Kastar 4-Pack BP-21 Battery and LTD2 USB Charger Replacement - Dual

In this review the Kastar 4-Pack BP-21 Battery and LTD2 USB Charger replacement is judged as a practical power solution for photographers using Sigma SD1, SD1 Merrill, SD14 and SD15 cameras. The bottom line: this kit is for shooters who need multiple spare batteries and a portable, flexible charger that can handle two batteries at once. The review finds the combination of four 2400mAh lithium-ion cells and a USB-powered dual charger delivers reliable runtime and convenient charging options for travel or extended shoots.

Key Features

• High capacity batteries: Each 2400mAh lithium-ion cell provides extended shooting time so photographers can spend longer between recharges.
• Dual battery charging: The LTD2 charger can charge two batteries simultaneously, reducing downtime between sessions.
• Interchangeable plates: The charger plate is changeable so it can accept different compatible battery plates when needed.
• USB powered convenience: With Micro-USB and Type-C inputs and a 5V 2-3A input spec, the charger can be powered from power banks or common USB adapters.
• Intelligent LED display: The LED system indicates charging status and relative battery capacity so users can monitor progress at a glance.
• Portable kit: The compact batteries and lightweight charger make the pack easy to carry on location or in a camera bag.

Who It's For

This kit is best for DSLR and mirrorless photographers who own compatible Sigma, Pentax, Konica Minolta or Samsung cameras and who need multiple spare batteries for long shoots, travel, or field work. Wedding and event shooters who rotate batteries frequently will appreciate having four cells and the ability to top up two at once.

Those who should look elsewhere include photographers who require OEM branded batteries for warranty reasons or extremely high discharge professional video rigs that demand manufacturer-specified battery performance. If you need integrated in-camera charging or single-bay fast charging above the stated 800mA outputs, consider a different charger design.

Pros & Cons

Pros

• Provides four 2400mAh lithium-ion batteries for extended runtime during shoots.
• Charger supports simultaneous dual charging, saving time between sessions.
• USB input options and included Micro-USB cable make it easy to charge from power banks or common adapters.
• LED indicators give a clear visual of charge progress and battery capacity.

Cons

• Charger output is limited to 8.4V 800mA per bay, which is adequate but not a high-speed professional fast charge.
• Package uses a universal plate system which may require swapping plates for some legacy camera batteries.

Specifications

Battery Type	Lithium-Ion
Battery Voltage	7.4V
Battery Capacity	2400mAh
Charger Input	5V 2-3A (15W)
Charger Output	8.4V 800mA x1 or 800mA x2
Charging Options	Micro-USB input, Type-C input (Micro USB cable included)
Compatibility	Sigma BP-21 and listed Konica Minolta, Pentax, Samsung models

Our Verdict

The Kastar 4-Pack BP-21 Battery and LTD2 USB Charger is a sensible, cost-effective kit for photographers who need multiple spare batteries and flexible USB charging. It delivers reliable capacity, portable dual charging and clear LED status feedback, making it good value for travel and event use, though it is not a specialized high-speed charger for pro video rigs.

Frequently Asked Questions

Are these batteries compatible with Sigma BP-21?
Yes, the pack is designed to replace Sigma BP-21 and is listed compatible with several Konica Minolta, Pentax and Samsung models as well.

Can the charger charge two batteries at once?
Yes, the LTD2 charger supports charging two batteries simultaneously with an output of 8.4V 800mA per bay.

What cables are included?
The kit includes a Micro-USB cable and the charger supports both Micro-USB and Type-C input for flexible power sources.