← Back to context

Comment by klooney

9 hours ago

> run at a nominal 1.2V instead of the 1.5V of alkaline batteries.

I've suddenly figured out why so many toys don't work with rechargeable batteries

29 comments

klooney

Reply
dragontamer  8 hours ago

That's not the reason.

Alkaline batteries only have 1.5V for a short time. In practice, toys are designed to opeerate off of 1V to 1.5V, because Alkalines vary _wildly_ in voltage during use.

NiMH at 1.2V _STAYS_ at 1.2V, even when drawing 1Amp or more (under these conditions, Alkaline would have long dropped below 1V).

EDIT: This is also a problem because "nicer toys" will measure the voltage assuming an Alkaline is "full" at 1.5V and dies at 1.0V. However, NiMH starts at 1.35V, then "plateau" at 1.2V, and stays there for most of its life, before rapidly falling off to 1.0V or .8V like a cliff at the end of its life. So NiMH life "cannot be predicted" by any simple metric.

  • jonpurdy  8 hours ago

    I had an issue with the original Apple Magic Mouse that would not work correctly with NiMH batteries but work fine with disposable AA. The mouse would be fine for a few days then randomly stop working; using fresh NiMH would revive it again. I assumed it was due to 1.2v vs 1.5v but perhaps that particular mouse (or all Magic Mice) was just bad.

bux93  8 hours ago

You can now find 1.5V Li-on AA batteries with, and that's a game changer, built-in charger and a type-C port!

I have one in my wireless mouse. If it dies, I change it to a spare and charge it right from my laptop (and the battery that was empty becomes the spare)

  • oskarkk  5 hours ago

    I haven't used them, but IIRC they maintain a constant voltage until they're discharged, when it instantly drops to 0. That may be a problem, because if your device has any battery indicator, it will show the battery as full until the end. Nothing will tell you that you need to replace the battery before the device powers off. That's why I decided not to buy them. My mouse knows when my alkaline AA battery is low and gives me a warning.

  • ramses0  8 hours ago

    Came here to post this. I'm 100% agreed with Mr. Geerling.

    For a fun challenge try to find a non-built-in-battery arc lighter (eg: candles, grills, etc). When I found one I bought four (think camping/disaster bag... if everything is AA/AAA then having a shelf-stable fire starter is easier/safer than lighter fluid).

    For a fun sidebar check out the "Panasonic BQ-CC87AKBBA" which is effectively a combo "in/out" battery charger OR USB battery pack(!). It'll suck in (unfortunately) Micro-USB and charge your AA's, then switch a button and it'll spit that power back out as a battery bank. When I find one like that for USB-C, it's going on my christmas list.

    Look up plastic battery holders that hold 8-10 along with a 4x charger and I just swap batteries out and recharge them into that buffer/holding cell. I'll have to look into the Eneloops as I've been working with the Amazon Basics and generally have 1-2 batteries fail out every few months (and am specifically looking for heat-resistant / outdoor applications).

    Last one: Lots of cheap solar products have cheap rechargeable AA batteries inside... you can generally open them up and swap the battery out if they're not working any more (and/or potentially scavenge the charging panel if you think about it!).

    • Rediscover  2 hours ago

      The NITECORE UM10 is an "in/out" charger too - it handles various sized LiIon batteries one-at-a-time. A switch on the end determines if it is charging or discharging. Their site says it's discontinued, but I thought I recently saw them at a shop in Seattle. Time to pick up a spare.

      https://charger.nitecore.com/product/um10

    • mystifyingpoi  4 hours ago

      I had this charger once! Really cool with the powerbank option. Although, these days, 5V@1A with no PD is probably something to use maybe in emergency, it's too slow for modern devices.

jchw  8 hours ago

I believe I have zero Alkaline batteries left in my house and I'm relatively surprised that pretty much everything works fine. If anything, I suspect the only problem is that some devices have an inaccurate account of how dead the batteries are. But I use Eneloops on everything, even things surely not designed at all to run on them. (And I reckon you could probably make more devices work if you really wanted to; adding an additional cell or two in series would surely give you a voltage that's in range, if you can figure out a good way to do it.)

Of course not all rechargable batteries are the same; there are a few different rechargable battery chemistries in the AA form factor. I like Eneloop Pros, though; they've been very reliable for me. I've been using them for years and I've never had to throw one out yet; supposedly they last over a thousand cycles with most of their capacity.

  • accounting2026  2 hours ago

    I have a weather station that takes two 1.2 V. The LCD screen is a bit dim compared to when used with fresh 1.5 V alkalines. Other than that, most things take the 1.2 V well. But they better do because alkalines reach 1.2 V with >50% capacity left.

  • zabzonk  8 hours ago

    I think I have only one device that uses AA - my central heating's radio thermostat. This thing has caused me untold hassle, which is only partially down to the batteries, but still...

    Totally OT, but does anyone have a good link on how the thermostat gets paired with the boiler? I'm thinking of getting replaced and would like to talk to the gas fitter from a vaguely informed point of view.

    • ghaff  7 hours ago

      Personally, I keep things simple. Got a new (pretty basic) Honeywell thermostat after a kitchen fire; thermostat was pretty old anyway. For wiring, you mostly have 2-wire and 3-wire although there are a lot of variations as you get fancier: https://nassaunationalcable.com/blogs/blog/a-full-guide-to-t...

      Number of zones in the house may affect things as may boiler only or AC being in the picture as well.

    • quickthrowman  1 hour ago

      Thermostats (aka space temperature sensors) can have between two and eight wires. A boiler will usually have three: 24V power, call for heat, and common.

      If your boiler has inputs on the terminal block for a thermostat, I would highly recommend buying a wired one, the 24V constant power removes the need for batteries.

      If you can provide a link to your boiler’s installation and operations manual, I can tell you.

    • bluGill  5 hours ago

      > good link on how the thermostat gets paired with the boiler?

      You should have a book with the boiler that says how your system is setup. They nearly always include schematics and are very helpful. Typically you can open a cover and see the wiring details as well.

      Forget about web sites, there are too many different ways a system can be setup, so even if they are not slop they can still be inapplicable for you. Once you know what you are looking at you can sometimes get useful information from the web, but until then you can't sort out what is useful for you.

      6 replies →

  • bxparks  7 hours ago

    Three things prevent me from eliminating all alkalines:

    * smoke and CO detectors with low-battery voltage sensors calibrated to alkaline

    * some older electronics (e.g. multimeters) using 9V batteries

    * my non-contact voltage tester refuses to turn on using NiMH, for safety reasons presumably

direwolf20  8 hours ago

If they don't work at 1.2V they weren't very good quality to begin with. AAs are dead at 1.0 or 0.9V.

There are a lot of low–quality toys.

c0nsumer  8 hours ago

A weird flipside is things like... the IKEA Zigbee devices. Many of these do not work right at all with 1.5V batteries and basically require rechargables.