Hey all,
I’m here for the brain trust.
I have changed almost all of the batteries in my home to rechargeables. I know it’s probably super naive and/or stupid but it’s one of the microscopic things in my power to do in regards to trying to not be a total cancer on this planet.
That being said I have 1.5v lithium rechargeable ebl batteries and they won’t even power up the sensor. Can someone explain why? I thought maybe the voltage is too high but alkaline aaa are 1.5v too, yes? The nimh ones work and those are 1.2v. I’m just curious as to why the lithium ones don’t.
Thanks!
I’m not an electrician. I’d be print to ask someone like @K6CCC to tell me if they have good ideas why a Wyze contact sensor would work with AAA batteries but not lithium.
An AI told me this could explain it (open drop-down)
Your observation is spot on, and the issue likely lies in the way lithium rechargeable batteries deliver power compared to alkaline or NiMH batteries.
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Voltage Behavior: While both alkaline and lithium rechargeable batteries are labeled as 1.5V, their actual behavior differs. Alkaline batteries start at 1.5V but gradually drop in voltage as they discharge. Lithium rechargeables, on the other hand, maintain a steady voltage (often slightly lower than 1.5V) throughout their discharge cycle. Some devices, like your contact sensor, might be designed to work with the gradual voltage drop of alkaline batteries and may not recognize the steady voltage of lithium rechargeables.
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Current Output: Lithium rechargeable batteries can have a lower current output compared to alkaline or NiMH batteries. If your contact sensor requires a higher initial current to power up, the lithium rechargeables might not be able to provide it, causing the sensor to fail to power on.
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NiMH Compatibility: NiMH batteries, despite being 1.2V, are often more compatible with devices because they can deliver a higher current and maintain a stable voltage under load. Many modern devices are designed to work well with NiMH batteries for this reason.
If you want to use rechargeable batteries, NiMH might be your best bet for this sensor. Alternatively, you could check the sensor’s specifications or consult the manufacturer to confirm its compatibility with lithium rechargeables. Let me know if you’d like help exploring other options!
But I really don’t know enough to judge if those are reasonable possibilities.
Thanks! I did actually see this under an AI answer, but I figured an actual person could make more sense of it to/for me. The AI part about output didn’t pan out because any battery I tested “powered up” at 1.53 or lower. I tested the battery and it does come in at 1.53-1.55v at various levels of drain, so good there. They fall off to 1.1-1.2 when almost depleted, which is where nimh batteries start! So even if the contact sensor requires some spike voltage, the Lithium should work.
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Yeah, doesn’t really make sense to me. Even if there is a flatter discharge curve, or lower internal resistance or whatever other differences there could be, I don’t see why that would matter so much when they’re still ultimately batteries giving off similar DC power. Something just isn’t making sense.