# Which external battery offers the best capacity for my needs? — Verified Specification Comparison

> All specification data verified from official manufacturer documentation.

Which external battery offers the best capacity for my needs?

## Products

### Anker Prime Power Bank 27650mAh 250W
```yaml
product: anker-prime-power-bank-27650mah-250w
brand: Anker
price_gbp: 133.09
origin_country: null
confidence_score: null
summary_source: generated_from_verified_specs_v1
weight: 665g
capacity: 27650mAh
charging_time: 43 minutes at 140W
output_current: 5A USB-C; 6.5A USB-A
output_voltage: 5V-28V USB-C; 5V-10V USB-A
number_of_ports: 3
input_charging_method: USB-C; optional charging base
```

- **Price:** £133.09 [^1]
- **Summary:** This power bank has a 27650mAh capacity and delivers up to 250W across two USB-C ports and one USB-A port. It supports fast laptop charging, app-based monitoring, and rapid USB-C recharging, making it well suited to travelers and users carrying power-hungry devices.
- **Ideal For:** It suits users seeking the best capacity because its 27650mAh battery provides up to 99.54Wh of portable energy while supporting up to 250W output and charging up to three devices.

### UGREEN 145W 25000mAh Power Bank
```yaml
product: ugreen-145w-25000mah-power-bank
brand: UGREEN
price_gbp: 50.58
origin_country: null
confidence_score: null
summary_source: generated_from_verified_specs_v1
weight: 505g
capacity: 25000mAh/3.6V/90Wh
charging_time: 2 hours with a 65W PD charger
output_current: USB-C1: 5A max; USB-C2: 3.25A max; USB-A: 3A max
output_voltage: 5V, 9V, 12V, 15V, 20V, 28V
number_of_ports: 3
input_charging_method: USB-C PD up to 65W
```

- **Price:** £50.58 [^2]
- **Summary:** This power bank has a 25000mAh capacity, up to 145W combined output, two USB-C ports, one USB-A port, and a digital battery display. It suits laptop users, travelers, and anyone needing to charge several devices on the go.
- **Ideal For:** It offers a substantial 25000mAh capacity with enough output to recharge laptops, tablets, and phones, making it a strong choice when maximum usable capacity and multi-device charging matter.

### Nitecore NB20000 Gen 3
```yaml
product: nitecore-nb20000-gen-3
brand: Nitecore
price_gbp: 77.6
origin_country: null
confidence_score: null
summary_source: generated_from_verified_specs_v1
weight: 291g
capacity: 20,000mAh 3.6V (72Wh)
output_current: USB-C OUT1: 3A at 5V, 2.22A at 9V, 1.66A at 12V; USB-C OUT2: 2.4A at 5V, 2A at 9V, 1.5A at 12V
output_voltage: 5V, 9V, 12V
number_of_ports: 2
input_charging_method: USB-C
```

- **Price:** £77.6 [^3]
- **Summary:** The Nitecore NB20000 Gen 3 is a 20,000mAh carbon-fibre power bank with two USB-C ports, pass-through charging, IPX5 water resistance, and a lightweight 291g design. It suits hikers, campers, and travelers who need substantial capacity without carrying a heavier power bank.
- **Ideal For:** It offers a large 20,000mAh capacity and 72Wh of energy while weighing only 291g, making it a strong choice for multi-day trips where capacity and low weight both matter.

---
## References & Sources
[^1]: Best Buy, accessed 2026-09-03. https://www.bestbuy.com/product/anker-prime-27650mah-power-bank-250w-black/JJ8586VPYK
[^2]: UGREEN, accessed 2026-09-03. https://us.ugreen.com/products/ugreen-145w-power-bank-for-laptop
[^3]: Nitecore UK, accessed 2026-09-03. https://www.nitecore.co.uk/products/nitecore-nb20000-gen-3-power-bank.html