Boondocking - - will battery last 3 days

[Morgan A]

We have a SAMLEX 135 watt Portable Trifold Solar Panel (a suitcase unit which has a controller) which we got from "Little House Customs," which is where a lot of Casita owners had customizations done before Larry Gamble retired. The online store is still open, and still carries them. I'm glad we got the 135 watt panels as what camping we do up here in NYS is in treed sites, and we can't count on uncloudy days, so having more panels works for us. 100 watts would probably be ample for you if you switch out your bulbs to LED, though I still recommend getting a couple of Luci Lights. You're going to want to at some point, and the sooner you can, assuming your bankbook allows, the sooner you'll be reaping the benefit. Zamp and Renology are other brands which are often mentioned by Casitans as being quite good.

I don't know about the controller issue. We had Casita install their "Solar Ready" package, so that was not an issue, though Larry would have done that too. He and Mike had a very heavy day of it as it was, as we wanted to get all the things done while we were still in the area, and because of his then impending retirement. So I defer to people who have a clue.

[Glenn Baglo]

Your solar controller should not be located inside the battery box. Can't recall the source of the info, but I believe the reason is gases from the charging battery can damage the controller electronics.

[DebiT]

Hmm, then maybe the answer to all of it is remove that controller and then just buy a "normal " 100 w solar plus controller. Seller only used it once, may not have realized. I love this forum already,

[Glenn Baglo]

I'm still working out my solution. Bought a food storage container that is water and air tight. I plan on mounting it next to the battery box. However solar cable has to get to the controller (inside ) and cables ( with alligator clips ) have to reach the battery.

[DebiT]

I would have thought this was really.common, with tried and true solutions already. Not true?

[Adirondack Anthony]

No solar here, but our well charged standard, non AGM battery has lasted us for a week at a time. It's only needed for the refrigerator lights/controls and for the propane/CO2 detector. Minimal draws.Be conservative with lights and water pump, use propane for cooking, flashlights and lanterns outside and you'll be fine. In fact,our grey water tank needed emptying way sooner than the battery showed any significant discharge. We were not using ac/fan or tv, if those things are important then then you'll likely need solar or a generator. So, to quote previous posters, "it depends".

[DebiT]

I have a feeling it will be fine. I think I'm just getting excited, given that my trailer is here but my tow vehicle isn't, so am putting my energy into learning. I will admit I like the idea of having plenty of "juice" without concern.

[Raspy]

Debi,

Usage can or will always rise to meet capacity.

I too have Renogy 100 watt suitcase solar and I love it. It comes pre-wired with it's own controller. All you have to do is hook it up to your battery and point it at the sun. That's it. Don't try to use it through your other solar controller. Make it simple and simply connect it to the battery. I bought a 12 gauge extension cord and made up my wire at about 20 feet long so I could always reach from wherever the sun was. I installed a plug on the outside of the trailer to plug into, that is wired inside to the batteries. The cord rolls up and fits in the suitcase setup. And the panels come in a nice carrying case and have adjustable legs to get the angle right. This is a nice setup, but you could also use alligator clips in the beginning to see how it works.

In your case, with somewhat careful use and a 100 watt solar system, I'm sure you could get by fine for two days. Once you see how it goes, you'll get a feel for how much power you have. Get a battery voltage meter that plugs into a cigarette lighter. These are very simple devices that monitor your voltage. when charging, the voltage will go up to about 14 and then settle down to a float of about 13.1. Fully charged, the battery should be at 12.6 volts with nothing running and not charging. At 50% discharged it will be at about 12.1 volts, again, with nothing running and not charging. You should not let it get lower than that.

So, simply monitor your voltage, run the solar charger and after a while you'll see how much power you have. Sounds to me like it will work out just fine with your limited use. Switch to LED bulbs if you haven't already..

[Glenn Baglo]

My battery is easily accessed on the back bumper. I have two Coleman 40 watt portable panels that connect to a hub that connects to the controller, which connects to the battery by alligator clips.
BTW, the generator now stays home.

[Mike_L]

I'm a die hard boondocker. Shore power is never available. I do have a generator which I used once in about 15 years. It certainly meets my power needs but uses a liter of fuel per hour and that adds up.
A fully charged group 27 deep cycle battery easily lasts me 2 days before going down to 50% capacity, which is as far as I would ever discharge a deep cycle battery.
I replaced all the filament bulbs in my unit with LEDs, makes a huge difference.
I started with 80 watts of solar power. Kept my batteries up during the summer. Fall camping with fewer sun hours and less intense sunshine didn't always keep my batteries top high. I went to 150 watts and now my batteries are always fully charged. I haven't done winter camping for some time now so I don't know how well this would work in the winter.
I added up the various loads (lights, fridge, gas detectors etc.) my unit would place on a battery. These numbers should be listed in your trailer manual. Multiply these numbers by the maximum hours of anticipated use for each and add them together. This number represents the demand, in amp hours, placed on your battery over a 24 hour period.
Divide the amp/hour rating of your battery in half for the recommended 50% discharge level. Now divide this number (half the amp/hour rating of your battery) by the load your calculated and you have an indication of how long your battery will last.
Remember, solar power only lasts as long as the sun is shining. Early morning and evenings the sunlight is less intense so solar power rating is diminished. Also, the solar panels must replace the 24 hour consumption during the daylight hours. My solar panels generate at about twice the consumption rate. This keeps my battery fully charged during the day. Recovery from night time battery use usually occurs before noon the following day.

In my opinion, solar is the way to go. Except for the initial purchase price of the panels, the power is free.
The charge controller prevents over charging your battery which means they consume much less water.

Solar panels don't recharge a battery as much as they maintain a charge in a battery. During the day the battery is topped off every time it's used. The power used during the night is replaced the next morning. This minimizes the depth of discharge which greatly extends battery life. My batteries are 7 years old and still going strong thanks to solar power.

[thrifty bill]

So why do people even bother with a generator?

Solar will not keep up with big loads like AC, microwave, etc., unless you get a lot of solar.

[DebiT]

So first step for me will be to replace all Casita interior lights with LEDs. Need to check A-Z book for brand recommendations. Just realized first several camping reservations are in hookup spots, so I can boondocks and observe at no risk. Cool!

[thrifty bill]

Other first step is to get your battery tested to make sure its good. RV batteries have a way of failing. Four years is not unusual life for a standard lead acid RV battery.

[DebiT]

Battery is supposed to be new. I guess I need to look up how to test the battery. In other news, I just discovered that I have LED lights, and in a nice warm color to boot! So that's done.

[floyd]

I have a Scamp13D.

I have often boondocked and never ran out of power in a weekend.
We watch a couple of hours of TV each night, run water pumps for showers each day and run lights without conservation while charging phones and tablets. A day on the road quickly brings the battery back to full charge.
After several days of boondocking you can bring your battery back to full charge in about twenty minutes with a good pair of jumper cables attached to your tow vehicle at an idle.
15 years with our Scamp has shown me no need for solar, but even a small panel ought to be enough if you really want one.


I once had a low battery on my tow vehicle after a few days of camping and was able to jump start my Tow vehicle from the trailer.
We have a group 27 battery instead of a 24 but only because it has twice the warranty.

[RogerDat]

math on the solar panel needed is pretty straight forward. Look not at the watts but the amps the panel provides.

Figure 4 hours at full amps + 4 hours at 1/2 amperage output for morning and evening.

So for a typical 100 watt panel you would see the amperage stated as Maximum Power Current (Imp): 5.1A

That means it puts out 5.1 amps. when fully producing power. In one hour it is capable of putting 5.1 amp hours back into the battery or powering a 5 amp device for an hour.

Using 4 hours at 5.1 equals 20.4 amp hours.
Add that to the 4 hours at half power of 2.5 equals 10 amp hours.
Total amount you can replace in a day is 30.4 amp hours.

Typical deep cycle house battery of approx. 100 amp hours can be drawn down to 1/2 charge without damage so you have 50 amp hours to use. With a 100 watt solar panel able to contribute 30 amp hours to demand or building back up the amp hours in the battery.

Then it just boils down to what your stuff draws and how long it runs for in typical use. For the short duration stay described in original post it is perfectly acceptable to "lose ground" every day as long as over the course of your stay you don't pull the battery below 50% charge.

If for example you use 40 amp hours and replace 30 from the panel it would take 5 days to deplete a charged 100 amp hour battery to 50% charge. You are only "losing ground" from your battery at a rate of 10 amp hours a day.

One issue that might crop up is rainy weather. Less charge from solar plus more time spent in camper possibly using power. So having a bit of buffer in your calculations for amp hours used per day is a good idea. The other is the furnace in most campers won't work without power so if you will be depending on that appliance you may want a more substantial reserve of capacity in either battery or solar output. Or both.

Anything that uses 12 volt converted to 110 is using a lot more battery capacity than the same amp usage in a straight 12 volt appliance or application. E.g a small 12 volt fan drawing the same amperage as a 110 volt fan being powered via an inverter the 110 volt fan will draw down your battery faster. Laptops, TV's or similar devices are good examples. Camera battery charger is the one that I use that draws a lot because it is plugged in for so long.


P.S in line with what Floyd says we have a 40 watt suitcase panel it was compact enough to store easily and provides an "extender" power supply rather than enough to provide complete replacement of power used. We won't typically boondock for long enough to run battery down and will recharge from tow vehicle as soon as we hit the road.

[Mike_L]

I've never had much success charging an RV battery from a vehicle.
My tug is a diesel with dual 1050 amp batteries and a heavy alternator. I can charge an automotive battery using booster cables rather quickly but not an RV battery. These things take a long time to charge.

[Jann Todd]

Originally Posted by DebiT

I have just purchased a new to me 2015 Spirit Deluxe 17. I love to camp at a local beach campground, arriving Friday noon and leaving Sunday noon.

Is it likely the battery will last for that length of time? Our old Class A did, but it had 2 12 v house batteries. I think the seller told me it was battery; I can easily check.

I have a connector for solar, but I don't want to deal with it if it's not necessary. Any longer trips would always have hookups

Thanks in advance. 

Your battery should last the 3 days if you only use the pump for water and turn it off after using the water each time, have LED lights and use the fridge on propane. Our 2007 Casita will last that long with those uses as long as the battery is good.

[Raspy]

Originally Posted by Mike_L

I've never had much success charging an RV battery from a vehicle.
My tug is a diesel with dual 1050 amp batteries and a heavy alternator. I can charge an automotive battery using booster cables rather quickly but not an RV battery. These things take a long time to charge.

I stopped taking my 2000 watt generator and have been charging my house batteries with jumper cables to the truck. They always charge faster this way than when I plug the trailer into the generator.

But one thing that might slow the charging on mine is that the truck alternator is a smart charger in that it has a bulk phase of 14.1 volts and a float phase of 13.1volts. So, in theory, if the truck batteries are fully charged when I connect the house, it might go into "float" before the house is fully charged. But either way. it is still faster than the 2000 watt generator.

I have (4) Trojan T-105 house batts and two large starting bats in the truck, and I use a very heavy gauge set of jumper cables to connect them.

I just got my new suitcase 100 watt solar dialed in and ready for service, so we'll see if I even need to charge from the truck at all. Hope not, but it does seem that usage always rises to meet capacity.

[Jann Todd]

Originally Posted by Mike_L

I've never had much success charging an RV battery from a vehicle.
My tug is a diesel with dual 1050 amp batteries and a heavy alternator. I can charge an automotive battery using booster cables rather quickly but not an RV battery. These things take a long time to charge.

We have always charged our trailer battery from our tv while driving and it is always fully charged when we reach our destination even when we boondock and go to another campground it is fully charged if on the road for a few hours.