Way to fit more solar panels on roof
- Thread starter BobBski
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Canine
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The video is 7 minutes, 31 seconds long. Here is an overview for those of you with limited bandwidth:
He has a van with limited roof space. You would pretty much need to wire in parallel. He installs two solar panels directly on top of one another. The bottom one is on a 230 pound rated industrial drawer slide. Instead of a ladder he uses a small paint roller (sans roller) on a telescopic rod to release the lever that secures the panel and pulls the panel out. Deploying the solar panel is super easy. It's a good video.
You could still design the panels to tip up to better catch the winter sun and to slough off rain and snow.
He has a van with limited roof space. You would pretty much need to wire in parallel. He installs two solar panels directly on top of one another. The bottom one is on a 230 pound rated industrial drawer slide. Instead of a ladder he uses a small paint roller (sans roller) on a telescopic rod to release the lever that secures the panel and pulls the panel out. Deploying the solar panel is super easy. It's a good video.
You could still design the panels to tip up to better catch the winter sun and to slough off rain and snow.
highdesertranger
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boy that blows my fix out the window. I was just going to say get a bigger roof. a note about that pic you posted unless the sun is directly over head you are going to get partial shading on some of the panels, cutting back power out put. I would think it would be better to have a couple of portables that you can put anywhere, simpler and less expensive. highdesertranger
Canine
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I watched the video about the camper with 15 panels.Wow! That's a lot for a camper.
Canine
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highdesertranger said:
Having portable panels placed outside are more subject to theft, so some regions wouldn't be suitable for that. If someone walked off with those panels, that would be more expensive. Putting large panels in the van would be a pain; not only are large panels heavy, they take up room. Maybe securing portables on the side would be a good place for transport. Tethering the panels to the van would deter theft.
If portables were the best for every situation, no one would be roof-mounting them. I do agree that using portable panels is an excellent idea and definitely has its place.
jimindenver
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For me it's a combination of mounted and portable if needed. My 230w portable tracking the sun can kick my 750w flat systems butt for quite a while in the morning before the sun gets high enough.
It is a interesting solution, kind of like the Wynns that have panels that slide to expose flex panels under them. A lot of power but the downsides are top weight, wind and shading.
One thing about designing and building a system like this is it is obsolete by the time you are done. Panels are growing in wattage so fast that it would be easier to replace my three 250w polys with three 435w polys and nearly double my system. No racks, slides, what not. Were I to build up the mounts to avoid shading I could put four 435w up there for 1740w. Those four panels would weigh 200 lbs.
Another thing to consider is that unless you have a bank of Lifelines that can take pretty much whatever you can throw at them and giggle, you have to have a bank that is in balance with the system. Most people worry about not having enough panel for their bank but you can damage batteries with too much current too.
It is a interesting solution, kind of like the Wynns that have panels that slide to expose flex panels under them. A lot of power but the downsides are top weight, wind and shading.
One thing about designing and building a system like this is it is obsolete by the time you are done. Panels are growing in wattage so fast that it would be easier to replace my three 250w polys with three 435w polys and nearly double my system. No racks, slides, what not. Were I to build up the mounts to avoid shading I could put four 435w up there for 1740w. Those four panels would weigh 200 lbs.
Another thing to consider is that unless you have a bank of Lifelines that can take pretty much whatever you can throw at them and giggle, you have to have a bank that is in balance with the system. Most people worry about not having enough panel for their bank but you can damage batteries with too much current too.
SternWake
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As long as a battery is kept to normal charging voltages, there is little danger the battery will allow itself to suck in so much current that it can be damaged.
Some of the le$ser AGM's state no more than 30 amps per 100AH of capacity.
What person is going to put ~ 550 watts of solar on one single group27 AGM at 100Ah capacity?
The battery only accepts what it wants at the voltage allowed. As long as the voltage is regulated, there is little danger of too much current.
With most solar systems the issue is usually way too much battery capacity for the solar wattage available. Too much wattage for the capacity, well as long as the voltage is regulated, should never be an issue.
Rolls Surrette, who make the Benchmark Flooded deep cycle batteries, says the Solar at noon, in an off grid system, should be able to meet a 10 to 20% charging rate.
http://rollsbattery.com/uploads/pdfs/documents/user_manuals/Rolls_Battery_Manual.pdf
scroll down to Page 26, then read the whole thing
So at high noon it should make 10 to 20 amps per 100AH of capacity.
Obviously very few dweller systems will even come close to this.
I've got 198 watts feeding 90AH of High Amp loving AGM, and I would need twice as much solar if Solar were my Only charging source, to keep my AGM happy with ~50% discharges nightly.
The charging rate is important. Low and Slow is 'just fine' when one has all the time needed to recharge before the next discharge cycle begins.
When that next discharge cycle begins late afternoon, low and slow is a recipe for batterycide, especially with an AGM
For those only discharging to 80% nightly, then the 1 to 1 oft repeated capacity to solar wattage ratio can work 'just fine'. It is a Whole different ballgame when the battery is depleted to 50%, and here in this range, even 2 to 1 is insufficient.
But they are only batteries and only rented anyway. They will work just fine until the day they do not. 90% of people never know when that day will come, only that one day the 'batteries no longer take a charge' If an acceptable amount of time has passed the battery owner shrugs and gets new batteries. If it is premature failure, they blame the battery when the battery failed due to chronic incomplete charging and the fault lies in the mirror.
Know what/who to blame when the rental contract expires.
It is more important to get the battery to as high a state of charge as possible before the next discharge cycle begins, than worry about allowing them to feed upon too much available current, especially from a solar system whose power takes half a day to ramp upto maximum.
Some of the le$ser AGM's state no more than 30 amps per 100AH of capacity.
What person is going to put ~ 550 watts of solar on one single group27 AGM at 100Ah capacity?
The battery only accepts what it wants at the voltage allowed. As long as the voltage is regulated, there is little danger of too much current.
With most solar systems the issue is usually way too much battery capacity for the solar wattage available. Too much wattage for the capacity, well as long as the voltage is regulated, should never be an issue.
Rolls Surrette, who make the Benchmark Flooded deep cycle batteries, says the Solar at noon, in an off grid system, should be able to meet a 10 to 20% charging rate.
http://rollsbattery.com/uploads/pdfs/documents/user_manuals/Rolls_Battery_Manual.pdf
scroll down to Page 26, then read the whole thing
So at high noon it should make 10 to 20 amps per 100AH of capacity.
Obviously very few dweller systems will even come close to this.
I've got 198 watts feeding 90AH of High Amp loving AGM, and I would need twice as much solar if Solar were my Only charging source, to keep my AGM happy with ~50% discharges nightly.
The charging rate is important. Low and Slow is 'just fine' when one has all the time needed to recharge before the next discharge cycle begins.
When that next discharge cycle begins late afternoon, low and slow is a recipe for batterycide, especially with an AGM
For those only discharging to 80% nightly, then the 1 to 1 oft repeated capacity to solar wattage ratio can work 'just fine'. It is a Whole different ballgame when the battery is depleted to 50%, and here in this range, even 2 to 1 is insufficient.
But they are only batteries and only rented anyway. They will work just fine until the day they do not. 90% of people never know when that day will come, only that one day the 'batteries no longer take a charge' If an acceptable amount of time has passed the battery owner shrugs and gets new batteries. If it is premature failure, they blame the battery when the battery failed due to chronic incomplete charging and the fault lies in the mirror.
Know what/who to blame when the rental contract expires.
It is more important to get the battery to as high a state of charge as possible before the next discharge cycle begins, than worry about allowing them to feed upon too much available current, especially from a solar system whose power takes half a day to ramp upto maximum.
