As Crusty181 said, run a dedicated line direct from battery to outside, panel should go straight to battery via the panels controller, the added advantage is this anderson plug can also be used as a 12v supply for things like a compressor etc. so fit it on the off side of van not under the awning.
Solar The Solar Panel Thread
- Thread starter cruza driver
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Hey @Brenton, I take it from the comment that the pic of the flexi panels on the roof sheets are not on your van. Im interested in the 2 more panels but I dont want another 25kgs on the roof and that seems like a reasonable compromiseyes a lot of people glue them to 10mm polycarbonate sheets to help them breath like this. in my opinion the glass ones are more durable and will last longer, they may be heavier but if permanently mounting them i always go glass panels. my flex panel is good to keep in the back of the car.
I want to add upto another 300-500w in a couple of panels to my current single 150w system, and somewhere I recall a comment about needing to match wattage, same for same. Ive been reading a number of articles, and searching the Inter Wide Google Web and the common consensus is whilst connected in series this is true, connected in parallel its only required to match panels in max voltage, with watts not entering into consideration.
I could just remove my 150w and add a couple of 250's, but if it doesnt cause any issues I may as well keep it
From the articles Ive found Im yet to find a detractor from the "who cares about the watts camp". Does anyone have any practical knowledge, or peripheral issues that impact negatively.
I could just remove my 150w and add a couple of 250's, but if it doesnt cause any issues I may as well keep it
From the articles Ive found Im yet to find a detractor from the "who cares about the watts camp". Does anyone have any practical knowledge, or peripheral issues that impact negatively.
I have .
We have 5 panels 540W all up . If I recall right 1 x120w 2x110w and 2x100w all work fine together.
I find its better to spread the panels over the roof than relying on one large panel as I've found you can't always get a treeless spot. The chances of some panels getting sun are better spread over a greater area .
Been looking at things the same as you @Crusty181 and from what I gather while there may be some loss or something on paper in Real World it's really stuff all, which made me quite happy actually more important to have high rated cable and connections.........recent yarns with some folks about the flexy panels it seems they don't have the long term life of a solid job on the roof.
This is a genuine minefield. We coped with the single 150w panel, but we virtually had full sun for a year. On the handful of occasions we were off the grid in either shade or crappy weather we started struggling very quickly. With the relatively cheap price of panels, and the large real estate up top of the van, more panels its a bit of a no brainer.
Im now in the middle of reading about a twist to the mixing of panel size consensus. Its difficult to find specific detailed articles, but a late development that's mentioned more than once is whilst mixing of panels is ok for panel efficiency, its not so good for mppt reg efficiency. Im now reading a mppt reg will struggle with differing size panels, ultimately and adversely effecting charge efficiency.
The articles mention the result, but doesn't elaborate on the theory why. It's not clear on how an mppt reg can detect there are different size panels on a single parallel input; but I refuse to give up. One articles work around was a separate mppt reg for each of the panel sizes, in your case that would be 3 regs, in my case 2. I have no issue with that because regulators are cheap enough, but I was hoping to connect all the panels through single existing roof penetration making the adding of the panels much more a mechanical exercise, and much less a technical one.
iTechworld advertises an "Intelligent PWM Regulator" which kinda, without saying, suggests it may offer a solution. Im guessing, being PWM technology based, that it may come with its own technology inefficiencies so Im no better off . Im waiting for clarification from iTechworld
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Yeah, not sure what the issue is with longevity but my van lives inside unless Im using it, so longevity isnt as much as issue for me because they would be protected most of the time. Weight is the major overriding factor for me as well .... we're right on the limit and every kg counts. Im happy to sacrifice longevity for kg's, just not efficiency which defeats the purpose really.
I do find the portable 120 plonked on the ground actually provides more juice over a longer period than the rooftop 150 by the time the roof gets up to speed the ground one has nearly got the battery up, which allows laptops and stuff to get charged up in the middle of the day withtout battery loss.
I have been tossing up plugging ute into van as it has panels on roof as well.
I have been tossing up plugging ute into van as it has panels on roof as well.
Another important issue youve raised @Drover, flat panels (as on the roof) can reduce the panels efficiency by half. Your properly angled ground panel is working at 120w, and the 150w flat roof panel could be down as low as 80w.
I know youve upgraded the reg, but do you have all your panels feeding in via the original factory wiring
No they aren't sorry. I did have a contact a while ago for a guy who sold them wholesale to retailers so I sourced those for a friend however the bloke has gone under due to so many importers now and no money being in it. I would just have a look on eBay.
Sorry @Brenton, my fault. I'm not after panels just feedback on the flexi panels mounted to poly roofing. Seems like a great idea to avoid the dreaded excess kg's of framed panels
For what it's worth....we're in the final stages of a two month trip north and have mainly free camped.
New van so not entirely convinced that the solar setup was as efficient as on our Expanda so did some calculations, rough estimates and vague guesses before we left.
120 panel on roof needed additional oomph so got a 120 flexipanel to add.....kept it in its original cardboard box, added a good quality regulator and good cabling and just shoved it under the mats in the back of the car. Used it about five times and it was easy just to slide out of the cardboard box, lean against the car or van and it worked brilliantly.....so I'm very happy with it. No extra weight in the roof and setup in a minute. It weighs just 2.2 kgs and has no rough edges.
This has replaced the 120 folding panel we tried a couple of years ago....the model that folds into eight smaller panels and fits in a drawer. It's too heavy and unwieldy as it has to be braced so it doesn't collapse and I dislike just throwing it on the car bonnet.
Anyway, this works for us. I agree that a permanent fix ofthese panels won't last but they certainly work as an easy portable.
New van so not entirely convinced that the solar setup was as efficient as on our Expanda so did some calculations, rough estimates and vague guesses before we left.
120 panel on roof needed additional oomph so got a 120 flexipanel to add.....kept it in its original cardboard box, added a good quality regulator and good cabling and just shoved it under the mats in the back of the car. Used it about five times and it was easy just to slide out of the cardboard box, lean against the car or van and it worked brilliantly.....so I'm very happy with it. No extra weight in the roof and setup in a minute. It weighs just 2.2 kgs and has no rough edges.
This has replaced the 120 folding panel we tried a couple of years ago....the model that folds into eight smaller panels and fits in a drawer. It's too heavy and unwieldy as it has to be braced so it doesn't collapse and I dislike just throwing it on the car bonnet.
Anyway, this works for us. I agree that a permanent fix ofthese panels won't last but they certainly work as an easy portable.
They dont last as long as quite often aren't as efficient as the glass ones, so if you have the space and weight is ok go the glass as they will last longer.
Not sure that's correct but maybe were lucky.
I used our flexible one this morning to top up the second battery in the car...it went from 10.6 to 13.4 in 90 minutes.....far better than our older heavy panels but that could be the fact that the old panels are old....about six or seven years at least and technological improvements are evident, or it could be a better regulator.
Whatever it is we find the flexible ones very efficient.
I used our flexible one this morning to top up the second battery in the car...it went from 10.6 to 13.4 in 90 minutes.....far better than our older heavy panels but that could be the fact that the old panels are old....about six or seven years at least and technological improvements are evident, or it could be a better regulator.
Whatever it is we find the flexible ones very efficient.
Hi. Slightly off track but I recently mounted a solar panel on the roof of the caravan shed to keep the van charged. We don't have power on that side of the house and I had a spare panel off the old camper trailer. I wired an Anderson plug into the batteries and screwed it under the van just in front of the wheels on the drivers side. The 120 w panel is mounted on the roof using plastic mounting blocks . It is a regulated panel so now I don't have to worry about it any more.
Cheers
Cheers
Hi @Crusty181,
here is my understanding. Sorry for the long explanation.
With a single panel, there is a maximum short circuit current and a maximum open circuit voltage.
At the maximum short circuit current, the output voltage will be zero and thus the power output (volts x amps) will be 0 Watts. Similarly, at the maximum open circuit voltage, the current will be 0 Amps and again the power output will be 0 Watts.
But somewhere between these two extremes is a value for Voltage and Current that gives the Maximum power output.
This is usually stated on the Solar panel certificate on the back of the panel: Maximum Power (Pmax), Maximum Power Voltage (Vpm), and Maximum Power Current (Ipm).
However, this varies due things such as Temperature and the amount of solar power hitting the panel.
An MPPT controller works by choosing a load to put on the panel and then varying it slightly one way or the other.
If one of these attempts results in a higher power output, the regulator varies the load to the higher value. This continues until the controller finds a load, that when varied in either direction results in a lower power output from the panel.
If you put two dissimilar panels in parallel (i.e different Vpm), the MPPT controller will still find a setting for maximum power output of both panels, but it will probably not be the points where each panel would be individually efficient.
If you have different panels and want the Maximum efficiency from each panel, one should have a separate MPPT controller on each panel. But, if one considers costs that is not likely to be the most economic. Given the cost of good MPPT controllers I would consider, first finding an additional panel with about the same Vpm and connecting them in parallel ensuring they have blocking diodes.
Otherwise, I would buy an extra panel, whatever was good value, but oversize it by about 10% to allow for the fact that a single MPPT controller may not extract the maximum efficiency. I would think this would be cheaper and simpler than having two MPPT controllers.
Just a note, many cheap so-called MPPT controllers are just PWM controllers. If you look inside and cannot see a quite big coil (inductor) it cannot be an MPPT controller.
cheers
Mike
Um .... Yup. I going to say your right. Ha. Give me a few weeks, and I'll know why your right. It's certainly much more complex than slapping a panel on the roof, and by the end of this exercise I'll be an armchair expert. And yes, the pwm v mppt thing is not helping the research. Anything under $100, and looks remotely anything like this
.... regardless what is says is not mppt.
Some corroborating qualified advice hot off the press, as you said, the good oil on varying watts is match the voltage and the world will keep spinning.
I'm tossing up 2 x additional 150w flexi panels mounted on the poly roofing sheets, or replacing my 150w with 2 x 250w glass panels. I suspect the overall weight would end up similar in either scenario ... oh, and plus a real mppt controller probably this
Hi there @Crusty181 , I too have been reading about the connections of different wattage panels connected to a single regulator. Recently, with all my fridge cooling and heat exhaust fans (not controlled by thermostats yet), unswitched LED lights in fridge going, I decided to upgrade my PWM solar controller with a more efficient MPPT type. (Not one of the fake ones around either!!!) Reportedly better (up to 30%) especially in marginal conditions. I have 1 X 80 watt panel and 1 X 180 watt panel both portable and up to 18 to 20 volts, which I previously had connected up in parallel with my PWM controller. I could get up to 12.8 amps at 13 volts under good conditions too. However, after reading on sites about how best to get the most out of a MPPT controller, they recommend connecting panels in series to get a higher voltage (and less voltage drop in lines) so now there is 36 volts charging a battery of say 12.6 volts. The way MPPT chargers work is that they convert the higher voltage available into additional amps and this is greatest if battery is low (voltage differentiation), which is when you want it!!. A PWM controller is limited to the battery voltage and is unable to use the extra voltage to advantage. Enough said about the operation. Highly technical stuff!!!
However, on one of the MPPT sites, it tested a parallel circuit against a series circuit using LIKE and DIFFERING wattage panels. No problems with a parallel circuit with similar or differing wattages, but not as efficient as a series connection with similar wattages. It did mention that in a SERIES connection with a 150 w and a 80 w, the current produced would be limited to what was able to go through the lesser wattage panel and would not be the best way to go. It did not explain why. Can anyone confirm this??? I will be away in two weeks time and will have ample opportunity to fully test out this theory as I have volt meter connected separately across battery and my MPPT controller tells me PANEL voltage to controller, as well as battery voltage and current flow in charging battery (120 AH AGM.) I will be happy to let you know and other members of this forum of the outcome in practical application. Hope this helps all.