Topic: 24 hr solar FARS problem

[JohnAweather]

Hi all, I have a 5 year old Pro2 with the solar fars. I have been having an ongoing issue with the fars unit. I've now installed 3 placement fans and each has stopped working after about a week's time. I am starting to wonder if the problem could be something entirely different than the typical "the fan motor sucks" issue.

The most recent fan/battery replacement was installed last week to try and get the fars working again after 3 years without it. Same thing... fan quit spinning yesterday. Upon inspection the fan seems fine visually, and the fins move freely with the fling of a finger. And it receives sufficient sunlight exposure btw.

I had planned on next replacing the solar panel and fars circuit board and seeing if that fixes the problem.

But when push came to shove, and not knowing exactly what the problem is, I just went ahead ordered a whole new 24-hr solar fars shield from Ryan at Scaled Instruments. New fan, batteries, plates, filter, sleeves, solar panel, circuitry, wiring, nuts/bolts.. everything new $221. Lots of parts I don't need. But this will solve any ongoing problem lol

My first question is did I just waste a whole bunch of money on replacing the whole solar fars system when the problem could just be a $15 replacement part. Or did I save myself a giant headache of trial and error, ordering parts, returning parts, etc?

Second question is has anyone else had an issue with their solar fars that was NOT related to the fan motor. Am I missing an easy fix?

[Aardvark]

so you are not using the daytime fars.

I have the one you are describing.  I had to bend the solar panel a bit to improve the angle for the sun to hit it.  I even bought different batteries that were better for the rechargeables.  I even bought a battery charger so I could charge up the rechargeable batteries before I put them into the unit so the solar panel could run the fan during the day and the batteries would have some charge left the next morning so the panel could charge them again and run the fan too.
  I had to replace the motor and batteries every year.   I finally came to a decision. stop with the fan replacement and batteries. It will be a passive unit.

I think the problem is with the charging circuit.  The solar panel probably is good, but where it hits that circuit board by the fan housing, something isn't working. Either it is a faulty design  or it is defective.     

Perhaps you could buy a new circuit panel, and solder that into place.    BUt  I bet you are not alone here.   I'd contact Davis in the meantime, lay it out for them and see if they have a solution.

[azchrisf]

If the panel is severely degraded, that can be an issue. FARS is a rather simple system electrically - daytime, it powers the fan and charges the batteries. Below a certain voltage I. E dusk it runs straight from batteries. If something with the resistors on the FARS board or the batteries have failed that could be an issue too. Did it fail during bright sun or always during clouds or night?

Honestly I think you made the right choice. I'd offer to do a electrical postmortem on it if you want to pay shipping costs.

If you can run power to your unit the case fan mod is a great cost saver.

[JohnAweather]

Aardvark, I certainly do understand not wanting to run the fars anymore and using a passive shield instead. No headaches! I have not gotten to that point... yet, because when it works, it's wonderful. There is little-to-no second-guessing the temp reading with the fars, wondering what is the actual temperature! When it's working...

Azchrisf, thank you for offering to look into the unit. I may cross that bridge later and let you know. I'll probably just let it sit for the time. But I think you've talked me into keeping the order of the new solar fars unit.

That frees me up to use the old housing and panel down the road to experiment with a PC fan as I do have an extra unpackaged temp/hum sensor. With my full time Davis station, though, I prefer to keep that wireless... for now.

DIY fars is so much fun when time permits. A few years ago I built a wired fars tower using a white vinyl post and cap. It was an idea stolen from a member of this site many years ago. I installed a PC fan, wired into the mains power using a switchable 1-12V power supply. All non Davis stuff. Man that thing was a beast. Several moves later, I have no idea what happened to it 

[kobuki]

I'm wondering if you ever tried running the "faulty" fans from a separate power source, like a battery or a small power supply.

[JohnAweather]

How would I do that? Could I use regular C batteries in the fars unit? I would disconnect the solar panel from the fars circuit board first, right?

[kobuki]

How would I do that? Could I use regular C batteries in the fars unit? I would disconnect the solar panel from the fars circuit board first, right?

I don't have a FARS but from images it looks like the fans have a standard Molex type female fan connector. Find a pair of solid core wires you can plug in to that, then attach the other end to some power source providing 3+ V like the CR23 in the ISS backup battery to test. Polarity should not matter as it's just a test, but if it doesn't start one way, try the other as well.

C batteries would probably fit but we're testing the fan motor in itself, not anything else.

[azchrisf]

John try kobuki's suggestion. If it is spinning correctly then it must be something else, either way, as I originally said chasing down each individual part is very time consuming for most, so just replacing in a package as you did is the smarter choice.

[JohnAweather]

Greatly appreciate the thoughts and suggestions coming in. I plan on building some sort of power source for fan testing purposes as kobuki suggested.

I like the idea of having a brand new Davis SFARS unit delivered over the next few days for a quick fix solution. Glad that azchrisf is behind that idea.

But I am glad that it also leaves me with a spare FARS unit to play with and help develop an alternative power supply option. When the new Davis FARS system inevitably fails, ideally it will be replaced with the alternative option.

I like the hardwired case fan option for reliability/durability reasons. May not be flexible enough however.