On Thursday, April 25, 2019 at 2:21:45 PM UTC-4, default wrote:
On Thu, 25 Apr 2019 06:25:44 -0700 (PDT), George Herold
gherold@teachspin.com> wrote:
On Tuesday, April 23, 2019 at 1:21:43 PM UTC-4, AK wrote:
On Tuesday, April 23, 2019 at 1:00:45 AM UTC-5, whit3rd wrote:
On Sunday, April 21, 2019 at 4:46:59 AM UTC-7, AK wrote:
On Sunday, April 21, 2019 at 5:10:50 AM UTC-5, default wrote:
On Sat, 20 Apr 2019 20:18:46 -0700 (PDT), AK
scientist77017@gmail.com> wrote:
I have (8) 5 watt leds that are run from a 12VDC source.
(3 18650 batteries at 3000 Ma hrs each.
I did not see any calculation that determines run time.
Oh, that's easy; the 18650 batteries are 4V each, so to get 12V you
have them in series. 12V * 3000 mAh = energy in the batteries
about 36 watt-hours. So, 7 hours at 5W (one LED), or under an hour
with eight at a time.
That assumes no energy-losing other components (which is unlikely; most
LED assemblies for "12V" nominal input have some required ballast resistance.
The leds are strange looking and there are 5 of them.
Ahh. Say have you pulled one apart and looked inside? There may be
some sort of switching IC controlling the current.
George
I bought some (on Ebay) for my truck awhile ago ('91 Dodge) they were
1157 replacements. Other than the dual contact bayonet base, they
looked identical to his. They didn't satisfy me though - they looked
too yellow (not amber) and the light output, compared to the
incandescent ones, was too weak. So I pulled one apart and there were
something like 5 yellow LEDs in series with a series resistor for each
lighted surface.
IMO the crappy performance is something of a safety concern, so I
didn't put them in the truck.
My lifetime motto: stay safe, have fun, don't get caught.
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