Trout on soggy toast

@W5VO: I'd like an explanation on why this answer was deleted. I kinda get what might be wrong with the answer but it is not obvious absent some explanation (there were no comments or other information).

If the answer was flagged, what was the reason given?

@Skyler What kind of battery are you working with? Is this a lithium button cell, cylindrical primary or rechargeable cell like AA, lithium-ion, or some proprietary bype?

@NickAlexeev I was playing around with some LR2032s so lithium ion

@Skyler I assume you mean CR2032? That's lithium primary, not rechargeable lithium-ion.

theres rechargeable versions

Hmm...

I would not seal a rechargeable Li-ion battery.

amazon.com/Battery-Li-Ion-Rechargeable-Button-LR2032/dp/…

@bwDraco can they combust in an oxygen free environment?

Li-ion batteries make their own oxygen in the event of a fire, so an oxygen-free environment would not protect against fire.

Hmm...any idea on safer rechargable options that I should look into then??

You'd need something like LiFePO4, an alternative lithium-ion chemistry which is very hard to ignite. I'm not sure there are cells with this chemistry in the form factor your application requires...

I'm assuming the cell you mentioned has an LiCoO2 chemistry (which is self-oxidizing in the event of thermal runaway), but I can't find much info on these sorts of cells.

yea

that was a bit of an issues I was having

I actually kind of had some luck finding a local battery manufacturer that might fit the bill and is hosting a battery competition this winter, but I'm still trying to see if cheaper options already exist on the market

I would not recommend the use of conventional Li-ion batteries in a permanently sealed and non-serviceable environment of this sort.

@bwDraco Why not? What difference does sealing make? This type of Lithium cell itself is sealed. If it has to catch fire, it will do so: sealed or nay.

Hmm...

Nick has a point.

@Skyler what are your requirements in terms of space available, cycle life, voltage, peak current, capacity?

@Nick "If it has to catch fire, it will do so" That's great.

What is your application?

@bwDraco wearable lightsource, about as simple as it gets

...okay. Li-ion makes sense here.

If you think sealing a LiPo will help, take a page from Boeing: i.kinja-img.com/gawker-media/image/upload/t_original/…

:)

@Skyler As an aside: If it has got a rechargeable Li-ion battery, it can no longer qualify for "as simple a it gets".

Not that I'm trying to discourage you from this project.

@NickAlexeev about as simple as it gets while it's still rechargable =P

thats part of the reason I'm trying to see if other battery options can work

and dont worry about the discouraging part

That coin cell probably can't give more than a 2nd degree burn. It's fairly small.

@Skyler hrm...why does it have to be rechargeable?

and also, how much light are you trying to put out?

@Shalvenay Currently I'm working with CR2032 that are removable so I mean it doesn't HAVE to be rechargable, but I'd like to make it waterproof and pretty shock resistant and so you can really easily and cheaply do that if you dont have to pull the battery out

@Skyler aah, right

@Shalvenay also hello there friend from another chat

@Skyler Another good thing about LR (as compared to CR) is that they can source a lot more current. The downside is the lower capacity of LR, and Lithium-ion fire safety concerns.

would NiMH be an option here?

@Skyler and how much light/current are we talking about?

@Shalvenay 20mA, as Skyler have mentioned earlier

alright

didn't catch that :p

@Shalvenay so far I'm really trying to keep the current low. Currently (har har) I'm drawing 5-20mA.

@Skyler how long does it need to last?

@Skyler Where on the body will it go? In other words, after the Lithium-ion cell catches fire, and the burn heals, where will you get a manly scar?

head, so thats why Li sounds like a no go

yeah -- how long does it need to run on a single charge?

NiMH button cells are beginning to look attractive here

and id like to get like 40 hrs out of 5-10 mA regime

but as its rechargable i can be flexible

@Skyler Not that it's a fundamental nogo: there are head lamps with Lithium-ion batteries. But for a first project with a Lithium-ion cell, it would make sense to build something that runs a little further from the user's face.

@Skyler -- is fast charging a requirement at all, or is trickle charging sufficient?

@Shalvenay trickle is probably fine, depends how slow you mean

@Skyler say, 10 mA of charge current

how exactly would that chnage things vs rapid

lets say sure, but can we explore both cases so I actually understand this problem

@Skyler trickle charging is a lot simpler

you don't need charge control electronics for a trickle charger, vs a fast charger

so its mainly a design change in the charger rather than battery

right

what are you charging this from BTW?

@Skyler -- you still about?

hello

im alive

ah...what are you charging this light from?

@Shalvenay kinda wanna try usb

@Skyler alright, so roughly 4-5V @ 100mA

@Shalvenay yea

soo....

any suggestions

@Shalvenay whats the right way to current cap USB chargers

@Skyler looking for a charge IC atm

ah thanks

I like the MAX1555 series myself, pretty cheap, 100ma

@Giskard42 wrong chemistry though -- we're looking for NiMH not Li-Ion here

digikey.com/product-detail/en/texas-instruments/BQ2002TSN/… << one of these should do the job along with a NTC + a couple of 1% resistors to set the temperature limits on charging

varta-microbattery.com/applications/mb_data/documents/… << one of these for the battery

digikey.com/product-detail/en/ZXSC380FHTA/ZXSC380FHCT-ND/…

^^ and last but not least, the LED driver

which just needs an inductor and the LED

oh, and you'll need a power transistor + a few drive parts for the BQ2002T

got all that @Skyler?

looking now

also, useful resource: varta-microbattery.com/fileadmin/user_upload/downloads/products/…

thanks, I'll mull over these things for a while

yeah, you'll probably have to breadboard the BQ2002T some as it's not exactly the best documented IC in the world

anyways, im off, ill ttyl

thanks again

np

@bwDraco We didn't need another "clever" answer saying exactly the same thing on that question.

Thanks, but I kinda expected a more polite tone.

If the answer is a duplicate, at least put a comment on the answer prior to deleting it...

It's not always obvious what went wrong when a post gets deleted.

Not that I object to the deletion itself, but this kind of attitude does risk scaring away newcomers.

newcomers attracted by nonsensical questions?

That question was a train wreck that got put on the "Hot Network Questions" list, which is probably where you first found it.

Yeah, I was leaning towards flagging for closure.

But I'd strongly prefer not being so harsh about mod actions. I've been on SE for long enough that I have a sense of what should and shouldn't be posted, but I did check the other posts and it wasn't obvious that it duplicated existing content.

And you still felt like you had something to add even with the question being protected.

Seriously, though, the tone of these responses seems more patronizing than polite.

I expected better from a mod.

I'm just a bitter mod - what more do you want?

...and this is why new users are finding Stack Exchange unwelcoming.

@W5VO You're evading the question.

Go ahead, what's the question?

I'd rather drop it at this point.

Chinese solar Christmas outdoor lighting: operating temperature 0°C - 40°C

Because it probably has a rechargeable battery of Lithium Type and no intelligent protections

In fact, it probably has LiPo which should not be used sub zero at all

@PlasmaHH at first glance I thought you typed : 0C to -40C.

@Marla that would only be a slightly bit more odd ^^

Maybe for next year I do my own solar powered solution, these solar panels are tiny

I hate it when websites pretend to be a German version of the shop and then charge your credit card from abroad and cause extra fees and then for whatever reason charge the whole sum in multiple chunks

Get a better Credit Card?

Fooding, fooding. Nom Nom Nom.

Almost all below platinum level either pay per transaction fee in other countries, or you pay a monthly for a certain country group

I'm dealing with an EMI issue with USB 3.0 cables. Would ferrite beads adversely affect the integrity of the signal within the cable?

Hm, I guess the blood on the opamp could be a reason for bad readings...

hey there @Skyler