Designing Whole house LED night lights.

[clare at snyder.on.ca]

Well, George would say that, but as always he'd be wrong. Never drive
an LED without some kind of current limiting.

But MANY commercial apps do just that. If the voltage is right, the
current WILL be limitted.

 

[Ecnerwal]

But MANY commercial apps do just that. If the voltage is right, the
current WILL be limitted.

Those commercial apps would be the ones that are "designed" to be tossed
every 6 months, or whihc lead people to believe that LEDs "burn out".

Individual variations in LEDs mean that the correct forward voltage is
never quite the same, and the IV curve is non-linear. What that means in
practice is that a system which depends on LED forward voltage-drop to
run an LED is prone to failure - and one based off a lead acid battery
bank is even more so, since the voltage varies by a significant amount.

Given the availability of cheap tools to do the job of current limiting
correctly, only a fool (or a designer working for a penny-pinching fool)
will choose to avoid them.

 

[William P.N. Smith]

But MANY commercial apps do just that. If the voltage is right, the
current WILL be limitted.

What commercial apps drive LEDs in voltage mode instead of current
mode? [Note that 'direct drive' LED flashlights are using the
intrinsic ESR of the battery to (attempt to properly) current-limit
the circuit, and that hardly counts as "design".]

 

[Steve Spence]

Given the availability of cheap tools to do the job of current limiting
correctly, only a fool (or a designer working for a penny-pinching fool)
will choose to avoid them.

Or a clown masquerading as a solar power consultant. oh, wait, you said
fool already ;-)

 

[George Ghio]

Love the word "IF"

Those commercial apps would be the ones that are "designed" to be tossed
every 6 months, or whihc lead people to believe that LEDs "burn out".

But they do burn out. Give one 4 volts and see how long it lasts.

Individual variations in LEDs mean that the correct forward voltage is
never quite the same, and the IV curve is non-linear. What that means in
practice is that a system which depends on LED forward voltage-drop to
run an LED is prone to failure - and one based off a lead acid battery
bank is even more so, since the voltage varies by a significant amount.

I have to agree. A 48 volt system can hit 60V not a problem.

Given the availability of cheap tools to do the job of current limiting
correctly, only a fool (or a designer working for a penny-pinching fool)
will choose to avoid them.

Don't pick on Steve Spence.

 

[Derek Broughton]

Those commercial apps would be the ones that are "designed" to be tossed
every 6 months, or whihc lead people to believe that LEDs "burn out". ....
Given the availability of cheap tools to do the job of current limiting
correctly, only a fool (or a designer working for a penny-pinching fool)
will choose to avoid them.

Or a company counting on consumerism - nothing foolish from the
manufacturer's viewpoint about planned obsolescence.

 

[wmbjk]

George Ghio wrote:

hardly. Maybe Ecnerwal is right, but ISTR George being right on some
things a while ago. Just not consistently.

ISTR that all hookers were virgins once. Just not consistently.

Wayne

 

[Ecnerwal]

Or a company counting on consumerism - nothing foolish from the
manufacturer's viewpoint about planned obsolescence.

You think? Will I ever buy another electro-luminescent plug-in light?
Will I speak out against others wasting their money on those?

The answers are no and yes, respectively, and all due to a design that
consistently fails to work after a rather brief period.

 

[Derek Broughton]

You think? Will I ever buy another electro-luminescent plug-in light?
Will I speak out against others wasting their money on those?

The answers are no and yes, respectively, and all due to a design that
consistently fails to work after a rather brief period.

You won't, but you can't reach as many people as said company's advertisers
can. If they can pick a cheap manufacturing method that means a product
lasts a year, or a more expensive one that means the product lasts a
lifetime, most companies are going to choose the cheap method every time -
even if the saving is miniscule, because they have no interest in selling
something they'll never get a chance to sell you again.

 

[Pop]

....
they have no interest in selling
: something they'll never get a chance to sell you again.
: --
: derek

A basic truism, and a disgusting one, but ... whatcha gonna do?
I suppose they figure eventually it'll be OK 'cause we'll blast
all our throw-away stuff into space once the landfills and oceans
are full.

On the other hand, a good, reliable product with a healthy,
intelligent company behind them, doesn't need immediate repeat
business. In my experience, the most profitable cost centers in
the telecom industry have always been the repair facilities.
They're gold mines.

Pop

 

[JoeSP]

Must make y'all proud to correct somebody's spelling
huh?

LOL
in message

Cats?