Do AA Rechargeable Li-Ion Batteries cause noise?

[BeBuLamar]

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.

[beatman]

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.

[tggzzz]

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.

[thephil]

Yes, switching regulators do produce noise. How much will depend on the quality of the specific regulator (or its output filtering).

[mwb1100]

From a couple years ago (I don't know how much improvement - if any - may have been made since):

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[Andy Chee]

A battery should be effectively noiseless. A switching regulator won't be.

Perhaps 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=1

https://www.cocoonpower.com/product-page/ebl-usb-rechargeable-aa-batteries-3300mwh-quick-charge-4-pack

In 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.

[tggzzz]

A battery should be effectively noiseless. A switching regulator won't be.

Perhaps 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=1

https://www.cocoonpower.com/product-page/ebl-usb-rechargeable-aa-batteries-3300mwh-quick-charge-4-pack

In 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.

I 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.

[ivo]

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.

[BeBuLamar]

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.

It 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.

[TimFox]

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).