light to run off a battery

[JohnW2]

My initial idea was to use a 1.5v bulb and use a refective case as these bulbs are only 0.3w and have 200ma draw but not sure how bright it would be. I would use maybe 3 D battery's to give a decent life span.

If you're talking non-rechargeable, I think an alkaline D-cell would provide something between 10Ah and 15Ah at 200mA. If that's correct, then one of those would therefore theoretically represent about 50-75 hours for a single 1.5V/0.3W/200mA bulb.

It's not a good idea to put batteries in parallel. If you put 3 D-cells in series, you'd have to use either three 1.5V bulbs in series or else use a 4.5V bulb. If the totally wattage was still 0.9W, that would again equate to 50-75 hours.

Kind Regards, John

 

[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?

 

[maltaron]

12v 1watt Bus lamps are ideal for that purpose, standard BC cap fits any table lamp. I used these some years ago for table lamps at a corporate dinner, used 12v 7ah sla batteries in plastic boxes covered with cloth as stands for the table lamps.

 

[JohnW2]

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

 

[big-all]

a point to take note off
rechargeable batteries can be 20% over volt dependant on charging regime so up to 14v that may cause damage

 

[333rocky333]

Also, everyone seems to be assuming that you would be using fairly large re-chargeable batteries

I didnt, I actually thought of 996 lantern batteries but for some reason thought they were 12 volt rather than 6v

 

[JohnW2]

Also, everyone seems to be assuming that you would be using fairly large re-chargeable batteries

I didnt, I actually thought of 996 lantern batteries but for some reason thought they were 12 volt rather than 6v

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

Kind Regards, John

 

[JohnW2]

a point to take note off ... rechargeable batteries can be 20% over volt dependant on charging regime so up to 14v that may cause damage

ericmark made a similar comment, either in this or some other recent thread. Is it really true that there are 12V LEDs around that would be damaged by 14V? I wouldn't have thought that even cheap ones would be working as close to their limit as that.

Kind Regards, John

 

[Astra99]

I am using 12v LED lights and strips in my garage. A 12V battery pack is recharged by a solar panel, which peaks at 15V plus. In bright sunlight the ammeter shows zero, meaning that the solar panel (nominally 12V 20W) is supplying the entire current draw of the three LED lights. Therefore, don't be too concerned about putting 13.4V across the LED lamp, unless it's a "very grey import" marked "CE" (Chinese Export) it will cope.

 

[big-all]

a point to take note off ... rechargeable batteries can be 20% over volt dependant on charging regime so up to 14v that may cause damage

ericmark made a similar comment, either in this or some other recent thread. Is it really true that there are 12V LEDs around that would be damaged by 14V? I wouldn't have thought that even cheap ones would be working as close to their limit as that.

Kind Regards, John

i have an unregulated 9-12v this sort
http://www.ebay.co.uk/itm/1pc-10W-H...t=LH_DefaultDomain_3&var=&hash=item19e67982c3
this is just an example
i tried running it off a 10.8v bosch blue battery around 13v fully charged
its on a big bit off aluminium as a heat sink but when put on a fully charged battery its as bright if not a bit more than the same chip in a mains bulb
i dont connect it to a fully charged battery in case it burns out as its so bright

 

[333rocky333]

Also, everyone seems to be assuming that you would be using fairly large re-chargeable batteries

I didnt, I actually thought of 996 lantern batteries but for some reason thought they were 12 volt rather than 6v

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

Kind Regards, John

Actually, reading back I said cube shape battery, so I actually meant PP7
Anyway there only 9v so no good either

 

[JohnW2]

Actually, reading back I said cube shape battery, so I actually meant PP7 .... Anyway there only 9v so no good either

Fair enough, but it's many years since I saw one of those, either! Are they still made?

Kind Regards, John

 

[JohnW2]

i have an unregulated 9-12v this sort
http://www.ebay.co.uk/itm/1pc-10W-H...t=LH_DefaultDomain_3&var=&hash=item19e67982c3
i tried running it off a 10.8v bosch blue battery around 13v fully charged ... i dont connect it to a fully charged battery in case it burns out as its so bright

Item location: Hongkong, Hong Kong

... Therefore, don't be too concerned about putting 13.4V across the LED lamp, unless it's a "very grey import" marked "CE" (Chinese Export) it will cope.

Kind Regards, John

 

[big-all]

an example

 

[big-all]

Actually, reading back I said cube shape battery, so I actually meant PP7 .... Anyway there only 9v so no good either

Fair enough, but it's many years since I saw one of those, either! Are they still made?

Kind Regards, John

9v lantern batteries
https://www.google.co.uk/search?q=9...&oe=utf-8&gws_rd=cr&ei=BgRZVdjHEMyI7AbdlYPoBQ