I know these are currently out of fashion but I'm still thankful they exist.
Let's remind ourselves of devices that use(d) these standardized batteries:
- Toys
- Digital cameras
- Torches
- Gadgets like fans
- Wireless keyboards
- TV remotes
Thanks to having a standardized system of batteries,
- You can use the same battery across several devices. This is a no brainer but it's very practical.
- Batteries can charge quicker thanks to being put in a dedicated charger and not being limited by USB cables. (But yes I concede that USB has been updated for faster charging over the years)
- Devices don't have down time when their battery is charging. To charge, the battery is removed from the device and can immediately be replaced with a fresh one.
- You'll never have to trash a device due to an expired battery. Just buy a replacement. And building on this...
- Any improvements in future battery technology can be retro-fitted into your existing devices. And there is a high incentive for future improvement, because...
- An accessible (due to easy replacement) and large (due to many devices) battery market is very attractive to competition.
If you look at the pros I listed, they all happen to be things that would be very useful for electric cars. So I think it would aid the adoption of electric cars if their batteries were standardized too.
The downside is the volt is not 1.5volts. Its closer to 1.2volts. This is fine if you're using 2 batteries for things like the TV remote. But when you're using things that require more than 4 batteries, then you might get into some weirdness. I have a remote for my DSLR that sends infrared to the softbox. Every 10 shots, it would miss the shot. It turned out to be the batteries. It needed all 6Volts vs 4.8Volts.
Alkaline batteries lose voltage as they drain, so 1.5V is at full charge but it drops down to about 1.2V very quickly and then stays at 1.0V - 1.2V for most of the alkaline battery’s operating life.
NiMH batteries tend to consistently stay at their nominal voltage (1.2V) through their entire charge.
So in other words, if you have devices that really expect exactly 1.5V per battery, they would only work with alkalines at the very top of their charge. Nowadays most non-garbage circuits should be designed to work just fine with anything above 1V per battery.
Every battery has a voltage curve though; even alkaline batteries will drop off the 1.5v region after some time. Comparatively, ni-mh rechargeables will hold 1.2v more consistently and for longer than an alkaline, where it's voltage drops pretty quickly as the battery dies.
This
These days there's also Lithium ion AA batteries, with different voltages. You can get them downvolted to anything from 1.5 to 1.8V.
The ones over 1.5V are commonly used in applications with electronic motors, since it allows you to effectively overdrive the toy or whatever it is you're powering.
Life hax right here
Nickel Zinc rechargeable, peak 1.8V with 1.6V nominal.
Or newish LiIon cells that operate right at 1.5V.