ok now here is some additional info if you are buying some of the more recent solar lights, if you buy them and they use 18650 battery under brand name on battery of
"ultra fire" send them back, there are still some of these fake batteries popping up on occasion. the market is so hard to watch and too many fakes out there in both batteries and led's themselves coming mostly out of china that are poor quality and re-label under other names
real 18650 battery will weight in at 45 g a few at 43g and some as high as 50g in weight , anything less then 42 to 43g question the validity of the battery. most reputable makers of lights will tell you battery and led brand name and the battery weight and a cri number and power draw of the led and charge rates of the solar
simplified .......
leds
the older style 5mm diameter 2.5 to 3.3 volt drawing 30mA draw giving off about 5 lumen like the older yellow ones
versus today's surface mounts like the samsung 5630 5.6 x 3.0 mm 2.8-2.9 V 65mA draw giving off 28 lumen pure white light
or cobs like the Vollong 3w high white cob led 3.7 v at 750 ma draw 180 and up to 200 lumen
The
Samsung 25R remains our top seller for for the 18650 series battery. With a capacity of 2500mAh so 2 of these i a circuit in theory could power a single 5630 for days until the battery power dropped below the 2.8 trigger voltage of the light.
so long winded story short all this being said the final key is the size and type of solar charging panel the type of solar cell itself makes a huge difference Monocrystalline are the more efficient of the two most common cells they look like a black banded cell versus Polycrystalline the snowflake patter blue that everyone is familiar with.....
most manufactures do not balance size versus load of the solar cell to the requirements of the battery draw so i won't even get in to this but most of those light using multiple 5630 led would need a panel no less the about a surface area of 5 x 5 inches minimum to insure the batteries are charged assuming 2 batteries and 4 or 5 of the leds
single biggest killers of all solar lights and this holds true more for the folks down in hotter climates then to use here in colder climate HEAT....
as heat goes up the efficiency of the solar cell and life of the batteries drops off and at a fast dramatic curve every degree above 77F the eff. drops at about 0.26% per degree but if no air flow this can go as high as 149f in some rare cases at the surface of the solar cell itself in no air flow is allowed under or behind it in affect killed off 20% or more of the solar cells efficiency
so just a rough guide of issues around led lights for outdoors so so many factors including climate of your area bt like i said before look at actual independant product reviews not just one source and look for know name brand components and specs
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