Solar The Solar Panel Thread

[Boots in Action]

Uncalled for dig Booties, I have nothing against MPPT controllers but they aren't worth throwing away a top line PWM controller and that link laid out the facts quite well I thought..................replacing some of the cheap rubbish PWM and MPPT controllers that come with most portable panels of course with a quality MPPT unit would be the way to go.

Getting a bit touchy there @Drover . Nothing personal and not directed at you at all. As it says in that link about chargers, many a camp fire conversation discusses this matter at length without rancour. In fact, I agree with your thoughts completely about not throwing away a quality PWM controller just to replace it with a MPPT one, UNLESS there is a very good reason. Unfortunately, few of us have had the chance to start from scratch with our designs/demands with solar power. I for one had a need and found it was the best way for me. I also had the funds.

 

[Coldspace]

My apologies @Coldspace . You appear to be all over it with all the luxury (for me anyway) items you are running with your set up. Great gear the Red Arc as I have done some research on that piece of equipment. Guess that you will have to watch your input verses output to maintain all that energy hungry gear, but with proper care, you should get by. Good luck!! I am envious of what you have, but still happy with my lot.

Nearly all over it, still learning about solar panels working in togeather and the way they can influence each other.
Yes, will need to keep up with plenty of generation to satisfy our power needs, plus it's fun.
Handy been an electrician by trade to work on our van.
I have learned a lot from this site anyway and from other sites.

Just wish we had more time to use our van a lot more.....

 

[Boots in Action]

Mixed day on many fronts yesterday. The new "250w " roof panels arrived yesterday, and the Victron the day before. Exciting times.

I connected the panels individually to the new Victron controller with a very mixed results. The Victron was impressive with its bluetooth phone App connection .... the panels themselves not so impressive. Yesterday was warm in Melb, with magnificent clear blue sunny skies. At 1pm, well within the solar collection sweet spot I tested the 250w panels on my truck's battery which was feeding a 150psi tyre pump. I started with the panel standing up ,then flat , then the magical 37, then everywhere in between, the best I could get out of each 250w (individually) was 8.4amps ... I got 7amps from the 150w on the van currently being flat, probably dusty and bird pooped and thru a PWM.

Preliminary results from the fridge bucket experiment are also disappointing ... the fridge buckets may soon become just buckets

One bright light on the otherwise underwelming day was when I tested my cheap and nasty 150w Super Cheap blanket panel which I had low expectations for. Thrown flat on the lumpy ground next to the 250w panel .... 7amps straight up. Woo hoo. I did some testing shading various areas of the panels with staggering results. Bit of a David and Goliath thing, with a little bit of shade knocking the bejesus out of the panels capacity to generate power.

Hi @Crusty181 , time to put on your "Tech Head" cap now. Very interested in your testing with shading. Also, I would put my money on the Epever MPPT controller to be more efficient that the Victron. Try hooking up each of the new panels, singly, in parallel and then in series with the Epever and record what happens. If you go back to my earlier posts, I had a similar start, but now seem to be able to generate heaps of current in all conditions. If I can get more than 21A out of my dissimilar panels (total 380w rated??) when connected in Series, it would be unusual for you not to easily exceed this with two similar panels totalling 500w rating. See my post to @Coldspace about generation.
Perhaps I get a little more because I changed the ordinary standard diodes (10A and 1000V) at the back of the panels with Schottky 15A 60V type as my bypass diodes. IN THEORY, that would give me less forward voltage drop and therefore slightly higher charging voltage to my MPPT controller?? What is the max working voltage of your new panels available to the controller??? You can always call on @mikerezny as your local expert/assistant. Noted your "cheap and nasty 150w Super Cheap blanket panel" does not seem too bad at all. 7A from a 150w panel when lying on ground getting hot is good stuff! On your new 250w rated panels, if charging voltage is 18v, then you should expect more than 13A from each panel under STC, without the help of the MPPT controller. Good luck and keen to hear how you go. Cheers.

 

[mikerezny]

Perhaps I get a little more because I changed the ordinary standard diodes (10A and 1000V) at the back of the panels with Schottky 15A 60V type as my bypass diodes. IN THEORY, that would give me less forward voltage drop and therefore slightly higher charging voltage to my MPPT controller??

Hi @Boots in Action,
When panels are connected in series, bypass diodes are only forward biassed IF the panel is in the shade. In normal operation, with all panels in the sun, the bypass diodes are reverse biassed (i.e. open circuit).

cheers
Mike

 

[Crusty181]

Hi @Crusty181 , time to put on your "Tech Head" cap now. Very interested in your testing with shading. Also, I would put my money on the Epever MPPT controller to be more efficient that the Victron. Try hooking up each of the new panels, singly, in parallel and then in series with the Epever and record what happens. If you go back to my earlier posts, I had a similar start, but now seem to be able to generate heaps of current in all conditions. If I can get more than 21A out of my dissimilar panels (total 380w rated??) when connected in Series, it would be unusual for you not to easily exceed this with two similar panels totalling 500w rating. See my post to @Coldspace about generation.
Perhaps I get a little more because I changed the ordinary standard diodes (10A and 1000V) at the back of the panels with Schottky 15A 60V type as my bypass diodes. IN THEORY, that would give me less forward voltage drop and therefore slightly higher charging voltage to my MPPT controller?? What is the max working voltage of your new panels available to the controller??? You can always call on @mikerezny as your local expert/assistant. Noted your "cheap and nasty 150w Super Cheap blanket panel" does not seem too bad at all. 7A from a 150w panel when lying on ground getting hot is good stuff! On your new 250w rated panels, if charging voltage is 18v, then you should expect more than 13A from each panel under STC, without the help of the MPPT controller. Good luck and keen to hear how you go. Cheers.

Bit of bad luck with the 250w panels. The cheap price I paid may have resulted in a significant trade off in output. The 250w panels are 22v, and the best I could get out of each on a beautiful clear day was 8.4 amps. My initial reaction was to contact the supplier for him to install them, ironically, where the sun doesnt shine. . What were your issues?

 

[mikerezny]

Bit of bad luck with the 250w panels. The cheap price I paid may have resulted in a significant trade off in output. The 250w panels are 22v, and the best I could get out of each on a beautiful clear day was 8.4 amps. My initial reaction was to contact the supplier for him to install them, ironically, where the sun doesnt shine. . What were your issues?

Hi @Crusty181,
put each panel in bright sunlight. Measure the Open Circuit voltage (Voc) and the short circuit current (Isc). Then compare these values to the specification sticker on the rear of the panel. The voltage should be about correct. If the measured current is less than the specifications then contact the supplier and demand a refund. If you don't get a satisfactory response and you bought them on eBay, you can lodge a dispute on the eBay site.
You are also covered by PayPal and your credit card issuer for such purchases. Take photos of the panels in sunlight, the volt and amp readings, and the specification sticker.

You won't have been the first to get stung and if you let them get away with it, you will only ensure there are many more.

A year or so ago, there were identical panels advertised on eBay being sold by three or so suppliers. They stated the panel specs, but the Imax x Vmax was substatantially less than the advertised wattage of the panel. I rang one of the suppliers in Melbourne who told me that they were lab readings and I would not get the same in normal conditions. I was quite assertive that the panels were incorrectly advertised and requested they put th ecorrect wattage on their ads. By the next day they had banned me from all the sites. No loss since I intended to never purchase any producte from them anyway. I emailed eBay and in their reply they stated that their policy is that ANY advertiser can ban anyone and they don't actually have to give a reason.

cheers
Mike

 

[Crusty181]

Hi @Crusty181,
put each panel in bright sunlight. Measure the Open Circuit voltage (Voc) and the short circuit current (Isc). Then compare these values to the specification sticker on the rear of the panel. The voltage should be about correct. If the measured current is less than the specifications then contact the supplier and demand a refund. If you don't get a satisfactory response and you bought them on eBay, you can lodge a dispute on the eBay site.
You are also covered by PayPal and your credit card issuer for such purchases. Take photos of the panels in sunlight, the volt and amp readings, and the specification sticker.

You won't have been the first to get stung and if you let them get away with it, you will only ensure there are many more.

A year or so ago, there were identical panels advertised on eBay being sold by three or so suppliers. They stated the panel specs, but the Imax x Vmax was substatantially less than the advertised wattage of the panel. I rang one of the suppliers in Melbourne who told me that they were lab readings and I would not get the same in normal conditions. I was quite assertive that the panels were incorrectly advertised and requested they put th ecorrect wattage on their ads. By the next day they had banned me from all the sites. No loss since I intended to never purchase any producte from them anyway. I emailed eBay and in their reply they stated that their policy is that ANY advertiser can ban anyone and they don't actually have to give a reason.

cheers
Mike

Thanks Mike, Ive been (for me) unusually polite with the seller, possibly because I suspected it was always going to be a gamble. After some token resistance, multiple offers of discounts, and some very funky camp lights the seller has eventually agreed to have the panels collected by a courier for a full refund, so aside from the inconvenience no real harm done.

Actually, its provided a good lesson. The next installment of my quest for panels may need to be in person. That will eliminate the potential to use the anonimity of online sales to engage in weasel like behavior by trying to avoid taking responsibilty for a crap product.

My issue measuring the panels direct output was the panels should produce in excess of the 10amp capacity of my standard meter, and I not in favour of buying a 20amp $100 meter to test a cheap solar panel. The voltage was close enough on my meter, and I relied on the Victron output for the amps which peaked at a much less than expected 8.4amps.

 

[mikerezny]

Thanks Mike, Ive been (for me) unusually polite with the seller, possibly because I suspected it was always going to be a gamble. After some token resistance, multiple offers of discounts, and some very funky camp lights the seller has eventually agreed to have the panels collected by a courier for a full refund, so aside from the inconvenience no real harm done.

Actually, its provided a good lesson. The next installment of my quest for panels may need to be in person. That will eliminate the potential to use the anonimity of online sales to engage in weasel like behavior by trying to avoid taking responsibilty for a crap product.

My issue measuring the panels direct output was the panels should produce in excess of the 10amp capacity of my standard meter, and I not in favour of buying a 20amp $100 meter to test a cheap solar panel. The voltage was close enough on my meter, and I relied on the Victron output for the amps which peaked at a much less than expected 8.4amps.

Hi @Crusty181,
good result! Glad you didn't just write them off as a bad investment.

I bit the bullet the other day and ordered the clamp meter discussed in this thread some time ago. It should arrive shortly and you are most welcome to borrow it if and when you need it.

cheers
Mike

 

[Boots in Action]

Hi @Crusty181,
good result! Glad you didn't just write them off as a bad investment.

I bit the bullet the other day and ordered the clamp meter discussed in this thread some time ago. It should arrive shortly and you are most welcome to borrow it if and when you need it.

cheers
Mike

Hi @mikerezny , the clamp meter that I purchased has come in very handy in measuring current in and out of charging systems. I am sure you will find it very useful. Just remember to change setting from AC to DC reading after selecting range. @Crusty181 will be able to do all the checking he needs with that clamp meter.

 

[Boots in Action]

Thanks Mike, Ive been (for me) unusually polite with the seller, possibly because I suspected it was always going to be a gamble. After some token resistance, multiple offers of discounts, and some very funky camp lights the seller has eventually agreed to have the panels collected by a courier for a full refund, so aside from the inconvenience no real harm done.

Actually, its provided a good lesson. The next installment of my quest for panels may need to be in person. That will eliminate the potential to use the anonimity of online sales to engage in weasel like behavior by trying to avoid taking responsibilty for a crap product.

My issue measuring the panels direct output was the panels should produce in excess of the 10amp capacity of my standard meter, and I not in favour of buying a 20amp $100 meter to test a cheap solar panel. The voltage was close enough on my meter, and I relied on the Victron output for the amps which peaked at a much less than expected 8.4amps.

Hi @Crusty181 , sorry to hear that your order did not fulfil your expectations. Initially @mikerezny and @G Daddy brought to my attention that performance of my 200w panel seemed a bit low and I too had my doubts when I first tried it out at home. Did some more checking to satisfy myself that panel was acceptable. Issues I found were time of day (late afternoon), and angle of panels to sun (changed poor panel supports and angle), poor PWM controller (now using MPPT controller) and battery connected was nearly fully charged and not accepting much current. There was also some confusion caused by me on the connections of diodes. You see I have two FOLDING panels (200w and 180w) and each has two folds of panels connected in parallel. In addition, each sub panel has two sub sections, each producing approx 21V. Now when I connect both panels (complete) in Series, I actually have two sub panels (each with 2 X 2 sub sections) all parallel connected, in Series with a similar set of two sub panels (each again with 2 X 2 sub sections) . That is why I believe that I have less forward voltage drop with the Schottky diodes which keeps my Voc up around 22.5V and working voltage in series around 36.0V as displayed on MPPT controller when battery is full and controller in FLOAT mode. How is a large 250W panel arranged??
Also, did some more research on two controllers onto the one battery. Yes, it does work, but the greater the disparity in controllers, the less efficient but better than not at all and not through the one lead into battery. Basically what I have been saying without mentioning the extra monitoring that MAY be required.
Found this article which supports my thoughts on putting all solar input through one efficient MPPT controller when connecting a portable panel to augment shaded or flat panels on roof of van. This does not mention "lack of air movement between back of panel and roof of van" and the losses through heat. Just more "grist to the mill" to stimulate your thoughts. I wish you every success in purchasing better panels in future.

https://itechworld.com.au/blogs/learn/two-regulators-one-battery

 

[Coldspace]

Hey everyone,
Just got back from Easter hols been away for 9 nights in our van and loving it , back to reality.

Question /opinion for you guys,
I run with a couple of traditional folding panels for our energy needs when off grid sometimes for upto 2 weeks on school hols, these have been great but alittle awkward in storing them in transport etc as they are rigid, 15 kgs and non flexi.
200-250 watts of capacity is plenty for our needs I've found especially with the 40 amp redarc and 2 x 130 batts in the van.

I have been thinking of doing away with these heavy panels, and going a light weight better modern option. Especially now with pricing etc on ebay, Something I can store away in the van when not needed , if we pull up for 1-3 nights our batt capacity and redarc is ample for no solar, but if wanna stay put for longer then I need solar.

I thinking due to the low cost these days of flexible or blankets I might invest in 2 x 120 watt ones that if I need solar I can just throw out on the car windscreen and flat on the ground near the van, connected in togeather with Anderson plugs, running up my heavy 8 mtr 6 b&s solar lead to the redarc should give me around 12 -13 amps in good conditions similar to my glass panels which is enough for us ATM .

So,

Are these flexible ones reasonably good, they say they are strong ect, I'm thinking of when not in use as they are only 2 mm thick storing them flat under my daughters bed which is the club lounge converted to king single bed with flat ply base and then 150 mm innerspring matress ontop. Been sandwiched between the mattress and base would keep them flat , but will they handle the weight of someone lying on the bed etc.?

Or , spend double and buy 2 blankets which can be stored in one of the compartments etc ?

Looking for feedback on if the flexible panels storage option under the mattress will be ok.

These panels will probably only see sun for a few weeks a year so mid quality will suit my budget and it would be just handy to have them hidden away and if needed just grab out as required, which I recon going to be better than lugging the glass ones around.
Don't want them on the roof as we often camp under a bushy safe tree etc and can put these out in the sun. The redarc supplies plenty of juice when travelling etc.. And the van is stored under carport at home.

Cheers everyone,

 

[Crusty181]

Late last year I purchased a Ridge Ryder (Super Cheap) 150w blanket panel as a backup just because it was cheap ... how bad could it be. I already have a fixed roof panel and a 100w blanket. I didnt expect too much from a Super Cheap panel but its been outstanding performance wise. Its typical denier contruction, and its certainly lighter and folds up smaller than a glass panel. The 100w panel is 4 x panels in a row and can be stood up on metal polls. The 150w is a true blanket 3 rows of 4 panels and impossible to do anything other than lay flat.

Weekend just gone the 150w blew a 10amp fuse on the feed into my car battery ... not suggesting it was producing more than 10amp, but it must have been getting close enough to pop a Chinese fuse. A comparison test with my caravan's factory fixed 150w glass panel and its achieving at least equal if not a touch better. I ditched the included controller in favour of a Victron MPPT contoller, but the panel itself Im very impressed with.

Ive thrown in on the ground, and draped it unevenly over the cars roof racks.

Super Cheap sell them for $499, but regularly have them on sale for $399

 

[Axl]

@Coldspace I brought a 120w Korr flexible solar blanket last month when I did an upgrade on my Expanda's solar and whilst I didn't get to test it on the van last time we were away (as the sun wouldn't shine) I have used it to top up both my tugs battery and my boats batteries and I am very impressed. Using the supplied regulator they performed exactly as advertised, when I get a chance to plug them into the van with its MPPT reg I believe I will see even better results out of something that weighs 4kg and takes up no space at all.
I wont ever ditch my 120w folding glass panels that weigh 15plus kg and take up a fare amount of space but I can see them sitting in the shed gathering dust in the near future. I am about to start modifying a new Dmax I've just purchased, it will have a DCDC/solar controller installed in the dual battery system and my plan was to mount glass panels between the three roof racks on the canopy but I can see them getting in the way, so I have now decided that I will run an external Anderson plug to the DCDC/solar reg and use the flexible panels when required.
If I need to down the track I will buy another set and for the price and from what I have read I wouldn't discount the Kings flexible panels, the regulator probably isn't all that good but if you don't need to use it for 280 odd dollars they might just be the answer you are looking for.
I am amazed at how far portable solar has come in such a short time, when I brought the 120w folding glass panels back in 2013 at a very hefty price compared to today there was no such thing as these blankets. In 5 years portable solar has gone ahead in leaps and bounds needless to say I will never buy another set of folding glass panels again.

 

[Drover]

I suppose the thing glass panels have is with little effort you can adjust them to get max power with ease.

 

[Coldspace]

Yes, I'll check the kings blankets out.
I use 2 folding glass panels and they punch out 20 amps wired togeather but just a little bulky for travel.

I might mount them on the roof someday and get a blanket for top ups/chasing the sun.

Do you think the 120 watt solar blanket would fit inside the skinny rear storage compartment at the rear of our 18.57-5 van under the bed, it has 2 access doors from the top inside the van. ?

Cheers

 

[Eddii]

Kings solar blanket is currently the cheapest out there, compared to supercheapauto or BCF anyway. Just under $300 for 120w. Not sure about eBay tho.

 

[Drover]

Browsing things and noticed that some of the Epever MPPT regulators are Positive Ground, something to watch out for....... so @Boots in Action why is this so ???

 

[mikerezny]

Browsing things and noticed that some of the Epever MPPT regulators are Positive Ground, something to watch out for....... so @Boots in Action why is this so ???

What do you mean by +ve ground?

It is not uncommon for dimmers, controllers, etc to have a straight through connection on the +ve input and output leads and put the controlling electronics etc in series with the -ve leads. Is this what you mean?

Or do you mean that the conductive case of the regulator is connected to the +ve terminals? This would certainly be a problem if the case is screwed to the metal chassis and the chassis is -ve ground.

cheers
Mike

 

[Drover]

I mean the spec sheet says Positive ground which I assume means it is positive to ground not negative.
If you look for the Epever units on eBay you will notice some are + Pos ground and some - Neg ground, that's Aust ones not chinky suppliers.

So I assume some problems if you hook them up with our normally Neg ground stuff, actually haven't had anything to do with Pos ground stuff since early mini's

 

[mikerezny]

Ok, I will try to explain where I am coming from.

Probably more information than you want!

Old days: cars could be +ve or -ve ground. Meaning which terminal of the battery was wired to the chassis. To connect anything one had to only run one wire to the device and the return path was through a connection to the chassis. Never a problem with lights etc which were not sensitive to polarity.
Big problem with generators however and one had to zap the field coils to ensure the generator would generate the correct polarity for the vehicle.
Worse still were the new-fangled car radios which were polarity sensitive. Some fancy ones could be switched to +ve or -ve polarity. Otherwise, one had to hunt around for a radio to match the polarity of the vehicle. In those early days, I thought I would be clever and just isolate the radio from the chassis and put the hot wire to ground and the vehicle power to the chassis. Great idea until I plugged in the car aerial. That had the shield firmly connected to the chassis and the car chassis was now firmly connected to the power. Sparks everywhere! Can't remember now if it blew the radio up. That was almost 50 years ago. I also remember completely changing the polarity of a vehicle so I could use a radio I already had.

The situation with a solar regulator seems to be a little different in that both the -ve and +ve terminals for both the solar input and the output to battery are supplied. There is actually no reliance on a chassis earth. The only problem I can foresee is IF the case of the regulator is metal AND is internally connected to either the +ve or -ve terminals of the regulator. Then IF the regulator is screwed to the metal chassis of the van AND the chassis is connected to either the +ve or -ve terminal of the battery, then there could be a short circuit if the device is the opposite polarity to the van wiring.

Or there is something else going on that I am not aware of.

cheers
Mike