adds cn3163 datasheet
[thefekete.net.git] / blog / 2020-06-24_solar-pmic.md
1 % Solar Lithium Battery Charge Controller
2
3 I've been rolling the idea around to make a WiFi weather station with an ESP32.
4 I'd like it to be solar powered and use an 18650 battery, since they're pretty easy to get a hold of.
5 Of course, a battery charge controller is needed to make sure I don't end up with a garden fire.
6
7 At first I just hooked up a standard lithium charge controller between my 5-6V solar cell and the battery.
8 It worked quite well, charging the battery at around 250 mA.
9 However, since the charge controller is designed for USB input,
10 I wondered if it was maybe sub-optimal for solar.
11
12 I started looking around for an MPPT (maximum power point) charge controller for single cell lithium packs and found that a certain chip, the CN3163, was used in a few of them.
13
14 As you can see below, it's pretty simple to use.
15 You just have to be sure that you don't exceed the 6.5 V input limit.
16 A simple zener diode can take care of spikes,
17 or a buck converter can handle a panel that outputs higher voltages.
18 I found the english datasheet and have it available [here][datasheet].
19
20 ![CN3163 Typical Application Schematic](../img/cn3163-sch.png)
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22 The best part is that it is super [cheap][lcsc] and an SOIC-8 package. So totally hand solder-able!
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24 Next step would be to design a little board and make a few. Question is, do I just use headers for batter connection or make an all in one package with a battery clip?
25
26 [datasheet]: ../files/cn3163-datasheet.pdf
27 [lcsc]: https://lcsc.com/product-detail/PMIC-Battery-Management_ShangHai-Consonance-Elec-CN3163_C559031.html