Rechargable Battery Savings vs NonRecarg

Just getting in to this 'sport'. in the last 3 days just bought a TK40, a EDC Elektrolumens and a Firesword from Elektrolumens.

As part of making this investment i had to decide on torches powered by rechargables vs not.

Here is my homemade math. I'm sure it's wrong, but it's directionally correct. Read this if you have ever wondered how much you save via rechargable.

I used the TK40 as the base assumption flashlight. it takes 8 AAs for about a 3 hour run. I priced out three options to make that 8 hour run

Kirland AA (samsclub)
Duracell AA (anywhere)
AW 14500s and a WA143 charger (8 batteries and two chargers)

here is the cost:
Kirkland cost per AA battery is $.26. a 3 hr run on a TK40 will cost $2.10 in total.

Duracell cost per batt is $.80. a 3 hr run will cost you $6.40 in total

AW 1400s (assuming you ammoritize the total cost over 100 charges over the life) will cost you $.19 per battery. a 3 hr run will cost $1.54 in total (yes, this includes electricity to charge each battery of $.05 per battery per charge).


Now, if you believe that, here is the good news:

- it only takes 23 charge cycles of breakeven on the investment of rechargables. Rechargables save you over $4 per charge cycle versus Duracell.

- if you actually run 100 charge cycles you wind up saving $489


I have a spreadsheet with the calcs but couldn't figure out how to post it legibly. I'll send it to one of the Admins if they wnat to post it.

:tired:

where do you live where it costs a nickle to charge a battery?
it is about a nickle per kwh here which could charge 200+ batteries perhaps.

Nice analysis. But don't forget you also get a high quality/brightness of light with 14500. And there's also the dangers of rechargeables. There's also the environmental factor too. I myself will be switching to rechargeables soon.

vigalass said:

I used the TK40 as the base assumption flashlight. it takes 8 AAs for about a 3 hour run.

AW 14500s and a WA143 charger (8 batteries and two chargers)

Click to expand...

I do not hope you will test this combination, it will blow the TK40.
The TK40 needs NiHM batteries not LiIon.

HKJ,
I'm glad you asked. yes, i had planned to test it. not becuase i want to blow up my light though.

I see you are right per the spec on Fenix.com where they warn.
Alkaline, Ni-MH compatible. Do not use Energizer Lithium AA cells for this light.

But....
I thought a 14500 versus a standard AA battery was was .2v on a basis of 1.5 (15%). I thought i read a string here in CPF where a 14500 was identified as a solution alternative for the TK40.

WHy would the TK40 not be able to take 14500's, mathamatically or experentially?

Eitherway, i don't want to blow myself up so please do educate me.

vigalass said:

HKJ,
I see you are right per the spec on Fenix.com where they warn.
Alkaline, Ni-MH compatible. Do not use Energizer Lithium AA cells for this light.

But....
I thought a 14500 versus a standard AA battery was was .2v on a basis of 1.5 (15%). I thought i read a string here in CPF where a 14500 was identified as a solution alternative for the TK40.

WHy would the TK40 not be able to take 14500's, mathamatically or experentially?

Eitherway, i don't want to blow myself up so please do educate me.

Click to expand...

Here you are confusing Energizer Lithium (1.7 volt) and LiIon (3.7 volt) batteries. TK40 can work with Energizer, but it is not recommend.

There was one thread here on cpf about a guy that used LiIon in the TK40 and it did die.

It does not take long to pay off the investment in decent quality rechargeable NiMH batteries and a mid-priced charger. What's more, there are loads of household gadgets that can use NiMH cells. Mine include a GPS receiver and a Nikon flash unit.

Also, non-rechargeable chemistries can and do leak. I recently found two torches in my car that had sat there for many years, one an old non LED 2AA Maglite, the other a cheapo torch, and the batteries in the cheapo torch had leaked. Why pay $100 for a nice light only to have it screwed by a $1 battery?

It is said here so often, and is so well known, but it's worth saying the obvious. Get low self discharge NiMH such as the forums pet LSD battery, the Eneloop, or one of the other equally good LSD batteries. Mine claim to take 1000 charges!!!!

The savings are nice, as is their lesser environmental impact, but for me the best part are the "guilt free" lumens. Makes playing with all these lights much more fun.

Geoff

Another voice in support of Eneloops. They occasionally go on sale - I watch DealsPl.US and Amazon, but none quite as good as Circuit City's flameout sale - and are exceptional performers. They also don't need to be topped up weekly (or semi-daily, like my cheapass Energizers before them).

They'll also be brighter longer than alkalines.

Kirland batteries are often closer to 50% the power of a good name brand AA. Your experience may differ.

Flying Turtle said:

The savings are nice, as is their lesser environmental impact, but for me the best part are the "guilt free" lumens. Makes playing with all these lights much more fun.

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This is the crux of the matter for me as well. If I used primary cells, I'd mostly use efficient, modest lights, and would seldom really 'let it all out'.

But with rechargeables, I can run at maximum outputs and fully enjoy all the free lumens. It really does come down to fun.

Lighthouse one said:

Kirland batteries are often closer to 50% the power of a good name brand AA. Your experience may differ.

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they actually top the list
https://www.candlepowerforums.com/threads/64660

Its very simple to see the value of a good charger and LSD Ni-Mh cells.

Remember the charger/cells still have a 2nd hand value, this is always there, it only depreciates over time.
You break even a lot quicker than you think as you still own the asset.


Yes please don't use 3.7v (4.2v when charged) AW14500 in your TK40, get Sanyo Eneloops or GP Recyko low self discharge NiMh's.

14500's + TK40 = .............................

IMO it all comes down to the application. In many of my son's toys, the battery drain is so low that I would easily destroy rechargeables by way of deep discharge if I did not recharge them on a regular basis. The toys, while many, get so infrequent use that it makes using alkaline an easy choice. Anything with a high rate of discharge - cameras, camera flashes, flashlights, etc. do get fed rechargeables in my house because they make it worthwhile.

Lighthouse one said:

Kirland batteries are often closer to 50% the power of a good name brand AA. Your experience may differ.

Click to expand...

Ragiska said:

they actually top the list
https://www.candlepowerforums.com/threads/64660

Click to expand...

I am told, reliably but off the record, that Kirklands are 100% regular Duracells but with a different coat on. And it wouldn't surprise me if the K batteries were in fact made slightly better, since Costco is very picky about their good name. But I prefer e'loops over alkalines, for the previously mentioned alkaline leaking and environmental factors if nothing else.

My second favorite feature of rechargeable batteries is that you can easily top them off so you know you have a fully loaded torch ready to go. Of course the best feature is the 'guilt free lumens' as many put it here.

I think the major difference in cost is the environmental impact, especially if you don't scrupulously recycle your dead primary batteries.

That said, I run primary 123 cells in my lights because it better suits my use cases.