Battery Charger that's simple and doesn't catch fire?

Hi! I’m an old disabled guy scraping by on a barely adequate monthly fixed income, so I have to mind my pennies and rely almost entirely on hand-me-downs for my computers and electronics.

A while back, through FreeCycle Seattle, I was given a little (512 MB) MP3 player that uses a single AAA battery. I’ve been using NiMH batteries which I charge in a little charger I got at the drug store. I carry a spare rechargeable battery with me, but the NiMH batteries don’t seem to hold a charge very well, so by the time I need to put it into the player, it’s lost most of it’s charge. :frowning:

I looked around the web for a solution to this problem and I found this Metaefficient article dated November 13, 2009:

According to this article, the best rechargeable batteries are hybrid Nickel-Metal Hydride (Ni-MH) cells such as the eneloop by Sanyo or the E8GE 1000.

Does that still hold true nearly a year later?

I also would like to replace my charger with one of the newer “smart” chargers because I suspect that my older batteries are no longer taking a full charge and I also suspect that my bargain sale drug store charger could be overcharging my batteries and wasting electricity by continuing to keep charging them even after they are fully charged.

Based on that article I cited above, here’s what I think I need in a charger:

  1. Doesn’t catch on fire

  2. Can “recondition” or “renew” old batteries

  3. Stops charging when battery is fully charged.

  4. Can charge single batteries one at a time

  5. Charges mixed battery sizes

  6. Charges mixed battery types including hybrid Ni-MH.

  7. Uncomplicated, intuitive, easy to use interface (I suffer from disabling cognitive impairment, memory loss and poor eyesight)

I’d be grateful for recommendations. Price is a factor, but at my age I figure this will be the last charger I ever buy, and I want one that is well built, so in this case I think it makes sense to pay for a good one.

I admit I’ve spent a lot of time researching battery chargers and batteries over the years, as I’ve a lot of electronics, lights, etc. that run on AAs and AAAs.

Hard to believe, the best Ni-MH charger for AA/AAAs is the basic dumb (no CPU) overnight charger which takes 14 to 16 hours and there are several reasons for this:

[li]These typically charge AAs at ~200mA and AAAs at ~80mA. As this is less than a rate of 1/10Ah for most Ni-MH batteries, they can be left in the charger for extended periods with little risk of harming the batteries as most Ni-MH batteries will not be damaged by overcharging if charged at less than a rate of 1/10Ah, e.g. 250mA for a 2500mAh battery.[/li][li]From my experience with pretty much all the smart chargers that charge batteries independently, occasionally the charger falsely detects a battery as full while continuing to charge the others. As overnight chargers usually don’t have a timer, there is no risk of one or more batteries being only partially filled, unless not inserted properly.[/li][li]Rechargeable batteries tend to have a longer life when slow charged.[/li][li]The batteries store more energy than with a fast charger. I can’t remember where I saw the comparison review, but a slow charger was the only way to get the batteries to store as close to their rated capacity as possible.[/li][/ol]

Of course the main catch with the overnight charger is that it does take overnight.

For the batteries, I highly recommend going for the hybrids (pre-charged) over traditional batteries. I’ve been using these now for over a year and would not go back. My camera flash takes AAs and with traditional Ni-MHs, I’ve been caught out enough times trying to grab a quick photo only to find that the flash would not fire. I’d then grab the spares that I thought were charged and maybe got two or three photos to find they were flat also. :doh: However, ever since I started using the pre-charged hybrids, I’ve never had a single issue where the batteries were flat after storage, even after several months sitting in a drawer.

Do shop around. :slight_smile: The hybrids I’m using were from the online store 7DayShop (£4 / 4-pack.) The charger I’m using is the La Cross BC-900, which has an LCD display to display the battery readings (e.g. measured mAh capacity, charge rate, etc.) It charges at 200mA by default, which takes overnight and this is the main setting I use. It can charge batteries individually or at a faster speed (up to 1800mA for 2 or 1000mA for 4). It’s a bit pricey, but it does the job.

for the price of a charger and batteries to go in it you can buy a heck of a lot of cheap alkaline batteries. I used to use a similar mp3 player and they lasted ages in it.

The long storage/precharged NiMH is creeping in to OEM product.

As well as charge loss, the device may not have a very good voltage margin for rechargables, devices using only one cell often do not recommend them.