I was in Home Depot today and I spotted this strange sign – it said: “LED Intellibulb Battery Backup.” I understood three out of four words, but the concept wasn’t clicking in my head. Then I read the package and had an aha moment…”this is pretty cool!”
The next thought that struck me was the size and weight of the package… “wait, this thing the size of an A21 light bulb and it can run for up to 3.5 hours?” It didn’t feel any heavier than a normal LED light bulb — lighter in fact than some of the ones with a big metal heat sink.
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After a little reading I figured out how the bulb works. It obviously needs to be in a light socket that is powered on to charge. When the power goes out, and only when the bulb is in a fixture that is still turned on, will the bulb run off the internal battery. It also will not provide the stated 600 Lumens at that point, but hopefully the output is still enough to navigate by.
Thinking about it, this makes sense that it operates in this fashion. It has to be in a closed circuit, or otherwise you couldn’t turn the thing off; it would just come on when you turn the light switch off or removed the bulb. (I wonder if your hand or body could close the circuit; pulling an Uncle Fester and lighting up a bulb in your mouth might be a good party trick – but do NOT try this at home!)
Here are the manufacturer’s specs:
- 600 Lumens (40W equiv)
- 8.5 Watts
- 70.6 Lumens per watt
- 13.7-years life (based on 3-hours/day)
- 2700K (soft white)
- CRI ≥ 80
- A21 size
- E26 base
- Mercury free
- Instant on
At one of my local Home Depots, this bulb is running for $13, but if you look at the website it’s full price at $15. Amazon has what appears to be the same bulb for $11.
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First Thoughts
I can definitely see the utility in this type of bulb in a few locations. For instance, our basement has no outside illumination, and so when the power goes out, you are in total darkness. I’ve been stuck down there before, feeling my way around in the dim light of a battery backup LED. A few of these bulbs placed in strategic places, like the stairway, might make navigating in a power outage easier.
I’m kinda curious about what’s inside this bulb. With a 13.7 year lifespan, what kind of battery can they be using? Based on the weight of the bulb, it can’t be a very large battery. For the light weight and long run time, it’s got to be Li-ion or LiPo, and given the strange shape they have to deal, with probably LiPo.
The bulb uses 8.5W on line voltage, so lets say that it uses 4 watts on battery. So 3.5 hours on battery at 4W is 14W. That’s approaching the watt-hours of a 1.5Ah M12 battery.
If we go down to 2W on battery, that means 7Wh. That’s approximately a 2000mAh, 3.7V LiPo battery, which is in the neighborhood of 20 grams. That makes sense, as it doesn’t seem to weigh much more than a normal LED bulb. I don’t know if I could tell if a 200 gram light bulb weighed an extra 20 grams.
Update: Hackaday did a teardown a few months back, detailing how the Feit battery backup light bulb works.
Wayne R.
“When the power goes out, and only when the bulb is in a fixture that is still turned on, will the bulb run off the internal battery.”
I do not understand.
John Fal
Well I have one of these
and it’s pretty cool, but you do kindof forget about it till it comes on. For instance when I flipped my breaker to do some work my lamp I have it in stayed on, which cut out the need for a flashlight. Now when I turn the lamp off it goes off, when I unplug the lamp it goes off. So it seems pretty smart and it last about 4 hours. I would love to have these all through my house. Btw I got mine on clearance at lowes a while back.
Plus it seems allot brighter than stated.
Wayne R.
Oh, so when you turn off the breaker, the light stays on, but when you turn off the switch, the light turns off?
Still don’t get it. But thanks!
Corey
If it’s in a circuit that’s “on” or closed, it sees the minute resistance of the circuit and will activate the battery. When it’s circuit is off or open, it sees infinite resistance or an open circuit and registers to turn off as it would normally act in the absence of power.
John
How can it tell the difference between a breaker and a switch though? Both break the hot wire (if wired correctly), it seems like fundamentally they are doing the same thing as far as the light is concerned.
Benjamen
To John: Watch the video that Bob H posts below. Actually I’ll repost the link again.
https://www.youtube.com/watch?v=EDwc4pL0TdI
It’s not the most exciting, and it’s slow, but it gets the point across.
John Fal
Correct, works like a regular bulb and stays on when you need it to. I love mine.
Jack S.
use a lamp or pluggable drop light, insert the bulb and turn it on for 30 minutes or so. while bulb is on the battery inside charges. now unplug the cord of the lamp or light. take something metal like a squeeze clamp and clamp over both prongs on male end of cord and the light will work full brightness for a little over 3-3.5 hours.
with lamp or drop light the cords are shorter and less loss of energy when the circuit is bridged by metal across both metal prongs on cord end. so you get the full brightness of the light. instead of it traveling all way through house wiring to box and back or where ever the electric bridge is.
Jared
Maybe I missed it, but does this come on if you flick the light switch on when the power is out? I.e. I understand that if the light is on when the power goes out it stays on, but if it’s off can I turn it on? That would seem more useful to me.
Certainly it would also be useful to have the light stay on when the power goes out, but, for example, I could imagine putting this in the room where your circuit breaker resides so if you turned off the power for some reason, you can see to turn it back on.
John Fal
Hi Jared
Only goes off if u through your breaker or the power goes out.
Big Adam
https://www.ikea.com/gb/en/products/lighting/light-bulbs-accessories/tosthult-rechargeable-led-bulb-art-00400418/
Rock Hound
I wonder if this would be a good solution for fixtures in older houses with so-so wiring, ones that burn out LEDs quickly but worked fine with incandescent bulbs.
Nathan
Makes sense for say hall ways or something like that.
I bet inside it has a solid state relay that latches on when first powered on – and if the power comes off but the sense circult shows continuity – the battery power is opened and maybe half the LED’s come on or stay on.
Wonder if it flickers for a quick ms?
neat idea looking for a problem I suspect.
Hilton
I bought bulb not dissimilar to this one about three years ago. The concept was great but it didn’t last long though, doesn’t charge anymore but the bulb still works.
The one I bought came with a wire hanger so you could take it out of the socket and hang it wherever you wanted to.
BTW the 26 in E26 refers to the diameter of the bulb screw base. In South Africa we use E27 bulbs but the E26 bulbs also fit.
SteveP
I was thinking these type of bulbs were pretty common in SA – given Eskom’s load-shedding (rolling planned blackouts)
Koko the Talking Ape
So apparently this thing starts powering itself when the power goes out, but not when you turn the fixture switch. So how does it tell the difference? When you turn the switch, the bulb is connected to one short wire that is connected to nothing, and one long wire that is still energized but with no electricity flowing through it. When you have a black out, the bulb is connected to two very long wires that are not energized.
I wonder if it requires polarized plugs, or a grounded plug. (I know most appliances use polarized plugs, but I wonder if this guy REQUIRES a polarized plug.)
John
We bought Intermatic PR3C power failure lights at Ace Hardware several years ago. We keep them plugged into an outlet and they turn on automatically when the power goes out. You can leave them in place as a guide light, or unplug them and carry them around as a flashlight. We have them in hallways and next to the fuse box and they put out a good amount of light . I’m not sure if the Intermatic model is still available, but there are similar products out there. Flashlight-style power failure lights seem like a more versatile solution than a battery-backup light bulb.
farid
I have had several brands over the years and they do come in handy every now and then, especially if the lights go out while in the basement or shower. Some have a night light feature. Typical life varies but mine averaged 5 years. I forget who made the last set I bought (GE?), but I just had 2 fail last week and they are just about 5-years old. Time for a new set.
Redcastle
Based on the IKEA product and the Home Depot being equivalent for once the UK price is lower than the US one. I have to change some stairway fittings and will now use ES (Edison Screw) instead of normal bayonet caps so I can use these lamps. From a safety point of view they seem to be a good idea.
Big Adam
Beware, the Ikea version is different. It uses a manual switch to activate the lower-lumen emergency function.
redcastle
Thank yuo for the information that would be a deal breaker the emergency action needs to be automatic to work.
Bob H
I found a video that explains how it works…
https://www.youtube.com/watch?v=EDwc4pL0TdI
Thank you for sharing this very fascinating bulb!
Benjamen
Good find.
That’s not exactly how I thought it worked, I knew it it sensed resistance so it needs a completed circuit.
I thought it was completing the circuit through the transformer, because when the power goes out it goes out it usually goes out on the high voltage line, not locally. It makes sense that it there is anything else plugged in that it can complete the circuit too.
ktash
Reading this I was feeling not very bright, that is, kind of dim. For some reason I first got the idea that the bulb couldn’t go on normally when the power was on and you flipped the switch, but if you waited till you had an outage, it would shine forth! I re-read it and realized that it worked like a regular bulb except for when the power went out, then it still worked as long as the light was on when the power went out.
It was a long day. I’m not even going to try to understand the rest tonight.
Comms Guy
I can see thousands of these showing up at Halloween parties. Stick it on a part of your anatomy and it lights.
Kit
Ooh, given both my partner and I have an interest in repurposing items on occasion, it’s nice to see this light bulb! Makes me wonder what all we can build….
John
My wife brought 2 x 25W units a couple of years ago and they are handy when the power goes off. We get power outs weekly so they get used often.
Jon
It also wil work if you just tip of the screw end with side you can even do it in water just dont go past the screw or you can wet your hand and hold screw and it works or put it in your mouth it will also work just need the battery to be charged and thats it
Rick C
I bet it would confuse the heck out of an electrician who wasn’t told about one or more of these!
Ruth
I bought several similar ones so I would have plenty for extended power outages. I used each for a time until I decided (?) they were probably fully charged, then put some away for a no-power event. Are they going to hold their charge indefinitely?
Thomas
Bought one and like it. Wanted to use it in a hallway where we have no outlet to a lamp. Was wondering if it is safe to use a piece of wire to close the loop on the plug. Currently it will only operate if I hold the plug with my hand and create some closed circuit.
Doug
I just bought these from lowes 9.99 there feit brand . No one ever mentioned that there is a little switch rite on the side of the bulb for off and on . Bulb doesn’t have to be in a socket to work. Just to charge. You wouldnt want it on during the day to run down battery that’s why it has a switch on the bulb. Take a look! Just thought yous would like this info. Thanks