5 ms·

All About Batteries

117 points by MichaelAO 12y ago

lam 12y ago
The article is not accurate in some places. E.g., some coin cells are rechargeable such as the LIR2032.
- userbinator 12y ago
  Also funny to see "and lithiums are 3V" (not mentioning li-ion at all) next to... the 3.7V lions they're selling on the same page. Fortunately the actual page on li-ion gives 3.6V Personally I think the safety risks of using li-ion cells like 18650s are a bit overexaggerated -- the torch/"vape" community has been using them in large quantities (in China they are becoming nearly as common as AAs), and there have only been a few notable cases of significant damage. Yes they are not as safe as something like an alkaline but even lead-acid and NiMH/NiCd can source significant amounts of current too.
  - gdrulia 12y ago
    These days lMR(IMR) batteries (so called safe chemistry) are probably most commonly used by "vape" community. The benefit is that they do not explode and proven to be safe choice when you need high drain batteries. Granted, you need a good charger for them, to make sure you're not overcharging them, but this should be on your safety list anyway.
pkolaczk 12y ago
"All" in the title is a heavy exaggeration. The site covers very basics only.
jacquesm 12y ago
All about batteries: http://batteryuniversity.com/ http://batteryuniversity.com/
nraynaud 12y ago
just when I thinking about ditching batteries in favor of capacitors for some projects.
- IgorPartola 12y ago
  From what I've read, super capacitors still have about 1/10th of the energy density of good rechargeables.
- krohling 12y ago
  These guys (http://blueshiftpdx.com http://blueshiftpdx.com) have a speaker system that runs entirely on super caps. It charges in 5 minutes and plays for 6 hours. Downside I guess is its a bit expensive.
TeMPOraL 12y ago
Hah, how nice it's here today. I just started a small hardware project (hopefully a Show HN in a month or two) and I got hit by the fact that I don't understand jack squat about batteries, especially Li-Ions and Li-Polys. This (and jacquesm's) link is godsend.
IgorPartola 12y ago
Important thing I learned today: 9 Volt batteries are crap. I was just about to re-build my charcoal grill air blower which used two 9V's. Now I will go with some AA's or even a lantern battery.
- joshvm 12y ago
  9V's aren't crap, they're useful because you can linearly regulate them down to the majority of the common bus voltages used in electronics. Mainly they're by far the simplest way to get 5V in a portable system (9V + LM7805). LiPOs will do fine for anything below 3.7V so most modern systems with 3.3/2.7/1.8 will be OK. But if you need a 5V system with anything aside from a dedicated supply or a 9V battery you need to include a step-up converter which adds complexity (though some ICs only need a few capacitors) and cost. The main downside [for a 9V battery] is that linear regulation is inherently wasteful and you lose (4V x your current) to heat. They also have a comparably low capacity compared to AA's so they're not the best choice for a long life application. In that case you're better off using a 95%+ efficient switch mode supply, but then if your system requires low noise you have other considerations. It's not cut and dry!
  - IgorPartola 12y ago
    Fair enough. What I meant to say is that they suck in terms of power density. They are obviously a useful form factor, but having a battery that lasts for a while would be better, especially in my application.
    - sitkack 12y ago
      The best use of 9V is to run a pair of them for powering opamps that need to swing +-.
  - mindslight 12y ago
    9v+7805 is fine if you're playing around, but if you're making something to use and especially if it's to be powered continuously, you'd be better off with 4 AAAs and a low-quiescent low-dropout regulator. 9v batteries can't supply much current (a guideline of 20mA is mentioned in the article). The first 7805 datasheet I came across specifies it's bias current at 4.3mA typ/8mA max. So just by powering the regulator, you're drawing a significant load from the battery even if the rest of the circuit is doing nothing. Funnily enough, I've never seen a stacked 9v as pictured in the article. The few that I've opened up have had elongated cells laid out like a six pack of beer.
minikites 12y ago
Some lead-acid batteries can also be completely drained, unlike many other rechargables: https://www.youtube.com/watch?v=rhIRD5YVNbs https://www.youtube.com/watch?v=rhIRD5YVNbs
K2h 12y ago
I have found wikipedia useful on the basics, especially around form factor, chemistry, and protection circuitry (or not) in lithium. for example, 18650 lithium cell now popular in flashlights, computers and cars that can be very confusing when it is referenced with protection circuitry and 18650 does not have protection officially. http://en.m.wikipedia.org/wiki/List_of_battery_sizes http://en.m.wikipedia.org/wiki/List_of_battery_sizes
zwieback 12y ago
I saw this 220um thin battery in an ST update recently, thought that was pretty cool for ultra-low power apps: http://www.st.com/st-web-ui/static/active/en/resource/technical/document/datasheet/CD00270103.pdf http://www.st.com/st-web-ui/static/active/en/resource/techni...
- Wingman4l7 12y ago
  There is also the THINERGY thin-film lithium rechargeable battery, which was used in a prototype super-slim eInk watch on Kickstarter.
rasz_pl 12y ago
all about rechargeables? : http://www.lygte-info.dk/info/indexBatteriesAndChargers%20UK.html http://www.lygte-info.dk/info/indexBatteriesAndChargers%20UK...

All About Batteries

117 points by MichaelAO 12y ago

lam 12y ago

The article is not accurate in some places. E.g., some coin cells are rechargeable such as the LIR2032.

userbinator 12y ago
Also funny to see "and lithiums are 3V" (not mentioning li-ion at all) next to... the 3.7V lions they're selling on the same page. Fortunately the actual page on li-ion gives 3.6V Personally I think the safety risks of using li-ion cells like 18650s are a bit overexaggerated -- the torch/"vape" community has been using them in large quantities (in China they are becoming nearly as common as AAs), and there have only been a few notable cases of significant damage. Yes they are not as safe as something like an alkaline but even lead-acid and NiMH/NiCd can source significant amounts of current too.
- gdrulia 12y ago
  These days lMR(IMR) batteries (so called safe chemistry) are probably most commonly used by "vape" community. The benefit is that they do not explode and proven to be safe choice when you need high drain batteries. Granted, you need a good charger for them, to make sure you're not overcharging them, but this should be on your safety list anyway.

pkolaczk 12y ago

"All" in the title is a heavy exaggeration. The site covers very basics only.

jacquesm 12y ago

All about batteries: http://batteryuniversity.com/ http://batteryuniversity.com/

nraynaud 12y ago

just when I thinking about ditching batteries in favor of capacitors for some projects.

IgorPartola 12y ago
From what I've read, super capacitors still have about 1/10th of the energy density of good rechargeables.
krohling 12y ago
These guys (http://blueshiftpdx.com http://blueshiftpdx.com) have a speaker system that runs entirely on super caps. It charges in 5 minutes and plays for 6 hours. Downside I guess is its a bit expensive.

TeMPOraL 12y ago

Hah, how nice it's here today. I just started a small hardware project (hopefully a Show HN in a month or two) and I got hit by the fact that I don't understand jack squat about batteries, especially Li-Ions and Li-Polys. This (and jacquesm's) link is godsend.

IgorPartola 12y ago

Important thing I learned today: 9 Volt batteries are crap. I was just about to re-build my charcoal grill air blower which used two 9V's. Now I will go with some AA's or even a lantern battery.

joshvm 12y ago
9V's aren't crap, they're useful because you can linearly regulate them down to the majority of the common bus voltages used in electronics. Mainly they're by far the simplest way to get 5V in a portable system (9V + LM7805). LiPOs will do fine for anything below 3.7V so most modern systems with 3.3/2.7/1.8 will be OK. But if you need a 5V system with anything aside from a dedicated supply or a 9V battery you need to include a step-up converter which adds complexity (though some ICs only need a few capacitors) and cost. The main downside [for a 9V battery] is that linear regulation is inherently wasteful and you lose (4V x your current) to heat. They also have a comparably low capacity compared to AA's so they're not the best choice for a long life application. In that case you're better off using a 95%+ efficient switch mode supply, but then if your system requires low noise you have other considerations. It's not cut and dry!
- IgorPartola 12y ago
  Fair enough. What I meant to say is that they suck in terms of power density. They are obviously a useful form factor, but having a battery that lasts for a while would be better, especially in my application.
  - sitkack 12y ago
    The best use of 9V is to run a pair of them for powering opamps that need to swing +-.
- mindslight 12y ago
  9v+7805 is fine if you're playing around, but if you're making something to use and especially if it's to be powered continuously, you'd be better off with 4 AAAs and a low-quiescent low-dropout regulator. 9v batteries can't supply much current (a guideline of 20mA is mentioned in the article). The first 7805 datasheet I came across specifies it's bias current at 4.3mA typ/8mA max. So just by powering the regulator, you're drawing a significant load from the battery even if the rest of the circuit is doing nothing. Funnily enough, I've never seen a stacked 9v as pictured in the article. The few that I've opened up have had elongated cells laid out like a six pack of beer.

minikites 12y ago

Some lead-acid batteries can also be completely drained, unlike many other rechargables: https://www.youtube.com/watch?v=rhIRD5YVNbs https://www.youtube.com/watch?v=rhIRD5YVNbs

K2h 12y ago

I have found wikipedia useful on the basics, especially around form factor, chemistry, and protection circuitry (or not) in lithium. for example, 18650 lithium cell now popular in flashlights, computers and cars that can be very confusing when it is referenced with protection circuitry and 18650 does not have protection officially. http://en.m.wikipedia.org/wiki/List_of_battery_sizes http://en.m.wikipedia.org/wiki/List_of_battery_sizes

zwieback 12y ago

I saw this 220um thin battery in an ST update recently, thought that was pretty cool for ultra-low power apps: http://www.st.com/st-web-ui/static/active/en/resource/technical/document/datasheet/CD00270103.pdf http://www.st.com/st-web-ui/static/active/en/resource/techni...

Wingman4l7 12y ago
There is also the THINERGY thin-film lithium rechargeable battery, which was used in a prototype super-slim eInk watch on Kickstarter.

rasz_pl 12y ago

all about rechargeables? : http://www.lygte-info.dk/info/indexBatteriesAndChargers%20UK.html http://www.lygte-info.dk/info/indexBatteriesAndChargers%20UK...