EPDM Coatings
rvupgradestore.com Composet Products PO Box Zone
Over The Network Custom Yacht Interiors

Author Topic: Solar panels and charge controllers  (Read 3484 times)

Tom

  • Administrator
  • ---
  • *
  • Posts: 44373
    • RV Forum web site
Solar panels and charge controllers
« on: September 24, 2007, 09:26:11 PM »
I haven't really paid a lot of attention to discussions here on solar panels, but I'm at the point where I'd like solar to keep the batteries topped up while the coach is in storage. A solar supplier at the Monaco rally in Salem last week quoted (ballparked) ... gulp ... $1,800 for a panel, controller and display, and I quickly lost interest. That's way too rich for me and for what I need. My past fleeting glances in Camping World revealed panels and controllers for a lot less money.

Can anyone tell me what I really need, approx what I should expect to pay, and where to buy?

My main concern are the two 12V chassis batteries, but it would be nice, although not essential, to also keep the four 6V house batteries topped up.

TIA.
Tom.  Need help? Click the Help button in the toolbar above.

Ron

  • Former Staff
  • ---
  • Posts: 18087
Re: Solar panels and charge controllers
« Reply #1 on: September 24, 2007, 09:55:41 PM »
Hopefully Wally will see this and be able to give you some advice.
Ron & Sam-home is where we park it. Currently located   HERE

Tom

  • Administrator
  • ---
  • *
  • Posts: 44373
    • RV Forum web site
Re: Solar panels and charge controllers
« Reply #2 on: September 24, 2007, 10:12:40 PM »
Hope so Ron.
Tom.  Need help? Click the Help button in the toolbar above.

baadpuppy

  • ---
  • Posts: 307
  • fulltimer wannabe (not there yet)
    • baadpuppy's Skoolie Project
Re: Solar panels and charge controllers
« Reply #3 on: September 25, 2007, 08:25:43 AM »
Just read an article about a new process for manufacturing solar panels that is supposedly going to be in full swing in about a year where it will cost about $1/watt to produce the solar panels, and the cost to consumer will be about $2/watt.

Article here.

Hard to know whether it is worth waiting.

jim

Gary RV_Wizard

  • Forum Staff
  • ---
  • *
  • Posts: 60346
  • RVer Emeritus
Re: Solar panels and charge controllers
« Reply #4 on: September 25, 2007, 12:19:04 PM »
The price depends on how many watts of charging you were getting, but $1800  probably included a real nice profit for the vendor.  If you just need an amp or two to each battery bank to replace the phantom loss, it could be done for less. A pair of 20-25 watt panels might be enough if that's all you are looking for.

Here are some places to get an idea of kit pricing (labor not included)

PPL

AZ Solar

Silicon Solar
Gary
--------------
Gary Brinck
Summers: Black Mountain, NC
Home: Ocala National Forest, FL

Wendy

  • Forum Staff
  • ---
  • *
  • Posts: 12481
Re: Solar panels and charge controllers
« Reply #5 on: September 25, 2007, 12:39:12 PM »
We paid $2800 last year for our solar system. That included upgraded panels and $800 for an inverter. You already have an inverter so if you were going to spend $1800, you might as well get the full system that you could use boondocking.

But for around $200-$400 you could get something that would keep the batteries charged.

Enjoy
Wendy
Wendy, Mike, and Gordon
~We can't be lost because we don't care where we're going~
Here's where we are http://map.datastormusers.com/user2.cfm?user=2276
2015 Allegro Ooen Road
1973 Sunshine Yellow VW Bug

Tom

  • Administrator
  • ---
  • *
  • Posts: 44373
    • RV Forum web site
Re: Solar panels and charge controllers
« Reply #6 on: September 25, 2007, 01:08:18 PM »
Thanks Gary, Wendy. Those prices look much more like what I'd be prepared to pay.

Wendy, we don't plan to reply on solar for boondocking, so the smaller systems will work for us.
Tom.  Need help? Click the Help button in the toolbar above.

Lou Schneider

  • Forum Staff
  • ---
  • *
  • Posts: 7304
Re: Solar panels and charge controllers
« Reply #7 on: September 25, 2007, 07:54:16 PM »
The previous owner of my Class C put a 1 ft. square amorphous panel on it and it does a good job keeping the rig's house batteries up while the rig is in storage.   Of course, you have to store the rig where direct sunlight will reach the panels - solar panels do no good in the shade.

If you just want to keep the batteries topped up while in storage, something like Harbor Freight's 45 watt solar panel kit and their 7 amp solar controller would do the trick.  Throw away the little box and wire the panels to the controller, then to the chassis batteries.

The panels are 1 amp each, or 3 amps total - more than enough to keep up a float charge.

Or get two controllers - at $30 each they're cheap - and put one on the chassis batteries, the other on the house system to let the panels trickle charge both of them.
« Last Edit: September 25, 2007, 08:07:35 PM by Lou Schneider »

BIGDOG

  • ---
  • Posts: 57
Re: Solar panels and charge controllers
« Reply #8 on: October 01, 2007, 11:34:10 AM »
I'm in the same situation as Tom. Just looking for something to keep the charge up on the chassis batteries over the winter. I'm confused as to how much wattage I need, amps, etc.

The costs mentioned in this thread are enough to put me off the idea entirely. I can replace many, many chassis batteries before I ever will spend in the range of $1800.00 to keep up a charge!

I'm looking at a 15W panel and a charge controller for around two hundred bucks. Will 15W do the trick??

Bigdog

Lou Schneider

  • Forum Staff
  • ---
  • *
  • Posts: 7304
Re: Solar panels and charge controllers
« Reply #9 on: October 02, 2007, 01:57:52 AM »
15 watts is approximately 1 amp of current - a pretty fair trickle charge.   Assuming you have 5 hours of sunlight per day, and 200 amp-hours of battery capacity (a single 8-D or two conventional batteries), you'll be replacing the battery's capacity every 40 days.  (200 / 5 = 40).

If your setup matches this example and your battery takes more than 40 days to discharge the panel should keep it topped up indefinitely.

Another way to tell how much of a panel you need is to measure the residual draw from the chassis batteries.   With everything turned off (i.e. the way the coach will be sitting in storage), lift the negative lead off of the battery and put a multimeter set to measure current between the battery and the lead.  You will probably measure something around 1/4 of an ampere (250 milliamperes) or less.  Multiply this amount by 24 to see how many amp-hours you need to replace each day.  1/4 amp * 24 hours = 6 amp-hours, the amount of power you need to generate. 
« Last Edit: October 02, 2007, 02:02:59 AM by Lou Schneider »

BIGDOG

  • ---
  • Posts: 57
Re: Solar panels and charge controllers
« Reply #10 on: October 02, 2007, 10:04:31 AM »
Thanks for this information Lou. Exactly the thing I'm looking for.

I actually got a much better deal than I thought on the panel and controller: 15W panel and 7 amp controller for $120.00. Fits nicely on the dash and runs through the cigarette lighter.

Bigdog

Dave Stringham

  • ---
  • Posts: 344
Re: Solar panels and charge controllers
« Reply #11 on: October 02, 2007, 10:27:10 AM »
The electrical wizz kids may have to correct me but I am under the impression that my solar system(that came with my monaco) charges the house only and if you want to go to chassis, it would be another system entirely.  Even if you turn on the inverter...you are inverting in the house only.
Dave Stringham
Monaco Executive (The Luv Shack)

JerArdra

  • ---
  • Posts: 1812
Re: Solar panels and charge controllers
« Reply #12 on: October 02, 2007, 11:10:56 AM »
DaveS,

Tell me more about your Monaco because on a factory installed solar panel/controller Monaco usually wires it so BOTH the coach and the engine batteries are being charged by the solar panel(s).

JerryF
JerryF  ;D  ;D

Dave Stringham

  • ---
  • Posts: 344
Re: Solar panels and charge controllers
« Reply #13 on: October 02, 2007, 11:32:09 AM »
DaveS,

Tell me more about your Monaco because on a factory installed solar panel/controller Monaco usually wires it so BOTH the coach and the engine batteries are being charged by the solar panel(s).

JerryF

Mine is a 97 Executive.........and if I am understanding my manual correcly.......my solar charges the house only........and for emergencies (chassis batteries are dead), I have my emergency start toggle that will start the coach off of the house and then the altenator charges the chassis once the engine is running.......It is also my impression, that the house and chassis are separate circuits all together........but I have been wrong on many things in my life time so this wont be a first ::)

Dave Stringham
Monaco Executive (The Luv Shack)

Phil

  • ---
  • Posts: 982
Re: Solar panels and charge controllers
« Reply #14 on: October 02, 2007, 11:47:48 AM »
The electrical wizz kids may have to correct me but I am under the impression that my solar system(that came with my monaco) charges the house only and if you want to go to chassis, it would be another system entirely.  Even if you turn on the inverter...you are inverting in the house only.

Dave,

The solar panel system that came with my 99 Windsor has charge lines to both the chassis and house batteries.  They are isolated and fused.

Phil

JerArdra

  • ---
  • Posts: 1812
Re: Solar panels and charge controllers
« Reply #15 on: October 02, 2007, 02:08:35 PM »
DaveS,

Phil said it all.  Also, the solar on my 99 Windsor and my current 03 Executive charges both the house and chassis batteries.

JerryF
JerryF  ;D  ;D

Dave Stringham

  • ---
  • Posts: 344
Re: Solar panels and charge controllers
« Reply #16 on: October 02, 2007, 03:34:13 PM »
Thanks for the info.......I will re-consult my manuals and see where I went wrong.
Dave Stringham
Monaco Executive (The Luv Shack)

 

Hosted by Over The Network