Home » Public Forums » GMCnet » Solar to keep the house batteries charged
| Solar to keep the house batteries charged [message #98267] |
Thu, 02 September 2010 18:05  |
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ljdavick
Messages: 3548
Registered: March 2007
Location: Fremont, CA
Karma: -3
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I wanted to start a new thread to keep the conversation going about solar.
I had been thinking of adding a solar panel to our Palm Beach to keep the house batteries topped up. We have loads of sunshine in California, and we rarely use the coach for more than 2 days sitting dry. I've seen what Greg (solarsonic?) <http://solar-sonic.com/> has done with his coaches and though it's very interesting it's also well beyond anything I would attempt.
How do you keep the solar panels from boiling the batteries - would they connect to my Progressive Dynamics charger and use its maintenance mode?
If there is a good write-up about solar out there I'd love to read it.
Larry Davick
A Mystery Machine
1976(ish) Palm Beach
Fremont, Ca
Howell EFI + EBL + Electronic Dizzy
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| Re: Solar to keep the house batteries charged [message #98300 is a reply to message #98267] |
Thu, 02 September 2010 21:38  |
idrob
Messages: 645
Registered: January 2005
Location: Central Idaho
Karma: 0
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| ljdavick wrote on Thu, 02 September 2010 16:05 |
I wanted to start a new thread to keep the conversation going about solar.
How do you keep the solar panels from boiling the batteries - would they connect to my Progressive Dynamics charger and use its maintenance mode?
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You will need a solar charge controller, which is like a voltage regulator in the engine alternator or Charge Wizard in the PD. You cannot use the one in the PD, it must be a separate unit. For your use, I would recommend a Xantrex C30 charge controller, which, without meters, is about $100 on line. Others are available, but I am familiar with this one, and know it is a high quality unit and will work well. I have installed several in my volunteer work for the National Forest Service. Morningstar also makes good charge controllers. As always there are many others but some are more hype than quality.
Rob Allen
former owner of '76 x-PB
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| Re: solar reading [message #98356 is a reply to message #98330] |
Fri, 03 September 2010 12:03 |
idrob
Messages: 645
Registered: January 2005
Location: Central Idaho
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Bukzin: I agree, both are excellent articles and show that although solar and batteries seem and are simple systems, there are many details that can and must be considered. Thanks for posting the URL's.
Rob Allen
former owner of '76 x-PB
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| Re: solar reading [message #98363 is a reply to message #98356] |
Fri, 03 September 2010 13:46 |
tphipps
Messages: 3005
Registered: August 2004
Location: Spanish Fort, AL
Karma: 9
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I manage to keep the engine starting battery up by using one of the simple solar panels that every new VW comes with. Of course, the VW dealer does not give them way, but they are available for $10 or so at any decent ham radio flea market. I am thinking about putting one on the outside of each engine hood, and getting it out of the window.
Harbor Freight has a solar charge controller available for under $80, but no personal knowledge about this item. Sometimes you just have to buy the real thing, not the Chinese copy.
Tom Phipps
2012 Phoenix Cruiser model 2552
KA4CSG
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| Re: [GMCnet] solar reading [message #98437 is a reply to message #98363] |
Fri, 03 September 2010 21:43 |
gmcrv1
Messages: 839
Registered: August 2007
Location: Memphis
Karma: -1
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I have 3 small solar panels that I bought at the Dayton hamfest this
spring. This flea marketer has been going to Dayton as long as I remember.
The three panels were measures in the overcast sky at putting out 14 volts
and 300MAH. He said in the sun they will do much better then that. The
panels are about 12" sq. black in color. About 7-8 years ago, I bought a
panel from the same vendor - it was approximately 15"x 36" and completely
weather sealed - like the one's seen on the side of the road doing various
traffic duties. I had it charging a jump start pack and that pack supplied
power for a 12 volt halogen under cabinet light system in my small
storage/workshop on the back of my property. It worked extremely well. My
goal was to buy a couple more of the larger size, but he didn't have any.
Question is, will the smaller ones be worth using on the GMC? So far I have
replaced about 75% of the interior 12 volt automotive type bulbs with led
lights. The reduction in lighting power requirements is significant.
Example:
Amperage
OEM LED
Replacement
Left Dinette light 2.88 Amps 4.2 watts .3
Amps
Rt Dinette light 2.88 Amps 4.2 watts .3 Amps
Hall light 2.88 Amps 4,2 watts .3 Amps
Kitchen light 1.44 Amps 2.1 watts .175 Amps
Bath Room lights 5.64 Amps 8.4 watts .6 Amps
Total Demand 15.72 Amps 1.67 Amps
I converted the larger power hog lights first, Next will be the porch,
step, compartment lights etc.
I appreciate any and all constructive criticism.
Thanks,
Tom Eckert N2VWN
73 Glacier
Oakland, TN
On Fri, Sep 3, 2010 at 1:46 PM, Thomas Phipps <tph1pp5@yahoo.com> wrote:
>
>
> I manage to keep the engine starting battery up by using one of the simple
> solar panels that every new VW comes with. Of course, the VW dealer does
> not give them way, but they are available for $10 or so at any decent ham
> radio flea market. I am thinking about putting one on the outside of each
> engine hood, and getting it out of the window.
> Harbor Freight has a solar charge controller available for under $80, but
> no personal knowledge about this item. Sometimes you just have to buy the
> real thing, not the Chinese copy.
>
> Tom Phipps
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
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| Re: [GMCnet] solar reading [message #98444 is a reply to message #98437] |
Fri, 03 September 2010 22:22 |
idrob
Messages: 645
Registered: January 2005
Location: Central Idaho
Karma: 0
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| gmcrv1 wrote on Fri, 03 September 2010 19:43 |
I have 3 small solar panels that I bought at the Dayton hamfest this
spring.
.....
goal was to buy a couple more of the larger size, but he didn't have any.
Question is, will the smaller ones be worth using on the GMC? So far I have
replaced about 75% of the interior 12 volt automotive type bulbs with led
lights. The reduction in lighting power requirements is significant.
I appreciate any and all constructive criticism.
Thanks,
Tom Eckert N2VWN
73 Glacier
Oakland, TN
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Tom: You have done a good job of reducing your lighting load, but of course there are other things that use 12 volt power, especially the furnace if you use it, and the electronic ignition system on the refrigerator, which tends to take in the range of .5 to 1 amp most of the time.
It is hard to say what your panels you purchased will put out, but my guess is less than an amp each, in full sun, or maybe 12 watts each. Overall, although it will reduce the rate of battery discharge as you use the coach dry camping, it will not overcome it.
Anything is better than nothing, but I would really not bother with anything less that about a 60 watt panel, and if I were doing it for my own use, I would probably put a 120 watt panel up there. This is a judgement of course, it really depends on your time out, your actual use of things, and how much sun you experience.
I no longer have my GMC, but recently put a few left over panels I had on my 20' travel trailer, which has 2 golf cart batteries and a PD 9145 converter/charger. All lighting is fluorescent, low draw, and the furnace is a small one which takes about 3.5 amps to run. The panels, in full sun, put out about 4.5 amps or close to 60 watts total. I just returned from a 10 day trip into Montana, and the last two days were cold and wet, with minimum temp in the morning of 40. The furnace ran a lot, I had lights on, and kept the laptop charged, which takes about 45 watts. I use the laptop a lot, probably averaging 4 hours a day.
When I returned home, and plugged into the grid, the PD was charging at 16 amps rate for many hours, and took 24 hours to reach full charge in the batteries again. So, I had been using more than I could put back in for the last colder days, and that included the charge from the tow vehicle, which is about 6 to 8 amps maximum (long wire runs from the front where the alternator is to the rear of the trailer where the batteries are). I drove about 250 miles in those last two days.
Solar works very well, but an undersized system will only leave you frustrated and wanting more. I would go for a "real" solar panel, in the 120 watt range. They cost $450 to $500. And you need a charge controller also. This place has a good selection of panels, charge controlers, and other items, along with good prices: http://www.ecodirect.com/
For my Travel trailer, I am thinking of placing a removable panel on the roof rack of the Jeep tow vehicle, and it will be a 120 watt panel. That will add significant power to the smaller 50 to 60 watts I have now.
So, more for you to think about.
Rob Allen
former owner of '76 x-PB
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| Re: Solar to keep the house batteries charged [message #98677 is a reply to message #98267] |
Sun, 05 September 2010 19:43 |
Gail Marks Cruiser
Messages: 125
Registered: August 2009
Location: Gold Coast, Australia
Karma: 0
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Senior Member |
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G'day,
We are solar power fanatics, have been for the past 14 years.
Currently we have 4x 123 watt solar panels, 4x 220 amp batteries, 45 amp regulator and 1500 watt inverter/charger.
Which runs a medium size 220 liter, 12 volt fridge and some times a beer fridge as well. We also run laptops, TV, DVD players, charge phones etc, and run the microwave through the inverter.
The only thing we can't run is the roof air, with out plugging in.
First thing we sold was the generator. When camping all I like to hear is the birds, the burble of a river and the crackle of a camp fire.
Questions always welcome.
Mark Bennett
Gail & Mark's Cruiser
Gold Coast, Australia.
Motorhoming Lifestyle.com
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| Re: [GMCnet] Solar to keep the house batteries charged [message #98696 is a reply to message #98677] |
Sun, 05 September 2010 21:42 |
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USAussie
Messages: 15912
Registered: July 2007
Location: Sydney, Australia
Karma: 6
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Senior Member |
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G'day,
Ask away!
I can assure you guys when I comes to solar systems Mark KNOWS what he's
talking about!
Er - the ones on the roof of a Motorhome that is! ;-)
Regards,
Rob M.
USAussie
-----Original Message-----
From: gmclist-bounces@temp.gmcnet.org
[mailto:gmclist-bounces@temp.gmcnet.org] On Behalf Of Mark Bennett
Sent: Sunday, September 05, 2010 8:43 PM
To: gmclist@temp.gmcnet.org
Subject: Re: [GMCnet] Solar to keep the house batteries charged
G'day,
We are solar power fanatics, have been for the past 14 years.
Currently we have 4x 123 watt solar panels, 4x 220 amp batteries, 45 amp
regulator and 1500 watt inverter/charger.
Which runs a medium size 220 liter, 12 volt fridge and some times a beer
fridge as well. We also run laptops, TV, DVD players, charge phones etc, and
run the microwave through the inverter.
The only thing we can't run is the roof air, with out plugging in.
First thing we sold was the generator. When camping all I like to hear is
the birds, the burble of a river and the crackle of a camp fire.
Questions always welcome.
--
Mark Bennett
Gail & Mark's Cruiser
Gold Coast, Australia.
Motorhoming Lifestyle.com
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Regards,
Rob M. (USAussie)
The Pedantic Mechanic
Sydney, Australia
'75 Avion - AUS - The Blue Streak TZE365V100428
'75 Avion - USA - Double Trouble TZE365V100426
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| Re: Solar to keep the house batteries charged [message #98749 is a reply to message #98677] |
Mon, 06 September 2010 13:30 |
Larry C
Messages: 1168
Registered: July 2004
Location: NE Illinois by the Illino...
Karma: 0
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Senior Member |
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First thing we sold was the generator. When camping all I like to hear is the birds, the burble of a river and the crackle of a camp fire.
_______________________________________________________
Poor old ONAN, what will you use to keep the GMC on the ground with all that weight missing????
So are you able to maintain battery voltage over a weeks time?
Your system sounds a lot like Dan G's.....
I have a 55 watt solar panel ( Don't laugh ) that keeps the coach batterys up and one of those VW solar panels for the vehicle battery.
I don't think it could keep up with any use over a period of time.
thanks
Gatsbys' CRUISER  08-18-04
74 GLACIER X, 260/455-APC-4 Bagg'r
Remflex Manifold gaskets
CampGrounds needed, Add yours to "PLACES" />
http://www.gmceast.com/travel
_
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| Re: Solar to keep the house batteries charged [message #98790 is a reply to message #98267] |
Mon, 06 September 2010 19:51 |
Gail Marks Cruiser
Messages: 125
Registered: August 2009
Location: Gold Coast, Australia
Karma: 0
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Senior Member |
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G'day,
I have included a couple more photos at,
www.gmcmhphotos.com/photos/showgallery.php?cat=5591
It was easier for us to install Solar whilst we had the GMC stripped.
As our mains voltage is 240 volt @50 hertz, we normally only need one circuit in a motorhome. I split this circuit, feeding one side through the inverter to every outlet but the roof air, the fridge transformer (runs on 12 volt when not plugged in) and the hot water(runs on gas/propane when not plugged in).The other side of the split circuit runs these.
The inverter sits beside the passenger seat, this means a short cable run to the batteries, it is out of the way, protected from dust and water, easy to monitor whilst parked and driving (we used to run a bread maker, put it on in the morning and by the time we stopped for lunch- fresh bread)
Whilst driving the alternator charges the battery bank as well, when the volt meter starts heading over 14 volt you know the solar has taken over the charging duties.
Initially we would watch the system like a hawk, but now we now can trust it,and don't have to worry about power, we just have to remember to check the battery water levels once a month.
Here is a couple of sites of friends of ours who travel full time,relying on their solar systems,
Gavin & Tracey bought our old bus many years ago ( they have changed it a lot) Gavin is an electronics whizz and has many articles on his site about Solar, from basic to advanced.
www.hobohome.com
Rob & Chris have built and rebuilt Wothahellizat and have a comprehensive blog, including solar.
www.robgray.com
Collyn Rivers has led an interesting life and has written many how to books on solar.
www.caravanandmotorhomebooks.com
Larry, we ditched a Honda water cooled twin Generator. It was wired incorrectly, had it's own fuel tank (had to be refilled from in-side)and it was huge, loud (external fan) and very heavy( had to come out the passenger door) If we ever find need the roof air away from plug-in sites, then we may look at a small portable around 3.5 kva.
If anyone wants a particular photo or clarity on anything I say, just ask here or PM.
Mark Bennett
Gail & Mark's Cruiser
Gold Coast, Australia.
Motorhoming Lifestyle.com
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| Re: [GMCnet] Solar to keep the house batteries charged [message #98807 is a reply to message #98752] |
Tue, 07 September 2010 01:10 |
Larry C
Messages: 1168
Registered: July 2004
Location: NE Illinois by the Illino...
Karma: 0
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Senior Member |
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What kind of battery bank and controllers does this take?
Well, look at it this way, you have to start somewhere... Learning comes from trying.
The battery bank can be almost anything depending on how you want to use them.
Example: the vehicle battery is not a deep cycle, its purpose is to give you fast current for start up then charges as the alternator takes over. Its current draw is limited.
The coach battery is usually a deep cycle, its purpose is to supply current in lesser amounts compared to the starting battery over a period of time.
The standard deep cycle battery would be ok for small supply but if you are looking at long boon docking periods, you have to build for it. Some of the guys are using go cart batteries, two 6 volt batts in series. for more current storage, put another pair in parallel with the other two.
Even if I wasn't solar and just charged off the alternator, I'd much rather have an inverter and big batteries than the gennie.
DC
Batteries take a while to charge. Using the engine alternator would be tough if camped in booning status.
the basic solar set up is easy, getting the numbers right is where you have to do some homework.
the Solar panels supply to the regulator, which charge the batteries.
in turn...
the batteries supply your coach 12v system / and or an inverter for 120v power (220 for our Aussie friends)
A gen set is used for cloudy days or air con use.
That is a very simplified version of how to do it.
You have to figure out the load you need in a day. The current needed is on the bulbs, fans, tv, etc
12 watts = 1 amp
I have a 55 watt solar panel on the roof that keeps the batteries charged when sitting. Not a good supply for using lights and tv. Dan G has a 300 watt supply on his roof, seems to almost keep up with usage, but not quite.
If you search solar panels on the web, you should find sites that talk about solar panels, regulators, even batteries.
It helps to change your lighting to lower power usage.
My GMC has florescents, about 3 long units in the liv / kitch area. each unit uses about 3 plus amps to run... that is a lot of power so I use them when camping and plugged in.
I have 4 marine screw in type bulbs that are 15 watt and put out 60 watt equivilant light lumens. that is much better and I can turn them on one at a time.
Cold cathod forescents are supposed to be low power as well and of course there are LEDs but watch them because the hi lighting LEDs are starting to use a lot of power, watch that spec label.
If you use propane for the frig, your use will be much less than trying to power an electric frig.
Also they make heaters that use no power, just propane, that is a huge plus over the stock furnace fan that can suck a battery down overnight.
Air con is still a generator or land supplied unit. If you wanted to supply the AC by battery you would have to carry a battery bank on a trailer to keep it going and I can't imagine the amount of solar cells you would need to keep them charged.
Thats the basics..... start playing with numbers, ask more questions, keep learning, experiment and you will begin to understand how things work.... lol havent I heard that before??
Gatsbys' CRUISER 08-18-04
74 GLACIER X, 260/455-APC-4 Bagg'r
Remflex Manifold gaskets
CampGrounds needed, Add yours to "PLACES" />
http://www.gmceast.com/travel
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| Re: Solar to keep the house batteries charged [message #98854 is a reply to message #98811] |
Tue, 07 September 2010 13:23 |
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WD0AFQ
Messages: 7111
Registered: November 2004
Location: Dexter, Mo.
Karma: 207
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| Rusty wrote on Tue, 07 September 2010 04:38 |
I found this guy from a link on AZcentral.com - he has turnkey portable solar solutions. I may contact them about their 62W portable package.
http://www.gosolarlife.com/
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Rusty, I have not looked at the link, but in general portable packages are just money getters. Even those sold at Harbor Freight. It is just enough to keep you upset most of the time. You would be far better off purchasing 2 75 watt panels and getting a decent charge contoller, if you want a portable set up. Now, if you only dry camp one or two nights in a row, you are totally wasting money for solar. If your engine battery is failing, just get one of the little VW solar panels and throw it on the dash. Too many folks are making a "killing" on solar. There is nothing at all complicated about installing your own system or building a portable unit. There have been many links posted. I am afraid that most folks just do not want to read up on this and waste their money instead. I wasted a few bux when I started because I thought I knew it all. I had no clue what a good charge contoller was. So, my first one was just a wasted 100 bux.
Dan
3 In Stainless Exhaust Headers
One Ton All Discs/Reaction Arm
355 FD/Quad Bag/Alum Radiator Manny Tran/New eng.
Holley EFI/10 Tire Air Monitoring System
Solarized Coach/Upgraded Windows
Satelite TV/On Demand Hot Water/3Way Refer
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