SCCARC Talk on flashlights, LiIon,
LiPO, Lumens, Lux, eBay,
18650, etc.
http://www.learnbydestroying.com/jeffl/SCCARC-talk-2017-09-15/SCCARC-talk-2017-09-15.doc
Ver 1.4
·
Introduction
o
Lumens = SI unit of luminous flux, equal to the
amount of light emitted per second in a unit solid angle of one steradian from a uniform source of one candela.
o
Foot Candles = unit of illumination (now little used)
equal to that given by a source of one candela at a distance of one foot
(equivalent to one lumen per square foot or 10.764 lux).
o
Lux = SI unit
of illuminance, equal to one lumen per square meter.
o
Lux meter,
integrating ABS pipe,
o
Lumens are measured with an integrating sphere.
https://www.google.com/search?q=integrating+sphere&tbm=isch
o
Circle of area 1 square meter = 1.13 meter or 44.5 inches
diameter. For a 1 square meter spot on
the wall, 1 lux = 1 lumen. Run demo of measuring lumens with lux meter.
o
White LED is typically 80-100 lumens/watt. Therefore, if you know the current and the
LED forward voltage, you can estimate the light output. Everything else is loss (lens, reflector, heating,
battery sag, etc). Don’t believe unreal
lumens and battery ma-hrs.
o
Yellow/blue balance.
Warm 2700-3200K, Daylight 4000-4500K, Cool 5000-6200 K.
https://cdn.instructables.com/F4P/B8FM/HS0CZZOY/F4PB8FMHS0CZZOY.MEDIUM.jpg
https://i.stack.imgur.com/CT604.png
o
Forums
http://www.candlepowerforums.com
http://budgetlightforum.com
·
Batteries
o
Why LiIon? High capacity, high peak current, high energy
density, doesn’t leak, no self-discharge, fairly fast charge, low cost per
watt-hr.
o
Types of LiIon and LiPo batteries:
http://batteryuniversity.com/learn/article/types_of_lithium_ion
§
Lithium Cobalt Oxide(LiCoO2)
§
Lithium Manganese Oxide (LiMn2O4)
§
Lithium Nickel Manganese Cobalt Oxide
§
Lithium Iron Phosphate
§
Lithium Titanate
o
http://batteryuniversity.com/learn/article/the_li_polymer_battery_substance_or_hype
o
Size. 18650,
14500, 21700(2170). Protected vs unprotected. BMS
(battery management system). Use in
electric bicycles and cars.
o
How batteries are rated (ma-hr, 0.2C rating, family
of curves). Try to use ma-hr at
operating conditions.
o
CBA II discharge tester.
http://www.learnbydestroying.com/jeffl/battery-tests/18650.jpg
o
http://www.learnbydestroying.com/jeffl/LiPo/
o
Salvage from laptop batteries.
o
Spot welder and nickel wire strips.
o
How to kill LiIon. Store at full charge. Store discharged below about 30% SoC. Don’t
overcharge (>4.2v).
o
Counterfeit batteries.
https://batterybro.com/blogs/18650-wholesale-battery-reviews/104619270-can-you-identify-the-fake-lg-hg2-18650-battery
·
Flashlights
o
Lens vs reflector. Front vs side
lighting. CoB
(chip on board). Importance of heat
sinking.
o
eBay at it’s
worst. Mostly junk, but at good prices.
o
Switches and control.
Tail vs side switch.
o
Sharp edges, bad threads, misaligned LED,
·
Demos
o
Show box of flashlights, batteries, and gadgets.
o
Green lasers.
·
Charging
o
Show various chargers. Specs, limits, quality, safety, junk, price.
o
http://www.lygte-info.dk/info/indexBatteriesAndChargers%20UK.html
o
Junk Charger:
http://lygte-info.dk/review/Review%20Charger%20Bowei%20HC-103W%20UK.html
o
Parallel cell charging.
o
Balance charger.
iMax B6.
https://hobbyking.com/en_us/imax-b6-50w-5a-charger-discharger-1-6-cells-genuine.html
·
Misc and trivia
o
XT60 connectors to replace Molex and
https://www.google.com/search?q=xt60&tbm=isch
https://www.aliexpress.com/store/product/10-Pairs-XT30-XT60-XT90-Yellow-Battery-Connector-Set-4-5mm-Male-Female-Gold-Plated-Banana/1764032_32819798560.html
