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Forum Index : Solar : Buying solar connectors, cct breakers - can we trust aliexpress/ebay

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rogerdw
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Joined: 22/10/2019
Location: Australia
Posts: 818
Posted: 02:11pm 09 May 2023
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I want to buy a heap of MC4 connectors, solar cable, cct breakers etc and wonder what the advice is regarding buying via Aliexpress or ebay etc  ...  or whether it's critical to buy from mainstream suppliers.

I noticed Madness mentioned he'd been using a TOMZN changeover switch for some years and been happy with them.

Any advice on best sources for reliable gear would be appreciated. Thanks.
Cheers,  Roger
 
Murphy's friend

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Joined: 04/10/2019
Location: Australia
Posts: 612
Posted: 02:45pm 09 May 2023
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Roger, its been a while ago since I bought a stack of MC4 connectors on ebay.
I chose an Eastern States shop (can't remember which) that shipped promptly and the connectors were OK. I get solar cable the same way, it pays to choose carefully on ebay if you want a decent length.
If you don't have a suitable crimping tool you might buy that on ebay too.
 
rogerdw
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Joined: 22/10/2019
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Posts: 818
Posted: 10:39am 10 May 2023
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Thanks Klaus, I appreciate your comments. There's a massive difference between mainstream and ali stuff, so I'll have to be careful.

I do have a good crimping tool, but will buy some MC4 jaws to suit. Just had a sales sheet from WES Components with all the different jaws they sell  ...  which happen to be the same type as my Rhino gear.
Cheers,  Roger
 
Revlac

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Joined: 31/12/2016
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Posts: 974
Posted: 11:21am 10 May 2023
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Do you really need a heap of MC4 connectors?
What did we do before MC4 was invented?  
Cheers Aaron
Off The Grid
 
rogerdw
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Joined: 22/10/2019
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Posted: 01:12am 11 May 2023
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Haha, yeah I see what you're getting at, though I have 48 panels to connect and I have to do at least some of my installation by the book.  
Cheers,  Roger
 
Revlac

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Posted: 02:51am 11 May 2023
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Thats a few panels,  with 3 in series I still use the connectors on the center panel etc, the positive and negative of the outer most panels get a new heavy duty wire running to a junction box with proper terminals.
Personal preference, was not happy with some of those MC4 connectors failing.
You could have a look at https://www.rockby.com.au/Index2012.cfm some times they have stuff on special, bought 2 boxes of Noark circuit breakers, been very handy.
Cheers Aaron
Off The Grid
 
Godoh
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Joined: 26/09/2020
Location: Australia
Posts: 395
Posted: 06:18am 11 May 2023
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I have bought MC4 connectors off ebay too, no problems with them. I get solar cable from a Gumtree seller. Generally pay around $160 for a 100 metre roll of twin 6mm cable.
My panels are wired 2 in series, then all paralleled, so there is not much stress on the system as far as voltages or high currents go.

Pete
 
Davo99
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Joined: 03/06/2019
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Posted: 12:50pm 12 May 2023
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I have only bought MC4's off fleabay, ;least a couple of hundred of them now.
I did get some given to me by my solar supplier and the only thing I could see different was they were a total and complete pain in the arse to get apart again as I often want to do in my stuffing around.

Never had fleabay ones fall apart so never had a problem with them. I inherently don't like Mc4'S, had too many fail.  had them fail even from factory on panels.  Too easy for them not to make good contact but that's what we are stuck with.

I bought a crimping tool from Fleabay for $20 that does 2.5, 4, and 6MM wire.
Seems to do a good connection as they cannot be pulled apart. May be cheaper than jaws for your other crimper.

Seems like you got a good score of panels mate! What size you get?

I have had some good scores with what my supplier has been chucking out.  Got 10 new 525's before Christmas, a batch of 18 x 330s also new and half a Dozen new 360'smonth or so back.

Those 525's are freaking huge and heavy but they sure cut down on the total number of panels you have to install, secure and wire up!
Got a few more of those to put up, I'll see how many of the 330's I can fit and then the house will be full again.

I'll then upgrade all the 250's I have on the shed. I did work it all out whats going where but I have been getting good amount so the plan keeps changing.  Latley I have got a lot of 2's and 3's in the high 400W range so I might throw a heap of them up.
The voltages are all similar and the losses are going to be bugger all in reality so may as well use them.  Got them for nothing so If I put 8 KW wort up there and only get 5kw out, what the hell do I care?
Free power in the true meaning.

Maxing out what the shed will take well and truly and had to put in yet another circuit for the house. With all this being about 32KW when done, still run short in winter.

Did you get to finish your tube heater?
 
rogerdw
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Joined: 22/10/2019
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Posts: 818
Posted: 02:22pm 12 May 2023
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Thanks for your input Aaron and Pete. I had forgotten about Rockby and hadn't visited their site for years. I am also planning on doing 3 in series and then 4 parallel to feed 3Kw into one of Poida's MPPTs  ...  then repeating 3 more times.

I was quoted $204 for 100m of twin 4mm by a local electrical wholesaler, so nowhere near as good as your price Pete  ...  and that's with 6mm. Mmmm.

I had a feeling I'd heard about issues with cheapie MC4's, but looks like I can take my chances and see what happens.

Davo the extra jaws are about $23 and I found a couple other sets that I can make use of so I'll probably still get them to complete my kit. The originals work very well so I'm confident these will be worth it.

The first panels I bought were 3Kw of 250's nearly 10 years ago for gulp around $1k including rails and tiled roof fittings as well as a nondescript inverter. I'm using 6 of these still for my pool pump  ...  though if I ever / no, WHEN I get my Warpverter going  ...  I'll probably revert it back to ac and run it off the inverter.

Fascinating that the DC pool pump has been running for nearly 3 and a half years already. I walked past the other day and thought it sounded pretty fast, so went and checked the pressure and it was up at 90psi, the same as what it would have been on mains  ...  and yet it was at least 75% cloud cover and definitely no direct sun. Most other days during cloudy weather it's running pretty slow, must have been something different about conditions that day. Probably chemtrails.  

The 2nd lot were identical 250W panels, 3Kw again but for $300 and including 3Kw SMA inverter and railing.

Then 6.6Kw of 275W panels and an inverter for $1k.

Always wished I lived a bit closer to you  ...  you seem to have access to much better prices over there.

I plan on fitting all 48 to the north facing roof on the shed  ...  in fact I could probably get another row across the top  ...  but they will end up pretty close to the peak of the roof and I understand you are not supposed to have them too close. Anyway I don't want to draw attention to the installation, so I'll keep it conservative.

Though if you found a heap of 525's for a good price, it'd be worth a drive over for myself  ...  and I'm confident I'd get most if not all of my money back for the ones I already have.

I am shocked that at 32Kw you still run short in winter. Maybe I'm gunna have to fill up the paddock to get enough output here.


Still didn't finish the tube heater   though the original is well into it's third season. We had some really sunny days a few weeks ago and the temp got up to 28 in the lounge. In fact it was pumping over 50 degrees for hours every day. But with the cloudy weather over the last week it's been a lot more sedate.

Really pleased that Tony talked me into fitting a differential controller. The thing comes on most mornings around 7.30 or so  ...  runs a few mins then off  ...  then builds up 5 mins later and eventually runs continually.

You suggested you'd like to know what it puts out on a sunny day, so thinking of you, I did try it. It went up over 100 but not much more, which seemed odd but I turned it off and forgot about it. Some time later (weeks) I went past and noticed the bottom 8" plastic tube was all caved in and collapsed!!! Looks like the heat just melted it and end cap popped off and glass tubes came away from their seals. I figured it was beyond repair, but once the cold kicked in again I had a closer look and resurrected it  ...  and now somehow it seems more efficient than before. So it will definitely be worthwhile getting the big one going, I just need to finish the inverter system first.

In the process of fixing it I replaced the temp sensors in the tubes. All that was left of the originals was a foot or so of rusty brittle wire that all crumbled away when I pulled them out. Totally destroyed.

I should mention that the morning I fixed it up was nice and cold but still sunny  ...  and when I fired it up, it was pumping out at 113 degrees  ...  probably a bit dangerous at that  ...  and still took at least 30 mins to get down to 50 which it ran at for hours. The only thing wrong is that it pumps into the lounge area  ...  if it was into the kitchen/living area it would be way more effective. I'll get there.  
Edited 2023-05-13 00:31 by rogerdw
Cheers,  Roger
 
Godoh
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Joined: 26/09/2020
Location: Australia
Posts: 395
Posted: 10:09pm 12 May 2023
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Hi Roger, I just had a look on Gumtree the seller I used to buy off doesn't seem to be there at the moment,
There is a seller on ebay offering 4mm twin for $167 for 100 metres but pick up in Morabbin

Pete
 
rogerdw
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Joined: 22/10/2019
Location: Australia
Posts: 818
Posted: 12:28am 13 May 2023
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Thanks Pete, I did check out gumtree as well as Ebay and have seen quite a few options over in Melbourne  ...  but there's no screaming hurry, so I'll keep watching. I'm in SA so local pickup from interstate is a bit tricky.

I know I'd seen some locally on Marketplace a fair while ago, but none just at the moment. Some will turn up.😊
Cheers,  Roger
 
Davo99
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Joined: 03/06/2019
Location: Australia
Posts: 1578
Posted: 09:12am 13 May 2023
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I have paid around $100 for twin core 4mm when I have bought it and the going rate was about 150.  Last year I got 2 Full rolls off my supplier as they changed the standard for the wire and this was no longer able to be installed.

Typical of the solar industry, always changing standards for " safety" nothing at all to do with making money by making what was installed in hundreds of thousands of home without problem, now a problem.

Anyway, I should have about a life time supply now.

I found that leaving about 300mm off the roof ridge works fine. I get some really bad winds here on occasion and none of my panels have lifted bar the ones direct behind the bib water tank. They on 2 Occasions tore the tek screws out the beam let alone the roof sheet but the ones either side were fine.  Left a gap there and had no more trouble so I can only assume the tank cause some sort of turbulance that created a low pressure spot like a plane wing and sucked the panel right off. I couldn't pull the thing out when I did try but the wing sure did.

Meanwhile on the other side of the shed, there have been panels laying the completely unsecured for 4 years and haven't moved a Mm.

I am ALL electric here, no gas, no wood so all heating is by electric.
My main inverter is 5 KW and presently has about 10 Kw of panels on it. I haven't seen it max out in the last fortnight.  Max sun hours here now are 5. in summer that's 12 so the difference is huge.  Add to that the fall off which is about 30% of summer insolation and there is the lack of power.

I had a new system installed in september bigger than the old one and supposedly much more efficient. The old one was pretty hopeless in Winter but OK, not great in summer.  In summer I run the ducted AC 24/7 for weeks and shut down half the system and still made excess power. Keeping the place cool is certainly no problem. For whatever reason, the heat is not as hard to compbat as the cold here although the temp differentials of Summer heat and winter cold are about the same difference to what I want the place to be.

Really all this over the top solar is to try to offset 3-4 Months of winter cold..... and the fact I just get obsessive with things I get involved with.

The days here of late have been fantastic. I was working in the yard yesterday and had to come in as I was too hot.  Last night was 4C so won't be long and we will be at zero.  I think I have lamented here ( and everywhere else) many times what a thermal disaster this place is.  The other night I had it sitting at 22 C. Wife came to bed and turned off the AC at about Midnight.  Got up at 6 and the place was like an icebox, or felt like it. 12 in here.  I surprised myself just how quick this place cools off. It's shocking.  Yes, I have insulation but the 40 huge windows that look stylish are terrible for retaining heat especially.  Next house I buy I'll look at in a very different way.


I have thought of your Tube system as well and spent some time the other week going through the long thread trying to find the differential controller you were using.
I was also trying to figure out if I could do the same thing using 2 Regular thermostats somehow linked.  If there is, I can't figure it.

I was thinking of running water though a tube system into an Insulated IBC or some old water heater tanks so I could store the heat but I did not want to be circulating when the tank temp was higher than what the output of the system was.

I have not seen many tube setups come up round here and when they do, people seem to want 3x what they would have cost new or they are broken or incomplete.
I also want to give my solar panel heating idea a good go as the test I did on that was quite positive with just one panel and I am convinced that using 6-8 Panels would produce a LOT of worthwhile thermal energy in using the heated air and the power they generated.

I am going to look next week at heating up a water heater I got couple of months ago through the day and then use that to put heat into the house at night. Still comes back to the inefficiency of panels  making power though.  The tank could store 25KWH of heat energy but it takes a decent array to put that into it in winter.

I'm thinking will be way better off just to go with the Co-gen system with the diesel engine driving an Induction motor.  Last weekend I got one of those small Bike sheds which I am going to line with insulation as sound proofing and put the engine in that.  I hope for it to be quiet enough to run at night.  I'll test with the little 6 Hp engine at first and then determine if I need more heat and power of that is enough. If I need more I have a 22 HP water cooled engine and a 12 KW induction motor I can use.

And because I am so paranoid of the cold, I have also been refining my waste oil burner setup and believe I have Ironed out the major weakness in that. Worked fine last year but I believe the weak point was the HE and the one I have set up now is laughably over capacity but it was the cheapest option and I figured out how to do it.

I only got the 10 X 525W panels but this week I discovered I have about 50 Brand new 250's up there.  Got them to put on my roof but then all these bigger ones showed up and the 250's got left. I 'll probably put them up on gumtree next week.
Edited 2023-05-13 19:15 by Davo99
 
rogerdw
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Joined: 22/10/2019
Location: Australia
Posts: 818
Posted: 01:43pm 14 May 2023
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  Davo99 said   I found that leaving about 300mm off the roof ridge works fine. I get some really bad winds here on occasion and none of my panels have lifted bar the ones direct behind the bib water tank.


I've just worked out that my roof will only take all 48 panels if I have each end hanging over exactly one inch!!! Obviously that is not going to fly, so I'm going to have to settle for 46 and fit the remaining 2 elsewhere.

Another alternative is to have the panels in landscape in rows of 4  ...  then I can get an extra 8 on there  ...  and still have at least 350mm gap all the way round. I don't know if I quite get the process of fitting all the rails that way. Will need to think about it some more.



  Quote  I have thought of your Tube system as well and spent some time the other week going through the long thread trying to find the differential controller you were using.
I was also trying to figure out if I could do the same thing using 2 Regular thermostats somehow linked.  If there is, I can't figure it.


I reckon Tony found the one I used. It's simply a controller with two temp sensors  ...  one inside the tubes and one inside the house.

When the temp inside the tubes gets 12 degrees above the indoor temp  ...  the fan kicks on.

Unless the sun is really strong, that pulls the temp down in the tubes and once it gets to 5 degrees above inside temp, the fan cuts off.

Those were numbers I finally settled on after the first winter, and seem to be quite suitable.

Here are links to the device  and to the instructions

  Quote  I have not seen many tube setups come up round here and when they do, people seem to want 3x what they would have cost new or they are broken or incomplete.
I also want to give my solar panel heating idea a good go as the test I did on that was quite positive with just one panel and I am convinced that using 6-8 Panels would produce a LOT of worthwhile thermal energy in using the heated air and the power they generated.


I haven't seen too many lately either. There were a lot for a while. I'd like to see the results for your ideas too, they sound like they could be quite decent and you certainly have no shortage of panels.  

I still need to chase up more solar railing and am starting to realise that it's going to be very expensive if I can't find a cheap supply. I did come across some rail-less systems, but while they leave out the rails, the alternative fittings are still pricey. I'm going to ring around tomorrow and talk to some of the more local solar installers to see what they might have lying around.
Cheers,  Roger
 
Murphy's friend

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Joined: 04/10/2019
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Posts: 612
Posted: 03:25pm 14 May 2023
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  rogerdw said  

I still need to chase up more solar railing and am starting to realise that it's going to be very expensive if I can't find a cheap supply. I did come across some rail-less systems, but while they leave out the rails, the alternative fittings are still pricey. I'm going to ring around tomorrow and talk to some of the more local solar installers to see what they might have lying around.


Why don't you make your own rails? All my rails are home made. I use angles mounted on brackets, the angle like an upside down L with the angle corner facing down roof.

The panels lock under the lip of the angle by means of bolted on special brackets.

I did a post about that some time back with pictures that explain it better.

This method (used for the smaller size -190W- panels) lets me install them single handed as the panel self locks in place when slid down over the angle rails.
 
rogerdw
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Joined: 22/10/2019
Location: Australia
Posts: 818
Posted: 12:36am 15 May 2023
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Thanks Klaus, I do vaguely recall that post. I tried a search but the search function doesn't like you for some reason. It lets me search for Tinker and others that I tried  ...  but not Murphy's friend!!!


Edit:
I did find it  ...  under Tinker  ...  here
Edited 2023-05-15 10:51 by rogerdw
Cheers,  Roger
 
Murphy's friend

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Posted: 08:53am 15 May 2023
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Well done Roger.
That forum does not like Murphy's friend, does not let me edit my posts either.

The latest version (for 12 panels for the hot water tank) has a few mods:

The special brackets have 2 roofing screws now, stops them twisting.
I use 4 of these per panel now, 2 on top & bottom rail.

The rails are alu angle now,  using an alu channel would be stiffer and easier to install on a tin roof if its pre drilled.

4 of the slide on brackets hold the panel very well, have not yet even bothered to fit end brackets and they're all in place still despite very strong winds.
 
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