Tracking vs flat panels - Page 2

doug30293 · 07-28-15, 07:20 PM

I agree about the moving parts. The flat panel approach is probably best for an RV.

My next concern is weight. Five 100W panels at 40 pounds each is 200 pounds. Add three batteries, wire, charge control, inverter, and the panel support and I've got 500 pounds.

Figure $1000 for everything and a generator looks cheap unless I went full time off grid. I bought a nice RV park membership so I wouldn't have to be off grid. I may abstain from solar until I've had some field experience.

Nibs: Did you visit Quartzite, and if so, did you enjoy it? There seems to be a love/hate relationship among those who talk about it on the web.

nibs · 08-01-15, 03:41 PM

Yes went to Qsite several times, sometimes for 2 months at a stretch.
15 yrs full time, never bought into a campground scheme.
A honda genset just big enough to run your AC when needed ( we do not have AC, even when travelling in Mexico. Start out with one 200 watt panel, ditch the batteries that came with the unit and install T105 golf cart batts, two or four will give you an amazing amount of storage. We figured that in a smallish 5th wheel we needed to replace about 500 watts per day, so a 200 watt panel comes very close.
If the mods think this is too far off the eco theme you can pm me and I will give more tips.

oil pan 4 · 08-10-15, 04:06 AM

Over on the solar-electric forum no one recommends trackers even for stationary applications.

Then once you have solar panels on top of your camper, the only gigantic design flaw I see is you have to leave your camper in the sun all day for the panels to work.

doug30293 · 08-10-15, 07:11 AM

Not really a design flaw. The object of snowbirding is to park your camper in the sun all day, preferably in some desolate part of the southwest where they have sun all day.

nibs · 08-10-15, 10:31 AM

In our Motor coach, we used to head south every Nov to the sunny desert, and north to the cool shady forest in the spring.
Now, with fuel at $4 +/- and using it at 8.5 mpg, it would cost us $1400 just for fuel. we leave the coach at home and take our car staying in a hotel in Mexico for much less impact on the wallet and environment.

where2 · 08-10-15, 07:50 PM

Quote:

Originally Posted by doug30293

My next concern is weight. Five 100W panels at 40 pounds each is 200 pounds.

Each of the twenty 220W panels on my roof weighs 42lbs. My quick search of 100W panels puts them in the 21-22lbs range per panel.

doug30293 · 08-11-15, 02:48 PM

I noticed the weight discrepancy as soon as I looked at bigger panels. 40 pounds for 100W was probably shipping weight. Now if only the same were true for the batteries.

creeky · 08-12-15, 11:28 AM

higher voltage panels are better. cheaper per watt. easier to install.

lose the lead acid battery. lithium batteries are far superior. available today. longer life span. 1/3 the weight. look for lifepo4. lithium ferrous phosphate.

esp. off grid or RV. the performance benefits are numerous.

Robaroni · 08-12-15, 04:50 PM

I go along with the gang.
When I built my racks I had the crazy idea of building trackers, never again, and I have some pretty sophisticated equipment here from electronics to machining. Bottom line, I wound up making the racks stationary and adding a couple of panels. lighter, less to go wrong and cheaper. My last modules cost me less than a buck a watt.

I think, if you can afford them, the Lipo batts will save you weight and space. I'm moving away from L/A batts now. After ten years of using them in my system (eight Rolls 530S's) I'm ready for less maintenance and a battery to simply take up the slack when the grid fails. The rest of the time I'm happy to feed the grid and have a negative electric bill.

One more thing, if I was doing an RV I'd look into flexible modules, there's something about dragging along rigid modules while going 70 mph that makes me uncomfortable!

Rob

creeky · 08-12-15, 07:11 PM

rob I'm just a bit north of you. I put my 1kw panel set on dock hinges. I get a good bit of extra power, nice on the cloudy days, by going 30 degrees for summer, 45 spring/fall, but the biggest thing is going 60 in the winter. I actually go a bit past 60. Makes the panels easier to clean/sweep the snow off of. which, needless to say, greatly improves power gathering capacity.
I put up a second kw for .80 used, third hand. Those I just leave at the winter angle. don't really need them in the summer. but come the fall/winter ... well you know.

the new lifepo4s. it's insane. 20 year lifespan (7000 discharge cycles) at 50% dod now. I mean I can trade in my 720 lbs of lead acid for 250 lbs of lfp and get twice the usable power. me like. (and the point here is that lifepo4 is 1/3 the weight for rvers.)

so hey. okay almost twice the cost. but 3-4 times the lifespan. me also like.

and no maintenance. yup still liking.

now if they would invent a battery that could work without problem at -20. Ah well. can't have everything.

08-12-15, 04:50 PM	#19
Robaroni Journeyman EcoRenovator Join Date: Jun 2013 Location: Delhi, NY Posts: 332 Thanks: 20 Thanked 53 Times in 40 Posts	Trackers aren't worth it anymore. I go along with the gang. When I built my racks I had the crazy idea of building trackers, never again, and I have some pretty sophisticated equipment here from electronics to machining. Bottom line, I wound up making the racks stationary and adding a couple of panels. lighter, less to go wrong and cheaper. My last modules cost me less than a buck a watt. I think, if you can afford them, the Lipo batts will save you weight and space. I'm moving away from L/A batts now. After ten years of using them in my system (eight Rolls 530S's) I'm ready for less maintenance and a battery to simply take up the slack when the grid fails. The rest of the time I'm happy to feed the grid and have a negative electric bill. One more thing, if I was doing an RV I'd look into flexible modules, there's something about dragging along rigid modules while going 70 mph that makes me uncomfortable! Rob

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07-28-15, 07:20 PM	#11
doug30293 Too Many Projects Join Date: Nov 2013 Location: georgia Posts: 91 Thanks: 0 Thanked 6 Times in 6 Posts	I agree about the moving parts. The flat panel approach is probably best for an RV. My next concern is weight. Five 100W panels at 40 pounds each is 200 pounds. Add three batteries, wire, charge control, inverter, and the panel support and I've got 500 pounds. Figure $1000 for everything and a generator looks cheap unless I went full time off grid. I bought a nice RV park membership so I wouldn't have to be off grid. I may abstain from solar until I've had some field experience. Nibs: Did you visit Quartzite, and if so, did you enjoy it? There seems to be a love/hate relationship among those who talk about it on the web.

08-01-15, 03:41 PM	#12
nibs Apprentice EcoRenovator Join Date: Jun 2010 Posts: 206 Thanks: 1 Thanked 18 Times in 17 Posts	Yes went to Qsite several times, sometimes for 2 months at a stretch. 15 yrs full time, never bought into a campground scheme. A honda genset just big enough to run your AC when needed ( we do not have AC, even when travelling in Mexico. Start out with one 200 watt panel, ditch the batteries that came with the unit and install T105 golf cart batts, two or four will give you an amazing amount of storage. We figured that in a smallish 5th wheel we needed to replace about 500 watts per day, so a 200 watt panel comes very close. If the mods think this is too far off the eco theme you can pm me and I will give more tips.

08-10-15, 04:06 AM	#13
oil pan 4 Land owner Join Date: Nov 2012 Location: NM Posts: 1,026 Thanks: 12 Thanked 127 Times in 107 Posts	Over on the solar-electric forum no one recommends trackers even for stationary applications. Then once you have solar panels on top of your camper, the only gigantic design flaw I see is you have to leave your camper in the sun all day for the panels to work.

08-10-15, 07:11 AM	#14
doug30293 Too Many Projects Join Date: Nov 2013 Location: georgia Posts: 91 Thanks: 0 Thanked 6 Times in 6 Posts	Not really a design flaw. The object of snowbirding is to park your camper in the sun all day, preferably in some desolate part of the southwest where they have sun all day.

08-10-15, 10:31 AM	#15
nibs Apprentice EcoRenovator Join Date: Jun 2010 Posts: 206 Thanks: 1 Thanked 18 Times in 17 Posts	In our Motor coach, we used to head south every Nov to the sunny desert, and north to the cool shady forest in the spring. Now, with fuel at $4 +/- and using it at 8.5 mpg, it would cost us $1400 just for fuel. we leave the coach at home and take our car staying in a hotel in Mexico for much less impact on the wallet and environment.

08-11-15, 02:48 PM	#17
doug30293 Too Many Projects Join Date: Nov 2013 Location: georgia Posts: 91 Thanks: 0 Thanked 6 Times in 6 Posts	I noticed the weight discrepancy as soon as I looked at bigger panels. 40 pounds for 100W was probably shipping weight. Now if only the same were true for the batteries.

08-12-15, 11:28 AM	#18
creeky Journeyman EcoRenovator Join Date: Jun 2011 Location: a field somewhere Posts: 304 Thanks: 64 Thanked 44 Times in 31 Posts	higher voltage panels are better. cheaper per watt. easier to install. lose the lead acid battery. lithium batteries are far superior. available today. longer life span. 1/3 the weight. look for lifepo4. lithium ferrous phosphate. esp. off grid or RV. the performance benefits are numerous.

08-12-15, 07:11 PM	#20
creeky Journeyman EcoRenovator Join Date: Jun 2011 Location: a field somewhere Posts: 304 Thanks: 64 Thanked 44 Times in 31 Posts	rob I'm just a bit north of you. I put my 1kw panel set on dock hinges. I get a good bit of extra power, nice on the cloudy days, by going 30 degrees for summer, 45 spring/fall, but the biggest thing is going 60 in the winter. I actually go a bit past 60. Makes the panels easier to clean/sweep the snow off of. which, needless to say, greatly improves power gathering capacity. I put up a second kw for .80 used, third hand. Those I just leave at the winter angle. don't really need them in the summer. but come the fall/winter ... well you know. the new lifepo4s. it's insane. 20 year lifespan (7000 discharge cycles) at 50% dod now. I mean I can trade in my 720 lbs of lead acid for 250 lbs of lfp and get twice the usable power. me like. (and the point here is that lifepo4 is 1/3 the weight for rvers.) so hey. okay almost twice the cost. but 3-4 times the lifespan. me also like. and no maintenance. yup still liking. now if they would invent a battery that could work without problem at -20. Ah well. can't have everything.