On Mon, 29 May 2017 18:10:06 -0700, mike wrote:
I'd agree, but many of my devices won't run on that voltage.
Wireless power monitors and thermometers, for example.
Most everything that will run on alkaline cells will also run on LSD
NiMH cells.
However, you can't just plug in a LiIon cell into a device made for
alkaline cells, even if they fit. For example, if you try to replace
a common AA alkaline cell with a 14500 LiIon cell, you are replacing a
1.5V cell with a 3.6V cell, which will likely burn out the device.
However, you may be able to replace two AA alkaline cells with a
single LiIon cell if device will tolerate a 20% increase in battery
voltage. Most devices that have a voltage regulator will work nicely.
Those without voltage regulators, will overheat.
What's your experience with 14500 in single AA flashlights?
Mine get hot enough with NiMH. I'm afraid to run them on 4V
at 7W.
Here's an example:
http://www.everbuying.net/product867812.html
I don't understand. 14500 is the size of a AA cell which applies to
alkaline, NiMH, and LiIon, LIPO, LiFePO4, etc, all of which have
different terminal voltages. The flashlight appears to be designed
for a 14500 size NiMH battery. Running it on a AA alkaline will kill
the battery in short order because it can't handle the current.
Running it on an LiIon battery will blow it up because it will be over
twice the rated voltage. There's no information on the above web site
as to whether the light is intended to operate on alkaline, NiMH, or
LiIon voltages, but a comment by a user indicating that "7 days on a
single AA Enelope" suggests NiMH. Do NOT install a LiIon 14500 cell
as it will probably burn out the electronics (also known as the
"pill").
The Cree XP-E Q5 LED is designed to operate at about 350ma and will
generate about 120 lumens depending on type and bin selection:
http://www.cree.com/led-components/media/documents/XLampXPE-25A.pdf
That's about
:
120 lm / (3.6v * 0.35A) = 95 lumens/watt
which is consistent with todays LEDs at room temp. There is no way
the XP-E Q5 LED will dissipate 7 watts or produce 600+ lumens.
In order to run on a single 1.35V nominal NiMH cell, the flashlight
will require a boost converter and a current regulator. Done
correctly, these work just fine. Done badly, they get hot and burn
up. My guess(tm) is that this flashlight is in the latter category.
Lowes has a six-cell 18650 lithium tool battery for $10.
Only 1.5AH, but rated for 30 Amps max.
Was gonna replace NiCd in an old drill, but I'm procrastinating.
It depends on which tool and how the conversion is done. I have
several Makita 9.6v nominal power tools, that were intended to run on
NiCd or NiMH, now converted to run on 11.3v (3 cells) LiIon cells. I
was concerned about the increase in voltage, so I added a series power
diode to drop the voltage. Works fine but admittedly does get warm
when run heavily. Many LiIon (LiPo) battery packs can be discharged
at 10C or more (that's 10 times the rated current in Amp-Hrs). That
sets the minimum cell size to 18650, where my junk cells test at about
1000ma-hr capacity at 1.5A. 14500 would be to small. For charging,
the recommended charge rate is 1C. If you plan to do this, make sure
you use a LiIon/LiPo/whatever charger. I should mention that cramming
18650 cells into some battery packs is a major project. The good part
is that such conversions require fewer cells. You might also consider
using prismatic cells such as:
https://hobbyking.com/en_us/turnigy-1000mah-1s-20c-lipoly-single-cell.html
Make sure you leave room to let them inflate when charging.
For example, this loser sells for about
$0.50 with many flashlight and battery combinations:
http://lygte-info.dk/review/Review%20Charger%20Bowei%20HC-103W%20UK.html
How customs even lets them into the country is a mystery.
I have one that looks identical except has US plug.
Spray a little water into the charger and then measure the AC voltage
between an electrical neutral wire and either battery terminal. The
life you save may be your own. I stupidly bought 10 of these before I
realized what a POS they were. I destroyed them before recycling so
that nobody would get hurt.
Terminates just fine below 4.2V. Doesn't seem to have any of the
characteristics shown in the review.
I didn't take mine apart.
I measured one of mine. When it got to 4.25V, I stopped to prevent
destroying the battery.
--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060
http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558