Need help building a replacement solar system for Davis Vantage Vue weather station 3v

[Hellman_x]

Hello!

I'm looking for a buck converter of some kind that can take a ~12v input from a solar panel and is able to output it to ~3v. The hard part is finding a cheap one that can also charge a battery that is not LiPo, but a LiFePO4 battery (I have no clue if they need a charge controller, I'm sure they do though) I'd like to not go over 3.2v as I'm not sure how long it'll run at that voltage before it fries itself.

The LiFePO4 battery I have now is 3.2v

The buck converter I was using was a DROK DC Buck Module that I could tune down to ~3v which worked great... Until it didn't, it died overnight just having the battery and the weather station running on the output circuit. It won't power on if any load whatsoever is connected to the output (except for a voltmeter)

The Amperage needed is almost non-existent. When the Buck Module was working and connected the weather station only drawed about 0.02Amps for every transmission it sent out.

I'm not sure if I should get the same Buck converter (maybe it was faulty, or I did something wrong?) or a different one.

 

[robbob2112]

LiFePO4 doesn't generally deal well with low temperatures.

I have the 15 year old vantage pro2 unit with the fan asperation. I think I replace the battery in it for the transmitter 5 or 6 years ago and the ones for the fan longer ago than that.

I am curious why you are switching from the original battery to something home grown?

 

[Hellman_x]

LiFePO4 doesn't generally deal well with low temperatures.

I have the 15 year old vantage pro2 unit with the fan asperation. I think I replace the battery in it for the transmitter 5 or 6 years ago and the ones for the fan longer ago than that.

I am curious why you are switching from the original battery to something home grown?

The Vantage Vue only has a Super Capacitor and CR123a battery for backup power.

I replaced the bad supercapacitor, but it didn't seem to have any effect, so I'm just going for a "replacement" solar solution.

 

[robbob2112]

AH, makes sense - my station has a CR123a + 2 sub-c nicads for the fan in it.

 

[solaruser120]

I have a weather station that uses solar to charge a Lithium Titanate battery, claims to allow charging down to -40C.