ESP8266 Community Forum

- Mon Aug 31, 2015 6:28 am #27423

Thanks! How about this? It's a 1000mah coin battery:
http://www.alibaba.com/product-detail/H ... 53101.html

If those CR2477s have similar current capabilities as a CR2450 then a single one probably wont work - see my attempts with CR2450s here and here.

And those button cells are quite expensive. If its small size you need what about a single AAA with a boost convertor to get 3.3v? Or a small LIPO like these 240mAh ones. Thats similar in size to an ESP-07 and should last a good few hours depending on the WiFi use.

Thanks! Is there a user-friendly way to charge such LIPO batteries? And about the coin cells - looks like it's a good idea to use 2 500-600 mAh connected in parallel. But in your case ESP8266 was sleeping most of the time. Does it mean that if you send 1 request on average every minute - they will die in 72 minutes?

Yes, i guess something like 72 minutes.

For the lipo charging i use these.

- Mon Aug 31, 2015 7:36 am #27427

Yes, i guess something like 72 minutes.

For the lipo charging i use these.

Do you think in such case a 240 mAh LIPO would last longer? It looks like a pretty small capacity for ESP8266. Or is there a difference in discharge between a coin cell and LIPO. Fox example: would a 1000 mAh LIPO last longer than 2 500 mAh coin cells connected in parallel?

- Mon Aug 31, 2015 9:16 am #27438

Yes, i guess something like 72 minutes.

For the lipo charging i use these.

Do you think in such case a 240 mAh LIPO would last longer? It looks like a pretty small capacity for ESP8266. Or is there a difference in discharge between a coin cell and LIPO. Fox example: would a 1000 mAh LIPO last longer than 2 500 mAh coin cells connected in parallel?

I'm not a battery expert so what i know is mostly from trial and error. I think the thing with those button batteries is they are designed for very low current use and the 1000mAh is for <1mA use, but having an ESP pull 140+mA from them significantly reduces the capacity. Here's a CR2477 datasheet which talks about a standard discharge of 0.4mA.

LIPO's are good with high currents though so work well, lets see how long the 240mAh one lasts...here it is freshly charged up publishing Vcc to sparkfun here.

- Mon Aug 31, 2015 9:32 am #27442

coin cells connected in parallel?

Placing batteries in parallel is looking for trouble and even taking risks of ignite a fire.