Do AA Rechargeable Li-Ion Batteries cause noise?  - Page 1
Forum section: electronics / beginners

author: BeBuLamar
author_rank: Super Contributor
timestamp: April 14, 2025, 08:56:52 pm
content: I have used the EBL AA Rechargeable Li-Ion batteries in several applications and they work fine. I want to use them in my shortwave radio which I don't use an AC adapter to prevent noise. Would these batteries cause noise because they do have bucking regulator in them to provide 1.5V.

author: beatman
author_rank: Regular Contributor
timestamp: April 15, 2025, 03:31:30 am
content: Yes they have.I use few for multimeters and few weeks ago i put one battery unter scope and load and there is noise i don t remember numbers i have to repeat the test. Other guys here have more info and measures.

author: tggzzz
author_rank: Super Contributor
timestamp: April 15, 2025, 10:25:03 am
content: A battery should be effectively noiseless. A switching regulator won't be.The extent to which the switching transients affect the rest of the system will depend on the detailed design of the regulator and system.

author: thephil
author_rank: Regular Contributor
timestamp: April 15, 2025, 10:26:33 am
content: Yes, switching regulators do produce noise. How much will depend on the quality of the specific regulator (or its output filtering).

author: mwb1100
author_rank: Frequent Contributor
timestamp: April 16, 2025, 05:16:14 am
content: From a couple years ago (I don't know how much improvement - if any - may have been made since):-

author: Andy Chee
author_rank: Super Contributor
timestamp: April 16, 2025, 05:23:04 am
content: Quote from: tggzzz on April 15, 2025, 10:25:03 amPerhaps you aren't aware of recent product development, which is a 3.7 lithium battery and 1.5V buck converter, all packaged inside an AA sized cylinder.https://www.amazon.com.au/Lithium-Rechargeable-Battery-2600mWh-Constant/dp/B0C3H1JH4F?th=1https://www.cocoonpower.com/product-page/ebl-usb-rechargeable-aa-batteries-3300mwh-quick-charge-4-packIn this context, the so-called "battery" as a complete AA assembly is noisy, rather than noiseless. No doubt the internal 3.7 lithium battery itself would be noiseless.Unfortunately I can't comment on the actual noise performance, as I've never used these batteries before, let alone measured their switching noise.

author: tggzzz
author_rank: Super Contributor
timestamp: April 16, 2025, 08:39:43 am
content: Quote from: Andy Chee on April 16, 2025, 05:23:04 amI was dimly aware of such things. They aren't, of course, "batteries".Since the switching regulator is "hidden", I would expect there could be a lot of variation in the noise depending on whoever manufactured the regulators.

author: ivo
author_rank: Regular Contributor
timestamp: April 16, 2025, 11:50:27 am
content: Standard NiMH chemistry rechargeable batteries will give you none of the noise that a LiPo/Li-ion battery with a buck/boost circuit on the end of it would. Or it might be possible in many situations to use a LiPo/Li-Ion 3.7V cell directly.

author: BeBuLamar
author_rank: Super Contributor
timestamp: April 16, 2025, 03:57:28 pm
content: Quote from: ivo on April 16, 2025, 11:50:27 amIt takes 3 AA so if I use 1 Li-Ion battery the voltage is on the low side. 2 of them would be too high. I think I would use the port for AC adapter and use an LM317 regulator to regulate 2 cells LiFePo4 down to 4.5V. There should be no noise that way.

author: TimFox
author_rank: Super Contributor
timestamp: April 16, 2025, 04:54:52 pm
content: For a cell or battery (without extra electronics), the theoretical noise is the thermal noise of the equivalent series resistance in the battery under operating conditions (load current).