Mixing Brands - Solar Panels & MPPT Smart Solar Charge Controller
Auzmel said
10:48 PM Dec 12, 2022
Would it work if I match 2 x Kings Mono 160watt Solar Panels with a Victron MPPT Smart Solar Charge Controller? or do they have to be matching brands? as I've done research and the Kings MPPT Smart Solar Charge Controller has got bad reviews. Thanks in advance, Melissa
Possum3 said
11:08 PM Dec 12, 2022
Welcome to GN's Melissa. Can't help with your electronics, but there are a few gurus on here that will.
rgren2 said
11:49 PM Dec 12, 2022
The Victron gear is good quality, shouldnt have any problems as long as its connected correctly.
Jaahn said
07:58 AM Dec 13, 2022
Auzmel wrote:
Would it work if I match 2 x Kings Mono 160watt Solar Panels with a Victron MPPT Smart Solar Charge Controller? or do they have to be matching brands? as I've done research and the Kings MPPT Smart Solar Charge Controller has got bad reviews. Thanks in advance, Melissa
Hi Auzmel,
That would work OK. I mix and match like that for good results. I do not think the Kings MPPT controller is very good either, performed very poorly in a friend van. and has been replaced. But the solar panels from there are well under performing too and only putting out half their specs power.
Jaahn
-- Edited by Jaahn on Tuesday 13th of December 2022 08:00:37 AM
Mike Harding said
08:01 AM Dec 13, 2022
As said; Victron equipment is excellent but expensive - I run it.
You can supply a MPPT controller with any panels at all. The panels should be the same (or very close to) wattage and voltage as one-another and preferably wired in parallel to avoid loss due to shading. The wires from panel to controller should be as short as possible - this can be difficult but do your best.
The King's panels may come with a built-in solar controller, this must be discarded and the panels fed directly into the Victron.
If you have space consider ex house panels, there are lots on the secondhand market currently - a year ago I bought 4 x 200W for $30 each.
Edit:
PS. Buy a bigger Victron controller than you need because, I have little doubt, you will later wish to add more solar panels.
-- Edited by Mike Harding on Tuesday 13th of December 2022 08:10:03 AM
Whenarewethere said
09:21 AM Dec 13, 2022
I have Projecta panels & Victron controller. Actually Victron everything else. I used the Projecta panels as I need a particular size to fit a space.
P.S. Don't skimp on wiring. No point putting in a good system & too much is wasted in resistance.
Auzmel said
10:23 AM Dec 13, 2022
Thanks for your reply, can you recommend any good solar panels?
Auzmel said
10:27 AM Dec 13, 2022
Thanks for your informative reply, very beneficial. :)
yobarr said
12:01 PM Dec 13, 2022
Auzmel wrote:
Thanks for your reply, can you recommend any good solar panels?
Not sure what you want but I bought 6x275 watt Suntech Polycrystalline panels from Hayman Electrical. Cost only $120 each. Cheers
-- Edited by yobarr on Tuesday 13th of December 2022 12:04:21 PM
TimTim said
11:09 PM Dec 13, 2022
-- Edited by TimTim on Tuesday 13th of December 2022 11:40:31 PM
TimTim said
11:40 PM Dec 13, 2022
Auzmel wrote:
Thanks for your reply, can you recommend any good solar panels?
Hi Mel,
I have just bought a 175W Monocrystalline Victron solar panel which I did another quick test today and it was producing 156W for a short while. That is 89% of the stated output. What may appear to be a clear blue sky to us is not always that clear and the solar irradiance may be lower than expected. I only have to look at my home solar to see how the output fluctuates oven though I cant see any change in the sky. 89% is pretty good.
Personally from past experience I would not buy the Kings and would agree with Jaahn, but others may have had a better experience. A better alternative would be the Victron 175W Polycrystalline panels which are around the $200 mark but a bit of a search may get you a better price.
Other than that someone may be able to advise you on the Hardcore 170W panel which appears to have good reviews and also around the $200 mark.
Just be careful buying many of the no name brands as they will never be able to put out the stated output because of their physical size.
Although I have a number of different brands of solar controller including a Victron, the Victron is good.
Good luck
Tim
-- Edited by TimTim on Wednesday 14th of December 2022 12:34:24 AM
dorian said
06:39 AM Dec 14, 2022
yobarr wrote:
Not sure what you want but I bought 6x275 watt Suntech Polycrystalline panels from Hayman Electrical.
I notice that the same panel comes in 3 grades -- 275W, 270W and 265W. It seems that cells are individually tested and selected for their efficiency.
I also notice that Suntech specifies the electrical characteristics according to two standards, STC and NOCT. Everyone uses the STC standard, but I've never seen any manufacturer quote NOCT. In fact, I had never heard of it before reading this datasheet. It appears that NOCT attempts to reflect real, average conditions.
STC: lrradiance 1000 W/m2, module temperature 25 °C, AM=1.5
NOCT: Irradiance 800 W/m2, ambient temperature 20 °C, AM=1.5, wind speed 1 m/s
Jaahn said
10:40 AM Dec 14, 2022
Auzmel wrote:
Thanks for your reply, can you recommend any good solar panels?
Hi Melissa it is hard to recommend panels because I do not know where you are or if you are familiar with ebay or Gumtree or want a retail shop.
I would buy and have bought ex-house panels for a very cheap price where Solar Panel fitters have removed older small systems to fit bigger systems. They just want to get rid of them for a modest price. Usually good quality panels suitable for a quality MPPT regulator like a Victron. These older panels are often each about 170-200 W or possibly up to 250W so easy to wire in. Note they are higher voltage than 12V nominal so must be used with a MPPT regulator to work well on a 12V battery system. Use good heavy wiring too as suggested.
Otherwise shop from say Jaycar or some well established retail outlet near you that will guarantee the output of the new panels. The newish 4WD/camping retailers often sell cheap low quality stuff in my opinion and the casual staff may not be helpful.
In the past I bought panels off ebay or Gumtree sellers and they all performed OK when I tested them. But I have not bought any like that for years now.
Good luck jaahn
PS Dorian solar panel suppliers have always individually matched their cells after testing the output, for each panel, and then test the panels and group them for output. Thus some retailers call the best ones grade A and lesser as grade B,C. But the cells are all the good just not putting out quite as much for the same area. The usual way to test the panels is on a light box which supplies a certified sun strength even light. Only takes a few seconds I was told to get the output reading.
I might wonder if all the Chinese factories test them so much. I was told the lower output cells below spec are sold off cheaply to "second tier" makers for their panels. A friends father had some cheap system put on his roof near the sea, and after some years it was not performing so they had it replaced. The sellers had long gone !! He tested the 10 panels for output and only two were any good. Actually half of them you could pick were bad just visually.
-- Edited by Jaahn on Wednesday 14th of December 2022 11:00:47 AM
Mike Harding said
11:00 AM Dec 14, 2022
Auzmel:
I get the impression that, like mine, your panels will be freestanding ie. not permanently fixed to a vehicle?
This is the best way to use solar panels when camping as it permits you to locate them in an area of minimum shade and adjust their angle during the day and year in order to maximise the position of the sun.
However, as with all good things (yes, even me :) ) there are downsides: they must be stored and packed safely for transport and, obviously, will not be collecting energy until unpacked and located and this often won't be practical for stays of one or two nights.
Don't underestimate the packing/storage aspect: I have 4 x 200W panels; each panel weighs 15kg and is 1520 x 850mm ie. a large and heavy(ish) item, it is the largest panel I can fit inside my 4WD.
On top of this, during transport, the panels must be protected from items falling on them and causing damage. To this end I made some simple brackets which permit me to bolt two panels together face-to-face thus providing some protection and stopping the panels banging against one-another when I go over a bump. Trouble is 2 x 15kg = 30kg and that's close to the limit of an object that size for me to manhandle (womanhandle? :) ) into a vehicle.
Just give some thought to all this stuff before you buy.
PS. I wonder if "womanhandle" is a verb or adjective? :)
-- Edited by Mike Harding on Wednesday 14th of December 2022 11:02:37 AM
Whenarewethere said
11:53 AM Dec 14, 2022
My 120w portable panel is 15kg, we only start using it on about the fourth day if we haven't moved, as we couldn't be bothered setting it up. Theoretically we can do 7 days off batteries.
Get plenty of extension leads for portable solar panels. Tall trees cast very long shadows.
You can also use your jumper leads for a few extra metres, if you set them up with a connector.
Warren-Pat_01 said
11:26 PM Dec 14, 2022
G'day Melissa,
Welcome to the GNF - I trust you'll be able to find what you need in advice on everything "caravan" & perhaps sometime you'll be able to help other new members. Mostly we're a good bunch - we all have experience in something that we worked on, at in the past or present.
I see lots of vehicles driving around with Kings stuff fitted - there is a saying "that you get what you pay."
Mid year, I bought the "bargain" 20A MPPT controller - it was too cheap but I decided to give it a trial. It "sort of" worked but I found the voltage cutout didn't work. Running an AGM battery to 17v is not healthy, for humans & batteries. I tried it twice - just to be sure. I removed it, took it back for a refund & the second issue cropped up. I had paid for it on a credit card but to get a refund, Kings require a BSB & bank account number. They say they cannot pay back on to the credit card - they don't have BSBs! Eventually I got my money back but it wasn't easy.
Their solar panels might be ok but the construction (to me) doesn't look good - plastic corner pieces to start with, light frames, next.
Victron panels are good - Springers Solar (often they have sales) & Outback Marine are two good firms that I know of & have used. Suntech are mentioned above - not certain if they are still available. They were excellent but
had trouble competing with the el-cheapos. Also Jaycar are mentioned - their gear is fairly good too (might not be the cheapest).
All the best.
Cuppa said
01:58 PM Dec 15, 2022
The point made about having freestanding/portable panels is worth paying attention to. Of course choice is a 'horses for courses' thing. Swings & roundabouts.
There is no doubt you van get more out of your panels & into your batteries if you are prepared to be around & willing to move them every hour or so throughout the day, in addition to the often heavy & cumbersome unpacking/setting up/packing away routine.
To my way of thinking this practice suits folk who rarely leave their camp, & who camp in places for at least a week or two at a time. Also folk who lack 'real estate' on their van or vehicle roof for permanent mounting.
Our first vehicle with solar had plenty of roof space so 'loose' panels were never a consideration.For a while on our current vehicle we had our roof full with a roof top tent so panels had to be 'loose'
I'd have to say that the practice of getting them out, packing away & moving them to catch the sun multiple times a day quickly wore pretty thin.
When we realised that actually we (I) hated rooftop tent living & took it off (& towed a camper instead) it was a relief to attach the solar panels to the roof. They are always there doing their job with no further thought required. & they can be left doing their job if you go for a walk or leave camp.without fear they will be stolen because they are bolted down.
The disadvantage is that panels laying flat (or close to flat) will not put out as much power as those angled always toward the sun. I use an old & well used formula (Courtesy of Collyn Rivers) to determine output & thus how much solar I need. For 12v panels divide the panel's rated wattage x 12 to get the max output in amps, & then multiply it by 70% to account for laying flat. Eg. 120w panel will theoretically put out around 10 amps (120 divided 12) but laid flat on a roof multiply 10 by 70% & you get 7amps. So you can see that if using fixed panels you will need more panels to do the same job (which is fine provided you have the roof space on top of vehicle/van.
I have used top quality Kyocera panels, back when a 120w panels cost $1150 each. Today they are *far* cheaper, & I have also used ebay cheap panels. The main difference seems to be in their shade tolerance. El cheapo panels can lose their entire output from just a tiny bit of shadow on the panel, better panels will only lose output proportional to the amount of shadow.
Of the more reliable , quality -wise online sellers at good prices I have found 'Low Energy Developments' to offer a good balance of quality & price.
Their solar panels might be ok but the construction (to me) doesn't look good - plastic corner pieces to start with, light frames, next.
The better solar panels do not have plastic corners.
When I started a few years ago I didn't have a clue on anything solar. So I bought what I felt was the best. I just couldn't be bothered with a list of unknowns. I have better things to do than waste time on third rate products. Let's be honest a lot of them simply lie about their performance.
I also have built in redundancy so if something fails while remote the fridge will still work.
yobarr said
04:20 PM Dec 15, 2022
If you have a caravan I cannot understand why you would even consider messing around with portable panels. As well as risking having said panels "borrowed" by some low life, there also is the hassle of regularly having to move them, as well as packing and storing them for travel. "No room on roof" is unlikely to stand scrutiny as evidenced by my design. As well as 1650 watts Solar (6x275 watts) I have a Sat TV and a 4 seasons hatch, and still there is plenty of spare room. Previously I had 9x190 watt panels but when a couple got smashed by rocks and replacements could not be sourced I gave the remaining 7 panels to an installer in return for fitting the new ones. Parking in the sun is not a problem as the panels are 4" off the roof so that they can breathe, and also prevent the sun shining directly onto the van's roof. On really hot days I simply leave the AC running. Cheers
If you have a caravan I cannot understand why you would even consider messing around with portable panels.
Because portable panels provide far, far better energy capture when one camps in forests and is able to move the panels a couple of times a day in order to minimise shade.
dorian said
06:34 AM Dec 16, 2022
I would think that fixed panels would give rise to a Catch 22 situation. If you park in the shade to get out of the sun on a hot day, your solar harvest is reduced. So to capture the optimal solar harvest you need to endure the heat. Portable panels would circumvent this problem.
Cuppa said
09:56 AM Dec 16, 2022
dorian wrote:
I would think that fixed panels would give rise to a Catch 22 situation. If you park in the shade to get out of the sun on a hot day, your solar harvest is reduced. So to capture the optimal solar harvest you need to endure the heat. Portable panels would circumvent this problem.
True ........... unless like us you tow & have the panels on the tow vehicle, which we connect to our camper via a 10 metre 6B&S 'umbilical cord' which enables us (most of the time) to camp in shade when desirable, whilst panels are out in the sun.
Although that said we had fixed panels on the roof of our bus, with a good air gap below them, plus heat reflecting paint on the roof & good cross ventilation airflow in the bus, & it was on average 3 degrees cooler inside the bus than outside - still hot in hot weather but quite manageable. Two roof hatches (one with a bi-directional fan) worked very well.
I would think that fixed panels would give rise to a Catch 22 situation. If you park in the shade to get out of the sun on a hot day, your solar harvest is reduced. So to capture the optimal solar harvest you need to endure the heat. Portable panels would circumvent this problem.
YES that is true. I do not have the perfect answer to this.
We have done both. I had a larger MH and portable panels. It had a 'gear box' on the back so I carried the 4 panels on top of that with some ply seperators/ stands and strapped them on. Easy enough to put out two in a few minutes or 4 if needed. I had a long electrical cable and a matching security cable to lock the panels to the MH. Easy enough to do.
Now we have a small HM with fixed panels center to front. But we do like to park in the shade in the heat. Hmm still working on that. But I think I will put another largish panel on the very back end and park with that out in the sun, that will probably give some shade and give enough power in the full sun anyway. Must get around to that soon. I would carry some portable panels if I was going away for a while but not so much spare room in this one.
The panels are not very fragile you know. They stand up to normal handling OK. I have never broken one from carrying them around in camper vans or putting them around and getting them blown flat. Years ago we went up to the bush block with the grandkids and the panels were spread around on the ground and propped up a bit one end. When I returned the kids were running around a 'track' that included the panels ?? No problems ! But I did stop them using the panels.
Jaahn
Mike Harding said
02:49 PM Dec 16, 2022
Just musing:
Bunnings often have 25m extension leads on sale for around $18, they are rated 10A so, I guess, are 1.5mm2. My 200W panels are about 7A which equates to about an 8% voltage drop over this cable and rather less at lower currents.
Could be a cheap way to provide a 25m radius for panel location?
Edit:
Afterthought: with a bit of fiddling two leads could be made to service three panels.
-- Edited by Mike Harding on Friday 16th of December 2022 02:51:13 PM
Cuppa said
10:15 PM Dec 16, 2022
Mike Harding wrote:
Just musing:
Bunnings often have 25m extension leads on sale for around $18, they are rated 10A so, I guess, are 1.5mm2. My 200W panels are about 7A which equates to about an 8% voltage drop over this cable and rather less at lower currents.
Could be a cheap way to provide a 25m radius for panel location?
Edit:
Afterthought: with a bit of fiddling two leads could be made to service three panels.
-- Edited by Mike Harding on Friday 16th of December 2022 02:51:13 PM
Are you forgetting that the 10 amp rating of those extension leads are designed to have 240v pushing those amps through. Try that at a nominal 12v & losses would be far higher. At 25 metres probably enough to get virtually nothing going into the batteries. Think of voltage as the pressure which pushes the current (amps) through the cable. The higher the voltage the thinner cables can be.
With my 6 B&S (13.5mm2 copper) 10 metre 'umbilical cable', it provides sufficient from the batteries in our car to run lights, radio, CPAP, & water pump. but if I plug the heavier load of my laptop in to charge it via the inverter in our camper (7 amps) the voltage drops from say 13.2v to around 12. 1v or 12.2v. This worried me until I realised that that the batteries 10 metres away weren't actually dropping anything like that, it was only at the camper end ie. losses in the cable. I decided not to worry about it as I new we had sufficient battery capacity to put up with wasting a bit whilst charging the Laptop. Of course if I measured the voltage at the camper end with no loads switched on it would show the same as at the battery, it's only when under load that you get voltage drop . Same reason why it's always best to have a solar reg close to the battery & not stuck on the rear of panels.
yobarr said
10:31 PM Dec 16, 2022
Cuppa wrote:
Are you forgetting that the 10 amp rating of those extension leads are designed to have 240v pushing those amps through. Try that at a nominal 12v & losses would be far higher. At 25 metres probably enough to get virtually nothing going into the batteries. Think of voltage as the pressure which pushes the current (amps) through the cable. The higher the voltage the thinner cables can be.
With my 6 B&S (13.5mm2 copper) 10 metre 'umbilical cable', it provides sufficient from the batteries in our car to run lights, radio, CPAP, & water pump. but if I plug the heavier load of my laptop in to charge it via the inverter in our camper (7 amps) the voltage drops from say 13.2v to around 12. 1v or 12.2v. This worried me until I realised that that the batteries 10 metres away weren't actually dropping anything like that, it was only at the camper end ie. losses in the cable. I decided not to worry about it as I new we had sufficient battery capacity to put up with wasting a bit whilst charging the Laptop. Of course if I measured the voltage at the camper end with no loads switched on it would show the same as at the battery, it's only when under load that you get voltage drop . Same reason why it's always best to have a solar reg close to the battery & not stuck on the rear of panels.
Thanks, Cuppa, for this simple explanation of how it all works! Sometimes my van's voltage drops into the high 12s when I'm running stuff at night, after getting to over 14 volts during the day. The system on the car regularly gets to 14.4 volts from sun-only charging, but the van has no back-up from 12 volt or 240 volt. Hasn't let me down yet, even though I spent winter in the South of WA where temps drop to zero or below. Cheers
dorian said
03:53 AM Dec 17, 2022
Cuppa wrote:
Are you forgetting that the 10 amp rating of those extension leads are designed to have 240v pushing those amps through. Try that at a nominal 12v & losses would be far higher. At 25 metres probably enough to get virtually nothing going into the batteries. Think of voltage as the pressure which pushes the current (amps) through the cable. The higher the voltage the thinner cables can be.
The IR voltage drop has nothing to do with the source voltage. The same current (I) will produce the same voltage drop (V = IR), irrespective of the ultimate supply source. The voltage drop is purely a function of the circuit current and the resistivity and cross-section of the conductor.
The current rating of an extension cord reflects the maximum permissible self-heating due to I2R losses. The voltage rating of the cord reflects its insulation resistance.
-- Edited by dorian on Saturday 17th of December 2022 04:05:42 AM
Mike Harding said
05:55 AM Dec 17, 2022
Cuppa wrote:
Mike Harding wrote:
Bunnings often have 25m extension leads on sale for around $18, they are rated 10A so, I guess, are 1.5mm2. My 200W panels are about 7A which equates to about an 8% voltage drop over this cable and rather less at lower currents.
Are you forgetting that the 10 amp rating of those extension leads are designed to have 240v pushing those amps through. Try that at a nominal 12v & losses would be far higher. At 25 metres probably enough to get virtually nothing going into the batteries. Think of voltage as the pressure which pushes the current (amps) through the cable.
As Dorian correctly points out that is not the way electricity behaves - this may help with understanding:
Are you forgetting that the 10 amp rating of those extension leads are designed to have 240v pushing those amps through. Try that at a nominal 12v & losses would be far higher. At 25 metres probably enough to get virtually nothing going into the batteries. Think of voltage as the pressure which pushes the current (amps) through the cable. The higher the voltage the thinner cables can be.
The IR voltage drop has nothing to do with the source voltage. The same current (I) will produce the same voltage drop (V = IR), irrespective of the ultimate supply source. The voltage drop is purely a function of the circuit current and the resistivity and cross-section of the conductor.
The current rating of an extension cord reflects the maximum permissible self-heating due to I2R losses. The voltage rating of the cord reflects its insulation resistance.
My experience with solar panels and long leads for them. If you use PWM regulators then a long lead is tolerated OK as the high voltage of the panel is much higher than the battery voltage and enough usually to not reduce the current or very little. When the sun is poor the current is small and the losses are insignificent. In past times I have used old 240V leads for solar panels with good effect. Back then all PWM regulators. If 3 core then double up two on one polarity. Cheap and easy to recycle a worn 240V cable for 12V.
If you use a MPPT regulator the panel lead resistance and associated voltage drop will have a greater effect, because it reduces the panel voltage getting to the regulator. This higher panel voltage above battery voltage is converted by the MPPT design magic into extra current. So If you want your MPPT reg to work well then heavy cables are essential. In my previous MH with portable panels I had about 5M cable and another 5m extension for difficult situations. I forget the gauge but I did increase it by doubling it up for the first run to improve the current output into the battery. That did improve the current noticeably.
So this will give you the parameters to look at for your cabling decisions on portable panels. Fixed panel are shorter runs so you should just put heavy ones in anyway.
Jaahn
dorian said
07:50 AM Dec 17, 2022
@Jaahn, I understand what you are saying, and I can understand what @Cuppa meant to say.
Let's say a particular cable run has a voltage drop of 1V at 10A. This means that the cable would be dissipating 10 watts. If you were powering a 240V, 10A appliance from a 240V source, the appliance would see 239V. If you were powering a 12V, 10A appliance from a 12V source, the appliance would see 11V. In both cases the cable would still be dissipating 10W. However, a loss of 1V for a 240V appliance would be negligible, whereas a loss of 1V for a 12V appliance would be significant.
As you say, one should select a cable on the basis of the acceptable IR voltage drop. For a solar installation, the acceptable loss would be a lot less than normal applications.
Would it work if I match 2 x Kings Mono 160watt Solar Panels with a Victron MPPT Smart Solar Charge Controller? or do they have to be matching brands? as I've done research and the Kings MPPT Smart Solar Charge Controller has got bad reviews. Thanks in advance, Melissa
Hi Auzmel,
That would work OK. I mix and match like that for good results. I do not think the Kings MPPT controller is very good either, performed very poorly in a friend van. and has been replaced. But the solar panels from there are well under performing too and only putting out half their specs power.
Jaahn
-- Edited by Jaahn on Tuesday 13th of December 2022 08:00:37 AM
As said; Victron equipment is excellent but expensive - I run it.
You can supply a MPPT controller with any panels at all. The panels should be the same (or very close to) wattage and voltage as one-another and preferably wired in parallel to avoid loss due to shading. The wires from panel to controller should be as short as possible - this can be difficult but do your best.
The King's panels may come with a built-in solar controller, this must be discarded and the panels fed directly into the Victron.
If you have space consider ex house panels, there are lots on the secondhand market currently - a year ago I bought 4 x 200W for $30 each.
Edit:
PS. Buy a bigger Victron controller than you need because, I have little doubt, you will later wish to add more solar panels.
-- Edited by Mike Harding on Tuesday 13th of December 2022 08:10:03 AM
I have Projecta panels & Victron controller. Actually Victron everything else. I used the Projecta panels as I need a particular size to fit a space.
P.S. Don't skimp on wiring. No point putting in a good system & too much is wasted in resistance.
Thanks for your reply, can you recommend any good solar panels?
Thanks for your informative reply, very beneficial. :)
Not sure what you want but I bought 6x275 watt Suntech Polycrystalline panels from Hayman Electrical. Cost only $120 each. Cheers
-- Edited by yobarr on Tuesday 13th of December 2022 12:04:21 PM
-- Edited by TimTim on Tuesday 13th of December 2022 11:40:31 PM
Hi Mel,
I have just bought a 175W Monocrystalline Victron solar panel which I did another quick test today and it was producing 156W for a short while. That is 89% of the stated output. What may appear to be a clear blue sky to us is not always that clear and the solar irradiance may be lower than expected. I only have to look at my home solar to see how the output fluctuates oven though I cant see any change in the sky. 89% is pretty good.
Personally from past experience I would not buy the Kings and would agree with Jaahn, but others may have had a better experience. A better alternative would be the Victron 175W Polycrystalline panels which are around the $200 mark but a bit of a search may get you a better price.
Other than that someone may be able to advise you on the Hardcore 170W panel which appears to have good reviews and also around the $200 mark.
Just be careful buying many of the no name brands as they will never be able to put out the stated output because of their physical size.
Although I have a number of different brands of solar controller including a Victron, the Victron is good.
Good luck
Tim
-- Edited by TimTim on Wednesday 14th of December 2022 12:34:24 AM
https://www.suntech-power.com.au/wp-content/uploads/2021/09/STP275_20_Wfj275_270_265_1500V.pdf
I notice that the same panel comes in 3 grades -- 275W, 270W and 265W. It seems that cells are individually tested and selected for their efficiency.
I also notice that Suntech specifies the electrical characteristics according to two standards, STC and NOCT. Everyone uses the STC standard, but I've never seen any manufacturer quote NOCT. In fact, I had never heard of it before reading this datasheet. It appears that NOCT attempts to reflect real, average conditions.
STC: lrradiance 1000 W/m2, module temperature 25 °C, AM=1.5
NOCT: Irradiance 800 W/m2, ambient temperature 20 °C, AM=1.5, wind speed 1 m/s
Hi Melissa it is hard to recommend panels because I do not know where you are or if you are familiar with ebay or Gumtree or want a retail shop.
I would buy and have bought ex-house panels for a very cheap price where Solar Panel fitters have removed older small systems to fit bigger systems. They just want to get rid of them for a modest price. Usually good quality panels suitable for a quality MPPT regulator like a Victron. These older panels are often each about 170-200 W or possibly up to 250W so easy to wire in. Note they are higher voltage than 12V nominal so must be used with a MPPT regulator to work well on a 12V battery system. Use good heavy wiring too as suggested.
Otherwise shop from say Jaycar or some well established retail outlet near you that will guarantee the output of the new panels. The newish 4WD/camping retailers often sell cheap low quality stuff in my opinion and the casual staff may not be helpful.
In the past I bought panels off ebay or Gumtree sellers and they all performed OK when I tested them. But I have not bought any like that for years now.
Good luck jaahn
PS Dorian solar panel suppliers have always individually matched their cells after testing the output, for each panel, and then test the panels and group them for output. Thus some retailers call the best ones grade A and lesser as grade B,C. But the cells are all the good just not putting out quite as much for the same area. The usual way to test the panels is on a light box which supplies a certified sun strength even light. Only takes a few seconds I was told to get the output reading.
I might wonder if all the Chinese factories test them so much. I was told the lower output cells below spec are sold off cheaply to "second tier" makers for their panels. A friends father had some cheap system put on his roof near the sea, and after some years it was not performing so they had it replaced. The sellers had long gone !! He tested the 10 panels for output and only two were any good. Actually half of them you could pick were bad just visually.
-- Edited by Jaahn on Wednesday 14th of December 2022 11:00:47 AM
Auzmel:
I get the impression that, like mine, your panels will be freestanding ie. not permanently fixed to a vehicle?
This is the best way to use solar panels when camping as it permits you to locate them in an area of minimum shade and adjust their angle during the day and year in order to maximise the position of the sun.
However, as with all good things (yes, even me :) ) there are downsides: they must be stored and packed safely for transport and, obviously, will not be collecting energy until unpacked and located and this often won't be practical for stays of one or two nights.
Don't underestimate the packing/storage aspect: I have 4 x 200W panels; each panel weighs 15kg and is 1520 x 850mm ie. a large and heavy(ish) item, it is the largest panel I can fit inside my 4WD.
On top of this, during transport, the panels must be protected from items falling on them and causing damage. To this end I made some simple brackets which permit me to bolt two panels together face-to-face thus providing some protection and stopping the panels banging against one-another when I go over a bump. Trouble is 2 x 15kg = 30kg and that's close to the limit of an object that size for me to manhandle (womanhandle? :) ) into a vehicle.
Just give some thought to all this stuff before you buy.
PS. I wonder if "womanhandle" is a verb or adjective? :)
-- Edited by Mike Harding on Wednesday 14th of December 2022 11:02:37 AM
My 120w portable panel is 15kg, we only start using it on about the fourth day if we haven't moved, as we couldn't be bothered setting it up. Theoretically we can do 7 days off batteries.
Get plenty of extension leads for portable solar panels. Tall trees cast very long shadows.
You can also use your jumper leads for a few extra metres, if you set them up with a connector.
Welcome to the GNF - I trust you'll be able to find what you need in advice on everything "caravan" & perhaps sometime you'll be able to help other new members. Mostly we're a good bunch - we all have experience in something that we worked on, at in the past or present.
I see lots of vehicles driving around with Kings stuff fitted - there is a saying "that you get what you pay."
Mid year, I bought the "bargain" 20A MPPT controller - it was too cheap but I decided to give it a trial. It "sort of" worked but I found the voltage cutout didn't work. Running an AGM battery to 17v is not healthy, for humans & batteries. I tried it twice - just to be sure. I removed it, took it back for a refund & the second issue cropped up. I had paid for it on a credit card but to get a refund, Kings require a BSB & bank account number. They say they cannot pay back on to the credit card - they don't have BSBs! Eventually I got my money back but it wasn't easy.
Their solar panels might be ok but the construction (to me) doesn't look good - plastic corner pieces to start with, light frames, next.
Victron panels are good - Springers Solar (often they have sales) & Outback Marine are two good firms that I know of & have used. Suntech are mentioned above - not certain if they are still available. They were excellent but
had trouble competing with the el-cheapos. Also Jaycar are mentioned - their gear is fairly good too (might not be the cheapest).
All the best.
There is no doubt you van get more out of your panels & into your batteries if you are prepared to be around & willing to move them every hour or so throughout the day, in addition to the often heavy & cumbersome unpacking/setting up/packing away routine.
To my way of thinking this practice suits folk who rarely leave their camp, & who camp in places for at least a week or two at a time. Also folk who lack 'real estate' on their van or vehicle roof for permanent mounting.
Our first vehicle with solar had plenty of roof space so 'loose' panels were never a consideration.For a while on our current vehicle we had our roof full with a roof top tent so panels had to be 'loose'
I'd have to say that the practice of getting them out, packing away & moving them to catch the sun multiple times a day quickly wore pretty thin.
When we realised that actually we (I) hated rooftop tent living & took it off (& towed a camper instead) it was a relief to attach the solar panels to the roof. They are always there doing their job with no further thought required. & they can be left doing their job if you go for a walk or leave camp.without fear they will be stolen because they are bolted down.
The disadvantage is that panels laying flat (or close to flat) will not put out as much power as those angled always toward the sun. I use an old & well used formula (Courtesy of Collyn Rivers) to determine output & thus how much solar I need. For 12v panels divide the panel's rated wattage x 12 to get the max output in amps, & then multiply it by 70% to account for laying flat. Eg. 120w panel will theoretically put out around 10 amps (120 divided 12) but laid flat on a roof multiply 10 by 70% & you get 7amps. So you can see that if using fixed panels you will need more panels to do the same job (which is fine provided you have the roof space on top of vehicle/van.
I have used top quality Kyocera panels, back when a 120w panels cost $1150 each. Today they are *far* cheaper, & I have also used ebay cheap panels. The main difference seems to be in their shade tolerance. El cheapo panels can lose their entire output from just a tiny bit of shadow on the panel, better panels will only lose output proportional to the amount of shadow.
Of the more reliable , quality -wise online sellers at good prices I have found 'Low Energy Developments' to offer a good balance of quality & price.
www.lowenergydevelopments.com.au/solarpanels-poly-mono/solar-panels-upto-200w-morethan-100w
The better solar panels do not have plastic corners.
When I started a few years ago I didn't have a clue on anything solar. So I bought what I felt was the best. I just couldn't be bothered with a list of unknowns. I have better things to do than waste time on third rate products. Let's be honest a lot of them simply lie about their performance.
I also have built in redundancy so if something fails while remote the fridge will still work.
If you have a caravan I cannot understand why you would even consider messing around with portable panels. As well as risking having said panels "borrowed" by some low life, there also is the hassle of regularly having to move them, as well as packing and storing them for travel. "No room on roof" is unlikely to stand scrutiny as evidenced by my design. As well as 1650 watts Solar (6x275 watts) I have a Sat TV and a 4 seasons hatch, and still there is plenty of spare room. Previously I had 9x190 watt panels but when a couple got smashed by rocks and replacements could not be sourced I gave the remaining 7 panels to an installer in return for fitting the new ones. Parking in the sun is not a problem as the panels are 4" off the roof so that they can breathe, and also prevent the sun shining directly onto the van's roof. On really hot days I simply leave the AC running. Cheers
Because portable panels provide far, far better energy capture when one camps in forests and is able to move the panels a couple of times a day in order to minimise shade.
True ........... unless like us you tow & have the panels on the tow vehicle, which we connect to our camper via a 10 metre 6B&S 'umbilical cord' which enables us (most of the time) to camp in shade when desirable, whilst panels are out in the sun.
Although that said we had fixed panels on the roof of our bus, with a good air gap below them, plus heat reflecting paint on the roof & good cross ventilation airflow in the bus, & it was on average 3 degrees cooler inside the bus than outside - still hot in hot weather but quite manageable. Two roof hatches (one with a bi-directional fan) worked very well.
YES that is true. I do not have the perfect answer to this.
We have done both. I had a larger MH and portable panels. It had a 'gear box' on the back so I carried the 4 panels on top of that with some ply seperators/ stands and strapped them on. Easy enough to put out two in a few minutes or 4 if needed. I had a long electrical cable and a matching security cable to lock the panels to the MH. Easy enough to do.
Now we have a small HM with fixed panels center to front. But we do like to park in the shade in the heat. Hmm still working on that. But I think I will put another largish panel on the very back end and park with that out in the sun, that will probably give some shade and give enough power in the full sun anyway. Must get around to that soon.
I would carry some portable panels if I was going away for a while but not so much spare room in this one.
The panels are not very fragile you know. They stand up to normal handling OK. I have never broken one from carrying them around in camper vans or putting them around and getting them blown flat. Years ago we went up to the bush block with the grandkids and the panels were spread around on the ground and propped up a bit one end. When I returned the kids were running around a 'track' that included the panels ?? No problems ! But I did stop them using the panels.
Jaahn
Just musing:
Bunnings often have 25m extension leads on sale for around $18, they are rated 10A so, I guess, are 1.5mm2. My 200W panels are about 7A which equates to about an 8% voltage drop over this cable and rather less at lower currents.
Could be a cheap way to provide a 25m radius for panel location?
Edit:
Afterthought: with a bit of fiddling two leads could be made to service three panels.
-- Edited by Mike Harding on Friday 16th of December 2022 02:51:13 PM
Are you forgetting that the 10 amp rating of those extension leads are designed to have 240v pushing those amps through. Try that at a nominal 12v & losses would be far higher. At 25 metres probably enough to get virtually nothing going into the batteries. Think of voltage as the pressure which pushes the current (amps) through the cable. The higher the voltage the thinner cables can be.
With my 6 B&S (13.5mm2 copper) 10 metre 'umbilical cable', it provides sufficient from the batteries in our car to run lights, radio, CPAP, & water pump. but if I plug the heavier load of my laptop in to charge it via the inverter in our camper (7 amps) the voltage drops from say 13.2v to around 12. 1v or 12.2v. This worried me until I realised that that the batteries 10 metres away weren't actually dropping anything like that, it was only at the camper end
ie. losses in the cable. I decided not to worry about it as I new we had sufficient battery capacity to put up with wasting a bit whilst charging the Laptop. Of course if I measured the voltage at the camper end with no loads switched on it would show the same as at the battery, it's only when under load that you get voltage drop . Same reason why it's always best to have a solar reg close to the battery & not stuck on the rear of panels.
Thanks, Cuppa, for this simple explanation of how it all works! Sometimes my van's voltage drops into the high 12s when I'm running stuff at night, after getting to over 14 volts during the day. The system on the car regularly gets to 14.4 volts from sun-only charging, but the van has no back-up from 12 volt or 240 volt. Hasn't let me down yet, even though I spent winter in the South of WA where temps drop to zero or below. Cheers
The IR voltage drop has nothing to do with the source voltage. The same current (I) will produce the same voltage drop (V = IR), irrespective of the ultimate supply source. The voltage drop is purely a function of the circuit current and the resistivity and cross-section of the conductor.
The current rating of an extension cord reflects the maximum permissible self-heating due to I2R losses. The voltage rating of the cord reflects its insulation resistance.
-- Edited by dorian on Saturday 17th of December 2022 04:05:42 AM
As Dorian correctly points out that is not the way electricity behaves - this may help with understanding:
Basic electricity and Ohms Law
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Hi all true Dorian.
My experience with solar panels and long leads for them. If you use PWM regulators then a long lead is tolerated OK as the high voltage of the panel is much higher than the battery voltage and enough usually to not reduce the current or very little. When the sun is poor the current is small and the losses are insignificent.
In past times I have used old 240V leads for solar panels with good effect. Back then all PWM regulators. If 3 core then double up two on one polarity. Cheap and easy to recycle a worn 240V cable for 12V.
If you use a MPPT regulator the panel lead resistance and associated voltage drop will have a greater effect, because it reduces the panel voltage getting to the regulator. This higher panel voltage above battery voltage is converted by the MPPT design magic into extra current. So If you want your MPPT reg to work well then heavy cables are essential.
In my previous MH with portable panels I had about 5M cable and another 5m extension for difficult situations. I forget the gauge but I did increase it by doubling it up for the first run to improve the current output into the battery. That did improve the current noticeably.
So this will give you the parameters to look at for your cabling decisions on portable panels. Fixed panel are shorter runs so you should just put heavy ones in anyway.
Jaahn
Let's say a particular cable run has a voltage drop of 1V at 10A. This means that the cable would be dissipating 10 watts. If you were powering a 240V, 10A appliance from a 240V source, the appliance would see 239V. If you were powering a 12V, 10A appliance from a 12V source, the appliance would see 11V. In both cases the cable would still be dissipating 10W. However, a loss of 1V for a 240V appliance would be negligible, whereas a loss of 1V for a 12V appliance would be significant.
As you say, one should select a cable on the basis of the acceptable IR voltage drop. For a solar installation, the acceptable loss would be a lot less than normal applications.