Using TV to charge battery

[VT_Skier]

I am sure this has been asked before I just couldn't find it..... Anyways we will be doing a lot of dry camping this summer but no more than three nights at a time, I have replaced all lights with LEDs and have some battery operated ones to use for lights as well. Our history has been tent camping so having tons of light at night is not an issue in fact I will miss tripping over one of the dogs at 1am.... Early season we have our first four times out going to. Coe where we will have electricity ( early May).

So the question is if I plug the tv back in and let it run for say half hr will that help recharge batteries? Also someone mentioned that you should put the slide out before you unhook to save any and all power.

Thanks again Oh and can someone have a talk with Mother Nature this 4 ft of snow here is really a problem??

[wintersun]

Have a Trimetric or similar digital charge monitor installed so you have an accurate picture of the state of your batteries at the start and what they are in the morning and how long it takes to recharge them and to what degree they get recharged when driving. Otherwise you are in the dark as the displays provided by most RV manufacturers are virtually worthless.

Once you know how much you are using you can make an informed decision as to whether to add more charging or more storage capacity. Usually it is cheaper for trips of 4 days or less to add another battery than to invest in a generator or solar charging setup.

[Golden_HVAC]

Hi,

If you are plugged in, then the trailer 45 amp 'converter/charger' will keep the batteries full.

If not plugged in then the tow vehicle #12 wire through 45 feet of wire, then a connector or two, it will barely charge at 15 amps, probably more like 10 amps. 1/2 hour = between 5 and at the very most 10 amp hours of power to the battery.

Your RV will be consuming 35 amp hours a day, not including lights or anything but the refrigerator, CO and propane detectors. If you do not have a generator, or 120 volt shore power, the battery will be dead in about 48 hours.

Hooking up the truck to jumper cables, letting them sit and charge the battery for about 1/2 hour, then start the engine and let it run about 1/2 hour, then let it sit another 1/2 hour to finish charging, you might get say 35 amp hours into a very low group 27 battery. If the battery is 105 AH capacity, you probably can never exceed 35 amps per hour into the battery (without getting the battery very hot). Even with 4 golf cart batteries, and 440 amp hours of total capacity, I can only charge at about 45 amps per hour while warming the batteries, and they must be charging at around 14.4 volts to stay at 45 amps (10% of my total battery capacity).

You will be best off with a pair of golf cart batteries (total of about 220 amp hours at 12 volts), second best is a pair of group 27 batteries (about 200 amp hours total at 12 volts). The advantage of golf cart batteries is that you have much more water in the battery, it will run cooler, last longer (like 13 years in my case) and be much more tolerant to not keeping the battery full of water each month.

The worst thing for battery life is leaving them discharged a few days - longer will compound the damage to the point they will never work again. Second worst thing for your battery is dry cells. This can lead to warped plates, and shorted cell. Overheating a battery due to quickly charging it, or running low on water can also warp the plates = new battery time.

You can get really long battery life by installing a solar panel or two. Because you will be consuming 35 amp hours daily just to run the CO meter, propane detector and refrigerator, those will use all the power that one 120 watt panel can make in one day.

SunELec.com They sell panels for about $1 per rated watt.

You can install those panels with 6" long 2" angle aluminum mounts. 3 holes 3/16" for #10 screws into the roof, and 5/16" hole for the panel bolt - 1/4-20 bolt and nylo nut that will not vibrate off, and takes time to remove, something someone trying to steal one will not have!

#10 direct burial wire is UV rated, can run from the panels to the refrigerator vent, and down to the controller, then on to the battery. It is pretty simple to install.

100 watts would be the minimum I would recommend, but 200 watts is much better, and will keep up with your usage. If you want to use a inverter to run a laptop, and watch a DVD, it will only use about 20 watts, and is easy to do with a portable 100 watt - 200 watt inverter. Costco used to sell a Colman 500 watt inverter for $40.

I installed some extra cigarette lighter receptacles in my RV (Radio shack) or your local auto parts store. I used #10 wire and 20 amp fuse.

Have fun camping!

Fred.

[VT_Skier]

Thanks this is good information, again the dry camping will be in June to possibly early Sept we have 3 weekends booked late Sept mid Oct. those are with full hookups also the TT is new so is the battery and we would not be watching tv just some lights fridge etc. Again as far as purchasing a generator that's definatley out till next summer daughter number 2 is getting married this fall so that puts a freeze on any extras for the camper.

[bikendan]

VT Skier wrote:

What value is there in possibly carrying a regular batter as a back up just an FYI after paying cash for this I'm not sure if another $1,000.00 for a generator is in the cards this year.

You can get a new 2000w quieter inverter generator for under $500.

[VT_Skier]

smkettner wrote:
I think you will be just fine as is if you camp like tenting.
Hopefully you have some jump cables you can bring along as they will do far more than the 7-pin connector. Probably need closer to an hour to get some decent charge into the very low battery.

If you fine yourself parked in the sun you will wonder why you don't have about 150 watts of solar on the roof.

This is VT it's usually a bit overcast the sun only shines bright on the fifth Tues of each month??

[K3WE]

This gets asked a lot and I see a wide array of answers...

So, here's my $.02- You said summer camping with minimal electrical use- so I'm thinking that maybe 30 min on the car might be ok.

The guys who say you can't charge much from the car...that it's very slow- they are right and my answer is based on your comments that you really won't be using lots of electricity for heating or watching TV. Just lights and the water pump and the fridge is not too much electricity- especially if you aren't running the lights all that much.

But, indeed, if you really pull the batteries down and want to FULLY recharge them, it's going to take hours, not minutes from the TV plug in.

Sort of like Toedtoes said- he goes 4 days without much of a problem. Conversely, I can tell you of cold nights and lots of furnace time (yes, you said summer) where we got less than 24 hours per battery- and struggled to recharge from the car.

Indeed- your results may vary- folks use patterns vary widely and battery health is a biggie too.

[time2roll]

I think you will be just fine as is if you camp like tenting.
Hopefully you have some jump cables you can bring along as they will do far more than the 7-pin connector. Probably need closer to an hour to get some decent charge into the very low battery.

If you fine yourself parked in the sun you will wonder why you don't have about 150 watts of solar on the roof.

[jauguston]

If you can tolerate some noise Harbor Freight has a 900w generator for $99.00. I just bought one for the occasional time I want portable power for a project. It has a two cycle motor so you have to mix oil with the gas like a chain saw or two stroke outboard. It is very small and weights 38 pounds. You could plug your shore power cord into it and use the converter built into your rig to charge your batteries.

Jim

[toedtoes]

Why don't you do a weekend camping trip at home (or where there are hookups) and not hook up. See how long you can go without needing to recharge.

You may find you can do 3 days no problem. Or maybe you can just add a second 12v battery (or 2 more 6v batteries). Or you'll find you really will need to invest in a generator or solar.

[VT_Skier]

Lynnmor wrote:
So how is 4' of snow a problem to a VT skier?

You will get very little charge from the tow vehicle. Even if you run it all day, the battery may still not be fully charged.

Skiing is spectacular BUT having just purchased our first TT in November and haven't been able to use it my mind starts to wander towards spring with excitement. Also we have a season up here called Mud Season most would call it spring but with nearly 40 percent of roads being dirt well when everything melts at one time you can imagine......

What value is there in possibly carrying a regular batter as a back up just an FYI after paying cash for this I'm not sure if another $1,000.00 for a generator is in the cards this year.

[RoyB]

We do alot of camping off the power grid with our OFF-ROAD POPUP camper.


What we did was to beef up our trailer battery systems and plan it all out to have enough battery capacity to run all of the 120VAC Appliances/Items using a right sized INVERTER and all of the 12VDC appliances/items direct connected to the battery bank. We get by just fine with our 255AH 12VDC Battery bank with all the things we want do when camping.

The concept is run all the things we want to have available to use using the battery bank and not run it down more than 50% charge state over night and then re-charge the batteries back up to their 90% charge state at 8AM the next morning when allowed to run our 2KW Honda Generator set. Using smart mode charging we can accomplish this is just three hours of generator run time. Now we are good for the next nights run off the batteries. Been doing this concept since 2009 and batteries are just now showing signs of needing to be replaced.

Very seldom have to tap into the truck start system for camping. This is designed to keep the truck running and would be breaking one of my rules to never do anything to the truck battery system as this is usually the only way to get back home on haha...

Once you get all setup it all becomes second nature camping off the power grid. Never have to worry if you are going to run down your batteries and do without the things you want to have available for you to use. We do just about everything we do at Electric and Water sites except no air conditioning or high wattage microwave use. Watch HDTV and play with my Ham Radio toys everynight...

Its all in the planning and having great PLAN Bs in place.. Try it out in your CAMP BACKYARD and see how you make out with no cheating...

Roy Ken

[toedtoes]

You're only needing battery power for 3 days. How much power do you expect to use during that time?

The reason I ask is because I put in a group 31 AGM 12v house battery in my clipper. I have LED and florescent lighting in the RV which I use only as needed. I leave the water pump on all the time (it only runs when water pressure is needed - flushing toilet or running water). I may listen to music (using computer speakers plugged into the 12v) or charge the netbook and/or cell phone and/or kindle as needed. Everything else is on propane (fridge, water heater, stove/oven) - no microwave, toaster, hair dryers, etc. I use a Mr Heater Little Buddy for heat if needed.

I can go four days without putting a dent in my battery power. No charging required at all. So, depending on your usage, the right battery may be all you need. As you're used to tent camping, you might find this an easier solution than dealing with solar, generators, etc.

[enblethen]

If you are disconnected from the trailer, turn the truck around and use a set of jumper cables. You will get a much better charge rate.
You could wire up a connector on the front, like used on trolling motor with larger wire instead of jumper cables.
You will not get as good of charge through the trailer connector.

[DrewE]

Charging through the connector from the tow vehicle to the trailer is very slow. You would get perhaps a couple or few AH in a half an hour, which may not be enough to keep up with usage if you're running the furnace or water heater or some lights. You'd be far better off with some other system—a little generator and a good battery charger (or a good modern converter) or a solar setup. Granted, either of these does cost more money than the tow vehicle you already have...

You would get faster charging if you hooked up a good pair of jumper cables between the tow vehicle and the trailer battery. Still far from an ideal solution, but closer to workable than charging via the trailer connector.