lock) — your SIM must get data and calls. Unlock codes or carrier-only prompts mean clarify “unlocked / worldwide” before talking price.
4. VPN & Device Management (MDM) — Settings → General → VPN & Device Management: no unknown profiles. Present profiles may mean business/school remote control — they can lock or wipe later. Unless removed on the spot, do not pay. Ultra-cheap “enterprise retired” units often hide this.

Extra self-protection (optional): IMEI / serial — the phone’s identity number. A blacklist / lost-stolen check asks whether it was reported lost or listed by a carrier or industry database — if listed, you may later face title / ownership problems or network blocks. Optional before you pay; do it after the lock checks above. This is not the same as Find My or Activation Lock (Apple account locks). Dial *#06#, or open Settings → General → About. Matching what is on screen with the device itself is even better. Proper / local channels vary — there is no free global “magic website.” Use your carrier, police / official routes, or a channel you trust; skip shady paid lookup sites. A “clear” result is not a guarantee.

Last: data wipe / factory reset — after lock checks, in person: Settings → General → Transfer or Reset iPhone → Erase All Content and Settings (or already factory-reset). After wipe: clean setup / activation — not still on the previous owner’s Apple ID with their photos and chats. Red flags: “wipe after you get it” / “pay first, then clear.” Wipe alone is not enough — finish step 2 first (Find My off); after wipe, glance again at VPN & Device Management. iCloud Photos / WhatsApp backups are the seller’s problem — you want a clean handoff.

Before you pay

• [ ] Open battery screen — note Maximum Capacity and screenshot
• [ ] About: no unknown part alerts; any flagged parts have a clear source
• [ ] Reach Home Screen — not stuck on activation / someone else’s account
• [ ] Previous Apple ID signed out · Find My off
• [ ] Your SIM works for data / calls
• [ ] VPN & Device Management: no unknown profiles
• [ ] (Optional) IMEI / serial looks clear
• [ ] Erased / clean setup OK — no leftover owner account or data

“Certified” = endorsement

Certification is not a sticker. It means someone stands behind the phone: checks done, after-sales reachable. A serious endorsement usually states:

• 80+ inspection points · battery health ≥85% · real-unit photos
• 6-month warranty · 14-day returns
• Grades A+ / A / B / C describe looks mainly; function and battery should meet the same check standard — a “nicer” grade does not mean better runtime

Optional: who is Giggle Fone

The method works wherever you buy. For an example of a shop that stands behind the product: Giggle Fone sells inspected used iPhones — real units, clear grades, warranty and returns. No rush: finish the checklist, then browse the catalog or ask on WhatsApp. Use the battery and lock checklist on Grade C / B iPhone 13 / 14.

WhatsApp: +852 5106 6241 · wa.me/85251066241
Email: [email protected]

General anti-scam guide — not limited to one city. Warranty and returns follow the product page at purchase.

Originally published on GiggleFone — certified graded iPhones for Hong Kong.