air travel – Can I take portable speakers with lithium batteries as carry-on on an Air India flight?

The regulations on Air India’s website are very clear. The relevant parts are :

“for lithium ion batteries the Watt-hour rating must not exceed 100 Wh”

“Batteries spare / loose, including lithium ion cells or batteries, for portable electronic devices must be carried in carry-on baggage only” and “Articles which have the primary purpose as a power source, e.g. power banks are considered as spare batteries”

“Each person is limited to a maximum of 20 spare batteries”

You have stated that all of your devices have Lithium-Ion based batteries that are 4500 mAh or less. To convert mAh (milliamp-hours) to Wh (watt-hours) you need to divide by 1000, and multiply by the internal voltage of the battery, which for Li-ion batteries is ~3.6 volts. Thus 4500 mAh is 4500/1000*3.6 = ~16 Wh – well below the allowed 100 Wh per battery.

Your power bank is clearly considered a “spare battery” per the rules. Even if your speaker is also considered a spare battery (which is unlikely, but possible), then you have 2 spare batteries – well below the 20 allowed.

So yes, it is allowed.

Macro flash ring for Nikon – but on li-ion batteries?

Im going through the internet to find a cheap macro ring for my Nikon D5100, but I really dislike the power input “4x AA battery”. I dislike those batteries, since (yes, they can be bought easily everywhere) I want to (and can!) charge my batteries at all times.

Is there such a thing or am I being too unrealistic?

Disc film cameras that use replacable batteries?

NO batteries required.

Use, or Modify?, a 4×5 Large format film holder so you can attach or tape the film, removed from the cartridge, in the middle of it. Assuming it will not interfere with the dark-slide, you may have to remove the plastic center piece in the disc of film.

Now use the 4×5 LF film holder in Pinhole camera that accepts 4×5 LF film holders. It will expose all of the negatives simultaneously. Make an enlarger negative holder for the film and print it as one photo. Or send it to a lab and have each neg printed and then assemble in the same orientation. Think outside the film cartridge.

Or variations on that theme. Experimentation encouraged.

NOTE: Of course all work with film will MUST be done in a dark room, I.E. A room with absolutely no light.

No affiliation with the zero image camera i linked to other then i own one and love it. (Another option is to make your own)

off camera flash – Does Yongnuo YN622C TX/RX accept rechargeable NiMh AA batteries?

They do not “need” 1.5 volts, you get a tiny bit of oomph due to the minutely greater voltage.

Here is one quote in reference to the particular model you are using: “Due to their higher voltage it’s often best to use good Alkaline Energizer or Duracell batteries rather than rechargeable NiMH batteries.”.

Here is another quote, from SLRLounge “Best Rechargeable AA Batteries for Flash and Photography – The Ultimate Guide Part II”:

“The short conclusion was that the Eneloop XX and Standard Eneloop not only performed better than all of the alkaline batteries, they were also more economical in the long run. However, if you had to use alkaline batteries, your best bet would simply be the standard Duracell AA alkaline batteries.”.

SLRLounge’s reasoning to use a (particular) Flash to test rechargeable batteries is: “The Vivitar 285HV has a very long full power to full power recycle time just by itself. This makes it wonderful for these kinds of tests since the results are a bit more exaggerated, and also because it allows the batteries and flashes to stay a bit cooler since the recycle times are more spread out.”.

My opinion: Ray-O-Vac.

Everyone has an opinion of what to do and how to do it. So that this question is not opinion based, the fact of the matter is that rechargeable batteries will save you a small fortune, the power difference is negligible, and it’s allowed for if the voltage regulator is doing it’s job; plus it’s environmentally friendly.

Do your research, choose a charger from the manufacturer of the batteries you decide upon (as opposed to a 3rd party unit) and be prepared to shell out U$40 to get started. You’ll get your money back in 6-12 months if you use a lot of batteries, the only ‘expense’ is the charger and the higher cost of a few sets of batteries. You can swap them out when there’s still a 1/3 of a charge left without penny-pinching them to the end because they are rechargeable.

Why is my Canon 5DMIII draining batteries overnight?

I know its a late reply but it could help someone with similar issue as mine.

I had given my camera to a friend for couple of days. After receiving the camera, the battery was drained overnight.

Changed couple of batteries, with and without lens, 3 firmwares. Nothing worked!

After installing Magic Lantern, saw that the Access light was continuously flashing after turning off the camera. This happens when the card is being accessed. Used a torch and noticed that one of the cf card contacts was bent and was touching the other contact. Bending it back fixed the issue for me.

You may want to give it a try before giving it to the service centre.


How long do laptop batteries last?

How many years have you had a laptop battery last?

I recently replaced mine and I think my laptop is 5 years old. The old battery was swelling and causing my touchpad to pop up out of the keyboard.

battery – 2011 Macbook Pro 15″ keeps eating batteries

I have an ancient 2011 MBP that keeps destroying batteries. I had the logic board replaced in 2016 for the integrated graphics recall, FWIW. I just replaced the current batt with one from OWC (NewerTech brand), and bought a new 85w Apple mag-safe charger at the same time.

This same scenario has happened 4 times now. The charge in the battery gets low, and the Macbook won’t power on anymore. I plug it in, and the magsafe charger light stays green. After starting the machine, it says “Battery not charging” in the status bar.

No amount of SMC resets, pulling / disconnecting the battery, or PRAM resets solve the problem. I’ve only ever been able to fix this by replacing the battery with a new one. Anyone else having this problem?

35mm – Canon IIIa Batteries

You mean this one from 1952?

From Canon IIIA, IVF, IVS Rangefinder Cameras of 1952

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Batteries in those days would have been nearly the size of the camera. You can be pretty sure nothing of that vintage is ever going to need batteries, except for a flash,

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which wouldn’t really be on rangefinder cameras for another few years.

Batteries in a lamp

Let n > 2 be an integer.
Part a] There are 2n + 1 batteries. We don’t know which batteries
are good and which are bad but we know that the number of
good batteries is greater by 1 than the number of bad
batteries. A lamp uses two batteries, and it works only if both
of them are good. What is the least number of attempts
sufficient to make the lamp work?
Part b] The same problem but the total number of batteries is 2n
and the numbers of good and bad batteries are equal.

how to replace the batteries in the logitech k800 wireless keyboard

I had the logitech k800 keyboard, wirelessly lit, for 9 months of use, but 2 years in the package before that. In the past 8 months it has been working well and I have successfully loaded it several times. But now he hesitates after a few repeated keystrokes, then shows them all at once or not at all. I don't see the battery changing when I remove the small panel at the bottom, so how do I find the battery compartment? I have both AA and AAA rechargeable batteries. Thank you. FOR EXAMPLE