Help with code please

Posted by: @ianns

@zander I am ready to give up it is still rocking backwards & forwards.

I believe here in Nova Scotia there is something to be gained by moving the panel three times in one day.

I do not have data to support that statement but please point me in the right direction on how I would do that. I  want to remove the ldr's and move it to three-set positions throughout the day.

 

@ianns Have you run the calculations? If not, tell me your approximate location and I will do 3 calculations, flat, 45 degrees, and the inverse lat. Either tell me the exact wattage or I can just use 1,000 watts and you simply use a formula of  your watts/1000 times the chart values.

@zander Elmsdale,

Nova Scotia 

Just a 10w panel keeping a lead acid battery charged to run a basic IoT weather station.

@ianns Ok, I already did it for Halifax and you are close enough it makes no difference. Your biggest problem is it's a lead acid battery. The hardest part of a lead acid battery to charge is the last 20% so solar is a really poor charger invest in a LiFePO4, they charge at a constant rate, just one of the benefits of Lithium. Of course you will want to keep it from getting too cold, I woul

d build an insulated box and stick a couple or even 1 old style light bulb, I do that with my water filters and sometimes it gets 80 degrees inside while 30 outside. I use 2 in case 1 burns out.

Here is the calc for 0 (flat) and 45 (since you are at 45lat, no need for inverse lat.

Attached chart is in kWh per 1,000 watts of solar. Notice how the flat panels do better in the summer. That is because at these latitudes the sun actually rises and sets to the north not the south. The cost of the motorized tilters for my panels is something like $300 so $2000 total. At $0.15 / kWh thats 13,333 kWh I would have to save to break even and at 209 a year it would take 64 years. I am 80 so that doesn't work, maybe you are a teenager? MOST alt energy enthusiasts don't know how to do cost benefit calculations. I spent half my time at IBM doing those, we even had to cost justify buying IBM gear. That's where I get it from. Good luck.

Posted by: @ianns

@zander I am ready to give up it is still rocking backwards & forwards.

I believe here in Nova Scotia there is something to be gained by moving the panel three times in one day.

I do not have data to support that statement but please point me in the right direction on how I would do that. I  want to remove the ldr's and move it to three-set positions throughout the day.

 

Can you take a picture of your rig for us?  If it is big... of the whole rig (panels and all) and then of the detail of the mechanism itself?  Maybe something will jump out at us.  Also, did you align it North/South as in the picture?  

Also, can you itemize your parts by numbers/name, etc.  I might try to reproduce your system... I just think things moving by electronics and environment is COOL! 😎 

"right direction on how I would do that" - Are we talking a 200w+ type panel or something that charges a phone?  If you have a charge controller for your system they can often tell you how much energy you are putting in (real time and over a period).  At least my one and only experience with one.  You could do an experiment over two consecutive days... one just laying flat and one with it tracking (once we get it working) and compare the numbers.  

But you'd want to weigh the answer with:

1. How much energy does it take to move.  Does it at least pay for itself?
2. A mechanism out in the elements 24/7/365 will break and require routine maintenance.
3. I believe @zander (if I am assuming correctly) is correctly biased for his situation... on top of an RV.  There is no way you want a mechanism like this on top of your RV while its going 75 mph down the road.  🤣 
4. I think many studies say there is some significant advantages to following... BUT around here, I see panel farms NEVER do it.  They only tilt their fixed position to the proper angle for their latitude.  They don't even change their tilt for seasonal differences.  

I have dismantled it, it worked well on the bench but not in sunlight 

Thank you everybody that helped

Ian

@ianns What most folks do in my community when wanting just a little more power is simply add another flat panel. It is cheaper and it works. I don't recall if you told us how much solar you have, but I do remember you were using it with lead acid (worst choice). You will get much better performance with some lithium batteries, either a straight replacement type, 12V @ 100AH all usable similar to a 200AH Pb or a bunch of 18650's, but at 3.7V you likely want 2 in series then drop the 7.4V to 5 with a voltage regulator. Each pair of those is about 3,000mAh so you would probably need at least 10 pairs. One of the advantageous of LiIon is it charges very easily whereas FLA resists any charge after about 80%. Given you can't draw down the FLA nore than 50%  a 200AH battery is effectively only (80-50) about 60AH so the LiIon pack is very doable.

What is your daily power requirements in watts.

@zander My consumption is very low ESP8266 & AM2302 sensor.

I have tried my clamp-on ammeter, got nothing & wired in a power meter and too low to register.

The panel is keeping the battery charged I just wanted to try the tracking for fun.

@ianns You spoke of your IoT weather station, do you not have more sensors, usually there are temp, humid, precip, UB, wind, solar radiation and I might have forgot some.

IF all you have is an 8266 and a 2302 you don't need a lead acid battery, a couple of 18650's or any of the medium sized LiPO soft packs will work with your panel lying flat. Tilting will gain about 12% but that is gross, net will be less because you need to power the tilting equipment.

@ianns 

When you were using the tracker, did you leave it level with the earth or tilted towards the sun ?

@will @ianns If it isn't inconvenient, 45 tilt most of the year and flat May, June, July is the optimum for your latitude of 44.948 degrees.

@zander I had the battery & I did not like what I was reading about charging Lipo's in extreme cold

@will It started towards the sun then would move to the west then back & forth.

I moved the sensors much closer together and had a good barrier between them.

In the morning you could hear the motor constantly on, late morning it started the back & forth.

In the end, I took Ron's advice & left the panel horizontal.

@ianns Good point, My LIFePO4 never see extreme cold on the west coast and besides they have a built in BMS that shuts off the charger if it were to get that cold. My point was simply that FLA has higher resistance than Li so that the last 20% is actually hard to charge for FLA and I think the cold affects the FLA as well but only in an OHM's law fashion, not a battery safety fashion.

Sounds like you have a decent solution, if you ever want to get more serious, I suggest AGM for low maintenance, if power requirements go up, a battery monitor and MPPT solar controller will all help. You do know I hope to never use more than 50% of an FLA and you need a shunt based battery monitor to know that. Have fun, and good luck.

@ianns 

Thanks for the info, I'm curious about why this failed as the principles on which it's founded are solid.

I can see it not working if it's not positioned facing the sun to start with, since then the shadow of the wall won't necessarily block out the sun enough to cause an imbalance.

@zander I am using A 5 A Mppt I am impressed with it