Basic battery charging and solar question

My wfco, when I had one
Did go to bulk, and did drop to float

Some people have had worst luck then others, with different make converters
I had bad look with powermax converters

donn0128 wrote:
How old is your trailer?

Boins wrote:
Its brand new, the guy who told me was the service tech.

Then the "tech" doesn't know what he's talking about. Years ago, sure, but for at least the last ten years trailers of every stripe have been equipped with converters with at least a 3-stage charger that won't overcharge your battery. Likely as not you have a WFCO converter and while it's certainly not the best (none of any I've owned have ever gone into full bulk charge mode at the advertised 14.4 volts) it certainly won't overcharge your battery. If it's convenient to you to simply plug your trailer into shore power while it's being stored then do so and allow the converter's charging system take care of the rest.

Here is a simple flow chart.

Budget-->Energy Audit-->Battery bank size-->number of watts-->PWM or MPPT. What ever type of controller is chosen, make sure it has adjustable set points and a temperature probe that is on the battery.

If you use solar as a battery charger, one rule of thumb is between 60 and 150 watts of panels per 100 amp-hours of storage. The smaller the battery bank the higher the wattage needed (per 100 amp-hours). Here is a link to the rather special spreadsheet which includes an energy audit, that N8GS has created to help size solar battery charging systems!

https://www.dropbox.com/s/ziwfjk5dnt375cs/Solar%20system%20sizing.xlsx?dl=0

If you full time or use an inverter lots, then populate the entire unshaded area of the roof with panels. I'm considering replacing my awning with solar panels.

For a nice explanation of solar, try this link:


http://www.jackdanmayer.com/rv_electrical_and_solar.htm#The%20Golden%20Rules

OK, here is the scoop. You need to get a volt meter. The battery indicator on your panel doesn't tell you much. 8 chances out of 10, your trailer will have a WFCO power center. Open it up and find out. While the newer WFCO converters are ok, they are far from the best thing for your batteries, especially being plugged in 24/7. The WFCO advertises 3 modes but it will never go to float mode and it will hardly ever go to bulk mode. A WFCO converter/charger is stuck at 13.6 volts most of the time. While this will not hurt your batteries, over time they will lose water so they will need to be checked every 3-6 months. That is why you need a volt meter, to know what is going on with your batteries. Also google "12 volt side of life" and read it. There is some very good information here. Your service tech is misinformed regarding this matter.

donn0128 wrote:
How old is your trailer? I have kept my RVs plugged in 24/7 since 1976 with no seriour problems. Check battery water level monthly and quit worrying about things. Your dealer(I assume salesman) is an idiot.

Its brand new, the guy who told me was the service tech.

Battery University. It doesn't take long to go from a Freshman to an Upperclassman. :B

12 volt side of life is RV-centric for a crash course.

Check out Renogy Solar... I'm copying this from my Lazy Daze owner's forum courtesy of Andy B.

"Solar rocks. Generators suck."

Amen!

"Our rig is too old to upgrade"

Perhaps you're thinking that you don't want to invest thousands of dollars (which is what a good solar power system used to cost in the Bad Old Days) in an older rig. But solar power no longer costs a mint. And as Huskerblue points out, with a suitcase-style system you can move the whole kit 'n' kaboodle to another rig at the drop of a hat. In short, I can't see why any rig would be too old for solar power.

If you want an off-the-shelf, no-installation-needed system, you can get a 100 W Renogy suitcase for about $265. Clip onto your batteries, set the panels out in the sun, and you're done. These suitcase systems are a great starter solution for someone with modest needs and a budget to match. You pay more per watt than if you put together a custom system, but for many people the convenience is worth it.

A step up is to get a couple of 100 W panels. For example, begin with Renogy's $170 Solar Bundle Kit, then add a second 100 W panel for another $140. For just over $300 you can have 200 watts of solar power. You can lay the panels out on the ground, which gives you flexibility (park in the shade but put the panels in the sun), at the cost of the minor hassle of putting them out and taking them in when you move. Or mount them on the roof and just let them work for you.

All the setups just mentioned use low-cost "PWM" (pulse width modulation) charging controllers. If you want to milk the maximum power from your panels, you can step up to an MPPT (maximum power point tracking) controller. There are affordable models from Blue Sky, Victron and others.

You get the point. There are plenty of solar options, starting at less than $300. You don't need to permanently install anything on your older rig. Unless you do all your camping at places with electric hookups, it's hard to imagine why you wouldn't go solar.

Maybe your dealer knows something about battery charging, maybe not.
The only clear answer will give you a voltmeter hooked up to battery.
If your charger stops charging at 13.5V - it is good one. If goes above 14V -it is killing the battery.
Same with solar charging. You want the batteries to be around 13V in the afternoon. Check the battery manufacturer site what they consider discharged battery and go from there.

How old is your trailer? I have kept my RVs plugged in 24/7 since 1976 with no seriour problems. Check battery water level monthly and quit worrying about things. Your dealer(I assume salesman) is an idiot.

Boins wrote:
If the trailer does over charge, what is a simple option to create an automatic cut off once the batteries are charged.

I'm not expecting a solar setup that does a fast recharge, just a trickle.

I think you'd be better off to get a good 3-stage converter.

A very small panel, say around 10w, will trickle charge.