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Thread: 4AAA - C cell & 3AA to D cell adapters & Eneloop Pro LSD charging?

  1. #1
    Flashaholic chaosdsm's Avatar
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    Default 4AAA - C cell & 3AA to D cell adapters & Eneloop Pro LSD charging?

    I did a search, but the newest topic I saw was from 2012. I had some Eneloops out in my shop, but roof developed a leak in the past 6 months and they got pretty wet. I just got 8pcs 4P AAA to C cell adapters & 12pcs 3P AA to D cell adapters from Amazon to use in lights & radio's that use C or D cell's, mainly because I picked up multiple 60ct boxes of Rayovac High Energy AAA & AA for $10/box (use by dates range from Feb 2028 to July 2029), which is very significantly cheaper than buying C or D cells.

    Anyway, I will be replacing the Eneloops over the next 6 - 8 months with Eneloop Pro XX LSD batteries for my 4 C-cell radio & 5 D-cell Maglite (which both see almost daily use), & was wondering if I would be able leave the Eneloops in the adapters for charging purposes, or would it be best to remove them & charge them individually? In the adapters I could charge up to 24 AA's or up to 32 AAA's at one time significantly shortening charging time. But I doubt that the adapters are of any decent quality level.

  2. #2

    Default Re: 4AAA - C cell & 3AA to D cell adapters & Eneloop Pro LSD charging?

    Just to set my mind straight, it sounds like you are using a battery charger that holds either 24 D-cells or 32 C-cells! That seems like quite a charger to me but I'm pretty new to this game . Just for fun, (and perhaps just for me) could you post a pic of your charger?
    I'm guessing your real question here is whether or not the adaptors will suffer any damage from the heat generated during the recharge cycle. Others may know for sure but since it's very easy to remove the AAs & AAAs from the adaptors, heat tolerance prolly wasn't a huge consideration when the type of plastic was chosen for the adaptors. I bought some rather inexpensive AA --> C adaptors (~$8 for 10pcs) that do what they were designed to do but I've yet to subject them to any significant heat. I do have one charger that handles either C or D cells but it's fallen into disuse as I no longer have any rechargeable cells of that size. I may try using it with a couple AA cells in the adaptors to see what happens 🤔.
    I do see the economy of the adaptors when the high count multi packs of alkaline batteries are so readily available and reasonably priced👍. Don't know just how many 60 count multi packs of batteries you actually purchased but 2 or 3 would keep me "well powered" for quite some time. I'm not much of a "power user" tho 😎.
    Sovende
    Last edited by Sovende; 01-11-2020 at 10:47 AM.

  3. #3

    Default Re: 4AAA - C cell & 3AA to D cell adapters & Eneloop Pro LSD charging?

    Quote Originally Posted by chaosdsm View Post
    I did a search, but the newest topic I saw was from 2012. I had some Eneloops out in my shop, but roof developed a leak in the past 6 months and they got pretty wet. I just got 8pcs 4P AAA to C cell adapters & 12pcs 3P AA to D cell adapters from Amazon to use in lights & radio's that use C or D cell's, mainly because I picked up multiple 60ct boxes of Rayovac High Energy AAA & AA for $10/box (use by dates range from Feb 2028 to July 2029), which is very significantly cheaper than buying C or D cells.

    Anyway, I will be replacing the Eneloops over the next 6 - 8 months with Eneloop Pro XX LSD batteries for my 4 C-cell radio & 5 D-cell Maglite (which both see almost daily use), & was wondering if I would be able leave the Eneloops in the adapters for charging purposes, or would it be best to remove them & charge them individually? In the adapters I could charge up to 24 AA's or up to 32 AAA's at one time significantly shortening charging time. But I doubt that the adapters are of any decent quality level.



    you can charge the cells in the adapters, but is best to charge each cell individually in a smart charger.

  4. #4
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    Default Re: 4AAA - C cell & 3AA to D cell adapters & Eneloop Pro LSD charging?

    It depends on your chargers and how you charge them to determine if you will be saving any time by leaving them in the 3P or 4P configuration rather than individually. Let’s say you have 4 D cell adapters with 12 1900mAh eneloop white AA’s inside. If you break them out and charge all 12 individually at 1A they will finish in a little over 2 hours. If you leave three of them together in parallel those packs at that same 1A will take over 6 hours to charge. Because you are charging a 5700mAh battery pack not a 1900mAh cell. If you can raise the charge current to 3A you will break even time wise. Do you have a charger that can charge multiple D size NiMh batteries at 3A’s? Not many can.


    Also if you go the pack route you have no balance functionality. The charger can’t monitor each cell in the pack individually and balance them. This is not good because it will get worse cycle by cycle. The weak cell will just get weaker every cycle.


    I vote individually charging.


    Frank

  5. #5
    Flashaholic chaosdsm's Avatar
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    Default Re: 4AAA - C cell & 3AA to D cell adapters & Eneloop Pro LSD charging?

    Quote Originally Posted by Sovende View Post
    Just to set my mind straight, it sounds like you are using a battery charger that holds either 24 D-cells or 32 C-cells!

    I'm guessing your real question here is whether or not the adaptors will suffer any damage from the heat generated during the recharge cycle.
    No, my real question was just as it says in the bold blue text in my original post... which would be best for the batteries. I'm not worried about the adapters. 1 D cell adapter holds 3 AA batteries.... therefore if I'm charging 24 batteries at the same time, I'm using 8 adapters

    Quote Originally Posted by fmc1
    Also if you go the pack route you have no balance functionality. The charger can't monitor each cell in the pack individually and balance them. This is not good because it will get worse cycle by cycle. The weak cell will just get weaker every cycle.
    No balance functionality anyway... Charger is a Maha C808M 2000mAh with 8 independent charging circuits, but no mAh readout & I would normally charge overnight while I sleep - thus the idea of charging them in the holders. I can always test the individual cells couple times a year in my Opus BT-3100 to check for bad cells, but charging 15 AA's or 16AAA's with the Opus ugh.... Sure they would charge quickly, but they might be on the charger 3 - 4 hours while I'm working on this or that or otherwise occupied & end up taking 2 days to charge all the cells instead of one shot overnight.

    Maha C808M specs:
    Supported Batteries AA / AAA / C / D
    Number of Cells 1 to 8
    Supported Battery Chemistry NiMH / NiCD
    Charge Time 1 Hr (AA in Rapid Charge)*
    Charge Rate (Default) 2000 mA
    Charge Rate (Soft) 1000 mA
    Battery Conditioner Yes
    Display Type LCD (Backlit)
    Power Supply 110-240V
    Last edited by chaosdsm; 01-14-2020 at 05:59 AM.

  6. #6
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    Default Re: 4AAA - C cell & 3AA to D cell adapters & Eneloop Pro LSD charging?

    I have a few 3AA to 1D adapters that I use with nimh batteries. I sometimes put the loaded adapters in the charger for a little top off but if they're pretty low then yes all the batteries come out of the adapters and are charged individually for full charge and balancing purposes too. I've noticed in the past the charger had a little trouble detecting a full charge with 3 batteries in the adapters so it's just a quick charge thing now.

  7. #7
    Flashaholic* Grijon's Avatar
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    Default Re: 4AAA - C cell & 3AA to D cell adapters & Eneloop Pro LSD charging?

    I have two brands of 3AA->D parallel adaptors that are in heavy use in incan Mags.

    There are 16 adaptors, each with two Eneloops, for a total of 32 AAs.

    In all the adaptors, in all the lights, the Eneloops are unevenly discharged when I charge them on my two Maha C9000s. Pretty much every single time I charge them, one requires 200+mAh more than the other. I let them finish their two-hour top-off charge, so both cells in each adaptor start with a full charge.

    My point: I would recommend charging the cells individually.

  8. #8

    Default Re: 4AAA - C cell & 3AA to D cell adapters & Eneloop Pro LSD charging?

    Did you consider buying full-size C and D size rechargeables instead of the AAA and AA Eneloops and holders? I bought some full-size D cells recently for my boombox and actually was surprised at how cheap they were... Amazon has them as Amazon Basics, and the 4-pack of D cells costs $24,95 (€ 19,15 for Austria). If you fill up 4 adapters with Eneloop Pro's, it would actually cost you a bit more than buying 4 full-size D cells. Then you won't have to worry about how to charge them because they are just single cells, and you can put them in the charger as they are.
    Then... I suppose you are planning to buy Eneloop Pro's rather than regular Eneloops because of the capacity advantage. That is, with 3 AA cells in an adapter you get 7.2 or 7.35 Ah instead of 5.7. But full-size D cells have 10 Ah, so that's another 40% capacity increase! Of course one drawback is that they are probably made in China rather than Japan and thus not of such good quality as the Eneloops are, but Eneloop Pro's have a reduced cycle life compared with regular Eneloops anyway, and since the full size cells don't push for capacity that hard, you may actually end up with a slightly higher cycle count on them compared with Eneloop Pro's even though they are made in China.

    As for charging multiple cells at once in the adapter, I actually think it could work out better than expected because they somewhat even out one another, that is, the stronger cells support the weaker ones. But since they don't fill up at the same time, an algorithm which detects a voltage drop to end the charge will probably fail, so in that case it'd be better to charge the cells individually.

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