Lithium AA/AAA Batteries for Use in Electronics - Page 1
Forum section: electronics / general

author: Boris_yo
author_rank: Frequent Contributor
timestamp: November 19, 2021, 12:56:50 pm
content: Hello,I was wondering whether lithium batteries are too strong for delicate electronic devices like blood pressure meter for example.What attracts me to lithium batteries is that they do not leak and I also think they supply higher voltage because compared to rechargeable NiMH LSD batteries, they provide more power. My hair trimmer works louder and stronger for example and my flashlight shines brighter.I remember reading that only AA alkalines should be used for blood pressure meters. I don't know why NiMH LSD batteries are not good for that. Would they negatively affect accuracy of test? I noticed also that NiMH batteries have 1.2V while alkalines have 1.5v so maybe this is why NiMH should not be used in blood pressure meters? Haven't heard anything mentioning lithium batteries though.

author: cortex_m0
author_rank: Regular Contributor
timestamp: November 19, 2021, 01:14:30 pm
content: Are we talking about Lithium Ion (aka Lithium Cobalt), which have a nominal voltage of 3.7V or Lithium Iron Disulfide which has a nominal voltage of 1.6V?Lithium Iron Disulfide should be fine for any device which has internal voltage regulation, which will include is most electronic devices. I obviously cannot speak to your particular blood pressure meter.Lower voltage types, like NiMH, may cause devices to drop out too soon, since a 1.2V Alkaline cell is nearly dead. Suppose you have a 5V supply rail in a device powered by 4x AA batteries. When fresh, the supply will be a solid 5V. With NiMH, the regulator can never reach the nominal 5V because the fresh batteries only total 4.8V.

author: deadlylover
author_rank: Frequent Contributor
timestamp: November 19, 2021, 02:37:34 pm
content: Off the top of my head, my old Omron blood pressure monitor only depletes around 20% of my eneloops before complaining. I don't know what the cutoff voltage is but it must be very high in the ~1.30V range for that to happen.I don't mind changing the batteries 5 times as often because it still lasts a few months with occasional use. (saves money and stops primaries ending up in the landfill)I would imagine anything "important" will just shut down before battery voltage will impact function/accuracy. I use IKEAloops anywhere and everywhere I can.

author: NiHaoMike
author_rank: Super Contributor
timestamp: November 20, 2021, 12:39:15 am
content: There are rechargeable lithium AAs that have built in voltage regulators.

author: Boris_yo
author_rank: Frequent Contributor
timestamp: November 20, 2021, 06:34:14 am
content: I have Black and Decker alkaline battery-operated screwdriver. It's battery compartment mentions to use only AA alkaline batteries. Why can't I use NiMH or lithium batteries?

author: mariush
author_rank: Super Contributor
timestamp: November 20, 2021, 09:56:04 am
content: There's also non-alkaline AA batteries, the "heavy duty" (carbon-zinc or zinc - manganese dioxide) ones which were made before alkaline batteries were a thing.Those don't have as high current output as the alkaline batteries have, they may have higher internal resistance .. so they may be too poor performance for a drill (too high current to start spinning or run for long periods of times before the voltage drops significantly)Heavy Duty AA batteries are usually rated for 950-1100mAh ... see for examplehttps://data.energizer.com/pdfs/1215.pdfAlkaline AA batteries ... they make them up to 3000 mAh, seehttps://www.digikey.com/short/jt0ffb2r

author: Nusa
author_rank: Super Contributor
timestamp: November 20, 2021, 05:29:36 pm
content: Quote from: Boris_yo on November 20, 2021, 06:34:14 amYou can use any version of AA batteries you want in that device since there are literally no electronics in it, just a motor and switch contacts. The differences between battery chemistries will primarily be endurance. Torque will vary with battery voltage, but the motor is not fussy at running at slightly higher or lower voltages than the 6V nominal.

author: Boris_yo
author_rank: Frequent Contributor
timestamp: November 22, 2021, 01:37:05 pm
content: Quote from: deadlylover on November 19, 2021, 02:37:34 pmI found USB Female to DC cable and it matched DC input on my blood pressure meter. However it requires 6v power while the most I can get is 5v. What would happen if I connected 5v DC cable to blood pressure meter? Nothing mentioned on blood pressure monitor about amperes... I have 5v 1A and 2A power wall chargers. Maybe it is safer to order 6v DC cable power supply for blood pressure meter?Quote from: deadlylover on November 19, 2021, 02:37:34 pmIkealoops? Actually I heard that Ikea makes quality alkalines. But loops are like Eneloops but by Ikea? Found this:https://www.facebook.com/eneloop101/posts/843865875979983

author: deadlylover
author_rank: Frequent Contributor
timestamp: November 23, 2021, 03:43:44 am
content: Quote from: Boris_yo on November 22, 2021, 01:37:05 pmIt depends on the region and specific model, but some of the IKEA LADDA NiMH batteries are made in Japan. There is only one rechargeable AA/AAA LSD NiMH battery factory in Japan, the FDK factory (where eneloops originate from). So now you know that if you ever see "made in Japan" on a pack of batteries, you'll know it will be excellent quality. They always write the country of origin so just check before you buy.I don't know if they bin them or reserve the best chemistry for the real eneloop pros, but when I tested a fresh pack of each, the IKEAloops were only 1% lower capacity. I will happily take that for half the cost or less!Here is my recent haul, all made in Japan. (new cells are a green/teal colour compared to the white of the old cells)

author: Boris_yo
author_rank: Frequent Contributor
timestamp: November 27, 2021, 09:58:53 am
content: Quote from: Nusa on November 20, 2021, 05:29:36 pmWhy rechargeable NiMH batteries have voltage of 1.2V while alkalines have 1.5V? I measured AA lithiums recently with battery tester and while their specs say 1.5V I was surprised to see 1.77V.I noticed that I get more torque from screwdriver with higher voltage and flashlight shines brighter. I heard that using higher voltage batteries can damage equipment but like you said it depends per device?Would it be a good idea to use 1.2V NiMH batteries for delicate work and use 1 5V or 1.77V lithiums for jobs where more tool power is required?

author: PlainName
author_rank: Super Contributor
timestamp: November 27, 2021, 10:29:46 am
content: QuoteYou could, but you'd be better off with a tool with torque and speed control built in. A fixed-speed tool with low-power batteries is still going to start suddenly at full speed and rely on twisting in your hand for torque limiting.

author: Nusa
author_rank: Super Contributor
timestamp: November 27, 2021, 05:36:24 pm
content: Quote from: Boris_yo on November 27, 2021, 09:58:53 amYou're overthinking it. It's not a precision device, it's a cheap convenience device. If you need delicate, stop before it's tight and do it manually. If you need power, stop when the tool stalls and do it manually.As for batteries, my generalization:NiMH: Pro-rechargeable con-lower voltage, self-discharges fast enough to be dead in less than a year (but you can recharge them)Alkaline: The baseline. Years of shelf life, assuming it doesn't decide to leak (main reason it's suggested not to leave batteries in tools long-term). Usually the most cost-effective.Primary Lithium: Higher initial voltage, but acceptable for your device. Pro- decades of shelf life and a more energy than most Alkalines. Con-more expensiveAll of them will lose voltage as they discharge, of course. Quality between brands will vary. Choose whatever works best for you.Personally, I tend to pull out a 12V or 18V drill driver (I have both) with rechargeable li-ion batteries for heavy or repetitive tasks. Delicate tasks I usually do manually from the start.