Ticket #1048 (new)

Opened 7 years ago

Last modified 6 years ago

Cost effective solar power supply for a single router

Reported by: Musti Owned by: Musti
Priority: normal Milestone: Next milestone
Component: hardware Version:
Keywords: Cc:
Related nodes: Realization state:
Blocking: Effort: normal
Blocked by: Security sensitive: no

Description

Develop a simple solar power supply system that can power a WiFi router with average power consumption 0.75W at 5V.

Develop it around MSP430 Launchpad.

Solar panels available: 0.9V - 2.2W (I sugges use of at least three in series)

It has to perform the following:

  • step up voltage from solar cells to 5V
  • charge a battery during the day, run ont he battery duting the night
  • measure current and voltage
  • hysteresis router control (so it doesnt try to turn on if voltage is too low)

For accumulators, I suggest NiMh, at least 3500mAh, 4 in series.

Attachments

zerodropout.png (23.6 KB) - added by matak 7 years ago.
Zero dropout voltage 5V regulator
BOD.png (37.1 KB) - added by matak 7 years ago.
4.5V undervoltage detector
CHARGElifepo4.png (43.1 KB) - added by matak 7 years ago.
Charger/balancer for LiFePo4
stepup.png (19.2 KB) - added by kablek 7 years ago.
High current step up
Kontrola punjenja i zastita (Pb12V)SCH.pdf (25.8 KB) - added by valentt 6 years ago.
schamatics
Kontrola punjenja i zastita (Pb12V)PCB.pdf (84.8 KB) - added by valentt 6 years ago.
PCB

Change History

comment:1 Changed 7 years ago by Musti

I have 9 of these solar panels intended for this.

comment:2 Changed 7 years ago by MCslo

I intend to build a test setup and maybe add a wind turbine.
Is 5V a must and why would you develop it around MSP430 Launchpad?

comment:3 Changed 7 years ago by Musti

Cool, please document it properly.

5V is minimum needed for a simpel router. This ticket task a development of a mini-power system for a single router, I am not sure wind turbine is meaningful for such a small system.

For bigger solar nodes 12V is better!

comment:4 Changed 7 years ago by MCslo

Aha,ok!
Well I'm currently building a test wind turbine and tought I could try it with a router.
What budget are we talking here 20€ max , 50?

Changed 7 years ago by matak

Zero dropout voltage 5V regulator

comment:5 Changed 7 years ago by matak

http://www.ti.com/lit/ds/symlink/lm2621.pdf
this step up converter sems nice, it has internal voltage regulator so it may be used directly to drive router. In this case you could actualy use single LiPo/LiOn cell, charged directly by solar cels, in this case you need 4 solar cells in series to provide 3.6V, these 3.6V should then be steped up.

comment:6 Changed 7 years ago by Musti

Budget for this in quantity of 10 is about 10-20EUR.

lm2621 seems useful, feel free to make a prototype.

Changed 7 years ago by matak

4.5V undervoltage detector

Changed 7 years ago by matak

Charger/balancer for LiFePo4

Changed 7 years ago by kablek

High current step up

comment:7 Changed 7 years ago by kablek

Added high current step up schematic. Efficiency should be 75%+minimum I think. How ever, I think it would of been beter to use single high capacity LiFePo4 cell charged directly from solar cells. In that case we would only need output step up (lower current). This would also probably lower the BOM cost.

comment:8 Changed 6 years ago by valentt

Very interesting article:
DC-DC converter starts up and operates from a single photocell

bq25504 integrated dc-dc coverter can power devices from single solar panel!

Stable operation of the converter is guaranteed when the input voltage is over 450mV, minimum required input voltage is 330mV.

Last edited 6 years ago by valentt (previous) (diff)

comment:9 Changed 6 years ago by valentt

bq25504 is ideal (and designed for) charging single Li-Ion cell from solar panel.

Changed 6 years ago by valentt

schamatics

Changed 6 years ago by valentt

PCB

comment:10 Changed 6 years ago by valentt

Hi we have found some designs for battery charging and done some modifications to it.

This schematics would provide charging for 12V Pb battery and under-voltage protection for it, and with slight modifications it could charge Li-Ion batteries as well.

Output voltage is also adjustable with 5V being the default in this case.

comment:11 Changed 6 years ago by valentt

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