Headphones use standard-sized but proprietary rechargeable batteries

Here’s something we haven’t run across before. We’re familiar with proprietary battery shapes (we’re looking at you, digital camera manufacturers), or custom recharge connections (look of death directed toward cellphone manufacturers), but using electrical tricks to force AAA brand loyalty is a new one. It seems that’s exactly what is happening with [OiD's] wireless headphones which were manufactured by Phillips.

The headphones take AAA sized batteries and can use either disposable or rechargeable varieties. There is a warning label advising that only Phillips brand rechargeables should be used, and sure enough, if you try a different brand the performance suffers both in charging time and in battery life. The original batteries are labelled as Nickel Metal Hydride at 1.2V and 550 mAh, which falls within common specs. But [OiD] noticed that there is an extra conductor in the battery compartment that makes contact with the sides of the battery case. Further inspection reveals that a reverse-biased diode makes contact through this conductor with a portion of the battery which has not been painted. This is not true with other brands, allowing the circuit to distinguish between OEM and replacements.

[OiD] shorted out that connection and immediately saw a performance boost from his replacement batteries. It’s hard to know exactly what’s going on here without a full schematic for the circuit, but we’d love to hear your speculation on this setup in the comments. Is this a low tech version of the identity chips that camera batteries sometimes hide?

Comments

  1. Norman Bates says:

    @reboots,

    That AmigoFM (or easylink/zoomlink and other Fm systems) are a MAJOR ripoff.
    I had to pay approx 1500 euro’s for this wireless microphone (which it basically is).
    And an additional 250 euro’s for having an telecoil attached to my Baha.
    (after talking the latter apart I found out that the telecoil is nothing else than a small induction coil, 3 smd capacitors, and that is it!, I copied it by using some stock parts, and had it working for less than a euro..)
    And of course the lipo’s in the easylink/zoomlink are not replacable by the user, you need to send those back to the manufacturer and pay a hefty price to replace the batteries.
    If it is or an hearing-aid/implant, the prices go insane!
    It is just morally sick that these greedy companies take advantage of the need of their customers.

  2. Onaka says:

    And so another company enters the blacklist.

    This sort of shit just makes my blood boil.

  3. Spork says:

    @HaD and outraged readers:
    You miss the point. They build the charger to the spec of their own batteries. If other (cheaper or non-rechargeable) batteries are charged to the same (higher) spec, they will explode/leak/otherwise cause damage.

    The only reason they implement this is to protect themselves from being sued. They could care less if you know about it, but ‘circumventing’ it gives them credibility in court that you do not get.

  4. therian says:

    I dont think we can call it proprietary, because this case inst about greed, think what other options does they have:
    1) add complicated circuit detecting battery internal resistance to distinguish between rechargeable and non rechargeable battery. so it would be major cost increase.
    2) abandon non-rechargeable batteries, put many warning labels and wait for lawsuits anyways

  5. Whatnot says:

    There are many stories like this about philips through the years, and employees have confirmed they do nasty stuff on purpose in the past, and more than once there were tricks to make devices fail quicker, and harder to repair after they did.

    Oh and philips semiconductors once was successfully sued by the US army for them shipping them dodgy parts.. But that was long ago and since then philips sold and splitted various parts of their company.

  6. dan fruzzetti says:

    It *is* the same thing as the camera battery-ID chip, except it’s carried onboard the phones and is only ‘enabled’ by connecting the correct battery.

  7. password says:

    i believe this is a combination of greed and safety because first the label says use only Phillips batteries and not use only approved batteries as some has pointed out that there are other brands with the same implementation plus it saves them the trouble and money of implementing a complicated charging circuit saving them money.

    secondly this greedy move also increases safety by some amount because it stops people from inserting poor quality batteries and non rechargeable batteries

    this trick can actually become useful if a standard were to be created where different rechargeable batteries have foil “rings” at different positions so a device can correctly charge the batteries put in it stopping the device from trying to recharge non rechargeable batteries

  8. that’s just crazy

  9. Paul says:

    Conclusion Inconclusive.

    Please replace all this gueswork with more reverse engineering.

  10. Johnny5 says:

    @Spork

    >They could care less if you know about it

  11. walt says:

    F U OiD/Phillips! You won’t see my money ever again.

  12. 802Chives says:

    wow look at all the drone haters out there… keep grazing on all the grass the farmer will be out with more grain soon.

    Has anyone even read the comments?? Before you boycott Phillips know that there is nothing proprietary about this, it is a SAFETY feature, and one commenter even suggests that the manual talks about how to get around it with off brand rechargables…

    This article was written to incite this kind of rage, however it is very mis-leading… The feature allows you to use off shelf batteries, boycotting should be reserved for the manufacturers that use proprietary batteries and make their products consumable by sheeple who trash dead products rather then replace the batteries.

  13. Flood_of_SYNs says:

    I bet the “Use only Phillips’ rechargeable batteries” is a legal move, if someone were to put non-rechargeables in the unit and something bad happens and they try to sue, Phillips can just point to the label and say told you so.

    “Low tech hardware authentication”

  14. bash says:

    just spit-ballin here. but could you not just scrape the paint shell off of a few regular AAA bat’s to short the circuit out? just a thought..

  15. Alan says:

    I’ve always just cut ~8mm of label away from the -ve end of a regular rechargeable battery.

  16. Donrata says:

    I’ve seen that on a Philips mobile phone like 10 years ago, anyway I liked to be able to use standard AA cells when I wasn’t able to charge the phone.
    So It’s the philips way!

  17. mah says:

    its not there only for profit , its there for a reason
    look,
    if they did not have this , stupid people will not use both their rechargeable batteries and non-rechargeable batteries in it , but ingenious people will find this and just short it
    philips did this just because they figured out that their consumers(which they think are stupid ) are too stupid to recognise between rechargeable batteries and non-rechargeable batteries

  18. Mike Bradley says:

    2x of the 1.2v batteries is 2.4v, 2x of the 1.5v batteries is 3v, a .6v difference. I just assume this is to allow standard 1.5 batteries to be used, and still supply 2.4v

  19. Dax says:

    To all of those claiming it’s a safety feature, all I can say is BULL.

    I took apart my table charger with the “feature”, and it was a simple current limited nicad/ni-mh charger with no voltage peak detection circuitry or anything. It’s a simple dumb slow charger.

    There’s NO quick charge. Putting the “wrong kind” of batteries in would just result in them getting warm. Leaving the batteries in would result in them getting worn out after a while due to constant overcharge. Putting alkalines in wouldn’t do much anything to them, except recharge them slightly.

    Nobody else does it with their slow chargers. All they have is a label that says “do not recharge non-rechargeable batteries”. Why don’t they feel the need to protect themselves from being sued?

    Because they don’t need to. Phillips is doing it only for the lock-in.

  20. kaidenshi says:

    I came across something like this at my part time job. We got a bunch of second-hand two way FRS/GMRS radios in and the boss wanted me to refurb them for employee use, as we work in a large warehouse and the phone paging system is inadequate for relaying info.

    A few of the radios were made by Midland and had a battery pack that was just four AAA NiMHs bridged and in a heat shrink package. Just for kicks I put four individual AAA NiMHs in and plugged in the charger. No dice. So I looked closer at the battery pack and the radio’s compartment and I noticed there was a bare patch on the pack that corresponded to a connector on the radio. I shaved some of the plastic off of the relevant loose battery, reinstalled them and it began charging normally.

    After prepping all of my loose NiMHs with a bare patch in the right spot, I can now substitute high capacity battery sets for the original packs and get nearly a week between charges, as opposed to daily recharging with the original low capacity packs.

  21. Phil says:

    In case it helps – I have successfully replaced the official Phillips ones with a generic rechargable battery.

    Use a sharp knife to score around the battery at the bottom, and the new batteries are accepted fine – they both play and recharge fine.

  22. Alex says:

    Thanks to this site, I was able to use my 3dr party batteries in my headphones, I just cut out the plastic from the end of the batteries and they now work like a charm.

  23. Arseny says:

    This is a safety feature to prevent charging of non-rechargeable batteries. Some Panasonic CD players also had this feature.

  24. pat100 says:

    Philips mention this feature in their manual. The fact that a charging connection is made to the lower side of the battery to prevent overheating if alkaline batteries are used in error instead of rechargeables.

    And that this safety feature will prevent other non-Philips rechargeable batteries from charging.

    Oh! Just a minute… No, they don’t!

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