Because of the type of my project I need a small battery which is rechargeable and which can supply about 3.3V and 2-3mA. The current varies , but I need to be able to do this at an average for about 10-15 days. I could not find any small battery (such as CR2032 which could do these). I may have a small solar panel to recharge, but it isnt going to produce much current. What is the best way to power such a circuit? Reducing current consumption is one, but it really is not possible


closed as off-topic by Brian Carlton, PeterJ, uint128_t, tcrosley, helloworld922 Apr 10 '16 at 6:05

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    \$\begingroup\$ "Good, fast, or cheap; choose any two." \$\endgroup\$ – user65586 Apr 10 '16 at 1:59
  • \$\begingroup\$ A Lithium rechargeable versión of the cr2032 with a solar cell can do what you want. At 250 mAh or so capacity, that's ten hours between recharges. If you can do bigger, there are AAA size lithium cells with better capacity. It's what's used in rechargeable e-cigs. \$\endgroup\$ – Passerby Apr 10 '16 at 2:11
  • \$\begingroup\$ @passerby, that is 100 hours between recharges. To last the whole 10 day period, the OP only needs a 750 mAh LiPo battery. Then depending on the panel output, it goes down from there. This is such a small current, it may be feasible to have it run indefinitely with a 250 mAh battery and a panel. I think the panel only needs to put out 20 mA or so. \$\endgroup\$ – mkeith Apr 10 '16 at 3:21
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    \$\begingroup\$ Well if you can deal with 2.8 to 3 volts, a cr2477 coin cell has 1000 mAh capacity, giving you roughly 14+ days at 3 mA. Not rechargeable. \$\endgroup\$ – Passerby Apr 10 '16 at 3:40
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    \$\begingroup\$ @tcrosley, I am not asking for places to purchase. I am just asking what battery is probably a good choice? There are a lot of newer batteries coming in everyday and someone on this forum may have some cool idea. Combining a solar panel + a good battery is not really a shopping question \$\endgroup\$ – red car Apr 10 '16 at 5:04

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