Recharging Your Batteries: USB vs. Separate Charger?

Anyone willing to take a risk back in the ’70s could attempt to recharge disposable alkaline batteries with a specially made charger. It didn’t always work well. Worse yet, it was dangerous. A poorly made charger could cause alkaline batteries to break open and leak acid all over the place.

Today’s rechargeable batteries are much better technologically. Consumers have access to NiCad, Ni-MH, and lithium-ion batteries that, unlike disposable alkalines, are intentionally designed to be recharged. Some are recharged with separate chargers while others can be recharged via a USB port. Is one option better than the other?

Charging with a Separate Charger

Until recently, USB charging wasn’t even an option. All rechargeable batteries had to be put into a separate charger you plugged into a wall socket. The system worked well enough. Plug in your batteries before you go to bed at night and you wake up to fully charged cells. The charger did the trick. It still does.

The benefit of this charging method is that you can buy chargers capable of accommodating as many as eight or 10 batteries at a time. That is a lot of charging going on. And for someone who uses a lot of batteries for photography, gaming, etc., being able to charge so many at once is a big plus. Yet this method does have its drawbacks.

For starters, it is really unwise to mix-and-match batteries and chargers. You have to be careful that the charger you purchase is safe to use with your batteries. And when you buy new batteries, they have to be compatible with the charger. Obviously, a separate charger will not work if you do not have an outlet to plug it into.

Charging with a USB Cable

USB charging recently made its way into the battery industry. Pale Blue Earth, a Salt Lake City company specializing in rechargeable lithium-ion batteries, is one company that utilizes the USB system. Their batteries do not require a separate charger you plug into a wall outlet.

Instead, their batteries are manufactured with built-in charging circuitry. You charge them by plugging them into any device with on-board USB. You can charge them using your desktop or laptop PC. Charge the batteries by plugging them into the USB port on your nightstand lamp. When traveling, plug them into any USB port you find at the airport or train station.

The obvious advantage here is convenience. Not having to utilize a separate charger requiring a wall outlet means not having to carry around an extra piece of equipment to keep your batteries charged. Better yet, the prevalence of USB charging stations these days is such that you can go virtually anywhere and still be able to charge your batteries.

The Overcharging Question

Both technologies engender a common question: is it possible to overcharge batteries? Technically, yes but practically, no. Modern charging technology has alleviated most concerns of overcharging.

Separate chargers for NiCad and Ni-MH batteries are designed to monitor charge level during normal operation. When batteries are fully charged, the charger cuts the circuit and stops charging. Unless the charger is malfunctioning, there is little risk of overcharging.

As for lithium-ion batteries, they are built with on-board circuitry that essentially does the same thing. However, faulty circuitry can lead to overcharging. In both cases, heat is the key. If batteries get hot, they should be unplugged. There is little to worry about as long as they stay cool.

So, is USB charging better than charging with a separate charger? That is up to you to decide. USB charging does seem to be more convenient overall.