New RV Concerns with Battery

[billdean]

I recently bought a GD Imagine RL2500. It came with one 12v battery made by Deka, a marine master deep cycle battery. It also comes with WFCO 8900 series control center which has a 3 mode converter. I will be boondocking in the south as much as I can from about December to around the first of April. I have a Honda 2000 generator also. My concerns are will the one battery be enough power for over night camping assuming I will charge it everyday with my Honda Generator? I will be running my refrigerator on propane. The only other usage I believe I will have is keeping my cell phone and computer charged as well as some heat if it gets close too or below freezing and a little hot water from time to time. I have been thinking about installing 2 Trojan T105's also but if one battery will give me the power I need I am not sure I would need to. I have been running all the LED lights and a couple of fans and have had the furnace on since about 10:00 this morning and I have about a 1/3 of the battery left or at least thats what the convenience center says. Not my first experience in a travel trailer but not to experienced with boondocking. 

[I'mdonewiththis forum]

If you are conservative with power one battery will do fine. Running the furnace will suck the power out of a battery fairly quickly IF you leave it on all night. I have run the furnace to get the trailer warm then shut it off all night and warm it up when got up. I had no problem on one battery, but when it failed I put two golf cart batteries in.

[Kirk W]

3 hours ago, billdean said:

I have been running all the LED lights and a couple of fans and have had the furnace on since about 10:00 this morning and I have about a 1/3 of the battery left or at least thats what the convenience center says.

You should know that those battery level indicators are notoriously inaccurate. I sure would not rely on one but get a quality, digital meter and measure at the battery. It is impossible for us to give you an evaluation of your power needs from the little that we know. I have years of background in RVing and electrical service work and could only guess. Your furnace is probably the largest 12V load but the ambient temperature is what determines the frequency and length of time that a furnace runs. It is the time your blower stays on that will determine most of what you need. The time that most of us discover that we do not have enough battery is when the night is cold and the furnace dies in the wee hours! If you have space I'd recommend two batteries. 

[lenp]

Keep in mind that a wet cell battery will last a LOT longer if you don't discharge it completely before recharging.    I remember reading a battery will last about 200 cycles if it is discharged down to 10% each time before recharge but it will last 2000 cycles if you keep it above 50%.

Best to keep it above the 50% level if you can.  Also, the marine battery you have is really not a deep cycle battery - kind of a hybrid  between a starting battery and a deep cycle.  The Trojans are deep cycle.  Look for AMP HOUR rating not cranking amps when buying a battery for your RV.  If you see cranking amps it is a starting battery!

Lenp

[Al F]

Are you truly planning on dry camping/boondocking for 4 months straight?  Even going 2 to 3 weeks w/o elect requires some planning. 4 months is doable, just needs planning.  We spent 4 1/2 months (139 days) on our Alaska trip in 2016 and only had elect hookups for 2 nights.  A lot of planning and setup went into the prep for that.

Either of the batteries you mention require being charged to 100% full at least every week. If you don't the plates sulfate and you loose capacity. An equalization cycle with the charger (if it has the option) will help with sulfation. 

A 100 watt 12V nominal (18 volts in the solar panel specs) will go a long way to keeping your stock battery charged.  With the Trojan batteries, I would go with a pair of 100 watt panels wired in parallel (200 watts at 12V).  A solar controller would be nice as well.  You don't need to mount the panels on the roof.  If you can set them up on the ground pointing to the sun. That will work.  Run the generator for an hour or two to get as much charge back in the battery as possible, then let to solar panels get them to as close to 100% as they can.

Do you know what the AH (Amp Hour) rating of the stock battery is.  I'm guessing it is about 75AH (group 24, maybe group 27 battery).  The Trojan's would be about 220AH.  Trojan's are much better at handling the furnace if you have to run it quite a bit.  You can save yourself a bunch of bucks by buying a pair of golf cart batteries at Sam's Club or Costco for about $80-$90.  They may ONLY give you 75%-80% of the life of the Trojan's, but they work just as well and the price is much better.  Think Cadillac versus Chevy.  They both get you to where you want to go.

You don't state which model of the 3 stage converter you have.  I'm guessing it is sized for the stock battery so it is probably around 35amps of 12VDC.  A 50-70 amp charger would be better if you go with the Trojan's.   

Since you are (I assume) are planning on continuous dry camping for 4 months, you must have a battery monitor, such as a Trimetric.  With a battery  monitor you know, not guess or estimate, how many AH's have been used and how well charged your batteries are.  Also when you leave it on the amp display you see how many amps are being used at that moment by whatever device is being used. 

Here are links to two articles which expand on what I have written above:

http://www.marxrv.com/12volt/12volt.htm

http://www.marxrv.com/12volt/12volta.htm

Come back with more questions as you have them.

[billdean]

Thanks AL F. I am not entirely new to adapting to condition as they arise in a TT. And planning I have done a lot of that. I lived in a 24 ft travel trailer in Big Lake, Alaska for 2 winters before building my house in 2011. Though I did have electric but it was still a challenge!

I believe my battery is a group 24 and my controller is an 8955PEC which puts out 55 amps DC I believe. I have been looking a the Trimetric monitor. My trailer does have a Furrion 95 watt solar plug on the outside and is suppose to be solar ready though that is probably not enough to do what I need. https://www.furrion.com/store/energy/net-zero-solar/95w-portable-solar-charger-p-944.html I am going to do as much boondocking as possible though.

[Pat & Pete]

Brr . 

I bet the air was pretty fresh . 

[Al F]

The Furrion solar package looks a bit pricey to me.  For example you can get a 100 watt or 180 watt panel here and a solar controller from Amazon for a lot less.  If you go with 180 or 200 watts I suggest you use #8 wire to connect the panels to the trailer.  Less voltage loss than #10 wire. 

A few years ago I bought 100 or 150 watt panels from AM Solar (the link above) and they were able to ship via UPS.  Larger panels have to ship via freight and that gets pretty pricey.

[Kirk W]

16 hours ago, billdean said:

It also comes with WFCO 8900 series control center which has a 3 mode converter.

Our current travel trailer has the WF8935 and it does a fair job of maintaining the one battery it came with.  We do very little dry camping so it is acceptable for our use but I wouldn't recommend it for long-term dry camping unless you get something additional such as AL F is suggesting. I have considered upgrading ours just to improve the battery life. If yours came with a marine battery, does that mean you bought it used? I wouldn't expect that in a new RV. 

[billdean]

24 minutes ago, Kirk Wood said:

Our current travel trailer has the WF8935 and it does a fair job of maintaining the one battery it came with.  We do very little dry camping so it is acceptable for our use but I wouldn't recommend it for long-term dry camping unless you get something additional such as AL F is suggesting. I have considered upgrading ours just to improve the battery life. If yours came with a marine battery, does that mean you bought it used? I wouldn't expect that in a new RV. 

I bought my TT  new 1st of this month at a 37% discount to MSRP. At that price they didn't want to do much extra stuff. They only wanted to give me 1 20lb propane tank, which I caught and made then put on 2 30 pounders. I wished I would of caught the battery, I would have made them change that.

The WF8955 that came with my trailer had my battery back up to 80-90% or so of capacity in a couple hours of charging it with my Honda 2000. I am interested in purchasing a solar panel to help me finish the battery charging. Theres so many out there I just don't know which one I actually need and I would want it to be portable. I am looking into the battery monitor and will purchase that this week. Any ideas on the best place to purchase monitors, and panel would help.

AL F thanks again for you input. I spent the night reading what you had given me. It was very helpful. I will be checking out the link you give me to the solar panel today. Question?? A inverter may me a must have for me. I sleep with a CPAP machine every night and would want to continue doing so while on the road without running my generator all night to supply 120v to it. Would something like a 750 watt inverter do the job? I can't imagine it would take the hole 6 amps to run it.

[Kirk W]

3 minutes ago, billdean said:

I sleep with a CPAP machine every night and would want to continue doing so while on the road without running my generator all night to supply 120v to it.

My son uses one and he is a Scoutmaster and has a power supply that he uses in a tent for several nights at a time. If you wish, I will find out what he has to supply that power. 

[billdean]

6 minutes ago, Kirk Wood said:

My son uses one and he is a Scoutmaster and has a power supply that he uses in a tent for several nights at a time. If you wish, I will find out what he has to supply that power. 

Thanks Kirk...That would be great!

[Kirk W]

4 hours ago, billdean said:

Thanks Kirk...That would be great!

Our son says that most cpap machines operate on 24V-dc and that he first got a 12/24v converter(cost about $90) and used a jump-start device as a power supply for it. He now has a 12V cpap for which he paid  $565. He says that most of them are 24v with a power supply converter that comes with them. He says that most travel cpap machines are 12v with a 12v accessory plug (formerly cigarette lighter). He suggests an online search to find the least expensive one. 

Travel cpap equipment.

[Al F]

My wife's CPAP, with the humidifier heater turned off, only pulls about 1amp of 12V DC.

The CPAP is a Phillps Respironics System One, which is about 5 years old.  It is a 12V machine.  I bought the 12V cord with a cigarette lighter plug on it. I picked up 12V from the reading light at the head of the bed and wired in the plug for the CPAP. The tag on the bottom of the machine shows 12VDC at 6.65 amps.  That high current listing is very miss leading though:

The CPAP has a heated humidifier with it.  If the heater is turned on and actually heating the water in the humidifier, then it pulls 5-6 amps.  The heater knob goes from 0-6, so the higher you turn it the more current it uses.  Note, the CPAP does not heat the air.  It only warms the water so more water evaporates into the air.

Anyways if you leave the heater off, the CPAP is very efficient.

For your CPAP, look on the bottom for a tag which shows the voltage and current used by the machine.  If you do need an inverter, calculate the wattage the CPAP uses by multiplying the voltage by the current.  So if it lists 24V at 4 amps that is 96watts, so a 200 watt inverter would work.  I wouldn't try to use a 100 watt inverter for a device which uses 96 watts, that does not give you any buffer for max draw. 

For any inverter over about 100-150 watts, don't try to wire the inverter into the trailers 12V wiring to the lights.  The wires to the lights are too small for that high of current.  Wire the inverter directly to the battery with #10 wire for a 200-600 watt inverter.  If the 12V wire to the inverter goes farther than about 5-8 feet use larger wire, like #8 wire.  Also most 12V outlets installed by the trailer mfg don't have wires any larger than the electric lights, so are not designed to power 200-400 watt inverters. 

BTW, for a quick and easy way to buy #8 wire, or maybe even #6 wire, buy a set of automotive battery jumper cables and cut the clamps off.  The jumper cables are usually pretty flexible and about 10' to 12' long.

As Kirk mentioned you can buy a 12V to 24V converter if you have a 24V machine.  I don't know that there is any better efficiency with the 12V-24V converter than with a 200 watt inverter.  Both use some amount of power to do the conversion.