Battery Run Time

[Levidada]

I'm curious how long my battery should run before dying while dry camping. Here in CA, the state campgrounds, you can only run the generator between 10am and 8pm, which leaves a substantial amount of time to be on battery only. The last weekend my battery could not withstand the duration. Im wondering if this is normal, or if I have a weak battery. Only thing running would be interior lights, awning LED light, and heater during sleeping hours (10-7).

[West_Coast_Canu]

Unfortunately we're we camp it is too shaded for effective solar charging Since I have to use my inverter generator which is quiet. I have a group 31 agm 105 ah battery on my TT and I carry two golf cart 6 volt batteries in my truck for back up. The golf cart batteries connected together gives me 232 ah use. I converted the 15 incandescent bulbs in my TT to led and use the heater sparingly...fridge is on propane and We cook outside. I do not use the heater at night, I can last about a week without charging.

[avoidcrowds]

I will also vote for 2 batteries and solar.

I have two 110 Ah batteries, and 2 100w solar panels. With this, I have done 3 nights with day temps in the 30s, and overnights in the low-20s. Furnace set for 65° in the evening (we aren't around during the day), and 45° at night.

I have all LED bulbs throughout, and don't have a TV. Use water heater (gas), water pump, furnace, and lights as we want. Always have plenty of battery power.

I love my solar, as we have been dry camping and used heat overnight for a week (overnight low of 30°, and wife needed heated during the day, as temps only went to 50°, for each of two weeks), and have not run low on power.

I am a solar advocate, as it works great for me.

[TheWB]

I think the best thing you can do is run your own tests at the convenience of your house when losing power won't matter. That's how I figured out my requirements. We do a lot of dry camping and figured out what's best for our situation.

Here's what I did using our own personal wants. Quiet hours are taken into consideration, so I don't mind running the genny all the time during those hours. I consider 8PM the quiet hours for my testing, although real world scenario is usually 9-10PM. After we've done whatever hiking (our main activity) we are going to do for the day, it's about 4-5 PM. That puts my genny period between 5-8. I assume I'll be able to charge 3-4 hours. At night, I want to have pretty much all (my) necessities on. Water pump. Water heater. Porch light. Everything else on stand-by (TV, DVD, Radio, etc). Also, phones, 2-way radios, kindle, etc will be charging off the DC ports sometimes. For the winter test, I set the heater at 68 degrees. Temps outside overnight dip to mid 30s. Day reaches into 50s, but warm enough to where it will heat up to the 70s inside the trailer without vents open.

At 5:30 PM I shut the shore power off, just to make sure that the the trailer will run off the batteries (2 x group 24 70 reserve amps) all night and into tomorrow morning. 8AM, still everything still running. Voltage down to 11.7V. By the end of daylight hours, My solar panels have charged batteries to 100%. On a cloudy day, they charge to ~60%, 3 hours of genny time gives it enough charge to last through the night on those conditions again, but still lower levels the following day. I'll be retrofitting the WFCO distro panel with a new converter this weekend to take care of that.

Running this same test in warm weather, genny is not really needed with my solar panels charging and not using the heater at night. However, I like using some AC devices if I can. Toaster, microwave popcorn. And of course air conditioning in our hot summer months.

After I install the coverter this weekend, my next project will be installing an inverter that will supply short bursts of AC, such as a toaster or microwave use without firing up the genny. The inverter output will be tied into the existing general purpose outlets. Be sure to have that done by qualified personell.

The main problem we had at first was that the battery would never be fully charged. Even after being plugged in for a couple days. That made us think something was wrong. Most of these stock converters don't really go into a true boost mode that would be capable of putting a full charge on the battery within 3-4 hours. We would have everything turned off except the fridge and the battery would still be dead by 2AM. After buying a high amp true battery charger and doubling my battery I then begain experiencing true dry camping with comforts. Now my rig never gets turned off. Hasn't been turned off since I installed the solar panels a few months ago. You can read about those in one of my other posts.

[time2roll]

Battery should last overnight without too much conservation. Generally I recommend two batteries for any off-grid camping.

Your real problem is probably not getting the battery fully charged. You need two to four hours at 14.2 to 14.8 volts to get close to 100% charged. Have you measured the charging voltage? What converter do you have? Most just trickle charge at 13.6 volts. You can upgrade the converter or bring a 20+ amp portable charger to help get where you need to be.

[rbpru]

One battery one night would be a good rule for us. It is not the battery life but the loss of the TV, microwave, coffeemaker, etc. that limits us.

Non-electiric camping is a temporary situation for us, usually as we traveling to our destination.

[pianotuna]

Hi,

Did you measure the fridge when the gas valve was open? You may find it does more like 18 watts and has a 2:3 duty cycle.

Here is a chart that shows what happens to capacity in an AGM battery as the load increases.

[bobndot]

I copied this from one of our members. I installed toggle switches to cut power to unwanted items when not being used. I use 2 agm grp 31 batts that are the same age .

Took some current readings today as I was curious about the current draw of my Norcold while running on gas, I went a little further so I thought this might be useful to others:

Current measured with battery at 12.68 volts.

- CO & LPG detectors together draw .061 amps (0.77 watts)
- Norcold 6 CF running on LPG = .609 amps (8.5 watts)
- Forced air heater running = 3.49 amps (44.25 watts)
- Dual bulb florescent fixture = 2.15 amps (27.25 watts)
- One overhead incandescent bulb = 1.45 amps (18.38 watts)
- Northern Breeze Fan on max speed = 3.99 amps (50.6 watts)
- Northern Breeze Fan on 1/2 speed = 1.15 amps (14.57 watts)
- Northern Breeze Fan OFF = 0.049 amps (0.62 watts)
- Cheapo Bathroom ceiling vent fan = 1.24 amps (15.71 watts)
- TV Antenna Amplifier = .041 amps (0.52 watts)
- Ventline range hood exhaust fan on HI = 1.32 amps (16.73 watts)
- Ventline range hood exhaust fan on LOW = .622 amps (7.89 watts)
- Ventline range hood exhaust fan light = 1.38 amps (17.49 watts)
- Stereo/DVD player with power off = .057 amps (0.72 watts)
- Stero on FM at mid volume = 1.1 amps (14.94 watts)
- 'Go Power' 300 watt PSW inverter 'ON' mode = .23 amps (2.9 watts)

Hope this can answer a few general questions about power draw in our campers.

useful info . in this link .
http://www.marxrv.com/12volt/12volt.htm

[CavemanCharlie]

It sounds like what you are experiencing is purdy normal for the way most Travel Trailers are set up from the factory.

What I did was to convert my light bulbs all to LED bulbs. Then I put 2-6 volt golf cart batteries on the front where the single battery was. ( I had enough room to do that) . I try not to run the furnace much, only after I'm going to sleep and I keep the thermostat set at 62 degrees and cover up with a sleeping bag. By doing this I can camp a whole weekend on cool (not cold) nights with no problem.

I have a older camper so I also changed the converter (which has the battery charger built in) to a newer style.

We would need a better description as to what Travel Trailer you have to give a better judgment of how long you can go.

Be aware; if you ran your standard Travel Trailer battery all the way down then you have probably killed it. Most TT only come with a standard car battery and they are not designed to be drawn down to nothing.

[fitznj]

1 battery - 1 Day......
Furnace will deplete you battery pretty quickly;

Options:
1 - convert to LED lights, turn off furnace at night (get more blankets)
2 - get 2 batteries and connect to solar panel to replenish batteries during the day.
3 - Use a propane heater like a Buddy Heater during waking hours

[2oldman]

Levidada wrote:
Only thing running would be interior lights, awning LED light, and heater during sleeping hours (10-7).

Lights are fine, and heater, assuming you mean furnace.. no.

[ADK_Camper]

It's impossible to say how long your battery should last. How long it will last depends on its overall capacity and condition and, of course, how much demand you place on it. There is a small current draw all the time for parasitic loads (such as CO detector and clock/sound system). The refrigerator will draw a small current for the control board and the gas ignition. The refrigerator also draws current continuously to power a heater in the door to prevent condensation in humid weather. Some refrigerators have a switch to turn off this heater. Turn it off to significantly extend your battery. The furnace fan draws a lot of current. If your interior lights are incandescent, they will draw a lot of current. Switching to LED's will save a lot of power.

Something else to consider: The length of time it takes to recharge a depleted battery not only depends on how depleted it is, but also how much charging current your charger produces. Many campers have WFCO converters as OEM equipment. Many of these don't seem to work as they should. They have a tendency to work only in the absorption mode (rather than automatically switching to boost mode). If your converter is not working correctly you can replace it or use an inexpensive stand-alone battery charger that outputs 10 Amps. If your converter is stuck in absorption mode it can literally take days to recharge a depleted battery where as a 10 amp charger will recharge it in a matter of hours.

[Old-Biscuit]

RV furnace....biggest DC hog

Basic rule of thumb
1 battery.....1 night

[rrupert]

You can save a good amount of battery run time by converting your 12 volt interior lighting from incandescent bulbs to LED. You may not save all that much by going to a smaller battery if it is a little used size. Do some pricing first.

[old_guy]

a lot depends on the type of battery you have on the TT. and of course how many amps you are drawing from the battery. a lot of us either use two six volts or two twelve volt batteries connected properly together or if you are using a regular car starting battery or a deep cycle battery. generally one night is about all you will get out of one 12 volt battery.