Vanning.com logo
Boxdin
Site Navigation


Advertisements
Recent Posts
Good day
by lukester - March 28th 2024 12:26 pm
Crazy mods
by MufflerMan Mike - March 28th 2024 9:38 am
Lew Greger
by MufflerMan Mike - March 27th 2024 5:15 pm
1987 G20 Gypsy
by SDMickey - March 25th 2024 9:39 pm
Featured Links


Previous Thread
Next Thread
Print Thread
Rate Thread
Page 1 of 2 1 2
cheap flexible solar panels from eBay?
#720543 February 28th 2017 10:23 am
Joined: Feb 2017
Posts: 32
1
newbie
OP Offline
newbie
1
Joined: Feb 2017
Posts: 32
I am new to the forum so don't chastise me if this has been covered a bunch before. I search the forum and did not see anything.

I just picked up a 1993 chevy g-20 conversion van. I am going through the van right now and changing fluids, checking out the brakes etc. Doing the normal inspections and maintenance. It seems like it's in pretty good shape mechanically. I do want to pull the carpet out and lay down a wood floor, we'll see.

A long-term goal is I would like to have a small office desk inside. I'd like to run a laptop and maybe a couple lights off of a secondary battery.

I'm in the process of figuring out how to keep the batteries charged. I'm pretty intrigued by flexible solar panels. I have seen them around for about $200 for 100 W panels. I've also seen panels on eBay as low as $16.

Has anyone tried these cheap flexible solar panels from eBay?

Thanks

AdSense long
Re: cheap flexible solar panels from eBay?
1993chevyg20 #720544 February 28th 2017 10:52 am
Joined: Dec 2000
Posts: 3,750
Likes: 13

Offline

Joined: Dec 2000
Posts: 3,750
Likes: 13
Just remember, you get what you pay for.
They're cheap Chinese junk, they may work a week, maybe a year.

I would use them to test and experiment with, when you figure it all out and get it the way you want upgrade to better panels

Last edited by Astro; February 28th 2017 10:52 am.

90 Astro - "The Grey Ghost" - Haulin Ass, Not kids.

E-Z Vanners and West Vanners
Council of Councils Board Member
National Truck-in Board Support Team

[Linked Image]

"No matter where you go, there you are."
"If you can't do something smart, Do something right"
"There are three kinds of people in the world, those who can count, and those who can't"
Re: cheap flexible solar panels from eBay?
Astro #720546 February 28th 2017 11:10 am
Joined: Feb 2017
Posts: 32
1
newbie
OP Offline
newbie
1
Joined: Feb 2017
Posts: 32
I understand what you are saying, but you never know until you have something like that in your hands. There are no moving parts so who knows. Someone must have ordered one just out of curiosity. Besides, just because it comes from china does not always mean it's not well made. iPhones come from china and they are very well made. I have bought tools years ago from harbor freight the have held up very well.

Re: cheap flexible solar panels from eBay?
1993chevyg20 #720566 February 28th 2017 7:59 pm
Joined: Apr 2010
Posts: 2,847
Likes: 42
W
veteran
Offline
veteran
W
Joined: Apr 2010
Posts: 2,847
Likes: 42
The flexible solar panels are troublesome, so much so that Renogy recalled the ones they sold and stopped carrying them.

This issues were related to heat and repeated flexing with some of the solar cells shorting out. There are flexible panels with much longer warranties( Solbian) but they are also 3 or 4x the price. One pays for the significantly higher level of quality control. Seems the ones which do not pass Solbian quality control Muster, are then sold to others who sell them for cheap.

I have a no longer made Unisolar pvl-68 watt self adhesive panel in addition to a 130 watt framed Kyocera on my roof.

I can get over 13 amps at noon on june 21 with them flat on the roof, but on Dec21 this is about 8 amps at best.

Solar panels are great for the 4+ hours it requires to take a battery from 80% charged to 100% charged, but they are best when the alternator or other charging source can get them to ~80% charged quickly. 80 to 100% cannot be done any faster than about 4 hours, no matter how powerful the charging source, the batteries simply cannot accept high amperage in this range, and the closer they get to full, the slower they recharge.

For good battery longevity, it is imperitave to get the battery to 100% true full charge regularly. Getting it to only 90% charged day after day will have the battery capacity decline rapidly, and it is very hard to restore it, if not impossible.

The cheap flexible panels can be used, and adhered to the roof, but since they get much hotter without any air movement under them, their output will decline well below their rating. So if one accepts this loss, and simply adds more solar to compensate for heating losses, then all should be well. Note the hot dark panels can also radiate much more heat to interior through the roof compared to a white roof. But with the electricity created, one can power fans to exhaust air.

Depending on the length of your outing, you could get away without solar, and simply plug in on your return to fully charged the baused batteries. However recharging via alternator is almost guaranteed to never fully charge a regularly depleted battery, as that 4 hours rule from 80 to 100% is not negated simply because of the common public perception that alternator gives free energy, and can also defy the laws of physics.

Also the alternator is basically controlled by a voltage regulator. The voltage regulator is primarily designed to not overcharge a battery. it is not concerned with properly recharging a depleted additional battery tacked onto the end of the circuit. Meaning a healthy but 50% depleted battery might require 6 hours of being brought to and held at 14.7v before reaching 99% charged range, when held at 14.7, but if 13.7v is all that is allowed, then time to recharge fully basically triples to no less than 18 hours.

So One could basically deplete their battery 50%, drive half way across the USA non stop, and still not have a fully charged battery if all the voltage regulator allowed is 13.7v.

So any and all charging sources should be used to keep the battery at as high a state of charge as possible, for good battery life. if one does not really care about battery life, then one simply can get away with less and replace the batteries more often. But replacing/warrantying batteries, and their final death throes when their capacity is too compromised to meet the needs of the Vanner, then it become stressful.

I can extract maximum possible life from my battery(s), as I have a manually Adjustable voltage regulator controlling my alternator, So I choose the target voltage, and I have a 40 amp adjustable voltage power supply for when I can plug into the grid, and my 198 watts of solar, is also adjustable as to voltage and the duration at which absorption voltage is to be held. So I can regularly get the battery back to 100% charged, quickly.

A battery is like a ballon. If this balloon is not regularly inflated to its maximum after deflating any amount, then the balloon skin becomes less strechy, and developes pinholes. Eventually it can contain so little air as to become useless.

A premature battery failure is almost never due to a battery defect, but a defect in the charging ability of the person who owns the battery.

Barring a defect in manufacturing, The worst battery kept fully charged, will outlast the best battery chronically undercharged. Without knowing how any particular battery was treated in its lifespan, reports as to longevity, good or bad, are entirely meaningless.

Re: cheap flexible solar panels from eBay?
1993chevyg20 #720594 March 01st 2017 12:53 pm
Joined: Sep 2005
Posts: 167
M
member
Offline
member
M
Joined: Sep 2005
Posts: 167
wrcsixeight is spot on as usual on the battery and charging stuff so I won't add anything to that. If you're looking at the flexible panels for an easier way to mount, I can suggest getting a roof rack for your van and mounting traditional framed panels to that. I made some small modifications to the provided brackets and used some U bolts to clamp down on the bars on the roof. Works well and stays very secure without permanent modifications.

I think a good starting point will be to determine how big of a system you'll need.
How many watts will you need to draw at any given time? How long will you need that power before you can recharge? This will determine how big of an inverter you'll need, and how big of a battery or batteries you'll need. Once you know these things you can determine how fast and often you'll need to charge the batteries, and choose your solar panels/generator/alternator based on that.

Keep in mind you'll need a charge controller to regulate the solar panel voltage. You'll want fuses to protect the wires, and probably a small fuse block to give you safe connections from your batteries.

Good luck, have fun!



76 Tradesman 200
Re: cheap flexible solar panels from eBay?
wrcsixeight #720596 March 01st 2017 2:57 pm
Joined: Feb 2017
Posts: 32
1
newbie
OP Offline
newbie
1
Joined: Feb 2017
Posts: 32
Thank you wrcsixeight and mattmansrus.

I have been doing a lot of research on the information you both talked about. I think I am getting close to having my needs figured out. I am planning on having multiple charging options, Solar was just one of them.

Again thank you

Re: cheap flexible solar panels from eBay?
1993chevyg20 #720610 March 01st 2017 6:19 pm
Joined: Sep 2005
Posts: 9,855
Likes: 234
carpal tunnel
Offline
carpal tunnel
Joined: Sep 2005
Posts: 9,855
Likes: 234
A good picture here from a stealth solar article on Cheap RV Living:
http://www.cheaprvliving.com/stealth-solar/

Re: cheap flexible solar panels from eBay?
CatFish #720644 March 02nd 2017 9:26 am
Joined: Feb 2017
Posts: 32
1
newbie
OP Offline
newbie
1
Joined: Feb 2017
Posts: 32
Thanks CatFish

I have the fiberglass top on my van, Have you seen solar panels mounted on a roof like this? See the photo link

Attached Files van top.jpg
Re: cheap flexible solar panels from eBay?
1993chevyg20 #720651 March 02nd 2017 2:01 pm
Joined: Sep 2005
Posts: 9,855
Likes: 234
carpal tunnel
Offline
carpal tunnel
Joined: Sep 2005
Posts: 9,855
Likes: 234
Most of the installations I have seen are, like mentioned before, elevated or have an air-gap under the panels to help keep them from getting too warm. Using the luggage rack is just a popular way to mount them with that gap. I looked into solar a few years ago and I know there has been advances made since that time but I haven't seen any 5-star reviews of flexible panels. I also know that the guys posting above know what they're talking about and you can take their advice to the bank.
While we never had solar on our old Ford we did have house batteries, converters, etc. We found we rarely used that equipment. Unless it was just for a quick overnight, we found we preferred camping with shore power.
When we began outfitting our GMC we wired for shore power. As you know, being in Georgia, camping/sleeping without AC can be a challenge. Add to that our age, the fact that we have many good friends to visit in the FVC and love Florida as much as the Smokeys, we just decided that our boondocking days were, for the most part, behind us.
I assume, having a mobile office or work area would pose the same issues.

BTW we live just north of Atlanta in the Alpharetta area.

Page 1 of 2 1 2

Moderated by  Astro, Ram4ever 

Link Copied to Clipboard
Donate


Upcoming Events
discovery
Who's Online Now
0 members (), 16 guests, and 5 robots.
Key: Admin, Global Mod, Mod
Newest Members
TheDrunkenGunsmith, Jac, LOVclassics, ZenMuffin, Milkman530
12724 Registered Users
Top Posters (30 Days)
SDMickey 129
CatFish 25
frscke1 25
Wedgy 21
Forum Statistics
Forums68
Topics35,746
Posts537,915
Members12,724
Most Online177
May 8th, 2013

Powered by UBB.threads™ PHP Forum Software 7.7.4