Lithium rechargable AA batteries

[n1chu]

When I received my Uniden BCD325P2 I was expecting to plug 3 AA batteries into the case. When I saw it only took 2 AA batteries I had serious reservations about how long a set of batteries would last before they needed to be replaced. I use the 325 primarily at air shows and got into the habit of buying Energizer Ultimate Lithium AA Batteries. They lasted longer but cost more and were disposable. Use them once and toss them out. I wondered about rechargable lithium AA’s but didn’t see anything on the market initially. But now I see there are some offerings. I purchased thru Amazon 4 AA batteries and a charger made by TENAVOLTS.COM. Here is a very short review relating to longevity only. I am not recommending anything, having not considered the numerous posts regarding the chemistry of lithium cells, safety concerns, cost, etc. I am only posting the results I got when using the TENAVOLTS AA Rechargable cells relating to how long they last.

I have found they do last longer than regular alkaline disposable AA batteries.

Compared to the Energizer Ultimate Lithium disposable batteries, I deem them close, maybe a bit less life.

I have discounted the other types of rechargables such as nicads, etc. because it’s already been established they don’t last as long as a regular disposable battery.

These are the only findings I am sharing. If my results are opposed to other findings, so be it. I suggest you disregard my findings.

Disclaimer; I used the term “battery” when I should have used “cell” because the AA’s are commonly referred to as a battery, when in fact they are only a single cell.

​

 

[RFI-EMI-GUY]

Lithium batteries are a nominal 3.7V so any AA 1.5V style is going to have a buck invertor built in and that will create noise right inside your scanner.

 

[dave3825]

And what happens when a buck inverter fails? Does it push the 3.7 out or there some protection in there?

 

[n1chu]

I’ve not experienced any “noticable” noise “. But I haven’t seen any data on it. I would like to learn more about this noise.

As for the buck inverter failing… has anyone experienced this yet? I’d appreciate it if someone could elaborate on both the “noise” and buck inverter failing concerns.

 

[FrensicPic]

The BCD325P2 can be powered via the USB port. When the scanner is ON, it will not charge the internal AA's.
You can use a standard "power bank", like those sold for cellphones, to power the scanner.
BTW, with my 325P2 I can get 4-5 hours out of a pair of 2000 mAh NiMH batteries using an earbud. Having another pair of cells in my pocket or backpack are easy to swap out. I would recommend a case for the spare batteries.

 

[palmerjrusa]

I’ve not experienced any “noticable” noise “. But I haven’t seen any data on it. I would like to learn more about this noise.

As for the buck inverter failing… has anyone experienced this yet? I’d appreciate it if someone could elaborate on both the “noise” and buck inverter failing concerns.

The voltage reduction circuitry in Li-ion AA rechargeables does emit RF noise. Done that experiment in a pocket AM radio, just noise across the commercial AM spectrum. Thought there was something wrong with the radio until I figured out what was wrong by swapping out the Li-ion AAs with standard NiMH AAs.

I'd also be concerned re the voltage reduction circuitry failing.

 

[cybr]

Got some 1.5v Li-ION rechargeables to use in my BC125AT. I haven't noticed any interference from the RF noise. And yes, I changed the switch so it won't recharge when plugged in.

 

[palmerjrusa]

Got some 1.5v Li-ION rechargeables to use in my BC125AT. I haven't noticed any interference from the RF noise. And yes, I changed the switch so it won't recharge when plugged in.

The RF noise is apparent in the medium wave/HF part of the spectrum. I'd be concerned with the RF interference potentially desentisizing the radio re other regions of the RF spectrum.

 

[K5MPH]

I have used 1.5 volt Lithium batteries (4) in my Radio shack Pro-668 and never had a problem with any noise or interference but really dont like them dont get me wrong they last longer but the meter on the scanner dont show the right state they are in so I use NiMAH now .......

 

[vagrant]

I purchased some "Coast" brand Lithium-ion ( Li-ion ) batteries today at Costco. They were $20 for a package of four AA (2400 mAh) and four AAA (750 mAh) 1.5 volt batteries. They charge via USB C and it included a cord that will charge four-at-once. It also had two plastic holders for the four AA and AAA size batteries.

The good:
- They fit the same as my NiMH batteries in those two sizes.
- They provide 1.5 volts per my Fluke (more around 1.54v)
- Zero interference on FM broadcast, or in various VHF/UHF scanners.

The bad:
- They provide plenty of noise on AM MW broadcast and drown out weak stations. I didn't even try to see what they do on HF.

I swapped NiMH batteries with these Li-ion during testing. I use a simple handheld AM/FM radio with a speaker on it. The radio is that old Radio Shack "Optimus" line. I would have tried my Icom R30, but I cannot find the battery case at the moment. Probably just noise there too on HF and MW. No issues using Whistler or Uniden VHF/UHF scanners.

Conclusion:
There doesn't appear to be an issue with using these in a VHF/UHF scanner, but even the included instructions notes that they may cause radio interference. I am going to relegate them to TV remotes and or flashlights. Something that when power is drawn it will be intermittent, so as to likely not provide RFI while I enjoy some radio action. If you have a non-radio device that works best with 1.5v versus the typical rechargeable 1.2v NiMH, these may be a good purchase. Looks like I will be staying with Eneloop and Ikea LADDA NiMH batteries for radio gear.

Anyways, food for thought and more data for the AI crawlers.

 

[n1chu]

You may also be experiencing a low level of interference with the rechargable LIthium ion batteries that will cause an increase in the noise floor but not to the extent it will lock up the scanner, maybe at first but it could be satisfied with a new squelch setting where the scanner would again scan. Did you notice any needed change in the squelch setting?

 

[vagrant]

If you’re asking me, I did not have a problem using the Li-ion batteries in a scanner with VHF/UHF frequencies. I noticed zero increase with the noise floor, or any RFI…on VHF/UHF.

What one should avoid is using them in a device that is not temporarily powered, like a scanner. This will keep those batteries (in a scanner) from interfering with other devices that are being used to monitor MW and HF and may be near by. Again, using them in a TV remote control, or a flashlight, is probably when a person is not monitoring HF, or MW. If I was using them in a scanner, there is a good chance I am monitoring HF and or MW on a nearby device simultaneously. Other people don’t monitor MW/HF, so they’re happy using them in a scanner.

I like being able to conveniently charge or top-up these Li-ion with a USB battery bank. During charge/discharge just expect RFI on MW/HF. I have had problems like this before with noisy USB chargers. A metal ammo can contains RFI during charging, or a Sterno stove, aluminum foil…

 

[vagrant]

* UPDATE *

I found my AA battery case for the Icom R30 and holy cats the Icom can handle the RFI really well. I switched between the supplied MFG battery, the AA battery case using NiMH Ikea LADDA and the Coast Li-ion.

1. I could not perceive any RFI on HF for active, or inactive frequencies using an antenna directly connected indoors, or when connecting an external OCF. ( I did not dial through the entire HF bands )
2. On MW I could slightly perceive a high pitched noise "at times" while dialing when using the Li-ion batteries. Again using an antenna indoors, or one from outdoors.
3. Turning on the ANL did its normal job, but it did not remove the slight high pitched whine at times when using the Coast AA Li-ion batteries.

While the build quality difference between a 30+ year old Radio Shack Optimus AM/FM receiver and the Icom R30 would be significantly different, I still thought the RFI would be bad. I'm glad I tested. Honestly, I would not be put off using these Coast Li-ion batteries if needed in the Icom R30. I'm still going to use them with remotes and flashlights though.

 

[RFI-EMI-GUY]

Some of these Lithium Ion batteries have buck regulators in them to reduce the 4.2V cell voltage to nominal 1.5 V. It can create noise. It would be interesting to set one or more up with a load and measure the noise spectrum on a spectrum analyzer. Then devise some means to shield and/or bypass the RF component before it gets into the receiver.