Solar Panel to Maintain Batteries

[WBG]

Hi All!!

I am thinking of adding a solar panel to trickle charge my batteries (two 12 volt in parallel) when the rig is in storage. I am getting too old to disconnect the batteries and drag them home to charge in the garage.

The solar panel and controller that seems to be the best (assuming user ratings are accurate) are the Windy Nation 30 watt Solar Panel and the Windy Nation P30 Controller. I know that this panel has way more power than I need, but the reviews on the smaller panel were not all that great.

Anyone have any advice as to what is the best unit to purchase?

Also, does anyone have any advice on how to mount the panel to the roof and how to route the cables to the front storage compartment?

Thanks so much for your opinions and advice.

WBG

 

[Jim.Allison]

There are flexible panels that require no hardware to mount and no roof penetrations.

http://www.soldonsun.com/Pr/Solar/Off-Grid/Off-Grid.html

Call them and tell them what you want to accomplish and they will recommend a complete kit to keep your batts up. Good luck.

 

[WBG]

There are flexible panels that require no hardware to mount and no roof penetrations.

http://www.soldonsun.com/Pr/Solar/Off-Grid/Off-Grid.html

Call them and tell them what you want to accomplish and they will recommend a complete kit to keep your batts up. Good luck.

Jim,

Thanks for the tip. I will give them a call. Not having to attach anything to the rood would be a real advantage.

WBG

 

[Lynn1130]

I don't think you need to spend hundreds for a solar trickle charger. I have one similar to this which is cabled to the hitch on the trailer when I am parked outside and it keeps the batteries charged up during down times. My batteries are always fully charged when I get ready to go. I have a lock on a cable that makes sure it stays on the hitch and run the cord up through the landing gear opening into the battery compartment.

http://www.amazon.com/Schumacher-SP...&keywords=24+watt+solar+panel+trickle+charger

 

[WBG]

Lynn,

Thanks for the tip but what I need is to be able to keep them charged when they are in storage, where there is no truck or other source of power.

WBG

 

[Lynn1130]

That is what this panel does. It is not connected to a vehicle. It is a solar panel that has a positive and negative line that run to the battery terminal and direct voltage from the panel, set in the sun, to the battery.

You may be mistaking the cig lighter plug as something running from the vehicle to the trailer. That plug is to allow the panel to charge your vehicle battery if you decide to hook it to the vehicle that way.

This is the one that I have; http://www.northerntool.com/shop/tools/product_200578631_200578631

 

[Mrsfish]

And this is the one that we have http://www.batterytender.com/Solar/10-Watt-Solar-Tender-Charger-With-Built-in-Controller.html

used it for 6 years now- works great for battery maintenance while in storage, works great while boondocking and using our batteries.

 

[WBG]

That is what this panel does. It is not connected to a vehicle. It is a solar panel that has a positive and negative line that run to the battery terminal and direct voltage from the panel, set in the sun, to the battery.

You may be mistaking the cig lighter plug as something running from the vehicle to the trailer. That plug is to allow the panel to charge your vehicle battery if you decide to hook it to the vehicle that way.

This is the one that I have; http://www.northerntool.com/shop/tools/product_200578631_200578631

Thanks Lynn,

I did not look at the link carefully. What you have proposed is a much cheaper solution than what I have been looking at.

Now it is time to decide

Thanks again

WBG

- - - Updated - - -

And this is the one that we have http://www.batterytender.com/Solar/10-Watt-Solar-Tender-Charger-With-Built-in-Controller.html

used it for 6 years now- works great for battery maintenance while in storage, works great while boondocking and using our batteries.

Mrsfish,

This too looks like a great option. Glad to know it has worked for 6 years. Gives one some confidence.

Happy RVing

WBG

 

[Miller0758]

Has anyone mounted a small panel to the pinbox and just ran the wire to the trailer connector box and connected to the 12v and ground (term 4&1). Don't know why this wouldn't work and should make for a nice neat installation rather than trying to route the wires to the battery ... Thoughts?

 

[Jim.Allison]

I don't think you need to spend hundreds for a solar trickle charger. I have one similar to this which is cabled to the hitch on the trailer when I am parked outside and it keeps the batteries charged up during down times. My batteries are always fully charged when I get ready to go. I have a lock on a cable that makes sure it stays on the hitch and run the cord up through the landing gear opening into the battery compartment.

http://www.amazon.com/Schumacher-SP...&keywords=24+watt+solar+panel+trickle+charger

Given 12.7v is a fully charged battery and that Volts x Amps = Watts

2.4 Watts / 12.7 Volts = .078 Amps @ 12.7v charging power, which will degrade over time. The stated output is also at ideal temperature, solar panels put out less at higher temps and more at lower temp. But batteries are the opposite, they take a charge better in higher temps, and resist charge at lower temps. Given these facts I do not think that .078 amps can maintain a battery such as those found in RV's. It might delay the natural discharge rate of the battery, but is not capable of providing enough power to overcome parasitic drain in your coach.

There was another from northern tool that claimed 7 watts, using the formula it would produce .55 amps in ideal conditions. None of these are designed to keep your batts healthy and are of no use to you on the road.

However, you could string several of these together to develop enough amperage to make a difference if you wanted to.

This subject is much more difficult and $25 gimmicks are not going to give you satisfaction over the long run, they may delay the total discharge but not the ultimate discharge of your batt. To achieve anything that remotely looks like maintenance you will have to be sure that you turn of your DC power. As the 2.4 watt is not enough to overcome the natural discharge of the batt, and surely not enough to overcome the parasitic drain. None of these will charge a batt.

When you consider that our minimum batts are the 12v RV/Marine batteries, expensive for what they are, can be kept healthy for several years if properly maintained and not 100% discharged between each season. An investment in a small/authentic solar array is cost effective when you consider battery replacement cost. In addition to adequately maintaining your batteries, a small solar array will provide some genuine use in the field by cutting down on generating times.

 

[Lynn1130]

I think sometimes we may over think some of these topics. We tend to make them much more difficult than they really are. Tire, Tow and Battery topics seem to be the worst. The Northern Tool item has kept my batteries fully charged in the Arizona sun for going on 5 years and the batteries are still alive which is a wonder in itself considering that batteries don't make it over 18 to 24 months at best here. I know that we are trying to be helpful but it seems we cause more confusion than help at times. Perhaps the KISS principle is called for.

Flame me if you wish but I seem to see more people asking these questions with the "no XXX police please" attached to it. That should tell us something.

 

[Jim.Allison]

Your batts should last way more than 1.5 to 2 years. I expect to get 8 to 10 years. Perhaps you should look into a more advanced system. Heat in itself does not destroy batteries. Mistreating them in the heat destroys batts. Or the selection of the wrong batt causes short life in automotive applications. In your case $400 on a PV array would pay for itself quite rapidly plus give you a little charge capability (without using your generator) while traveling.

7 watts can do nothing to charge a battery, it has 1/5 the power that is required to run a single 35 watt tail light bulb. Batteries have resistance and it takes voltage and amps to charge one. If you are observing a charge then you have a much better panel than what is described in the link. By comparison your 7 pin puts out about 134 watts, 13.4v and 10 amps, and it would take at least 10-15 hours to replace the energy in a partially depleted battery while driving. $25 to $40 is roughly ten percent of what a small EFFECTIVE system would cost, without even calculating the money you are spending on batteries. No flaming going on.........just a conversation about solar and battery maintainance.

Please elaborate on the "no xxx police" reference. I'm not clear on that issue.

I think sometimes we may over think some of these topics. We tend to make them much more difficult than they really are. Tire, Tow and Battery topics seem to be the worst. The Northern Tool item has kept my batteries fully charged in the Arizona sun for going on 5 years and the batteries are still alive which is a wonder in itself considering that batteries don't make it over 18 to 24 months at best here. I know that we are trying to be helpful but it seems we cause more confusion than help at times. Perhaps the KISS principle is called for.

Flame me if you wish but I seem to see more people asking these questions with the "no XXX police please" attached to it. That should tell us something.

 

[Lynn1130]

Sorry Jim but you know not of what you speak with batteries in Arizona. Call any of the local auto parts/Costco/Sam's Club outfits in this state and ask them when they get the replacement runs on their batteries and about how long batteries last here. It is a known and common happening here. This is just one of many blogs about batteries and Phoenix. The severe heat, constant air conditioner need and short in-town trips do the most damage. http://www.city-data.com/forum/phoenix-area/437991-car-battery-dying-desert.html.

I think, also, you misunderstood the original question. He is looking at a method to "trickle" the battery while it is not in use, not recharge the entire system and go completely off the grid. Since my trailer is now stored indoors, I no longer use the solar but my BatteryTender trickles my batteries fine at some very small wattage (I don't care what that is because it does it's job and that makes me happy). I don't need to put a full charge into them as they come into the storage unit charged, and that did not appear to be what he is trying to do.

The no ... comment is simply to the fact that when someone asks a question here the "experts" on towing, tires and batteries (and some other topics)come out of the woodwork and give 2 page university lectures on all of the inner workings of what-ever the question is. Hence KISS. Some help and knowledge is insightful, too much is, well, too much and more confusing than helpful is many cases. My degree is not in electrical engineering, rubber science or weights and measures and I along with many of us who ask questions don't care to know all of the minutiae. I do however appreciate a concise on-point set of details that will help with my decision.

$400 on a PV array would be waisted in my case because I don't full time, and in almost all cases where I am boon docking, which is what we do most, I am parked under trees in the forest. When it is stored it is indoors. I put batteries in, I charge them when I get back from where ever, and I put the Tender on it when it is stored. A KISS solution.

 

[Mrsfish]

I've lived in Az all my life, if someone can tell me how to get more than 2 years out of a battery I'm all ears. I can get longer out of my Rv batteries but you really have to baby them- and it took us years to figure that out.

 

[Lynn1130]

To my point. And with a diesel it means two batteries about every 18 months. At least with Costco I get full replacement in that short cycle. The RV batteries do last a little longer but not much and the 6 volts are only 12 month replacement. I have found that a BatteryTender seems to get me a little longer. I think because of the full charge situation and I check the water every month to be sure they do not get low. Our May to November heat is just a killer with batteries.

 

[Jim.Allison]

I've lived in Az all my life, if someone can tell me how to get more than 2 years out of a battery I'm all ears. I can get longer out of my Rv batteries but you really have to baby them- and it took us years to figure that out.

I lived in Tucson for 8 years and don't remember buying a battery. The reason you don't get life from your batteries is that you are buying excessive "Cold Cranking Amps" which are great for use in the north temps. When batteries get hot, let's say in south and west Texas or the extremes of southern AZ, and NM, they become hyper efficient. They charge easily and readily give up their energy when called up to do so, because their plates are designed for that purpose. Even more so when in the engine compartment is saturated with heat. To get more life from your batteries buy less "CCA's" which have thicker and less efficient plates which will hold up to the temps you are operating under.

For RV batts you need to buy some panels and a charge controller with a thermal coupling that will charge and maintain with the correct voltage and amps according to the temperature of the battery. Its not the heat. It is what is happening to the battery while it is hot. Unregulated charging at 113 degrees is killing your batts, plus that you need to buy quality industrial batts. There are solar arrays on mountain tops all over southern AZ operating cell towers and repeaters for law enforcement. They are not replacing batts every 2 years, I promise that.

 

[Lynn1130]

You might tell that to the other 5.5 million people living here that as well as the thousands of businesses that sell batteries in Arizona. I have lived here 45 years. That beats 8 for experience any day