Hello,
I created some projects with stand-alone atmega328pu (from arduino uno).
I also powered these projects with AA batteries.
When I opened an old toy I found the battery you can see in the picture.
I bought the charging board a long time ago online, so I can't link the website, but on its back it sais "TP4056". the battery is 3.7v and 90mAh.
How can I use this battery with arduino? is it safe to use the circuit for charging and protection? and how can I calculate how much time it will last, and print it with the arduino on a display?
That's a very common battery charger board. You could use it to power a 3.3v arduino (like a 3.3v pro mini, etc) (connect output of that board to Vcc and Gnd, so the board will run at 3.7v (not 3.3v - but this is fine). It's a fairly small battery; you will probably need to put the micro to sleep most of the time to be happy with the battery life (and the usual removal of power light and regulator)
If that battery were beefier, you could run a 5v board with a boost converter, but with a battery that size, you wouldn't be happy with the battery life.
Edit: On closer inspection, is that battery puffy? If a LiPo battery is puffing out, it is degraded and shouldn't be used.
No. You can't use that charger with your battery. As others have mentioned, that battery is a ticking bomb. On top of that, the charger probably has a charging current of 1000mA. Your battery has a capacity of only 90mAh, so at the recommended rate of 0.5C, that's a maximum charge rate of 45mA, which is well over 20 times less than the charger provides.
PieterP:
No. You can't use that charger with your battery. As others have mentioned, that battery is a ticking bomb. On top of that, the charger probably has a charging current of 1000mA. Your battery has a capacity of only 90mAh, so at the recommended rate of 0.5C, that's a maximum charge rate of 45mA, which is well over 20 times less than the charger provides.
srnet:
Very puffed = dangerous.
DrAzzy:
That's a very common battery charger board. You could use it to power a 3.3v arduino (like a 3.3v pro mini, etc) (connect output of that board to Vcc and Gnd, so the board will run at 3.7v (not 3.3v - but this is fine). It's a fairly small battery; you will probably need to put the micro to sleep most of the time to be happy with the battery life (and the usual removal of power light and regulator)
If that battery were beefier, you could run a 5v board with a boost converter, but with a battery that size, you wouldn't be happy with the battery life.
Edit: On closer inspection, is that battery puffy? If a LiPo battery is puffing out, it is degraded and shouldn't be used.
Yes to all of you, I know something is wrong with the battery! I am pretty new to the subject of lipo and li-ion, and other batteries looked less "puffier", but I thought it's ok.
Now when I know that I need to purchase a new battery, lets talk about the board. are you sure it will need a boost converter? don't it have a build in voltage converter? the reason is that I need to create a very compact project (simple smart watch), and I need small components. I guess I can own one of these tiny buck converters online... but I would prefer to be sure. I think I will need to hook up a battery and measure.
anyways, thank you for your help, do you know when i can buy a battery + boost converter online and for cheap and international? and because I live in Israel, I hope I will be able to get the battery (because its chemical or something).
Run the microcontroller at 3.7v, right off the battery (assuming you're using a 3.3v board that is okay to run at 3.7v, like an 8mhz pro mini). This is always what you do for best battery life.
This is essentially what I do for my keyfob transmitters...
I live in Israel, I hope I will be able to get the battery (because its chemical or something).
I don't know about your country. There are shipping limitations on lithium batteries in the US, because there have been spontaneous ignitions in depressurized cargo holds on airplanes. They are pretty ubiquitous though. If you use this charger, you should get a larger battery though. Or replace the 'RPROG2' resistor as shown, to accommodate your battery's best charge rate.
And yeah, use a lower voltage circuit if you want to use this battery.
ChrisTenone:
No it doesn't. Here is the datasheet. The circuit of your board is shown on page 3.
I don't know about your country. There are shipping limitations on lithium batteries in the US, because there have been spontaneous ignitions in depressurized cargo holds on airplanes. They are pretty ubiquitous though. If you use this charger, you should get a larger battery though. Or replace the 'RPROG2' resistor as shown, to accommodate your battery's best charge rate.
And yeah, use a lower voltage circuit if you want to use this battery.
ok, maybe I will replace the resistor in the circuit. but it looks like I will just have to find a different charging circuit for these batteries... and about the microcontroller, I really want to use the ATmega328, so I will boost up the voltage.
328 doesn't preclude using a lower voltage. Boost efficiency declines at very low current levels, so you will be throwing away a good bit of your already tiny battery.
Otoh, if you just want to play with a voltage booster circuit, it's pretty cool technology. Maybe get a bigger battery?
I use 1 unit 18650 3.7 LiIon to power an Arduino nano (5V).
I found a very small yet sufficiently powered DC boost module that offers 5 V out of my 3.7 unit.
I do not know about whether LiIon are allowed in your country, but since there are so many domestic devices powered buy this type of battery, I guess there are legal to buy in any hardware store (brick-and-mortar, street ones).
One unit 18650 costs me from 2.5 USD to 8 USD, depending on capacity, brand and some other factors.
The DC micro-source (the vendor call it so :-), being 4 mm x 4 mm or some) worth some 2.5 USD.
I also mounted in series a regular on-of switch to be sure everything is OK (no abnormal drainage, no fire danger etc.).
When I dont use the device, I simpley pull the unit out and store it.
