DIYbanter - View Single Post

Mike

On 5/22/2019 4:52 AM, wrote:
On Tuesday, 21 May 2019 17:29:22 UTC+1, Jeff Liebermann wrote:
On Tue, 21 May 2019 02:01:46 -0700 (PDT), tabbypurr wrote:
On Tuesday, 21 May 2019 02:57:08 UTC+1, Jeff Liebermann wrote:
On Mon, 20 May 2019 15:18:29 -0700 (PDT),
wrote:

I purchased a 3 pack of the model 350 at Costco. Everyone one of
them has this issue. 3 months is about right. Put new batteries
in all of them and a few months later they all are virtually
drained of battery life.
Matt C

...
cork instead of a wine bottle cork. However, I haven't seen anything
for doing it with 4 alkaline cells. That's probably a waste of time,
so I suggest you recycle the flashlight and buy something that runs on
a LiIon cell and not on alkaline cells.

or use NiMH
NT

Yep, that will work better than alkaline. 800ma-hr for NiMH instead
of 750ma-hr for alkaline. The actual difference will be larger
because NiMH tolerates high current loads better than alkaline.

I'm partial to LSD (low self discharge) NiMH cells. About $2.50/cell
from China:
https://www.ebay.com/itm/400827732093
or $4.00/cell from USA vendor:
https://www.ebay.com/itm/153458804452
Four cells per flashlight would cost $10 to $16 per flashlight. For
that price, I could buy an equivalent LiIon flashlight, and still have
some money left over for a crude LiIon charger. Most of these:
http://www.learnbydestroying.com/jeffl/crud/LiIon%20Flashlights.jpg
were $5 to $10/ea plus charger.

So the choice of $2.50/ cells was not a good one. Try 50 cent cells.

I forgot to mumble something about the leakage current. Because the
on-off switch is usually in series with the battery, the "off" leakage
current should be zero. Yet, the Duracell Durabeam Ultra 350
flashlights seem to be leaking some current. Therefore, my guess(tm)
is that the flashlight is wired in a somewhat different manner. Since
the purpose of this flashlight is to sell more AAA batteries, I
wouldn't put it past Duracell to put something across the switch or
use a different wiring configuration to produce some leakage current.

that may be a reason to go new.

NT

Conspiracy theory notwithstanding...

I suggest that some designer made a bad decision to use a cheap
part to manage the flashlight modes. Some manager made an uninformed
decision to remarket the result. Everybody saved a penny, except the user.
Caught with their pants down, some vendors are now advertising flashlights
with zero parasitic drain.
It's unlikely that Duracell had any malicious intent in this.

There really is no clean fix for this. If you use your flashlight every
day, it won't affect you much. If you use it infrequently for emergencies,
you absolutely, positively want it to work when needed.
About all you can do is put an insulator somewhere in the battery
assembly and remove it when the emergency happens.

Next time, buy one that advertises zero parasitic drain.