Today I Learned: There Are Dimmable LED Lights Bulbs That Have Built In Battery Back Up

[JAS]

EcoSmart 60-Watt Equivalent A21 Dimmable CEC Battery Backup LED Light Bulb with Selectable Color Temperature (1-Pack) 11A21060WCCTB01 - The Home Depot

This energy efficient Ecosmart LED light bulb is equipped with a power failure battery that will automatically illuminate the LED bulb if the power fails. In this sense, this LED light bulb can function

www.homedepot.com

 

[CanadianGuy]

I saw a similar one at the dollar store and wondered how it senses a power outage vs just the switch being turned off.

 

[JAS]

 

[JoakimFlorence]

I'm going to make an educated guess that the lightbulb probably either will either not put out a high amount of light when the power is cut off, or the light will not be able to stay on very long without outside power.

A basic calculation shows that at 8 Watts power consumption, a 3000mAh battery would only be able to provide power for 22 and a half minutes.
(I have difficulty seeing how a battery larger than that would be able to fit inside the bulb)

 

[Dave_H]

I have tried out a few different brands of this type of bulb. Some claims are a bit
optimistic/misleading but they generally seem to work OK.

I have opened up a couple, one which was not working. Line voltage is stepped down to
low voltage dc to power the LEDs (wired in parallel) and charge the battery (in two cases, single Li-ion 18650).

Latest one is from Amazon return liquidator. It claims 500 lumens, 7W, but appears
to only draw about half that even when charging the 2200mAh cell. Perhaps it's out of spec. Also, standby brightness runtime is limited. At lowest setting it is confirmed to hold up at least 10 hours, but only at 10% brightness which is somewhat but not much better than a night-light.

This bulb creates some RFI which interferes with a wireless ac switch operating
around 315MHz. Receiver does not operate when bulb is turned on within a few feet.

Dave

 

[Dave_H]

The function of coming on during power failure is a bit tricky. Lamp needs to light regardless of the line switch being on or off. It must sense the line connected, but no voltage present; but not when normally turning switch off. I read somewhere of one or more patents on this technology, so it is not trivial; no technical details though.

I did test one of these lamps by connecting to a dedicated wall socket in the basement
and switched its breaker off. Lamp performed as it should.

Dave

 

[PhotonWrangler]

The function of coming on during power failure is a bit tricky. Lamp needs to light regardless of the line switch being on or off. It must sense the line connected, but no voltage present; but not when normally turning switch off. I read somewhere of one or more patents on this technology, so it is not trivial; no technical details though.

I did test one of these lamps by connecting to a dedicated wall socket in the basement
and switched its breaker off. Lamp performed as it should.

Dave

If you remove the (fully charged) bulb from it's socket and press your hand against the base contacts, it will light up. It's apparently looking for a resistance across the contacts with the absence of line voltage to cause the light to turn on from it's battery supply.

It also makes for an amusing party trick.

 

[JAS]

 

[PhotonWrangler]

View attachment 70074

Yes, it can do that as well.

 

[Dave_H]

Yes, it can do that as well.

A great party trick!

Some of these bulbs come with a socket cap which shorts the contacts out to light the bulb.

Dave

 

[JAS]

We Asked the Experts: 7 Reasons LED Bulbs Fail Early

Do your LED bulbs seem to burn out way too fast? We found out why it's happening.

www.cnet.com