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Topic: Charge mini battery? (Read 656 times) previous topic - next topic

caleb121341

Hi, I lost my bluetooth charger so I opened it up to get scrap parts like the speaker and battery. I want to charge the battery for a min project of mine but I don't want to break it. The only thing it has on the battery is + 2H-451220 and I 3.7V HH04? Can anyone tell me how I can charge this without breaking it? Also it has a black and red wire (Ground and Power) Thanks so much for your time :D :D

semicolo

3.7V looks like Li/ion battery, you need a special charger for that, isn't it a standard micro or mini USB socket? The device probably already has all the electronics needed for safe charging, see what's cheaper, a new power plug or a li/ion charger.

caleb121341

I mean like how could I plug it into my breadboard and use arduino to charge it? Like put the 3.5 power using a resistor or something?

jonrobertd

It is li-poly, and do you understand the hazards of improperly charging and discharging one? They can be very nasty if done improperly, think fire or explosion most likely. Does the battery have a circuit board between it and the wires or not?  If not then the protection circuit is built into the bt board and you will have to charge and discharge through that.

MarkT

Its a lithium battery, its needs the correct protection and charging circuitry
to keep it in a safe state...

It seems to be this one:
[urlhttp://www.alibaba.com/product-gs/717743272/451220_lithium_ion_battery_3_7V.html[/url]

Gives data on charging the cell and seems to imply (in Product Advantages section) that it has
protection chips built in...  I'd take that with a pinch of salt - perhaps you can see a PCB
inside the thing?
[ I won't respond to messages, use the forum please ]

cjdelphi

After years of using high powered flashlights, lithium batteries can handle a fair amount of abuse, what you have to worry about is the  heat of the  battery, i once  by accident got a couple so hot the label melted, and still no thermal runaway, maybe i got lucky.. i was in a hurry so i took risks.

But to charge one, it's as simple as applying a voltage 4.2v.. but this could cause damage due to lack of constant current, so 4.v and a resistor to limit the current intake.

Still though that may not be good enough, pulse charging, check voltage, charge, check voltage, charge..  this is how most cc/cv chargers work.

Docedison

#6
Oct 07, 2013, 04:48 am Last Edit: Oct 07, 2013, 04:50 am by Docedison Reason: 1
Not in MY world, Perhaps in yours...
CV-CC means Constant Voltage (CV) - Constant Current (CC)... There is Nothing about a pulse involved...
Because a "Pulse" isn't constant... It (Pulse Mode) charging has a number of serious issues involved... The main one being that when loss of capacity (Age/Use) occurs the charging algorithm needs to be aware of the DV/DC (Delta Voltage/Delta Current curve and modify the charge cycle accordingly to compensate for low capacity and to warn the user that the battery is near it's failure point... Assuming that the device is monitored periodically.
I used it for many years to charge SLA (Gel Cells) batteries. I did however have a means of loading the battery and the controller monitored the recovery time from a timed load test to full recovery of the battery voltage when the solar panel voltage was at Max.
This was also a very good way to tell when the solar paner was dirty or failing (amorphous silicon solar cells are plagued by loss of capacity...
A 12V solar cell uses 26 to 28 (as I remember) .6V cells connected in series... It only takes one marginal cell to "Kill" a solar panel.
When the recovery time started to diminish I lit an led (10 mS pulsed activity indicator) to indicate the beginning of failure.
I should mention that the charger was thermally compensated because a 100% charge @ 20C is ~120% of a full charge @ 40C with an SLA type battery..

Doc
--> WA7EMS <--
"The solution of every problem is another problem." -Johann Wolfgang von Goethe
I do answer technical questions PM'd to me with whatever is in my clipboard

cjdelphi


Not in MY world, Perhaps in yours...
CV-CC means Constant Voltage (CV) - Constant Current (CC)... There is Nothing about a pulse involved...
Because a "Pulse" isn't constant... It (Pulse Mode) charging has a number of serious issues involved... The main one being that when loss of capacity (Age/Use) occurs the charging algorithm needs to be aware of the DV/DC (Delta Voltage/Delta Current curve and modify the charge cycle accordingly to compensate for low capacity and to warn the user that the battery is near it's failure point... Assuming that the device is monitored periodically.
I used it for many years to charge SLA (Gel Cells) batteries. I did however have a means of loading the battery and the controller monitored the recovery time from a timed load test to full recovery of the battery voltage when the solar panel voltage was at Max.
This was also a very good way to tell when the solar paner was dirty or failing (amorphous silicon solar cells are plagued by loss of capacity...
A 12V solar cell uses 26 to 28 (as I remember) .6V cells connected in series... It only takes one marginal cell to "Kill" a solar panel.
When the recovery time started to diminish I lit an led (10 mS pulsed activity indicator) to indicate the beginning of failure.
I should mention that the charger was thermally compensated because a 100% charge @ 20C is ~120% of a full charge @ 40C with an SLA type battery..

Doc



In your world you read things that were never said....  i made 3 different statements not one did i claim cc/cv is "pulse charging" you did... i said i would use pulse charging with a cc/cv source.

Perhaps an eye test?

cjdelphi



Still though that may not be good enough, pulse charging, check voltage, charge, check voltage, charge..  this is how most cc/cv chargers work.


For people who need every detail spelling out...

Pulse charging when used in conjunction with cc/cv is how most lithium ion battery chargers work, you could even use 555 timer, a zener, a couple of transistors (and resistors) and avoid a micro..

Typing on a phone is difficult even more so when you havd to type out everything!

tylernt

After years of using high powered flashlights, lithium batteries
Li-ion and Li-poly have very different characteristics. Li-poly is less forgiving than Li-ion.

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