Generators??? Time Self contained?

Hello,

I am new to my TM and to camping. Some of the places I will want to take my TM will not have hookups. So, what kind of generator would I need to power the AC (least expensive, Recomendations)? Also, what other tricks do you have to keep cool without AC (fans)?

With 1-2 adults, how long can you camp? When does the water and battery power run out?

Thanks, Emory.

Know your destination and try to get a shady spot.

[RockyMtnRay]

[quote author=RCaerobat link=board=22;threadid=2170;start=msg15037#msg1503 7 date=1090707070]
Hello,

I am new to my TM and to camping. Some of the places I will want to take my TM will not have hookups. So, what kind of generator would I need to power the AC (least expensive, Recomendations)? Also, what other tricks do you have to keep cool without AC (fans)?

With 1-2 adults, how long can you camp? When does the water and battery power run out?

Thanks, Emory.
[/quote]

What are "hookups"? ???

About 90% of my camping is in National Forest Service and other primitive campgrounds that don't have any hookups. About 9% of my camping is in State Parks that have electrical only hookups. Only once in 3 years have I used a commercial campground that had the whole works...water, electrical and sewer. So I have lots of experience with dry camping...

Other than electrical, the limiting factor in a non-hookups campground is usually the grey water holding tank...if you are not extremely frugal with water, you can fill this in a day or two. By frugal, I mean 3 minute "Navy" type showers with the water off while soaping...and only using a dribble of water for dish washing. If I'm extremely frugal, I can keep water use to under 7 gallons per day and can make the grey water tank last as long as 4 days.

If you use the toilet only for urine (as I do), you can expect a 4 - 7 day capacity for 1 or 2 adults; if you also use it to defecate, 1 to 3 days.

The fresh water tank is usually not a huge limiting factor if you bring along some kind of water tote...I use collapsible 5 gallon water carriers and put a short length of hose on the carrier's spout to fill the trailer's fresh tank. Virtually all developed campgrounds throughout North America have some source of potable water.

As for electrical, the standard Group 27 battery is good for 1 to 3 days if you are very frugal with electrical usage, about one night if you use lots of lights, the overhead fan, the furnace etc. Most of us who do extensive dry camping have installed a pair of 6 Volt Golf Cart batteries...and some of us have also added solar panels to recharge the battery(ies). Keep in mind that draining the standard RV/Marine battery below about 30-40% of its capacity will greatly shorten its life...despite the labeling, this is not a true "deep cycle" battery.

As for a generator, do NOT buy the least expensive! When it comes to cheapest, that invariably means the noisiest ("contractor grade&quot and often the heaviest. A noisy generator (over about 70 db) is a guaranteed way to alienate other folks in the campground and, in general, "contractor grade" generators are outright banned in many western campgrounds. Instead, I strongly recommend you buy the lightest and quietest such as the Honda EU series...these generators produce under 60 db of sound (very, very quiet) and are very small and light. Yes, they are a lot pricier but they are also very long lasting and, more importantly, you will actually be allowed to use them in campgrounds that have noise restrictions. And you won't be getting hostile looks from other campers. As for generator size, the older TMs with a side mounted AC should work with a 2000 Watt (max) generator....the models with the larger roof mounted ACs will need at least a 3000 Watt generator.

If you are concerned about an airconditioner, I'm assuming you live in a hot climate. Where will you expect to be camping? Ray camps in Colorado, mostly in the mountains it seems, so he doesn't need much cooling. Being from the midwest and travelling some in the south, I understand the need for A/C, at least in those locations.

Generators are pretty much frowned on in most campgrounds that don't have electricity (state, national parks, etc). Some places ban them completely. If you're just going someplace warm, try not to use it. If you really just have to have it, I recommend trying some place with at least electric hookups. I've found lots of state, county, and even some federal places that have electric hookups in the south. If you still decide you really, really have to have a generator to run your A/C, I second the recommendation for a Honda EU. Most folks I've heard of need the 3000 model or dual 2000s to get the juice for an A/C. To size it, look at the power draw of your unit and add 20-25% reserve. Make sure you look at the starting power; it's usually quite a bit higher than the running power. Generators are pricey, but the sound of the Honda one is significantly less than the contractor ones (which usually say you need ear protection!).

I'm not completely against generators. In fact I've got a Honda 2000 we use to charge the batteries when we're dry camping which we do a lot. We usually can run 3 days on battery power (one regular RV battery) for our family of 4, and we usually have to dump the gray water tank about as frequently. The toilet works fine for complete use for 2-3 days (no trips to the latrine), and works 5-6 days when combined with occasional latrine trips. If you don't want to move your trailer to dump you'll need to get a "blue tote", a generic name for a specialized container to hold the wastes that you take to the dump station.

Good luck with your camping and your new trailer.

Pam

Thanks for the advice so far. Some of my dry camping will be at remote control airplane fields, most of which do not have any type of electricity or water. Most of these trips will be in Alabama or Florida, so it does get hot. I don't mind not having AC during the day, but I don't want to be hot at night. I may be fine just using fans, but then I wonder how much time I can get out of the battery running those. Is there any way to guage how much charge is let in the battery?

Thanks,
Emory.

[shunter917]

You can add an inverter to convert 12v battery power to 110/120v to power "standard" items like coffee pot, etc. BUT those items tend to draw lots of power and may drain the batteries more quickly than you realize.

I have put an inverter in and it works very well, but we don't use it unless we have to.

[RockyMtnRay]

[quote author=RCaerobat link=board=22;threadid=2170;start=msg15052#msg1505 2 date=1090787780]
Thanks for the advice so far. Some of my dry camping will be at remote control airplane fields, most of which do not have any type of electricity or water. Most of these trips will be in Alabama or Florida, so it does get hot. I don't mind not having AC during the day, but I don't want to be hot at night. I may be fine just using fans, but then I wonder how much time I can get out of the battery running those. Is there any way to guage how much charge is let in the battery?

Thanks,
Emory.
[/quote]

TC is right...you want 12V fans, not 110V ones. I have a small one (about 8 inch blades) that I got at Camping World. Current drain is roughly 1 to 3 amps, depending on the fan speed setting.

Yes, as shunter notes, it's possible to run 110V appliances through an inverter...but the current drain on the battery for a typical 100 to 300 Watt appliance is very high. First, the inversion process is not 100% efficient...80% efficiency is typical; second, to get 100 watts at 110 Volts (about .9 amp) requires a current of roughly 9 amps at 12 volts (at 100% efficiency). This becomes around 11 amps at normal efficiency. For a 300 watt appliance, you can triple the 12 volt load to about 33 amps!

The problem is you have a very limited number of amp-hours to work with...a brand new, healthy Group 27 RV/Marine battery typically can provide 115 amp-hours before it's completely exhausted. Complete exhaustion rapidly kills the battery so you want to limit the amount of amp hours you will pull to about 70% of the rating...or roughly 80 amp-hours. That rating, BTW, is at a 5 amp drain rate....if you drain it at a 20 amp or higher rate, you have to reduce the total amp-hours by around 30%.

So, given typical usage of lights, water pump, and other internal drains, you can expect to use around 20 amp-hours minimum each day. That leaves you about 60 amp-hours for fans. If you have two fans, each using 3 amps to circulate the air, you have at most 10 hours of fan use available...about one afternoon and evening!

For your expected usage, I strongly recommend you get a pair of 6 Volt Golf Cart batteries and wire them in series. Using the best battery available...the Trojan T-105, you would then have about 225 amp-hours total and, because these are true deep cycle, you can use about 80% of the rated capacity.

As for measuring remaining battery capacity, the best approach is to get a very sensitve voltmeter and a charts of voltages vs remaining capacity for the temperatures the batteries will be at (exact battery voltage is determined by both state of charge and temperature).

If your typical camping location is shade-free much of the day, you may be a very good candidate for solar panels. I have a 170 Watt array on the roof of my TM which generates about 11 amps of steady power in full sunshine. Combined with a pair of Golf Cart batteries, I can literally go for weeks without worries about having enough electrical power. Solar is great but it has two big caveats...first, it's pretty expensive (my array and wiring was about $1000 in parts alone), second it does not work at all well on cloudy days or if the panels are even slightly shaded by trees.

[Bill]

Rocky Mtn Ray wrote:

As for measuring remaining battery capacity, the best approach is to get a very sensitve voltmeter and a chart of voltages vs remaining capacity for the temperatures the batteries will be at (exact battery voltage is determined by both state of charge and temperature).

In the spirit of proper nitpicking, let me add one thing. The voltmeter approach to measuring remaining battery capacity requires you to let the battery "relax" - i.e., no charging or discharging - for 2 or 3 hours before you make the measurement.

Rather than try to rephrase the answer of an expert, let me just present it whole. As you will see, the battery voltage changes quite a bit (almost a volt!) when the battery relaxes, and only the "relaxed" voltage can tell you the state-of-charge.

Bill
===============+

"Question:
An overnight charge gives me 13.6 volts. When I disconnect charger it slowly drops until about 12. 8 volts. Is this normal?

Answer: Yes, it's normal.

What you're seeing is a manifestation of what's called "surface charge". While charging, the specific gravity of the electrolyte directly in contact with the battery's positive plates is higher than that of the rest of the solution. This higher SG causes a "false" high reading on your voltmeter if you check the voltage immediately after removing the charger from the battery terminals.

The higher SG electrolyte will eventually diffuse through the rest of the electrolyte (kind of like tea steeping) after the charger is removed and the battery is allowed to "rest". The voltage of a fully-charged 12 V battery that has been allowed to rest (no charging, no discharging) for 3 hours or so should be around 12.8 V.

A similar phenomenon occurs during discharge. Under load, the battery voltage will read a bit low due to the dilution of the electrolyte that's in immediate contact with the positive plate. When the load is removed, the battery voltage will creep back up to a resting voltage commensurate with the battery's state-of-charge."

Thanks again for all the advice. I have read elsewhere and someone already suggested getting two 6v golf cart batteries and wiring them in series. Can someone show me a picture or have a good description of what it means to wire in series verses parallel. I always get those two confused.

As far as fans go, the idea to get them so they run on 12v is a good one. One thought I had reguarding fans was to have one in each window on opposite sides of the TM. Then, yopu could create some cross ventalation, instead of just blowing it around. Does anyone know of fans that will mount to the window?

Thanks, Emory.

Check out the auto supply places in the truck (as in 18 wheeler) section. Thay have little fans to cool those big rigs without running the AC. The one I saw was clipped to the center rear view mirror.