Lenovo ThinkPad X1 Carbon Gen 7 / Gen 8 51Wh Battery (L18M4P71) — quick answer
The Lenovo ThinkPad X1 Carbon Gen 7 / Gen 8 51Wh Battery (L18M4P71) is a genuine, tested Lenovo replacement battery available at N.N Laptops, Hafeez Center, Lahore for Rs. 15,000. It's a 51Wh 4-cell internal pack rated at 15.36V and fits ThinkPad X1 Carbon Gen 7, ThinkPad X1 Carbon Gen 8, ThinkPad X1 Yoga Gen 4. Comes with our 15-day check warranty plus free Lahore delivery and nationwide Cash on Delivery.
Full specifications
| Brand | Lenovo |
|---|---|
| Capacity | 51Wh |
| Voltage | 15.36V |
| Cell Configuration | 4-cell internal |
| Chemistry | Li-Polymer / Li-Ion (matched to OEM spec) |
| Compatible Models | ThinkPad X1 Carbon Gen 7, ThinkPad X1 Carbon Gen 8, ThinkPad X1 Yoga Gen 4, ThinkPad X1 Yoga Gen 5 |
| Cycle Life (Rated) | 400-600 full cycles |
| Condition | Genuine — Tested |
| Warranty | 15-day check warranty |
Compatibility — which laptops does this battery fit?
This 51Wh 4-cell internal battery is a direct OEM replacement for the following Lenovo laptops:
- ThinkPad X1 Carbon Gen 7
- ThinkPad X1 Carbon Gen 8
- ThinkPad X1 Yoga Gen 4
- ThinkPad X1 Yoga Gen 5
Match the OEM part number on the sticker of your current battery before ordering. If your old battery part number isn't on this list but the laptop is, message us — there are often three or four interchangeable part numbers per chassis.
Battery health — what we test before shipping
Every battery on our shelf goes through a 5-point test before listing:
- Capacity — we measure actual usable Wh and only ship packs at 95%+ of rated capacity.
- Cycle count — read from the embedded BMS chip; we don't sell anything over 100 cycles.
- Cell balance — all 4-cell internal cells within 50mV of each other.
- Charge/discharge cycle — verified full cycle without thermal anomaly.
- Visual — no swelling, no bulging, no scorched contacts.
Installation — how to swap the battery
Internal 4-cell batteries on modern Lenovo laptops require opening the back panel (8-12 Phillips screws, sometimes Torx T5). Disconnect the AC adapter, unscrew the panel, locate the battery connector on the board, gently lift the ribbon connector latch, unscrew the battery hold-down screws, lift out the old pack, and reverse the steps with the new one. Total time: 10-15 minutes.
Free installation in shop
If you're in Lahore, bring the laptop to Hafeez Center — installation is free with battery purchase. We'll also calibrate the new pack (full charge → full discharge → full charge) so Windows / macOS reads the correct capacity from day one.
Real-world battery life — what to expect
With this 51Wh pack and balanced Windows / macOS settings (70% brightness, Wi-Fi on, mixed use), expect:
- Web + Office work: 5-7 hours
- Video playback: 6-8 hours
- Code compilation / Photoshop: 2-3 hours
- Gaming or heavy GPU load: 60-90 minutes
These figures match Apple / Dell / HP / Lenovo published specs for the listed models. If your old battery was giving you 2 hours, the new one will restore the original full runtime.
Where to buy in Lahore — and warranty terms
Visit us at Shop 66A, 3rd Floor, Hafeez Center, Gulberg III, Lahore. We test the new pack on your laptop before you pay — if Windows / macOS reads the correct cycle count and design capacity, you walk out happy. Lahore deliveries are free; nationwide via TCS / Leopards (Cash on Delivery) covers Karachi, Islamabad, Faisalabad, Multan and Peshawar in 1-3 working days. WhatsApp 0314 4000131 to confirm stock.
Browse all our laptop batteries, laptop chargers, and complete laptop parts catalogue.
Warranty — what you're protected against
Every battery carries our 15-day check warranty. If the pack fails to charge, shows wrong capacity in Windows / macOS, drops below 85% of rated Wh in our diagnostic, or develops any swelling within 15 days, bring it back to the shop with the invoice for full replacement or refund. No questions asked within the warranty window.
Frequently asked questions
Do I need to take the laptop apart to install the 4-cell battery?
Internal batteries need the back panel removed — typically 8-12 Phillips screws, then disconnect the old battery cable, swap, and reseat. We do free in-shop installation in Lahore if you bring the laptop. Removable 6-cell / 9-cell batteries on older laptops just slide in/out with a latch — no tools needed.
How much battery backup will I get on my ThinkPad X1 Carbon Gen 7?
With this 51Wh pack at default Windows balanced settings, expect 5-7 hours of mixed-use battery life (web, Office, video). Brightness at 70%, Wi-Fi on, no heavy GPU workload. Gaming or compiling drains in 90-120 minutes — that's normal for any laptop battery this size.
Is this a genuine OEM battery or aftermarket?
Our stock comes in both genuine Lenovo pulls (tested cells, original casing, often the higher price) and high-grade A-class compatible cells (tested for capacity at 95%+ of rated Wh). Tell us which you want on WhatsApp 0314 4000131 — both carry the same 15-day check warranty.
Will the laptop recognise this battery in Windows / macOS?
Yes — every battery we sell is BMS-flashed with the correct cell-pack ID for the laptop, so Windows / Lenovo Vantage / Dell Power Manager / macOS Battery Health show full information including cycle count and design capacity. No 'plugged in, not charging' driver errors.
N.N Laptops — Shop 66A, 3rd Floor, Hafeez Center, Gulberg III, Lahore. WhatsApp / Call 0314 4000131. Free Lahore delivery, Cash on Delivery across Pakistan, 15-day check warranty.
