When the decision is about keeping the D3000 or D5000 powered through a BG-2A grip, the practical problem is usually battery rotation: you need a spare EN-EL9-series cell and a way to charge it without a big dock. The Kastar Battery LTD2 USB Charger for Nikon D3000 D5000 Camera Battery Grip BG-2A combines those two parts into one straightforward package.
Quick verdict
Priced at $9.99, the Kastar set gives you a 2000mAh lithium-ion replacement battery and a charger that draws from a 5V/2-3A USB source. It covers EN-EL9, EN-EL9a, and EN-EL9e battery models, so it matches the common cells for the D3000 and D5000. For the money, it is a simple way to solve the spare-battery-plus-charger problem.
Who it suits
This package suits shooters who want to charge from a USB source instead of relying on a dedicated wall charger. If you already have a BG-2A grip and use the original Nikon MH-23 charger, this spare battery can work in that charger as well. It is also an easy fit for a grab-and-go kit because the charger and battery stay together.
What stands out
The dual-bay design is the main practical feature: you can charge two batteries at once, with each bay getting 800mA. The replacement battery also has a built-in microchip intended to prevent overcharge and over-discharge, which is useful when a compatible battery is doing the job.
Kastar Battery LTD2 USB Charger for Nikon D3000 D5000 Camera Battery Grip BG-2A
Pick this Kastar package if the dual-bay charger is the selling point. It lets you charge two EN-EL9-series batteries at once, while the included battery provides a 2000mAh backup. The limitation is the per-bay current: at 800mA, you are looking at a modest charge rate rather than a fast top-up. You will also need a USB adapter that can supply 5V at 2-3A to feed the charger at its rated input.
Meaningful trade-offs
The biggest trade-off is charging speed: modest per-bay output is serviceable, but two depleted batteries will take a while to reach full. Also, because the charger depends on an external USB power source, a low-output port will slow things down further. If you favor original Nikon batteries, the replacement nature of this Kastar cell is the main compromise.
Bottom line
For the listed $9.99, the Kastar Battery LTD2 USB Charger for Nikon D3000 D5000 Camera Battery Grip BG-2A is a practical purchase if you want a compatible battery and USB charging in one. It won't win any speed awards, but it answers the basic question of how to keep a D3000 or D5000 going through the BG-2A grip without hunting for a separate charger.
