light to run off a battery

[333rocky333]

Are they still made?

Kind Regards, John

Seems so, the reason I thought of it was I only brought a PP7 last year , I bought it from a high street sweetshop in colchester about £8 I recall.

It was for an old back door alarm, consisting of a door contact, key switch and small buzzer.

 

[mattym]

Just found this http://www.maplin.co.uk/p/verbatim-1w-80-lumen-led-g4-capsule-a00nj#
if I ran it with a 5ah 12v battery that would give a decent life span?

Well, 1W at 12V is just over 80mA - so, if the battery could deliver 5Ah at that current, it ought to last around 60 hours (i.e. 2.5 days continuous).

However, one thing to watch about running LEDs off batteries is the minimum supply voltage to the LED which will still produce light - since battery voltage will gradually fall during use. Calculations as above assume that the battery can be used until it is 'flat', but the voltage may have fallen to a level insufficient for some LEDs appreciably before that.

Kind Regards, John

do you think this would be worth giving a go?

 

[JohnW2]

do you think this would be worth giving a go?

Well, it certainly should work initially. Whether you'll get anything like 60 hours before the battery voltage falls too low for the LED lamp is an unknown, at least as far as I am concerned!

Kind Regards, John

 

[JohnW2]

Seems so, the reason I thought of it was I only brought a PP7 last year , I bought it from a high street sweetshop in colchester about £8 I recall.

Good grief - I seem to recall them being about 2 shillings (aka 10p)

Kind Regards, John

 

[ban-all-sheds]

Blimey.

Yes, those were/are 6V - can one still get them?

Widely, and also widely available are new torches/lanterns which use them. Maybe not easy to use for this because of the spring terminals - a 915 or 918 would be better.

But D cells probably have the lowest £/mAh.

 

[333rocky333]

Good grief - I seem to recall them being about 2 shillings (aka 10p)

Kind Regards, John

You get 40p scrap for a rechargable panel battery now

 

[mattym]

To make this work is it as simple as wiring a bulb a battery and a switch together or am I missing something?