Headlamp AA battery replacement w/ rechargables

Discussion in 'General Electronics Chat' started by RogueRose, Jan 5, 2016.

  1. RogueRose

    Thread Starter Member

    Oct 10, 2014
    188
    4
    I had to upgrade my headlamp to the newer model (black diamopd Icon 480 lumen lamp) of my favorite manufacturer. It is the direct replacement for my previous model. I assumed it would have the same battery plug for a rechargable pack they sell (it was like $70 for a tiny LiPo so they were making $$$$!!!) but this only accepts 4 AA's. It seems they aren't lasting very long and I'm tired of wasting them.

    So, time to make some upgrades and add a LiPo. Last model I had ran on 3 AA's and a 6v pack (had a voltage converter chip) as well as a 5v DC input (also lacking on current model).

    So, I'm kind of stuck trying to figure out what battery will be best for this application. I can find a 3.7 or 7.4v battery that will fit inside. I'll either need a boost converter for he 3.7 and possibly a buck converter for the 7.4v pack - either will need to be pretty small.

    I'm not sure how much current this headlamp draws at its highest settings, probably less than 1A @ 6v. Is it better to go with 3.7v and boost the voltage or 7.4 and a buck converter? Do you think it would be a problem trying to run the device at 7.4 v? I know a freshly charged 7.4v pack may actually be 8.0-8.4v as the "max charge voltage".

    Anys suggestions on what would be the best solution for this? Also, is there a way to add a DC plug input on a device like this? (it is currently waterproof so the connector must be fairly small - it doesn't need to be a traditional round DC jack, any connection that would work is acceptable). Thanks for any suggestions!!
     
  2. dl324

    Distinguished Member

    Mar 30, 2015
    3,211
    619
    What is the light source? Incandescent? LED? Does the battery drive the lamp directly or does it have a driver?
     
  3. crutschow

    Expert

    Mar 14, 2008
    12,972
    3,219
    It states this in the instruction manual: "The Icon and Icon-Polar headlamps run on a power regulated circuit. Therefore, light output will be constant until the battery voltage reaches approximately 4.7 volts. It then transitions into a nonregulated system to extend battery life and to maximize efficiency.."

    So it would seem that the lamp is controlled by a switch-mode step-down current regulator and my gut feeling is that it would be okay with a voltage higher than 6V.
    But you'd have to contact the manufacturer to know for certain what maximum voltage it can tolerate.
     
    RogueRose likes this.
  4. KJ6EAD

    Senior Member

    Apr 30, 2011
    1,425
    363
  5. RogueRose

    Thread Starter Member

    Oct 10, 2014
    188
    4
    Thanks for the replies. I'll try hooking up the light to a 7.4v supply and see what happens, but I have an idea that it will work from what I have seen from previous models using a similar power pack. The biggest issue is finding li-po's that will fit into the strangely shaped battery case, but I have found a combination of 2 packs seems to be the best bet. Another alternative (and the reason for this post) is whether I should try the NiZn rechargables which put out 1.65v and look like they have a pretty nice voltage curve as it drops mildly for the first 10% or so of capacity and then levels out for the next 70% and then drops off steeply.

    As was stated, the lamp needs 4.7v before going into a "low bat" mode, so the NiZn should work nicely it would seem. The Li-po's are a good bet and they are a fairly well known tech. The NiZn are about $5.50 for 4 but I will need a charger (possibly build?? - found a 4 AA/AAA charger for ~$13). The reviews are few on Amazon for the batteries but they are all pretty good.

    Does anyone have any experience with the NiZn or have advice as to which would be best suited for this?
     
  6. crutschow

    Expert

    Mar 14, 2008
    12,972
    3,219
    Look at the battery's Ah capacity.
    I think the Li-po's will be significantly higher than the NiZn's.
    I believe the NiZns require a special charger.
     
Loading...