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12-05-2013, 03:12   #1
Sir Liamalot
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Solar Install; the on-going saga

I recently negative bell curve lost about 160ah through negligence and mismanagement of batteries, all the while I thought I was doing the right things. Before I decided to replace the bank I had I've been doing some serious research on how to prevent this from happening again.


Most of this install I can attribute to Handybob http://handybobsolar.wordpress.com/t...ging-puzzle-2/ [re-post]


It was not my intention to blatantly copy his system downspec'ed until I tried to find a better or similar one where none could be had as far as I could tell...and I've been looking for a month.
If you can make it to the end of that link I recommend the rest of the blog, particularly his meter rants.
I've been gauging my battery condition subconsciously for years and I have gotten rather good at estimating a state of charge, despite having two conflicting voltmeters.


After watching the voltmeter today running the module for the first time I'm glad I ordered the Trimetric. It's one thing to estimate the actual voltage while there's a load on the batteries. It's an entirely different story trying to do it when there's a load and a low current generator at the same time.




I also owe thanks to PaddyP for straightening my expectations out with his indispensable formula,
indispensable because after one month looking I have yet to find a site that makes the same comprehensive list of hidden losses.




Quote:
Originally Posted by paddyp View Post


Total annual solar insolation ireland - 900-1200 kwh/m2

100w panel = approx 0.5m2

450 - 600k kwh total to be captured

Panel efficiency 12-14% say 14%

63 - 80kwh per year

Lead acid charging efficiency 70%

44kwh - 56kwh = 10 - 12.8Ah per day annual average.

May/June/July Dublin 5kwh/m2/day

5 x .5 x .14 x .7 = 0.245kwh


245watts / 12 volts = 20.5Ah per day summer average.

Also there's high temperature inefficiencies to be considered (abroad) and I'm looking at a 40% output reduction for mounting the module flat.


Being the optimist that I am I up-spec'ed the module and cracked on. I'm going to install a shunt driven ammeter later so hopefully in a few weeks I can get back with some numbers.


I'm intending to retrofit adjustable tilting brackets (tiltable both sides) eventually but I daresay it'll be rare I use them as I don't often stay put very long so not a priority. In this case I think it's more practical to get 40% more panels to offset the loss.


Also on the long-finger agenda is a wind deflector because perhaps the best solution for too much ballast on the roof is more ballast on the roof.
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12-05-2013, 03:31   #2
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Mounting

I looked around and found all those “camper solar kits” were bundled with low end controllers;
I found a not bad one with a steca controller that has a built in ammeter until I did some more research and learned these are not accurate, nor are the solar charge controller remotes.
If you want to read amps you need a shunt or a clamp meter and a calculator.
I read of one customer complaining to Steca that the ah readouts were misleading and the reply received was that this feature was inaccurate, simply that it would be far more expensive for that feature to work correctly.?!


I settled on a 150watt Chinese panel with a decent warranty that came in at the right price and suited my roof dimensions. I had a look at european panels and speculated that they won't honour their warranties soon as China puts them out of business. Bosch are pullling out of the market, Q cells are being outsourced etc.


First agenda I had is to disguise it. My camper lives in the wild and urban, so I need a way to hide it from prying fingers and gobsh1teology.
Simpliest solution I had was make an unassuming roof box and paint it black outside (stealth) and yellow inside (reflective....white would be more reflective but I like yellow so meh!)


2 Mock up side .JPG


I mounted the box onto an existing roof rack with clamped U-brackets.
I secured the module to the box with adapted domestic solar PV brackets, this required a little angle grinding of the brackets and some padding of the panel. I'm not too fond of the extra ballast on the back of the module but it may be useful later for the tilting mounts.
I put a layer of road noise reducing rubber between the backboard and the module more to meet the bracket requirements than the sound ones.
This was cut from an old inner tube...if you want straight pieces cut from the center not the sides...



Road noise reducing filler.JPG
Back board.JPG
Scaffolding solution.JPG
Rack Box.JPG

Last edited by Sir Liamalot; 12-05-2013 at 04:02.
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12-05-2013, 03:42   #3
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Wiring

Wiring;


Wiring diagram.JPG

{EDIT; I just spotted this: the 20 amp fuse on the starter +ve is after the split to the automotive electrics and before the battery link switch. The diagram implies all the automotive electrics are off a single 20amp...in reality it's on it's own core independant of the auto-electric loom...thus the oversight}

I didn't use 4mm solar cable for a few reasons many I grew to regret.
I went with 4.5mm automotive cable single insulated...so I heat shrank 10 metres of it (one of the regrets).
It was easier and quicker for me to get thicker (so better) wire with no UV protection which works for my setup because I've no UV exposure.
I couldn't find a cable entry box quick enough either so I just plugged a cable entry gland straight into the roof, chased it with some sealant and doubled up on rubbers. It's covered by the roof box so I'm not concerned with a leak appearing. Besides the gland is one hole, a glanded box is 5 holes. I prefer the gland even vertical as it is.


Cable entry gland.JPG



There's a few lines on the wiring diagram with two fuses or a fuse and circuit breaker here's the logic. The solar module is rated for < 10amps. However fuses increase resistance and cause voltage drop so I put a 15amp fuse on the module to try to offset this and a 10 amp DC circuit-breaker beside the charge controller. It needs a fuse on the generator side before the risk of it grounding off the body...but hopefully the circuit breaker goes first if there's any other issue (lower rating) so I don't have to climb out on the roof to replace a bloody awkward fuse. Also it allows me to turn off the module from inside for whatever reason...like protecting the controller from open circuit voltage when I want to reset the controller.



Module fuse.JPG
Sealed module fuse.JPG


There's two fuses on the starter to leisure battery link (for switched alternator charge) the reason for this is there's two positives on opposite sides of a switch that is usually open.

The reason for the master breaker is it's handy to have a kill-everything switch, as well as this every live is fused, but some run several meters from the battery before it gets to that fuse. The master can thus detect a ground fault that fuses might not.


In my war on voltage drop I removed the MC4 connecting leads from the module (regret number 2)
Turns out the back of the module has non-standard crimp connections. I attempted to salvage the old crimps off the MC4 leads I removed and made a bags of it giving up after an hour or more. I didn't want to tail in on bare wires here because there was bad connectivity so I tried to order more and nobody had them, ordered the wrong ones from china and “made” them fit after 2 fun hours of crimping.

Last edited by Sir Liamalot; 12-05-2013 at 13:42. Reason: correction
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12-05-2013, 03:52   #4
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Solar controller;

I decided to spec. the new system to the alternator because that's the hardest component to change, which means getting flooded deep cycle batteries that can take 14.7volts. However I have a sealed battery now I want to make use of it for the time being.


Wiring mess.JPG


Given this I wanted a versatile solar controller, then I decided I wanted a programmable controller because well that's pretty versatile. I went for the Morningstar Tristar 45 because of this and also because it is the only solar controller that can run wind/hydro and hybrid systems too which I plan on using down the line for other projects.

Tristar patch.JPG


The leads from the controller to the battery are 8mm cores from stranded 125amp single phase TRS cable I got through work. I re-used the rubber shielding after wiring everything as cable trunking wrapped in electricians tape...does the job.


Tidied Cables...ish.JPG


The controller has separate battery sense leads (to avoid reading voltage from a load carrying wire), and remote temperature sensor connected to the battery negative terminal for temperature compensation.

Installed.JPG

As far as I can see PWM charging plays havoc with cheap voltmeters. For accurate readings I think you need an RMS meter. I've observed a 0.5v difference between the two after a minor fluster.

Last edited by Sir Liamalot; 12-05-2013 at 14:06. Reason: additional
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12-05-2013, 03:57   #5
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DC Circuit-breaker box

CBI DC Breaker box.JPG


10 amp; solar module 150watts / 18volts = 8.3amps
16amp ; solar controller 150watts / 12volts = 12.5amps
35amp; in the post
10amp; temporary master DC breaker




oops forgot to post this one earlier
Fixed flat mount.JPG




TBC
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12-05-2013, 13:45   #6
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Fuse holder money saving solution.

Retail blade fuse holder.JPG: €3 - €5 aprox.
Home made blade fuse holder.JPG: €0.30 aprox.
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30-05-2013, 00:04   #7
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TriMetric Meter

Fairly simple to install and program this unit. Wired it to the shunt and two battery +ives. It monitors the amps in/out off the leisure batteries and displays an accurate percentage charge via a series shunt. It also displays voltages for two separate battery banks (with a common ground) so I can monitor my starter battery with the same unit. I'm guessing it's RMS because it's verifying my multimeter and shaming my cheapo Chinese joby.

This requires 5 core cable (one twisted pair semi-recommended) on fairly small cable (0.5mm...depending on distance of course). I just used 7 core trailer cable for convenience because I had enough lying around for the job, the core set twists 360° every meter and two spare cores could eventually come in handy.
It's quite useful to compare ah to % charge to calculate what the current rating of your batteries are too (%Dod).

1 amp fast blow fuses on both +ives on battery side.

I have to admit although this is a very handy gizmo, I'm not entirely sure I need it now, as so far, since I installed the panel I've been fully charged everyday. ...time will tell, I may start running the fridge on 12volt and see how well that works. Besides it's always there now should I want to up-rate or salvage the system.




%charge.JPG
Absorption Amps in.JPG
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30-05-2013, 00:21   #8
Sir Liamalot
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Shunt

Goes in series with all negative returns to the leisure batteries and the chassis ground is to be connected to the shunt and not the -ive battery terminal . There's smaller kelvin connections on the sides to take voltage sensing wires, where the main current carrying wires are sent to the main lugs on the top. I wired the -ive solar controller battery sense lead onto the kelvin connection, I'm not entirely sure if this is right but it's made little difference.

Shunt Nearside.JPG
Shunt Farside.JPG


The saga isn't going to be as ongoing as I first predicted because, I had intended to do another few posts on refitting my sealed battery for 2 x 6volt flooded golf cart batteries in series, that weren't going to fit where I wanted them, but a few things have transpired since to make me re-evaluate.
I was going to up-rate my mains charger too for one that conforms to the battery manufacturer's spec.



A: My lone battered and bruised battery with solar is outperforming what two new of it's kind were doing with an alternator subsidised weekly mains charge. Oh I don't have to use the alternator anymore to top up the leisure batteries...but I still use the link switch to top up the starter off solar now.
B: I want to see if Morningstar's claims that PWM charging can recover lost battery capacity is true.
C: I don't want to throw out a working battery albeit it working very badly as a simple ecological issue.
D: I bought a car with my new battery budget and still have €40 change.
E: Winter will be the true teller if I need to invest given the less light more demand equation but I've already done three Winters in a camper so I'm kinda determined to go bricks and mortar next one.


I'll post some definitive figures where I get them but it might be a while.

Last edited by Sir Liamalot; 30-05-2013 at 00:41.
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04-06-2013, 20:21   #9
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Limalot - have followed your thread with interest. Am a keen supporter of solar in my home environment and would be interested in the merits of it for my camper.

Always hook up while away but there are those rare times when this is not possible. Any views on these as a top up when required? Intend to connect direct to battery and put back in box when not required.

http://www.sealey.co.uk/PLPageBuilde...roductid=12095

Can pick them up here for €70 - €80
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04-06-2013, 21:28   #10
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tehehe yeah I just put one on a car today to save another starter from the recycle heap. They're fairly rubbish. All it'll do is prevent a battery from self-discharge in the height of summer. We had it tilted 40° directed at the mid-day sun today at 20° Celcius and it took a battery from 12.5volts to 12.9volts producing < 100mA.

For that sort of money you should be considering something like this http://www.hollybrookps.co.uk/pv_mod...ystalline.html

That Sealy link is just a trickle charger, it might give you enough for a mobile phone charge. Aside from this the wires are too small and it's unregulated. Not that 100mA could harm a leisure battery at all but the principle of unbridled charge upsets me.

Last edited by Sir Liamalot; 04-06-2013 at 23:36.
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04-06-2013, 22:02   #11
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Link looks like a fairly top end product that is a permanent connection. I am looking at the portable the better.

Would this product from Maplins be an improvement? It is just top up that I am looking for? Self contained closing case is of interest as it should protect the panel when not being used.

http://www.maplin.co.uk/13w-solar-br...99760#overview

So for portable, protectable, top up is this value for money?
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04-06-2013, 22:33   #12
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Ah..no, my link is low end, it's a Chinese job...but value for money.

I try to avoid Maplins, they're rip-off merchants. Even though I post lots of links to them. It's a convenience thing. Definitely for solar they're triple what you ought to be paying.

The competitive price per watt on solar modules today is about €1.20 You can go lower or higher for brands, guarantees and warranties.
Also a typical warranty on a solar module is 20 - 25 years...think economy of scale.

The link I posted is portable, there's also smaller ones on that web-site. They have connecting leads on the back you can mount them outside your camper on brackets or rocks or whatever and run a temporary lead to a cheap charge controller near your batteries. You can store them in the back of a wardrobe when you don't want them. They're quite durable.

I really wouldn't consider anything less than 50watts for light camper use. That briefcase will leave you high and dry on a cloudy day, actually at 13watts probably on a sunny day too.

Sorry I haven't posted any figures from my system to compare yet. I've not been using my camper much and won't be until next month. Mostly working on a car these days. I'll post what I can this week but daily averages could be mid July.
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04-06-2013, 22:46   #13
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Quote:
Originally Posted by dfbemt View Post
It is just top up that I am looking for?
Any idea what this might be in terms of amp hours?

On a side note down the economy of scale road; is it worth factoring in the longevity of your leisure battery life on a maintained system relative to a depletive one? To me I estimate that's worth 4 times the value of batteries (half the bank I used to need giving me 6 years (at least) instead of 3)).
Although if you trickle charge in the down time then your result will be mute. ...mine rarely stays in dock more than two days.

Last edited by Sir Liamalot; 04-06-2013 at 22:59.
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04-06-2013, 23:03   #14
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Quote:
Originally Posted by Sir Liamalot View Post
Any idea what this might be in terms of amp hours?
Hard to know. Kids now have tablets. Will have to check the plugs to see what they need.

We tend to use EHU when away but last time in France we noticed that the battery was flat after a few days. Site had 10Amp hook up so was a bit surprised by this. Fridge was on all day (off main) and kids charged Nintendos overnight. Granted, within 12 months of minimal use we ended up needing a new battery
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04-06-2013, 23:25   #15
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10amp on mains is a lot more juice than on 12volt.

Any chance you have a clamp multi-meter?
Short of that if you can add up your ah usage, tell me your battery size and times between charges I can give you a guesstimate what you might need.

or you can take Aidan's word for it;

Quote:
Originally Posted by Aidan_M_M View Post
I fit the regulator beside the battery if at all possible. I dunno guys, it's easy get bogged down in the science of it, I just fit a decent wet battery, a good quality 75w panel with a decent non adjustae regulator , using high quality cabling. And I've never had an issue. In fact, I can't recall having to replace a battery for any customer that got a panel fitted once it was fitted as above.

If it was my choice, ALL MHs would have solar panels.

Last edited by Sir Liamalot; 04-06-2013 at 23:34.
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