solar panel

[smokeater1]

Is anyone using solar panel to trickle charge the vehicle battery ? I am interested in using one to maintain my battery when the rig is not in use, but do not like the idea of drilling any mounting holes on my roof ! How are you doing it  ?

Thanks,
Jack.

 

[John From Detroit]

If you are using one to maintain while in storage, You can set the panel anywhere it will get sun, On the roof, on the ground On a cargo tray.  The only thing is you want to secure it.  Those things can grow legs if not secure,  and security often means holes.

 

[Alaskansnowbirds]

Is anyone using solar panel to trickle charge the vehicle battery ? I am interested in using one to maintain my battery when the rig is not in use, but do not like the idea of drilling any mounting holes on my roof ! How are you doing it  ?

Thanks,
Jack.

Fasten it to the top of the refer vent cover.

 

[Rex]

Yep, have the same concerns.  I am planning on installing a solar panel in the next few weeks.  Have decided to glue the mounts down.  I will use a 3M 5200 adhesive caulk, and have been told it will stick anything permanently.  Also, it can be removed by using a heat gun if need be.

I will mount it close to the fridge vent and run the wiring down that vent, so no holes in the roof at all.  If the unit you purchase will fit on your air conditioner cover, that would be a good place to mount it rather than glue it to the roof.  I have a metal roof so that is not a problem, and my panel is to long for the air conditioner cover (bummer).

Good luck,

 

[Jerrygroah]

Smokeater, I have three small panels and they all fit on my dash. I have put the antislip? material underneath them. They are or can be ganged together or used seperately as they all have the cigarette plug in type connection on them. All together, (3) ,they produce about 25/27 volts open circuit. I switch them around from the coach batteries to the engine battery from time to time. The coach batteries eventually need to be connected to the charger for a short time. The panels keep the engine battery up to snuff.

Jerry

 

[DonTom]

"I am interested in using one to maintain my battery when the rig is not in use,"

Might not be the best idea. I have a 45 watt solar panel with a solar controller( but it never completely shuts off)  and the battery will still dry out in about two  months from the solar panel charging. It might be a better idea to just disconnect the battery or if you plan on not using it for a very long time (several months) put a 1.5 amp  battery maintainer (they turn off and on as needed) on it, if ~117 VAC shore power is available.

I use many of these 1.5 amp battery maintainers (don't confuse with a simple trickle charger that does not shut off) on motorcycles, electric (true deep cycle)  boat batteries and car batteries and I am happy with how they work with everything. I own two homes (250 miles apart) with many vehicles left at each and if I don't get to the other house in months, it's these battery maintainers that keep all the batteries at peak and they don't over charge.

You usually can find them in the battery department of your local Wall*Mart. If you have a choice of 1.5 amps or 2.0 amps, go for the 1.5. Less is usually better.

If you do not have shore power, I would vote for leaving the battery disconnected. Or, be sure to get a solar controller that shuts off completely and back on as needed, if anybody makes such.

My solar panel says "self regulating" as if no controller is necessary. Don't believe it. Don't even think about connecting one of these direct to your battery. It will dry it out and ruin it in no time. At least that's been my experience from learning the hard way.

                                                                      -Don-                                                                                             

                                                         

 

[chaajoad]

A quick question ...

The little red"on" light of my solar panel is mostly on but is there any way to determine if any juice at all is coming off it? In other words - how do you know it's working?

Also - if the coach is sitting for a few months, is it a good idea to disconnect the coach battery while running off shore power?

Just curious - thanks for any advice.

Danny
Poulsbo WA

 

[Gary RV_Wizard]

if the coach is sitting for a few months, is it a good idea to disconnect the coach battery while running off shore power?

It depends on the quality of your charger. Good, modern three stage chargers or high end, well regulated two stage chargers won't harm a battery by overcharging during storage.  Older Magnetek chargers, on the other hand, were notorious for "boiling" batteries if left connected after reaching full charge. By" older" I mean roughly before 2000 or so.  In any case, check the water in the batteries regularly and add distilled water as needed. I would check every 10 days or so until I had determined the rate of water depletion and then adjust the schedule accordingly. Usually monthly is sufficient.

If you have sealed batteries (gel or AGM), water loss is not an issue. However,I would occasionally feel the battery case for heat. If warm or hot to the touch, it is being overcharged and I would disconnect it except for periodic re-charging.

Many RV chargers are merely plugged into an outlet, so you can insert an appliance timer that will automatically turn the charger on for 2-3 hours a day while in storage. That's an easy way to eliminate any concern and still keep the batteries charged up.  Try not to let the batteries become deeply discharged (50% or less) - it's bad for their health and they are subject to freezing if the charge falls too low.

 

[DonTom]

By" older" I mean roughly before 2000 or so.

Okay on chargers but I wondered if somebody made a smarter solar controller yet! One that will shut off completely and on again as needed, like the battery maintainers.

                                            -Don-

 

[John From Detroit]

Yes, they make smart chargers... In fact, I can't even begin to list all the companies that make them

 

[DonTom]

"Yes, they make smart chargers.".

But I was asking about solar controllers, not "chargers". My solar controller reduces the pulse width (mine uses PWM <Pulse Width Modulation>) technology.  As the battery gets more charged up, it reduces the width of the charge pulse, but it never shuts off completely and dries out the batteries at least ten times faster than a 1.5 amp battery maintainer. So these solar controllers might be smart, but they work dumb when compared to a cheap 1.5 amp battery maintainer.

However, I see no reason why solar controllers cannot be made to shut totally off and on again as needed, just as with the battery maintainer. Or at least reduce the pulse width to so little that it cannot charge the battery at all, when not needed. It seems to not take much to dry the battery out, but I can leave one of these battery maintainers even on a motorcycle battery for years and almost never have to add water. On my Yamaha Venture battery, I added water to the battery once in three years with the battery  maintainer. I think that would be about the same as if the battery wasn't even connected to anything, yet the battery is always held at it's peak with the battery maintainer. Seems just like a new battery for many years.

                                                                          -Don-
                                           

 

[John From Detroit]

A solar controller with attached solar panel IS a charger, and as I said, I can not list all the companies that make them

Actually calling them "Solar Controllers" is a bit of a mis-nomer since they control the charge to the battery, Not the sun itself

However I do understand that is how the industry mis-labeled them

 

[DonTom]

Actually calling them "Solar Controllers" is a bit of a mis-nomer since they control the charge to the battery, Not the sun itself

Yes, of course, but I like the fact they are normally  called by a different name.  It helps avoid such confusion. A more accurate name would be Solar Panel Controller (or SPC).

                                                          -Don-.

 

[smokeater1]

Thanks to all for the input......Since I do have shore power in storage, I'm thinking a battery maintainer might be best !

Jack.

 

[Karl]

Don,

It should be fairly easy to rig a simple circuit with an op amp and output transistor, to shut off the power from the panels when the 'set' voltage has been reached; somewhere around 12.6V. Let me know and I'd be glad to assist.