Tecsun cautions against using Lithium AA cells in the PL-606

TecsunPL-606

SWling Post reader, Philip Dickinson, recently contacted me with the following question:

“I have just bought a Tecsun 606 which takes two AA batteries which I think are normally rated at 1.2 volts. I have just ordered some lithium ion AA and notice that they are 3.7 volts. Can I use them?”

I replied to Philip that I’m pretty sure I’ve used lithiums in my PL-380 and/or PL-310ET without experiencing any problems. I know I’ve certainly used lithiums in several other receivers. [Update: I’ve always used Energizer and Duracell 1.5 V Lithium AA batteries–not 3.6V AA batteries.]

As I was about to post his question here on the Post, Philip sent another message:

“I found Tecsun’s email address and they rule out the 3.7 volt lithiums. Good job I checked.”

Wow–indeed, I’m glad you checked as well!

I had searched the PL-606 owner’s manual (PDF), but found no reference for voltage tolerances. Now I’m curious if other Tecsun receivers would have difficulty handling the higher lithium voltage.

Please comment if you have insight!

[UPDATE: Please check out this follow-up post and primer on Lithium batteries.]

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17 thoughts on “Tecsun cautions against using Lithium AA cells in the PL-606

  1. Pingback: Primary, Ion, and Polymer: a lithium battery primer | The SWLing Post

  2. Mark Piaskiewicz

    There are lithium primaries (NON-rechargeable) that are about 1.7V. The most common ones being Energizer L91 type. Then there are lithium ion rechargeable cells that ARE rechargeable BUT they are not AA type batteries. They have a designation of 14500 and have a nominal voltage of 3.7V. Both cells have identical dimensions of 14 mm diameter and 500 mm length. Using the NON-rechargeable type is completely safe, while using the rechargeable type will likely let out all the magic blue smoke that makes electronics work.

    For further information see candlepowerforums.com. This is a website dedicated to flashlights and flashlight addiction, but it has an enormous wealth of information on the different types of batteries available.

    By the way, nickel cadmium and nickel metal hydride types of rechargeable AAs are also perfectly safe, but be very careful if you have a radio that can charge these types of AAs. These radios more likely than not have a switch (mechanical or electronic) that will allow you to disabled the charging feature if you’re using non-rechargeable batteries. Attempting to charge non-rechargeable batteries can cause a leak, a fire or an explosion.

    Reply
    1. Mark Piaskiewicz

      By the way, kudos for having the wisdom to check with Tecsun before trying these batteries!! You saved yourself a great deal of grief since Tecsun would probably consider powering your radio with almost 2 ½ times the rated voltage as abuse and not cover it under warranty.

      Just out of curiosity, did you purchase these batteries from a retailer who did not explain that they were not to be used as replacements for standard AAs?

      Reply
    2. Thomas Post author

      This post has ended up being quite the learning experience for me.

      I’m going to do a follow-up post with more details about these cells. Mark: thanks for the tip on the candlepowerforums–I’ll check it out!

      Reply
      1. Mark Piaskiewicz

        Enjoy CPF but be careful about getting bitten by the flashlight bug! LED flashlights have made quite a leap in the past dozen years, kind of like Atwater Kent to Drake R8!

        A quick note on the Energizer L91 cells, they’re expensive at about $2.50 a pop but they have a very long shelf life (now rated about 15 years, I think), they don’t leak and last a very long time. They’re perfect for emergency radios, especially analog ones. (It’s the digital clocks that will kill them.)

        I have a Sony ICF SW20 that lasted quite a while on plain alkalines so I decided to really give it a test and it ran about 40 hours at a reasonable listening volume. I decided to give the little radio a treat and fed it a couple first generation L91s. I was curious how long these batteries would last so I put a label with the installation date on one. The radio wasn’t my primary radio but it did get a few hours of use every summer Sunday listening to the SW rebroadcast of some CBC stuff while packing the car to go home from my weekly DXpedition.

        This went on for a few years and then the radio was delegated to just occasional use and then to emergency use where it gets used for a few hours a year for testing purposes, but those L91s I installed in March of ’94 are still working!

        Reply
        1. Thomas Post author

          Mark, you are wise to warn me about the dangers of flashlight addiction! I’ve always had a thing for good flashlights–especially the rugged, mil-spec variety.

          One fascinating little light I purchased inMay is the ThruNite keychain flashlight: http://amzn.to/1V7n5wd

          I simply can’t believe how much candlepower this thing throws out in the brightest setting!

          -Thomas

          Reply
        2. rcxb

          I would still go for LSD NiMH batteries for emergency radios. They hold power for years without a recharge. With a tiny solar panel (even a $2 solar garden light!), you can recharge them anywhere, over and over, for several years before they fail. And they still cost less than a set of disposible Lithiums. I do recomend putting a strip of plastic between the batteries to cut the circuit and prevent the radio from draining them, whether by the clock or just acidentally getting switched-on.

          Reply
          1. Mark Piaskiewicz

            IMO, LSD NiMH isn’t quite there yet, at least not nearly as LSD as L91 cells and more expensive. The solar cell recharging system is a good idea but complicates things and is impractical in many areas. For instance I live in an apartment with windows only on the east and west sides, all blocked by trees for the better part of the day. I do use Eneloops to power a number of things, but keep a large stock of L91 cells handy for long term outages.

            The plastic strip between cells is an excellent idea.

  3. Michael Black

    There’s a big difference between 3v or 3.7v and 7.4v.

    One could probably get away with one 3.7v battery (though I’m just speculating), and dummy cell that does nothing but take the space of one AA and connects both ends together.

    I don’t know where to get dummy cells, but they were available in the old days. A CB walkie-talkie would need 12v, eight AA cells. But if you used rechargeable, they had nominal 1.2v, requiring ten for the same 12v. So the unit would take ten AA cells, but if you used alkaline or carbon zinc, you’d use eight cells and two dummy cells to fill the gap.

    Michael

    Reply
    1. DL4NO

      3.7 V is much more than 2 * 1,6 V (absolute maximum voltage of primary cells). So dummy cells do not help.

      BTW: There are no 7.4 V cells – such batteries contain two lithium cells in series.

      Reply
  4. DL4NO

    The AA and AAA form factors came with primary-cell technology first. These cells deliver about 1.6 V when really new and with 1.5 V of nominal voltage.

    While depleting these cells their voltage drops. In low-current applications like radios their useful life ends at about 1.1 V. This the radio developers should take into account.

    When the NiCd secondary (rechachable) cells appeared their chemistry led to a nominal voltage of 1.2 V. Fully charched they delivered around 1.3 V or 1.4 V directly out of the charger. Their end-of discharge voltage is about 1.1 V – about the same as at the primary cells. This makes NiCd (and today’s NiMH cells) more or less compatible with primary cells.

    Litium cells provide much higher voltages – more that double the voltage (3.6 … 4.2 V) of even conventional primary cells. From my point of view they should not come in original AA or AAA form factors as they are sure to fry conventional equipment.

    Reply
    1. Shaun

      LiPo are nominally 3.7v per cell, LiFe are 1.4-1.6 and intended to be drop-ins for AA applications.

      There’s many different battery chemistries using lithium, and they’re far from equal. It’s just a case of finding the right tool for the job.

      Reply
  5. Ken Hansen n2vip

    You are confusing two different things that sound similar…

    Lithium batteries come in AA packaging and are designed for special-use applications – temp extremes, exceptionally long shelf life, etc. and are direct replacements for alkaline AA batteries. Lithium batteries are not rechargeable.

    Lithium Ion batteries are rechargeable batteries with higher voltages designed for building rechargeable battery packs. Though these batteries are the same physical size as alkaline AA batteries, they are not direct replacements, as their voltage is nearly 3x that of an alkaline battery and they require very special circuitry to recharge.

    Lithium and Lithium Ion batteries may sound similar, but they are not the same.

    Source: http://www.greenbatteries.com/faqs/

    Reply

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