Hi @Crusty181,
how are you wiring up the panels and what connectors are already on the panels?
cheers
Mike
how are you wiring up the panels and what connectors are already on the panels?
cheers
Mike
Solar The Solar Panel Thread
- Thread starter cruza driver
- Start date
Thanks Boots, I'm thankful for the great knowledge you guys provide but once it gets too technical and I start to need an electronics degree to whack a couple of panels on the roof it becomes a question of "this is getting a little too problematic, and learning'ness intense". I appreciate the dumbing down.
The panels come with MC4 connectors on short 900mm cables. The existing roof junction box is under the existing panel and as the replacement panel will use the same mounts the roof junction box will remain in the same place, untouched, protected, and factory sealed. I plan to cut the cables from the existing panel at the panels terminal box leaving the metre long cables hanging out of the untouched roof junction box. I see a clear benefit not interfering with the vans roof junction box by avoiding interfering with the existing watertight seal. I don't want any cabling to run along the roof surface, creating pooling or interfere with water runoff. I plan on running conduit between the panels alum frames, feeding each of the single cables through the conduit and then using MC4 connectors under each panel. That way there's no cabling on the roof, and the cables and MC4 connectors are protected from UV etc sitting under each of the panels. One panel (the existing one) is across the rear of the van and the other 2 will be mounted in front of that panel down each side, about 500mm between them. The longest cable being across the van between each of the panels mounted along the edge of the van roof, and that will be around a metre. I've put a lot of thought into this, so be gentle
Hey guys, love that you like going deep into things but you might not have to go that deep into it in regards to diodes.
If you look at the photo of the spec sheet it has a rating called max system volts or somthing like that. Those ones have a rating of 1,000V so you don't have to change out diodes. It more relates to insulation of the cables and the panels highest rating. They've all been made to connect in either series or parallel.
Great idea on leaving existing Jbox alone. I'd do the same. Maybe check or add some more silicon too.
As long as you have genuine MC4 plugs and crimper to use on the old panel leads and new panels are same type you'll be fine. If they're different brands they can burn. Seen heaps of photos of burnt panels. Great idea on conduit also.
Stainless steel cable ties are what you use in house installs as plastic ones don't last.
If you look at the photo of the spec sheet it has a rating called max system volts or somthing like that. Those ones have a rating of 1,000V so you don't have to change out diodes. It more relates to insulation of the cables and the panels highest rating. They've all been made to connect in either series or parallel.
Great idea on leaving existing Jbox alone. I'd do the same. Maybe check or add some more silicon too.
As long as you have genuine MC4 plugs and crimper to use on the old panel leads and new panels are same type you'll be fine. If they're different brands they can burn. Seen heaps of photos of burnt panels. Great idea on conduit also.
Stainless steel cable ties are what you use in house installs as plastic ones don't last.
Hello there @Clewsy and welcome to discussion on diodes. The standard axial diode on a lot (most?) solar panels is the silicon Barrier type 10A10 and yes, it is a general purpose type and cheap. Its specs say it can handle 10A of current and a reverse voltage of 50 to 1000 volts. I believe you are correct about the max voltage rating of 1000V for panels in that it refers to the panel and cable insulation properties. The topic of some concern was that @Crusty181's had the superior Schottky type which do not have such a wide band of voltage operation. The reason I changed mine from the 10A10 to the Schottky 15SQ60 was all Schottky diodes have a very low forward voltage drop (nearly half the standard Barrier type) which means more voltage/current to solar controller. The penalty for that is there are limitations on handling capacity for voltage and current just as there are for solar controllers.
Thanks for that. Good to know about the diodes.
I could well be wrong on what i write here and always learning.
I'd imagine if you have average diodes you probably have average waffers, encapsulant, insulation etc as well and thus a not great panel.
Unless you're a good solder'er then i wouldn't have thought it was worth the risk to maybe do a bad solder joint and risk it burning. I guess you won't have any warranty with 12v panels do doesn't matter there on risking changing the diodes over.
If you're putting up 600w of panels didn't think you'd have to be to worried about small losses here and there (i agree they do add up and you have to consider them)
I bought a set of 250w folding panels before we started on the lap and thought they'd be good after reading and asking questions. I load tested with a variable resistor, plotted the V/I curve and most i got was 65W. Terrible temp co-efficient cells. They paid to ttake them back luckily.
The kickass one's i've been using seem pretty good. Few bucks though for them
I could well be wrong on what i write here and always learning.
I'd imagine if you have average diodes you probably have average waffers, encapsulant, insulation etc as well and thus a not great panel.
Unless you're a good solder'er then i wouldn't have thought it was worth the risk to maybe do a bad solder joint and risk it burning. I guess you won't have any warranty with 12v panels do doesn't matter there on risking changing the diodes over.
If you're putting up 600w of panels didn't think you'd have to be to worried about small losses here and there (i agree they do add up and you have to consider them)
I bought a set of 250w folding panels before we started on the lap and thought they'd be good after reading and asking questions. I load tested with a variable resistor, plotted the V/I curve and most i got was 65W. Terrible temp co-efficient cells. They paid to ttake them back luckily.
The kickass one's i've been using seem pretty good. Few bucks though for them
I did temp fate some time back and got bitten with very underperforming 250w fixed panels. Id actually given up bothering again. The issue seems to be a huge gamble across an industry chockas with BS and thieves. Lots of big empty claims. I tripped over a Youtube review btw flexis; a very expensive iTech World and cheap nasty Chinese one. The iTech World was rubbish and cheap Chinese outperformed both the iTech and its own specs ... so i bought them $130 ea delivered and they tested ok
You lot are a pain, been trying ignore you all banging on about diodes and stuff, now I have to go out and have a look at what i have, can't remember back when I last checked everything whether it was on the To Do List, All Ok list or The Bugga It list.....................read the recent posts 3 times, my head now hurts...........@Crusty181 just get your truck so you forget about all this nerdy big ears stuff you have" Booties" and "Micky Mouse from Down South" drooling all over their keyboards and shorting things out..................... Thankgoodness God invented Honda gennys.
I have studied all this very extensively @Drover and I think I cant confidently sum it all with; I have big flat black things which the magic man uses to deliver (possible via Uber) Mr Shocko, and I then get to flush my van toilet which is much to the huge relief of everyone else in the van
I agree with you @Crusty181 a real gamble to buy a good one and pretty much unregulated the 12v panel market. awesome you got some good ones for that price, well done.
So much easier when we didn't have all the gadgets to make life easy and the family was happy to put in more effort!
So much easier when we didn't have all the gadgets to make life easy and the family was happy to put in more effort!
Hi,The panels come with MC4 connectors on short 900mm cables. The existing roof junction box is under the existing panel and as the replacement panel will use the same mounts the roof junction box will remain in the same place, untouched, protected, and factory sealed. I plan to cut the cables from the existing panel at the panels terminal box leaving the metre long cables hanging out of the untouched roof junction box. I see a clear benefit not interfering with the vans roof junction box by avoiding interfering with the existing watertight seal. I don't want any cabling to run along the roof surface, creating pooling or interfere with water runoff. I plan on running conduit between the panels alum frames, feeding each of the single cables through the conduit and then using MC4 connectors under each panel. That way there's no cabling on the roof, and the cables and MC4 connectors are protected from UV etc sitting under each of the panels. One panel (the existing one) is across the rear of the van and the other 2 will be mounted in front of that panel down each side, about 500mm between them. The longest cable being across the van between each of the panels mounted along the edge of the van roof, and that will be around a metre. I've put a lot of thought into this, so be gentle
nice work!
Three things I liked about your post:
1: MC4 connectors
2: No mention of Anderson plugs
3: A well thought out plan!!!!!
Make sure the wires going into the flanges of the connection boxes on the panels are waterproof. You don't want corrosion getting in and destroying the panel.
Keep this up and I may forgive you for not knowing about forward current and reverse voltages.
I assume you are using non-conducting conduit. Is that correct?
Is there any chance you have a diagram showing the junction box, solar panels, mc4 connectors, and the interconnecting wiring?
cheers
Mike
The panel connection boxes have a pretty snug lid with a nice rubber lip compression seal. Forward current and reverse voltages is a shocking thing to get my head around ... get it, "shocking".
The conduit would be std 20mm electrical HD rigid as in what's in your house for the 240v, I never thought about it being non-conductive but I would suspect if it's not it probably should be. No drawing, it's not complicated enough for that (the hands on stuff I mean, not that brain-twisting electronic stuff). Ill grab some pics of the process as I go. Ill test glue some alum angle brackets tomorrow to ensure the adhesive of choice is up to the task, to make sure I don't lose any panels because I get out of the suburb. I might try to pick up a roof rafter as well for the front mounts to be doubly sure that stay put. The van roof skin left unattached to allow for flex and contraction/expansion but either side of the rooftop aircon unit is only 700mm wide so should interfere with that if I screw it down.
Hi @Clewsy , don't be too worried about about what you write here. If it is not so, there are friendly experts on this forum who will normally pick you up on incorrect points. I have been picked up a few times and that is how I learn too, (or get reminded,) unless I have really good references to back it up. @mikerezny is a real "tech head" on a lot of things electrical, whilst my inputs are usually results of actual field testing of solar and battery charging, based on my electrical know how. With all solar panels, they are built down to a price. If the panels are good, then the controller is usually basic or the cover/construction is poor or vice versa. I agree with you about soldering, and it would not be feasible for some, but improvements can be made if you can do it. Just because I have 600w of panels does not mean I am going to use them all the time, although I have only one battery - 120ah AGM - and mainly camp off grid for up to 7 or 8 days. Any I do not require go to my Daughter and family for their van. So just testing and recording all details at times with all the right meters etc.
I note your knowledge on temperature co-efficient of solar cells, which has not been discussed technically here to the best of my knowledge, but most members are aware of output losses when panels get hot, especially those with roof mounted solar panels, both rigid glass type and flexible type. As the specs are based on STC in a laboratory, they would be difficult to replicate in the field. So I work on about 80% of stated output as being the best I am likely to get in the real world, after taking in factors such as angle to the light source, heat on panel and airflow over panel, efficiency and working voltage are just some. The "Kickass" panels need to be good the price they are asking, so not on my shopping list, so if I can get a panel with reasonable credentials, I can always try to up grade them (with better diodes). @Crusty181 seems to have obtained some panels with reasonably good outputs, but I reckon the controllers would be very basic. Not a problem for him as he is bypassing all the panel controllers (I hope) and connecting his string to his MPPT controller. Great to have you on board. Cheers
The complimentary controllers came in separate bags, I haven't opened the bags, to be honest so have not clue what they are
Hi @Boots in Action, thanks for that. There's heaps of good info here from you guys.
I did the same thing and don't use the regulators supplied. I put redarc's in the van and in ute for second battery.
I did the same thing and don't use the regulators supplied. I put redarc's in the van and in ute for second battery.
Hey Mike, a couple of pics. Original panel has been removed, and was across the rear of the van where the new is positioned. New mounts for the new panels done. Conduit ready, as are additional wiring and MC4s. Jayco had glued the underside old panel to the top of the roof junction box, that was interesting. The junction box was in pretty average condition to, hidden under the panel, so that will need some love
Im a bit anal about the panels staying put, so found the aircon alum mounting frame on the drivers side, and a rafter on the passenger side for the front mounts, the rear ones I don't care so much about they can just sit on the glass roof sheet. The driver side panel will be partially shaded by the aircon unit if we're not careful, but not too much other option. We always try to park the van that side to the sun where possible anyway, so we cast shade on the awning side so it should only be an issue on the rare occasion, and I can top up with one of the blankets if need be
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