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Topic: Small battery with 50mA output, does it exist? (Read 9069 times) previous topic - next topic

cjdelphi

an opamp could be used along with a voltage ref (eg a zener diode) as  charger (along with a 555 to pulse charge it depending on the output from the zener)

a microprocessor is not always required....

int2str

How do you know when to stop charging, does the chargers have some kind of indicator?


Lipo chargers (incl. the random one I linked) all have indicators.

Quote
It seems like that kind of battery is sold out everywhere I look do you have any tips on where I could get some of 'em?
Thanks for the information guys! (:


I bet you your local hobby shop has plenty.
Plus you can literally find them anywhere on the net. Just search for "1s lipo".

Example:
http://www.amazon.com/Heli-Max-LiPo-3-7V-250Mah-Battery/dp/B00B8ATBLU/ref=pd_sim_sbs_t_1

Erni

This one is in stock

http://www.hobbyking.com/hobbyking/store/__11893__Turnigy_nano_tech_160mah_1S_25_40C_Lipo_Pack_Kyosho_E_flite_Nano_CP_X_Parkzone_Etc_.html

polymorph

I would be -very- cautious about building my own LiPo charger. A little overcharge, temps rise to much, poof, fire.
Steve Greenfield AE7HD
Drawing Schematics: tinyurl.com/23mo9pf - tinyurl.com/o97ysyx - https://tinyurl.com/Technote8
Multitasking: forum.arduino.cc/index.php?topic=223286.0
gammon.com.au/blink - gammon.com.au/serial - gammon.com.au/interrupts

Archelon

#19
Sep 12, 2013, 02:08 pm Last Edit: Sep 12, 2013, 02:10 pm by Archelon Reason: 1

I would be -very- cautious about building my own LiPo charger. A little overcharge, temps rise to much, poof, fire.

Yeah I think I skip that, but is there some kind of universal Lipo charger which I can connect to the battery no matter of what connection it has?
^^
LiPo batteries are definitely the right way to go so I thank you once again guys.
Now I just have to find a battery with the right size(max 30*20*10 mm)
Thanks!

tylernt



How about a 123A

thanks! do you know if there's any smaller batteries with almost the same capacity? 'cause its just a litle to big :/
CR2.

Grumpy_Mike


I would be -very- cautious about building my own LiPo charger. A little overcharge, temps rise to much, poof, fire.

I would like to echo that. You have to know what battery characteristics you are dealing with.

mmcp42

I have used one of these before to build a LiPo charger MCP73831
there are only 10 types of people
them that understands binary
and them that doesn't

xl97

maybe these will work for you:

charger:
https://www.sparkfun.com/products/10217

40mA li-po:
https://www.sparkfun.com/products/11316

110mA li-po:
https://www.sparkfun.com/products/731

I have used all 3 of these in projects before...

NOTE:
Im not sure if that 'charger' is best to be used with the 40mA battery though.. (read comments...etc)
I think min current is like 100mA or 500mA or something?)  I 'have' chargedmy 40mA battery with in.. but never just left it charge....  brief periods.

Seems to 'work' (but not sure if its 'safe' to just trow it out there without a warning)

Archelon


maybe these will work for you:

charger:
https://www.sparkfun.com/products/10217

40mA li-po:
https://www.sparkfun.com/products/11316

110mA li-po:
https://www.sparkfun.com/products/731

I have used all 3 of these in projects before...

NOTE:
Im not sure if that 'charger' is best to be used with the 40mA battery though.. (read comments...etc)
I think min current is like 100mA or 500mA or something?)  I 'have' chargedmy 40mA battery with in.. but never just left it charge....  brief periods.

Seems to 'work' (but not sure if its 'safe' to just trow it out there without a warning)


Thanks for the info! Must the current the charger has as minimum match the batterys current or how will I know which charger won't burn the battery? :/

tylernt

http://www.rchelicopterfun.com/rc-lipo-batteries.html

"never charge a LiPo or LiIon pack greater than 1 times its capacity (1C)."

So, a 40mAh LiPo must never be charged at more than 40mA. Less is okay.

westfw

Batteries that are smaller than a CR123 include the CR2 and 1/3N (3V lithium camera batteries.)  The CR2 at least is also available in a rechargeable Li-ion version (probably higher voltage.)
There are some li-ion coin cells (2032 sized) that probably can do 50mA (with commercial chargers) ("LIR2032") http://www.batteryjunction.com/powerizer-ch-unce001-2032.html
And as pointed out, li-poly cells are available in all sorts of sizes (but have a charger problem.)

Archelon

thanks once again guys! it seem like finding an appropriate 1S LiPo battery is not that hard but finding a cheap 1 S LiPo charger with adjustable current is difficult!

As Tylernt quoted:

http://www.rchelicopterfun.com/rc-lipo-batteries.html

"never charge a LiPo or LiIon pack greater than 1 times its capacity (1C)."

So, a 40mAh LiPo must never be charged at more than 40mA. Less is okay.


I need to very precise about the charge current (and voltage?) when charging LiPo batteries.
I was thinking about one of these
240mAh with 20C
100mAh with 20C
I would prefere to use the first mentioned because of its size, I just have to solder a jst conncector to it but thats not a big problem. So what kind of cheap, USB? charger that I can adjust the current (and voltage?) in is available?
I'm not really fund about buying this very big charger with capabilities to charge 1-4S LiPos when I only need a simple one.
Thanks guys!

MarkT


Quote
LiPo batteries do not like to be deep discharged. If you completely discharge the battery, you risk a fire.


I don't believe that is true. LiPo can suffer fire damage from overcharging or over current draw if no protection device(s) are used, but overdischarge just causes a cell failure such that it will no longer except a new charge, but not fire damage.

Lefty

I believe all cell damage in a LiPo is potentially dangerous.  If the seal bursts oxygen can get in.  If a cell is
damaged / swelling you are advised to submerge in salt water for several weeks before disposal. See http://thunderpowerrc.com/PDF/DISPOSAL-OF-LIPO-BATTERIES.pdf
[ I will NOT respond to personal messages, I WILL delete them, use the forum please ]

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