Ozito 4Ah Battery Leaked - AITA

t_c on 24/05/2025 - 19:28
Last edited 25/05/2025 - 14:42 by 1 other user

Hi, so back in January I bought this slimline Ozito Twinpack.

And I noticed this chemical smell coming from my battery station in the garage, I also noticed a spray pattern on the back wall, and a chemical smelly sticky substance on all my batteries and chargers. I also noticed one of the batteries from the twin pack has corrosion on one terminal and when put on charge. it shows both red and green light. which indicated a fault. I strongly believe this one is faulty.

So I put both items from the twin pack in a box and head to Bunnings. They determined that one battery was ok, so they can only replace 1x. but it would be with a full size unit and not the slimline, as slimline is no longer sold. I argue that I use both batteries in a mower and I can't mix a slimline with a full size. Staff argues both are 4ah so should be ok, I'm like yeah but you're not supposed to mix different types. maybe they have different discharge rates. Staff member has to get another staff member as they would know more about batteries. New staff member supports staff member that it would be ok and it would work and Ozito wouldn't allow it if it works.

I reiterate my case that I use both at the same time in a 36v mower, they need to be the same. They then said they are used one at a time. and saying can't be 36v, these are 18v, 36v a whole other thing or battery and it would fit. (Confusion, at what they saying wasn't making sense). I'm like yeah 2 x18 volt batteries they both slot in the mower at the same time.

So, I'm like can you do a refund on the twin pack then. They can't do that. I'm like just exchange it then whatever, thinking I will email Ozito later. Confusingly they then got me another twin pack of the full size and all good after some mucking around because the new twin pack costs more.

But they thoroughly convinced me mixing the slim with the full size would be perfectly ok.

So AITA?

Electrical & Electronics 18V Ozito Rechargeable Battery

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Comments

  • cashless on 24/05/2025 - 19:51
    +1

    AMITA

    Another Manufacturer Is The Answer?
    Are My Instincts Totally Awful?

    • t_c on 24/05/2025 - 19:55
      -1

      Sorry typo. AITA

      • MS Paint on 24/05/2025 - 20:01
        +1

        All In To Albuquerque?

        I argue that I use both batteries in a mower and I cant mix a slimline with a full size.

        Why not? I can't see the harm if they are the same rating. It's just a form factor isn't it?

        • t_c on 24/05/2025 - 20:25
          -6

          The 4ah rating was the same,
          But maybe:
          different discharge rates,
          different cell types to achieve the slim factor,
          different chemistry.

          And battery manufacturers have always stated you should never mix old batteries with new.

          Given the propensity for these tool batteries to sometimes catch on fire.

          At face value it seems irresponsible to mix the 2 different types. But yeh maybe my concerns are unfounded.

          End of the day, I don’t particularly want to be the guinea pig.

        • Nugs on 25/05/2025 - 10:51
          +1

          And I Tossed'em Away?
          .

  • ihbh on 24/05/2025 - 21:10
    +2

    Why didn't you take them (staff and batteries) to the mower in store and show them the full sized ones don't fit?

    … Because you were greedy because the replacements cost more.

    What have you done with the full sized ones? Can you use your mower?

    • t_c on 24/05/2025 - 21:18
      -1

      You misunderstood.

      I brought both slimlines into store as I purchased as a twin pack, but they only wanted to replace the 1x battery with a different type. As they no longer stock the slimline.

      So they wanted me to use 1x slimline and 1x standard size in the mower at the same time.

      Ie. a mismatched pair.

      • ihbh on 24/05/2025 - 21:26

        I understand you now have a mismatched pair. How do you operate your mower?

        • t_c on 24/05/2025 - 21:39
          -1

          No, after I kicked up a stink they ended up changing my twin pack for another twin pack.

      • SBOB on 24/05/2025 - 22:52
        +2

        Ie. a mismatched pair.

        When ozito say you should use matched batteries they mean capacity (ie same ah) and charge state.

  • Downvoter on 24/05/2025 - 21:12
    -5

    Yeah you’re a (greedy) asshol3

    • t_c on 24/05/2025 - 21:39

      I guess I have to own it then.

  • AwesomeAndrew on 25/05/2025 - 00:43
    +8

    Generally you are not meant to mix batteries of different types or different ages (both calendar age and age in charge / discharge cycles). The reason behind this is that the battery cells may not be matched to each other, and when placed in series (like in your 36V mower) one (or more) of the cells will be weaker and have a slightly lower capacity than the other due to the mismatched type / age. The weaker cell will also wear out more compared to the other cells which experience a smaller percentage of their discharge cycle due to their slightly higher capacity, leading to the mismatch worsening over time. Note that this doesn't mean the degradation of the weak cell will be worse, it would be equivalent to if all the cells were matched and the same type / age as the weak cell. So the lifespan of the battery packs are limited by the weakest battery cell. The performance (capacity / output power capability) of the battery pack is also limited by the weakest cell.
    In a battery pack if you only replace the failing batteries with new ones, in the long run you will have to do more replacements as the batteries don't all fail at once (or very close in time to each other), which may not be very convenient and causes more system downtime which is unacceptable in some applications. And by doing this you will never get the full potential of the battery pack at any time as there will not be a time when there are only new cells in the pack.
    In some systems which do not closely monitor the voltage of each cell and only measure the full pack voltage, this could lead to the weakest cell being over discharged and being damaged, although most Lithium battery systems (including your Ozito battery) have a BMS to stop this from happening. Damage due to mismatch is more common with lead acid batteries and other chemistries.
    So in your case it is safe and acceptable to mix the old and replacement battery pack in a lawnmower as none of the reasons for not mixing batteries really applies to your case, and it could be argued that having a faulty battery in a two pack shouldn't mean that you get both replaced and get extra lifespan and performance from the non faulty one. Also, it's better for the environment if only the faulty pack is replaced, as I believe Bunnings just scraps the other good battery as it has already been used and cannot be sold anymore.

  • bargaino on 25/05/2025 - 00:56

    I'm like yeah but your not supposed to mix different types.

    Not true here. There is no problem with a mismatched pair in series of protected batteries.
    When one of them is "flat" it will shut off the current.

    If you were talking about battery cells in series, like D-cell or AA, that is another matter. They do not have protection electronics, so can be driven into reverse voltage.
    ( And batteries in parallel are another topic. )

  • payless69 on 25/05/2025 - 08:50

    Next time shop at Gerry so you know NO warranty to start with!

  • skid on 25/05/2025 - 09:22
    +1

    I don't work at Bunnings, but if I did, as a goodwill gesture, I would have refunded you the slimline twinpack and asked that you re-purchased the fat twinpack with you paying the difference. I would have asked for the working slimline battery as part of the refund.

    • REDRUM on 28/05/2025 - 15:24

      That's why you don't work at Bunnings, stop making sense.

  • topherboi on 25/05/2025 - 09:50

    Why don't Bunnings sell the compact style any more? Aren't they a newly-released product?

    Edit: comment from Kelpei on the original deal linked by OP explains it:

    The product you are looking for was a promotional item and we won't be getting any more of that one back in. However, we do currently have 3 x 4.0AH 18v Ozito batteries for $99 as a promotional offer. The item number for this is 0417097 if you'd like to check online or come in and purchase.

  • coxjon on 25/05/2025 - 10:34
    +3

    That’s weird - when I had one of my Ryobi 4 pack 4ah batteries die they wanted all four back to swap with a new four-pack.

  • CaptainJack on 25/05/2025 - 11:32

    This reminds me when I bought a suit. And there was an issue with trousers. They said theres no more stock of the trousers but can refund them instead. But not refund the jacket as it doesn't have any issues. I don't want a jacket without the trousers, as I needed a suit.

    It go awkward, then they realized they did have more stock.

    Anyway, can't help you OP.

  • rumblytangara on 25/05/2025 - 12:13
    +2

    They then said they are used one at a time.
    and saying cant be 36v, these are 18v, 36v a whole other thing or battery and it would fit.
    (confusion, at what they saying wasn't making sense)
    I'm like yeah 2x 18volt batteries they both slot in the mower at the same time.

    They both clearly know nothing about the product.

    The batteries are used in series to achieve 36V, so they are both used at the same time.

    Because you are using both, the older one has more wear/duty cycles on it. And they are giving you mismatched pairs. IRL this is probably fine but ideally you'd be using packs with similar amounts of wear on them. IMO the twin pack is one inventory item, they are used as a single unit, and frankly if one failed so badly as to spray electrolyte over a wall I'd not trust the other one which was the same batch. This would be my main point of contention- safety.

    (Edit: just realised awsomeandrew laid this out better than me above)

    I would not use slimline batteries in the first place- there's going to be some compromise somewhere. Whether that is in the cells themselves, the size of the PCB or ability to handle heat… for a lawnmower battery size surely does not matter. Slimline makes sense for a handheld tool that you're fitting into tight spaces, not for a lawnmower.

  • Abbycat on 25/05/2025 - 12:39
    +4

    Ex Bunnings employee here. They were completely in the wrong. The process for a fault of a non repairable item is pretty simple. You bring the complete unit back. They either replace the whole thing or refund it. If you hadn't brought back the entire unit including the non faulty parts it would have become difficult, but if you had the whole thing it's a straight swap.

  • skillet on 25/05/2025 - 23:29

    Mixing those batteries is okay but the weaker pack will work harder and experience higher charge discharge cycle. The battery management protection will kick in when one of the cells reach the minimum operating voltage.

  • prophet on 26/05/2025 - 16:53

    I think you posted it in the wrong place. Here you go: https://www.reddit.com/r/AmItheAsshole/

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