Jump to content

GPS update missed/should have been retired/hungover/someting else.


Recommended Posts

Cunning but a little small. 

There seems to be bugger all out there between Home very DIY tiny physical trackers i.e. need to see the sun to follow it, and large, often very large, commercial units running on almanacs. The small ones of these tend to be at least 2.5kW and go up, saw one that can carry over 7.5kW of panels, that's monstrous. The BIG units will become far more prevalent now the, at times, significant environment and animal damage large solar farms can do is starting to make MSM. And I suppose in a drive for better efficiency tracking surly must be a 'go to'. 

Anyway does anyone know of or seen or know anyone that may know more about smaller trackers, say something that can take 1000W of panels sort of size? More the control angle is what I'm after, whipping up the physical structure is not a worry.

Link to post
Share on other sites

Trackers are very easy to build. In essence two micro PV cells with a little shade wall between. A circuit compares the voltage between them and moves the panel till the voltage is equal . The circuit also does a " go home" operation after a pre set amount of time after no voltage. This then drives a relay to a linear actuator

A no power setup using heat expansion and a "hydraulic liquid" based on the shade no shade principal has been done many times.

If your arrays are on the same axis then one master controller is enough to control them all.

Link to post
Share on other sites

Yeap the frame is easy but the brains a little trickier for my one. I'm going with an almanac system rather than physically track the sun option. The main reason is overcast and heavy cloud that can throw physical tracking off track sometimes where the almanac just aims at where the sun is no matter what's in between it and the array.

I've spoken to one of my ex-staff who is big into mechatronics (spelling warning) i.e he builds robots, so he's looking at making the control system for me. I can do the frame easy enough.

Going for 2 axis as where we are the sun is down in the 30's during winter but up in the 70's during summer so quite a wide range to try and cover using static or only single axis. The closer I can get to square on the less area we'll need so the extra 2 axis cost should be well offset by the need for less gear.

Link to post
Share on other sites

10 panels + add 1 = 10% possible output increase. No extension to max output hours. Adds 10% more damage to the local environment. Cheap.

10 panels + a tracker = on average a 45% output. Extends max output hours considerably. Increases output in overcast  noticeably. Decreases but doesn't eliminate damage to the local environment. Costs more to set up but over it's life span it is cheaper.

Link to post
Share on other sites

Interesting stats there. 

We have a couple of hundred remote sites (GPS, seismic, etc) and design them with a 7:1 ratio between rated panel output and the site consumption-draw. That is if the site draws 2 amps we put in 14 amps of panel.

For marginal sites (hills that have morning cloud caps) etc we head towards 10:1. All are fixed orientations.

Link to post
Share on other sites

Eruptn.. yep.

For my home system the arays are fixed with a very basic summer/winter position. I can build trackers but can't be bothered with the extra moving parts . ( Or replacing linear actuators)

 

Panel output 😄.. I think l have heard as many tall stories as people's boat speed ..

So for those new to the subject. Panel ratings are based on a mythical place that is in perfect clear skies , at the equator with the sun in its zenith..and no heat..

It's not cheating , it's just an industry standard

 You may get half of that if you are lucky. ...and then obviously for a small percentage of time. Eruptn is spot on. If you want reliable constant power, you need to have a realistic quantity of real amp hours coming in. 

 

Link to post
Share on other sites
11 hours ago, idlerboat said:

So for those new to the subject. Panel ratings are based on a mythical place that is in perfect clear skies , at the equator with the sun in its zenith..and no heat..

Not quite. The standard test parameters are not new and include things like air clarity, angle of attack, temp and quite a few things, a key one that most use but a little wrongly is the Wattage. When testing that wattage is based on a test assuming 1000W of Sunbugs, some I word (iradiance??...spelling warning), per sq meter but what hits your back yard can vary wildly depending on your geographical location. NZ is lucky as we get more than 1000 on average at closer to 1250, Sweden not so as they are down around 650W.  The way the results are published by the many manufacturers and so on has been a wee bit messy but I have noticed a big increase on standardisation over the last few years, that's good.

The standard temperature when testing panels is 25 degrees C at seal level. So if you are testing panels at 5000ft the temp will need to be 15C, at 10,000ft the temp would need to be 5C. I am assuming they are using standard ISA adjustments.......... but don't argue that with a Judge without checking first.

At times fixed is a better option and I'd expect most of the monitoring panels like E's would present a wee maintenance and reliability issue if on trackers considering most will be in remote places and see humans only infrequently. As Idler rightly says trackers mean more moving parts which means more to possibly fail. When the tracker is 20m from your door that is not an issue.

10:1 is a interesting margin considering many of those panels will be putting up above average due to their altitude hence temp. Cold panels produce more then hot panels. But then we come back to remote locations so some over cooking would be wise I'd be thinking.

There is no doubt adding a tracker is far more efficient and gives far better output than adding fixed panels. Sure they cost more up front but over a lifetime trackers are cheaper. Like most things, buying based on lifetime cost is usually a lot cheaper than based on initial purchase price.

 

Link to post
Share on other sites

The two panels on my boat total 140w , I easily get above rated output on a good day when the batteries are needing it, quite surprised at that and at how much they put out when things are not so ideal.

Have gone several days sailing on and off anchor, running fridge and pilot, no engine. Solar is pretty good from my experience.

 

Link to post
Share on other sites
On 19/01/2021 at 2:47 PM, BOIGuy said:

The two panels on my boat total 140w , I easily get above rated output on a good day when the batteries are needing it, quite surprised at that and at how much they put out when things are not so ideal.

Have gone several days sailing on and off anchor, running fridge and pilot, no engine. Solar is pretty good from my experience.

If the panels are rated at 140W in NZ in the right conditions they will be running closer to 175W. Then there are controllers and there are controllers so you probably have a goodie which helps.

I just uprated the controller on the shed as I realised I ordered a 40A but with 500W of panels so they could be running at 600-650W which would over cook the controller. So I've gone to a 60A, it can take up to 800W.

After much sussing I'm going with a Epever 6415BN a good but minimal wank MPPT controller. I was going to get one that can handle both wind and solar inputs but a wind guru dude said 'Na, keep them separate' to save heat and if one packs up it doesn't take out the whole system.

Love those MPPT, must haves. PWM second.

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...