6 Energizer 1.5V Primary Lithiums + Fusion Showerhead Drop In - Safe?

The voltage isn't the issue, but apparently the Energizer Lithium Primaries have a different chemistry than normal Li-Ions. Do I have anything to worry about from using them in this (or any other) flashlight?

belomeclone said:

The voltage isn't the issue, but apparently the Energizer Lithium Primaries have a different chemistry than normal Li-Ions. Do I have anything to worry about from using them in this (or any other) flashlight?

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The Energizer Lithium Primary cells have a nominal voltage of 1.5 V and are considered interchangeable with alkaline, NiMH and NiCd cells in most (but not all) electronics. They are not rechargeable and definitely NOT drop-in replacements for lithium-ion, which operate in the 3.0V to 4.2V range.

Most commercial flashlights that take AA batteries will operate very well with the Energizer Ultimate Lithium AA batteries. They will always outperform alkaline batteries, and will generally outperform most NiMH cells in flashlights that have 2W draw or less per cell. Above 2W, you will get longer runtime form most NiMH cells.

The Energizer Lithium batteries are great for some applications. In others, you are better off using a good NiMH cell like the Eneloop. If you can provide more information about the load on the battery and your typical use pattern, that will help us to recommend the appropriate battery.

Cheers,
BG

You say the voltage isn't the issue, but the voltage might be an issue.

A "Fusion Showerhead" drop-in is not a commonly recognized standard item, so it might depend on exactly what it is. However, I see a suggested maximum voltage of 9 V for something like that, and six primary lithiums could deliver as much as 6 x 1.7 V = 10.2 V, so who knows?

On the other hand, it does seem to be a kind of disposable "eBay special" item, so there's not much lost if you do blow it up.

As Battery Guy said, we need more information about what you are considering.

I am considering six Energizer 1.5V Lithium Batteries. That should bring me to 9 Volts.

belomeclone said:

I am considering six Energizer 1.5V Lithium Batteries. That should bring me to 9 Volts.

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Remember there is no such thing as a "1.5 V" battery. A fresh alkaline battery is over 1.6 V, a fresh zinc-carbon battery is nearly 1.7 V, and a fresh Energizer Lithium battery is about 1.8 V. The voltage then decreases with load and with usage, but the voltage of a lithium battery is higher than an alkaline battery and remains higher throughout its lifetime. There are occasionally some devices for which the voltage of a lithium battery is too high.

belomeclone said:

I am considering six Energizer 1.5V Lithium Batteries. That should bring me to 9 Volts.

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Energizer Lithium AA's are actually 1.7V (I just tested 5 that were all about 1.78V) not 1.5V. It's not that big of a deal when using them individually or in pairs. But when used with 6 or more, that equates to 1.2-1.8 extra volts that could cause your led to go

So.. Eneloops?

Will Eneloops be okay in my trunk if I don't use them when it is below zero? Or, by going below zero, am I harming the battery.

Mr Happy said:

Remember there is no such thing as a "1.5 V" battery. A fresh alkaline battery is over 1.6 V, a fresh zinc-carbon battery is nearly 1.7 V, and a fresh Energizer Lithium battery is about 1.8 V. The voltage then decreases with load and with usage, but the voltage of a lithium battery is higher than an alkaline battery and remains higher throughout its lifetime. There are occasionally some devices for which the voltage of a lithium battery is too high.

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I found a thread on CPF here states that the tail cap current of the Fusion Showerhead is 1.42 A. While I don't have a discharge curve for the Energizer Ultimate Lithium AA at 1.42 A, the Energizer spec sheet shows a 1 amp constant current discharge curve, and it is clear that the voltage drops quickly and plateaus at about 1.4 V. At 1.42 amps, I would expect the voltage to be closer to 1.3 V under load. So I would expect that the voltage on the battery pack under load would be between 7.8 to 8.4 V.

Based on that analysis, my guess is that Energizer Ultimate Lithium batteries would be perfectly suited for this application.

Cheers,
BG

Battery Guy said:

I found a thread on CPF here states that the tail cap current of the Fusion Showerhead is 1.42 A. While I don't have a discharge curve for the Energizer Ultimate Lithium AA at 1.42 A, the Energizer spec sheet shows a 1 amp constant current discharge curve, and it is clear that the voltage drops quickly and plateaus at about 1.4 V. At 1.42 amps, I would expect the voltage to be closer to 1.3 V under load. So I would expect that the voltage on the battery pack under load would be between 7.8 to 8.4 V.

Based on that analysis, my guess is that Energizer Ultimate Lithium batteries would be perfectly suited for this application.

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Ah, good thread find. That looks like a fairly nice drop-in.

I see that the 1.42 A draw was measured with a 4s2p Eneloop configuration giving about 4.8 V. The drop-in is regulated, so the draw would likely be less at 9 V. From my reading the expected supply for that module is around 6 V (e.g. they recommended 4D alkaline or 2s lithium ion).

While it may work with six Energizer Lithium in series, if it were my light I don't think I would risk it. It doesn't seem like there is any advantage to that configuration compared to the recommended power supplies.

I currently have 3 of the units in the following configurations:

4DM*g - 5 "C" Duracells in a PVC tube
3DM*g - 9 "AA" Duracells in the cheap $1 3AA.D adapters
2DM*g - 2 "D" Duracells, will be changed to 6 AA when two new adapters arrive

No issues whatsoever...all provide great flood.

Mr Happy said:

I see that the 1.42 A draw was measured with a 4s2p Eneloop configuration giving about 4.8 V. The drop-in is regulated, so the draw would likely be less at 9 V. From my reading the expected supply for that module is around 6 V (e.g. they recommended 4D alkaline or 2s lithium ion).

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Arrggh! I totally missed that the drop-in is regulated. I assumed that, given the relatively low cost, that it was direct-drive. Nice save Mr. Happy!

If we assume that the efficiency of the voltage regulator is constant, then it would be safe to assume that the power draw on the battery pack is 6.8 W, or about 0.85 W per cell. I will run an Energizer Ultimate AA cell at 0.85 W tomorrow to see what the discharge curve looks like.

Mr Happy said:

While it may work with six Energizer Lithium in series, if it were my light I don't think I would risk it. It doesn't seem like there is any advantage to that configuration compared to the recommended power supplies.

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The OP did indicate that he wanted to use light in the car. While I would agree that Eneloops would be the best option for most applications, I think that the Energizer Lithiums are best suited for a flashlight stored in the car.

Cheers,
BG

So are saying the Energizer Lithium's are safe to use? Because at first you all said they weren't lol and it made me doubt my idea.

belomeclone said:

So are saying the Energizer Lithium's are safe to use? Because at first you all said they weren't lol and it made me doubt my idea.

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In short, we don't know, and we can't know. We didn't make the drop-in, and we have neither detailed specifications nor design notes.

The consensus seems to be that it will probably be OK. But you would have to try it at your own risk. And be aware that if things like this fail, they may not fail immediately, but only after some time.

If I were you, I would try to power it using four cells instead of six. That would keep it well inside the good voltage range.

Mr Happy said:

In short, we don't know, and we can't know. We didn't make the drop-in, and we have neither detailed specifications nor design notes.

The consensus seems to be that it will probably be OK. But you would have to try it at your own risk. And be aware that if things like this fail, they may not fail immediately, but only after some time.

If I were you, I would try to power it using four cells instead of six. That would keep it well inside the good voltage range.

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I am running an Energizer Ultimate Lithium and an Energizer Advanced Lithium (the "Advanced" has a higher internal resistance) at 0.85 W discharge now. I should have the results to share with you tomorrow, and hopefully that will help to answer the question. All I can say now is that the Advanced Lithium drops to <1.5 V within the first 10 seconds of discharge and that the Ultimate stays above 1.5 V for longer.

Cheers,
BG

As promised, here are the results of the Energizer Ultimate and Advanced AA lithium batteries discharged at 0.85 W:



The thing that you might need to worry about is the initial few seconds when the cell voltage is above 1.5 V. The Advanced lithium is >1.5 V for the first 14 seconds, and the Ultimate lithium is >1.5 V for the first 27 seconds.

If you had not mentioned that you were using/storing this flashlight in your vehicle, I would have recommended Eneloops without hesitation. However, Eneloops, or any NiMH cell for that matter, are not appropriate for a vehicle flashlight because the high storage temperature will cause them to rapidly self-discharge. The only battery I recommend for a vehicle flashlight is the Energizer lithium AA or AAA.

So, if you want to be on the safe side, go with 5 Energizer Ultimate or Advanced lithium AA batteries and one dummy cell. If it were me, I would risk using six Energizer Advanced lithium cells. My guess is that a few seconds above 9V is not going to blow your voltage regulator, but then again I am not an electrical engineer.

Kind of a wishy-washy answer, but the best I can do without additional info on the Fusion drop-in.

Cheers,
BG

Battery Guy said:

So, if you want to be on the safe side, go with 5 Energizer Ultimate or Advanced lithium AA batteries and one dummy cell. If it were me, I would risk using six Energizer Advanced lithium cells. My guess is that a few seconds above 9V is not going to blow your voltage regulator, but then again I am not an electrical engineer.

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I would also go with five cells plus a dummy cell unless you can afford to "lose" the drop-in due to a possible overvoltage problem ... Mine work very well on two 18650's (in a 2D) or two 18500's (in a 2C) but then the voltage is only 8.4V ... I doubt whether the few seconds of overvoltage would cause a problem but I've never tried it , so ??? ... That's into the unknown !

Stick with using five Energisers and a dummy cell and there should be no problem ... It will last for years in the car ... Some of my Energisers are dated 2023.
.

Nasty said:

I currently have 3 of the units in the following configurations:

4DM*g - 5 "C" Duracells in a PVC tube
3DM*g - 9 "AA" Duracells in the cheap $1 3AA.D adapters
2DM*g - 2 "D" Duracells, will be changed to 6 AA when two new adapters arrive

No issues whatsoever...all provide great flood.

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Wouldn't his 9 AAs be pushing the limit by... a large bit?

I've done no resistance mods to the old gal. I figure that between the old factory switch, tailspring, cheapo 3AA>D adapters and any corrosion, I am losing a good bit of voltage.

I've had no issues yet at all yet it sure does pump out the flood.

belomeclone said:

Wouldn't his 9 AAs be pushing the limit by... a large bit?

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depends on the current, 9AA alkaline gives you 13.5v without a load but put a 1amp load and that could sink a lot perhaps to less than 10v.

belomeclone said:

Wouldn't his 9 AAs be pushing the limit by... a large bit?

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See the thread title ^^^^
[Edit: oops, I missed the context. Forget what I said there.]