Solar Install; the on-going saga

holyhutzpa · 30-10-2013 12:22pm

paddyp wrote: »

Tristar looks interesting, diodes aren't so bad a decent shottky can drop as little as .4v http://www.ebay.co.uk/itm/20L15T-Schottky-Rectifier-Single-Diode-20A-15V-5-Pcs-/290913145471?pt=UK_BOI_Electrical_Components_Supplies_ET&hash=item43bbc6527f

At this stage you should consider getting a pic/arduino development kit. Its only a couple of lines of code to check a voltage and switch a relay, once you've done that its small step add another relay for another battery and do other seemingly 'complicated' things. You can even get development boards and relay boards preassembled so theres no soldering to be done.

You'd be amazed what you can accomplish with a few lins of code. Once you get comfortable with that you can get pre assembled modules dirtcheap like lcd, i/r remotes, blueooth, lcd etc. etc. before you know it you have a €xxxx control unit.

Yeah, arduinos are lovely bits of kit. Get an arduino, a breadboard prototyping kit, a handful of jumpers, lcd display... They're available on dealextreme for very little money

I have one but have been holding out installing it or the raspberry pi in the campervan... Although love the idea of being able to control things like the eberspacher remotely (although will have to get the eber working first!)

I've just looked at the current range of arduino goodies on dx.com and spotted a robotic claw.... Cruise control anyone?

30-10-2013 11:46pm

Those kits look pretty interesting alright. They'll have to join the queue of projects though. At this rate my I won't be finished rebuilding my Winter car until Summer.

Yee have me thinking again.
When I said earlier that I jumped the diode, I actually circumnavigated it and split charge between direct to battery (with the idiot switch/battery link lead) and across the diode into the solar controller. This is not the same thing.
I was blaming the diode for the alternators inability to voltage sense but I wonder now if I'll have the same problem sending all the charge to the solar controller's solar input which is the eventual intention.
Could be I need a battery sense lead which really defeats the purpose of the TS-45 as a regulator unless I introduce selective manual control which I'd rather not if I can prevent it.

More testing required methinks.

03-11-2013 3:59pm

I was hunting for more gubbins.
Found a cheaper source for a TS-45.

Looks like I'm down to ~6Ah p/d solar harvest.
Reasonably sunny, light cloud. Roof at approx. 5°-10° declination from horizontal, away from the sun.

04-11-2013 9:16pm

It's not actually that low it would seem.
Had a gander at the roof today. Panel was a little grubby.
The lower incidence of the sun is creating shading issues from my chimney and I reckon another month my stealth box will be another problem. I've only two bypass diodes so I suspect that shadow is halving my harvest.
Flat mount and shading it's only a 45 watt module (-50% output for shading & -40% for mounting). I can sort the chimney problem by parking the other way around. May have to chop a mite off the box.

holyhutzpa · 05-11-2013 11:28am

That was one of the most surprising things I read on handybob's site (in your first post) - a small amount of shadow over the panel drops the output massively!

Would you consider having some legs on the mounting box so you could get out and angle it a little better to the sun (30deg or whatever the optimum is...), or is that not stealthy enough?

05-11-2013 7:35pm

Both actually.
It's mostly due to that the solar cells are in a (parallel/)series configuration and a little loss drops the voltage with the knock on effect of increased transmission resistance so then a further voltage drop below what the regulator can push into the battery. This is why bypass diodes are installed; to minimise the negative effects of shading. So with two diodes I only lose half the output provided one correct half of the module is unshaded, the diode provides a bypass to the mute half (otherwise it would drain the charge from the other side...I think...something like that anyways).
Another solution would be to use higher voltage solar modules but I read that a voltage 150% of the batteries at the panel works best, can't specifically remember why this is either.

I'll take a closer look into it at a later date. I've seen 1kW of cells available for 40c per watt. Bitta wire, bag-o-diodes, wood, angle iron/aluminium, glass and solder I could have home assembled jobbies for a fraction of the cost. They obviously won't be as good as the connections won't be uniform and the glass will be inferior high iron content. However at that price I'll still be way ahead on price per watt.

I've got a backboard already fitted to receive tiltable brackets from inside the box. But it's rare I'd be parked in a location where it's worth the effort of setting up. It's not stealth and it's asking for trouble. I'm half considering a motorised satellite dish arm as a manual tracker. Dangerous thinking though because it's only a matter of time before I try to upgrade manual tracking to photosensitive actuators. :pac:
As I said earlier I think the most acceptable solution to the 40% loss is 40% more cells, then on rare occasion I could boost the output as desired.

In the meantime the alternator is meeting the shortfall without any unnecessary engine running. :cool:

06-11-2013 1:21am

First off this is not a serious suggestion I'm just having a laugh looking at logistics.

I do appreciate the physics of 120kmp/h winds and much as I can negotiate a DOE by bringing them back the serviceable parts they make me renew for show and tell, this

don't fly...or maybe it will in the wrong sort of way.

images?q=tbn:ANd9GcSPvLnJTfza8cK6NGFowTIlYRiubUPKGWjeNilH_VgkQ3XvmWkW

:pac:
Actuation;

Requires anchorage, 12v actuator, reduction of horizontal profile to about half what it is from the top of the pole attachment.
Demounting of actuator, folding and road bracing to lock ratcheted flat for travel and storms. Effective ratcheting would probably require module corner supports.

Actuator control link(add limit switches)
$T2eC16N,!ykFIelv8bBKBSeS5KZo7Q~~60_35.JPG?set_id=880000500F

$T2eC16N,!ykFIelv8bBKBSeS5KZo7Q~~60_35.JPG?set_id=880000500F

Way cheaper and easier just get more cells.

06-11-2013 2:06am

Probably the more practical solution

Easy make a sturdier set than those online chancers are flogging. Soon as I think I've missed an opportunity to make good use of a set I'll knock 'em out. :P

06-11-2013 4:20pm

Sir Liamalot wrote: »

What's the consensus about AC earthing to the chassis?

http://www.smartgauge.co.uk/earthing.html

..just pretend "fresh water" = tyres

09-11-2013 9:20pm

Traffo charger works great. The TS can compenstate for loads within a second so I can run 12v appliances without fear of overcharge. But it's so effin' noisey I can't be in the van when it's charging. It's like a lower frequency cathode ray tube TV hum at twice the volume. Any suggestions how I can shut those impudent worker bees up? Ground loop? Capacitor? Power factor loop(already has one of those though)? It's definitely TS related, it's fairly quiet when it's isolated.
I'll see if proper earthing makes any difference as that's on the cards anyways.

Another drawback inherit in the setup is solar charge naturally soft starts and slowly ramps up voltage over time the traffo just horses out max volts from the get-go. Hmmm.
Traffo does get quite warm too but given that the entire case is one giant heat sink I'm not quite concerned about this.
Oh well it is what it is and if it explodes I'll admit defeat.

09-11-2013 10:35pm

% Discharge........Ah DOD..........Diode..........Diode + Battery Sense...........Changeover Relay............C/O Relay + Battery Sense
20%....................36.5Ah.............5.5A................7.5A..............................................7.1A......................................7.9A............
16%....................29.8Ah.............4.4A................6.0A..............................................5.3A......................................6.0A............
15%....................27.4Ah.............3.7A................4.6A..............................................4.9A......................................4.9A............
14%....................25.7Ah.............2.1A................3.8A..............................................3.9A......................................4.0A............

With 10A load
% Discharge........Ah DOD..........Diode..........Diode + Battery Sense...........Changeover Relay............C/O Relay + Battery Sense
20%....................35.5Ah.............0.8A................4.3A..............................................3.1A......................................4.8A............
16%....................30.2Ah.............0.1A................3.2A..............................................2.0A......................................3.5A............
15%....................27.6Ah........... -0.4A................2.4A..............................................1.1A......................................2.6A............
14%....................26.9Ah........... -0.5A................2.8A..............................................0.8A......................................2.8A............

Traffo charger contribution @ 14% DOD = 7.8A

Hmmm this is a very tough call.
Clearly the diode is rubbish on it's own. The diode + battery sense is competitive but not correctly regulated.
Changeover relay + battery sense is best but not correctly regulated.
Changeover relay does what I want at the cost of solar input.
Diode + battery sense/selective manual regulation + solar + summer is a hands down winner below 25% DOD :rolleyes:.

I could compromise and make the fridge trigger the battery sense link via relay and combine the generators.

Or accept the loss of a few hours solar here and there and stick with the relay for automation and best of a bad lot purposes.

Expect another wiring diagram when I'm finished plumbing this one. 35F

10-11-2013 6:49pm

Connecting everything onboard to the same AC Earth & 0v Ground reference has done wonders for those angry traffo bees. I fiddled with the output adjust which seems quietest at 29v and also switches the fan on permanently, which considering how hot it gets (~60°C) is no bad thing. The bees have now been relegated by grumpy crickets. I'm thinking of covering the power factor windings in RTV sealant to eliminate vibration but it'll also increase heat so maybe not such a good idea. Torqued all the internal and housing screws so I can comfortably drown it out with a little music/radio. Happy to call that fixed now. Hopefully it stays fixed next time I ask it to bulk charge too.

Still open to suggestions all the same.
It's not so happy about switch mode either. I can tune the buzz with my LEDs.

10-11-2013 11:39pm

I've settled on the changeover at the sacrifice of solar for the following reasons;

It never allows the starter battery to operate at discharge.
Likely driving is short legs, at night, subject to shading and capable of higher generation when deep cycles are at greater discharge. So overall potential loss will be minimal.
It's much harder keep the batteries up in Winter where the alternator is needed to maintain the solar lag, I only needed the alternator to run the Fridge during Summer the rest was catered for with photons.
The changeover can handle charge exclusively to the TS-45 so I'm not in a situation where I need a battery sense lead to supply the amps and the TS backs off regulated charge because the battery sense lead is cooking the batteries. :rolleyes:
I still retain manual control of the battery sense lead for the best boost of constant voltage charge when the deep cycles are low enough to warrant it.
I've only got 2 diodes, even though at the moment they're acting like three...it's too messy to be permanent. Flick the wrong switch at the wrong time round here and I'll be charging the starter battery with 29V. :eek:

I also decided against a voltage sensing relay to combine unregulated solar charge when it's below 14.8v mostly because if the module's producing that little it's only a few hundred mA anyways and all that will do is back the alternator regulator off creating a greater deficit.

Having said all that; a temperature compensated 14.4v set point is generally around 14.8v in Ireland anyway.

The Whole Kit & Caboodle.JPG

[EDIT: AC earth is depicted incorrectly; it's bonded to the chassis and continues to AC earth via socket.
I'm not so confident what this will do in crazy European continental electrics. Definitely won't work in American; they ground through the neutral which will toast your inverter up nicely. UK and Éire works as intended.]

A word on the relays;
Every relay defaults so solar is normal open. This is to maximise solar harvest as it is the predominant and best not to have to it powering relay coils.
The 70A C/O relay may seem excessive but I reckon it's about right.
I couldn't find a bigger 24v relay to scale up and the 12v make and break 40A already installed is only a matter of time before it expires.
The higher ratings don't seem to have that significant an active coil consumption but does have a significant contact surface area and heat dissipation abilities.

Probably cheeky to post another SmartGauge link.

10-11-2013 11:57pm

Next on the agenda is programming the TM battery monitor. It's recognition of what 100% charge is still set to default, mostly because it's worked. Lately I've noticed it getting confused and knocking 10s of Ah off the DOD.
I believe it watches the batteries raise in volts to the preset set-point, continues to watch the amps charged taper off then, waits to see a float charge and soon as it does resets to 100% capacity regardless of the counter.
I think the reduced solar output makes actual charge look like float charge, add a bit of cloud edging and the monitor resets. I charged the bank to 105% last night. Usually I only see this when equalising.

I'll have to plug a computer into it and set a better profile, I might be able to pull some data while I'm at it...maybe...better read the manual first..:D

14-11-2013 12:18pm

300+W solar at €0.50 per watt anyone?

[EDIT: bad listing here 300W is for the 180 pack not 108, website has a bad link...still under construction I'm told, I was ordering non-listed stock]

€0.35 per watt by the kW (Poly cells).

14-11-2013 4:04pm

16-11-2013 4:03pm

15:00 and stealth box shading has terminated my harvest.
1310511472angle%20of%20inclination.png

According to this the highest lip of my stealth box ought to be acute to 22° from the nearest edge of the module, I'm guessing that diagram is for midday too so I'm going to aim 5°-10°.

16-11-2013 6:03pm

I think I've a better solution for brackets; UPVC friction window stays, I might exchange the fixed module frame brackets for riveted pin hinges with lockable pins.
I'm considering lifting the module rather than chopping the box...

See Heavy Duty page #39

spaceHopper · 18-11-2013 4:09pm

You might like this blog,

http://homemadecircuitsandschematics.blogspot.in/p/battery-chargers.html

I'm tempted to build this

http://homemadecircuitsandschematics.blogspot.ie/2012/10/make-this-3-step-automatic-battery.html

21-11-2013 12:57am

I like it when 2 jobs become one. I wasn't happy to lose 3 month's electrons due to silly shading. So I gave it a lift near flush to the carrier sides.

Flat-storm-drive Position.JPG

It's a 80cm rise of riveted chequered plate and (aerodynamic

) angle ali.
The reason I paneled the long sides is for storage and to prevent aerodynamic lift.

I jettisoned the backboard and old brackets in favour of the same weight in a braced frame.
The tilting braces are two heavy duty UPVC window slides I got for a tenner. I modified them with an angle grinder

to open to 60°.
I have a littlier set that opens to 90° but these are much smaller and not as robust
I fitted wooden wedges to limit the closed position to flat and added patio locks to brace the non hinged side when closed.

Patio Locks.JPG

The rise is just enough to accommodate the hinging mechanism.
The friction stays are not enough alone to hold the module. At the moment I have a wooden prop for the rear and/or vice-grips on the bracket slides.

Tilted Module.JPG

No photos of it in operation in-situe yet.

The lift has extended harvest hours to much earlier and later. Module was minutely shaded all day bar two hours the past fortnight.

21-11-2013 1:33am

spaceHopper wrote: »

You might like this blog,

http://homemadecircuitsandschematics.blogspot.in/p/battery-chargers.html

Thanks Space. That's a good read. I've seen a lot of charger circuits about. They have their merits for little used batteries that do more floating than operating. Having seen how badly most retail standard chargers perform and why, I think there's certain kit worth the dosh. A primary charger is one of these.
Any charge that is not 100% replaced in a battery will eventually turn to sulphation.
Electronically estimating a battery's SG and appropriately advocating the best charge profile without a hydrometer and a lot of time is highly sophisticated. Also the charging waveform has a part to play and this is quite difficult to control. Chargers that read voltage from the charging lines are generally not very good I find.

holyhutzpa · 21-11-2013 1:09pm

Sir Liamalot wrote: »

I like it when 2 jobs become one. I wasn't happy to lose 3 month's electrons due to silly shading. So I gave it a lift near flush to the carrier sides.

Flat-storm-drive Position.JPG

It's a 80cm rise of riveted chequered plate and (aerodynamic ) angle ali.
The reason I paneled the long sides is for storage and to prevent aerodynamic lift.

I jettisoned the backboard and old brackets in favour of the same weight in a braced frame.
The tilting braces are two heavy duty UPVC window slides I got for a tenner. I modified them with an angle grinder to open to 60°.
I have a littlier set that opens to 90° but these are much smaller and not as robust
I fitted wooden wedges to limit the closed position to flat and added patio locks to brace the non hinged side when closed.

Patio Locks.JPG

The rise is just enough to accommodate the hinging mechanism.
The friction stays are not enough alone to hold the module. At the moment I have a wooden prop for the rear and/or vice-grips on the bracket slides.

Tilted Module.JPG

No photos of it in operation in-situe yet.

The lift has extended harvest hours to much earlier and later. Module was minutely shaded all day bar two hours the past fortnight.

Looks good, and the harvest hours are already paying off. I wasn't sure if the UPVC window slides would be strong enough to hold the panel when it was hinged at the bottom, but it looks good. These things are probably over-built anyway

21-11-2013 1:34pm

Yeah the slides I have open gammyways because of the weight from the top. They ordinarily don't need clearance inside the runner. Works fine though I just lose 10° off max tilt.
Module is flat now and I'll be lucky to get maybe 3Ah today because of cloud.

I'm happy to over-engineer what goes on my roof. All of it is. Everything up there has to withstand 120kmph+ winds as a regular occurrence. I wouldn't take the risk of sheet metal flying off on a motorway.

21-11-2013 1:36pm

Figured out what's wrong with the TM battery monitor. It's still on summer setting. 14.4v charge termination and 13.6v float. Winter is consistently 14.7v termination and 13.9v float. Haven't gotten around to updating it though.

holyhutzpa · 21-11-2013 1:41pm

You ought to get yourself a nice old camper with a 1.6d engine, 120kph will be a thing of the past

You won't be driving with the panel up though, so it's only when you're stationary that it will matter :eek:
Have you got a leg to stop it slamming shut?

Also, are those solar panels built to take vibration forces through a single point (or two single points - the patio door lockers)? I would be a bit weary that the vibration could cause a stress point and crack the panels?

I hope you'll make a dummy's guide to solar soon

21-11-2013 2:00pm

holyhutzpa wrote: »

You ought to get yourself a nice old camper with a 1.6d engine, 120kph will be a thing of the past

It's a 2.3L and I drive at 70kmph

holyhutzpa wrote: »

You won't be driving with the panel up though, so it's only when you're stationary that it will matter :eek:
Have you got a leg to stop it slamming shut?

Panel is flat for driving and still over-engineered at that.
I'm using my stick-to-beat-the-girls-away to prop the panel at the moment and it's well sturdy. I might get around to making different legs or a sliding prop further down the line. I was really more concerned about the shading than the tilting.
Vice grips pinching the slide onto the runners work quite well too.
I reckon best way to focus it is with a clamp-meter.

holyhutzpa wrote: »

Also, are those solar panels built to take vibration forces through a single point (or two single points - the patio door lockers)? I would be a bit weary that the vibration could cause a stress point and crack the panels?

Up to a point. The module is aluminium framed 18mm ply sandwiching cells between glass.
There's minimum vibration it doesn't rattle on it's locks.
What's not depicted on the photos is wooden supports underneath the module that it sits on. The locks are holding the frame down on this.

I'm hoping the locks spread the stress along the longside of the ali. frame so it's a lateral not point stress.

If I crack the glass I'll post a "Don't do this at home kids" waiver.

holyhutzpa wrote: »

I hope you'll make a dummy's guide to solar soon

http://www.navitron.org.uk/forum/index.php/topic,20386.0.html

23-11-2013 3:35pm

I was going to post some comparative figures between flat and tilted mounting but seeing as I'm parked in the middle of a cloud today, there's not much point. As any ambient light is heavily diffused and coming from all directions.

Highly Scientific Test Conditions.JPG
Believe it or not I was getting 1.0A in this photo at midday.

Module from Ground.JPG
Tilt in Situe.JPG
Flat Mount.JPG

ted1 · 23-11-2013 3:42pm

Sir Liamalot wrote: »

I was going to post some comparative figures between flat and tilted mounting but seeing as I'm parked in the middle of a cloud today, there's not much point. As any ambient light is heavily diffused and coming from all directions.

Highly Scientific Test Conditions.JPG
Believe it or not I was getting 1.0A in this photo at midday.

Module from Ground.JPG
Tilt in Situe.JPG
Flat Mount.JPG

With the loss of fuel efficiency due to drag and resistance as a result of the solar mount. Might a small petrol generator be more efficient cost wise and as well as over CO2 emissions

23-11-2013 4:30pm

ted1 wrote: »

With the loss of fuel efficiency due to drag and resistance as a result of the solar mount. Might a small petrol generator be more efficient cost wise and as well as over CO2 emissions

Short answer; no!

I've zero loss on aerodynamics at 70kmph, I was never streamlined to begin with.
Over the course of the last 4 years I've increased my MPG from 27MPG to 36 MPG (tracking, square tyre pressure, firming of suspension, engine flushing, filters, belt tension, driving slower, idle adjustment, Dipetane, oil additives etc.) The 27MPG figure had a clean roof, no skylights, chimney or rack and ¾ ton lighter.

A petrol turbine produces 60% usable energy and 40% is wasted heat, mechanical labour, noise/friction and regulation loss, it's noisy, smokey, messy, hard to transport, not stealth, high upkeep and higher CO² than drag. Also an abundance of what a petrol turbine generates is wasted because I haven't got the demand for >400watts AC, and what I do want I'm going to waste 20% of to rectifying it and stepping it down to 12V.
Anything that small is also 2-stroke which is a pain. Also there's the liability of fumes in the van and a 4 hour run-time per tank with a battery bank that can take up to 12 hours to fully charge.

Costwise in the short-term only then yes. Long-term solar will work for 30 years with no up-keep other than the occasional wash. Can be demounted and installed elsewhere should it be required.

Now a big diesel lister 7kVA gene. running on waste engine oil and WVO I could be tempted. A petrol turbine is just swatting flies with manky smokey cannonballs.

I had a 2-stroke gene., it's failure was what inspired the solar fit. Used the gene once and threw it into a shed, syphoned the fuel out for a chainsaw and it's sat there since.

23-11-2013 4:49pm

As towards the argument of CO² emissions of deforestation, pulling crude oil from underground, refining and transportation vs pressing silicon wafers from nuclear reactor power, lead acid technology and the overall return of energy investment I'm still undecided. Although inclined to sway with the wafers.

Small scale wind turbines on the other hand can payback the energy footprint in under a year.

Solar Install; the on-going saga

Comments