Any tips for a LiPo battery, charger and solar panel for an always-on node?

End Devices (Nodes)
25

You are same kind of evil than @BoRRoZ to find them in France ! I will buy a set too :stuck_out_tongue:
Edit: even better !2

@oliv I saw these 4 one, but I’m pretty sure they’ll be send from China, not France, that is why I choose Amazon direct, they are evil also :wink:

26

void hal_sleep () {
// Not implemented
}

27

@our local store CHF 9.90 a piece.
great solar panel, gives 6.4V without load

28

No, after each IRQ (Rx, Tx or Timeout), the radio is switched back in sleep, cf this line

hal_sleep() is called here and is where we will put the uC and sensors sleep code when the library will be interrupt driven. I still hope to do that in following months

I never saw a Chinese seller on Amazon before, but delivery between 3 and 25 of August so you are probably right :stuck_out_tongue:
Never mind, I already have a lot of things to do !

29

I use 2 variant for solar charger (based on LTC3105).

  1. with 5V output connected to MCP73831 - but lost some energy
  2. with 4.2V output and connected directly to LiPo battery.
    Second variant more efficient.
    LTC3105 placed on bottom-right side of pcb and coil on other pcb side microtracker (this version with GSM module but LORA version the same size)
    solar panel 50x15 mm
30

Hi all

I’m liking the solar light idea for my LoPy node. Has anyone tried one of these yet?

2.5 watt solar, 2600ma battery (claimed)

31

Power usage LoPy
★ Input: 3.3V – 5.5V
★ Wi-Fi:12 mA in active mode, 5uA in standby
★ LoRa: 15mA in active mode, 10uA in standby

I don’t think that’s a problem, if there is sun > 4.2 V but at night the voltage can drop depending on the state of charge of the lipo (probably still no problem).
But you can use a buck/boost converter between the battery and your LoPy and then the voltage is always 5V, this can be important for sensors to.

32

source : https://community.particle.io/t/solar-powered-spark-core/3812/2

I’m thinking ’ why not make a transparant solarpanel/node combi enclosure myself, with the help of a simple technique ‘vacuum forming’

solar ideas
solar power 'manager’

3 Likes
33

Guys,

I just recycled early ULPNode prototypes to test and measure solar/lipo

All is done with custom classic Atmega328 early ULPNode prototype with

  • RFM69 RF module on board
  • Chinese Solar Panel
  • 240mA Chinese Lipo charging @100mA
  • Adafruit Mini Lipo Charger
  • RF/LowPower is done with unreleased ULPNode Library

RF Transmit is done every minute and LED is blinking every 8S (Watchdog wake), so it really not “Ultra Low Power” but I want to see how how far can we go with this not optimized settings

Inside

All mounted (nodeMCU is just for "size view)

Live view started

Dashboard published, you can follow and access them any time here if node and battery survive to this night :wink:
PS click week on dashboard since data shows default for year.

1 Like
34

@BoRRoZ
Got my Amazon gift today Solar Outdoor light talked above, seems pcb have changed

Seems the Lipo has lower size also (lower capacity?)

thank telling me about the on switch amazing to find it (but it clear on documentation we all must read it :wink:

35

where is IC 1 ?

36

I swear, I didn’t hacked it and removed, but I don’t know, what was it for?

37

check your other solarlights… if they all are the same it’s a feature by design and not a mondaymorning production

38

Here an other board out of the Solar_Wall_Light from Interdiscount in Zurich
LiPo has 900mAh

39

Humm, this one shows that “waterproof” word can have different appreciation :wink:

40

about waterproof enclosures for little chinese panels… be carefull because when they are the whole day full in the sun, it gets to hot inside the waterproof (airtight|) plastic box, the panelcapacity can decrease 15-30%…
I bought these little fans and my plan is to build one in the enclosure and switch it on a short time @ a certain temp, maybe controlled by a bi-metal and a transistor (not tested yet)
Another possibillity is drill a few holes in the bottom :wink:

41

I was thinking about that issue too and was considering small holes in the bottom, but I am concerned about condensation in front of the panel.

42

I’ll place a 30x30mm 5V fan at the far end (wall side) below the battery; placing some holes near the front, where the antenna will be mounted to exhaust. Temperature will be controlled by a TMP3x not wasting energy

1 Like
43

yes condensation will/can be a problem, I used a few sillica gel packs I saved from packaging, but they are very cheap

44

You do not have any regeneration when heating ? Typical regeneration temperature is at 120°C but I have seen people regenerating it behind a glass with direct sun…as our solar panels :confused:

Best way is vacuum, but will not match with holes nor fan :stuck_out_tongue: