Battery charging with your TV

[TroutBum]

How effective is trying to charge a battery with your TV?  How long should it take at idle to put on a decent charge?

Gas is expensive, but it is still cheaper than a generator.

[West Coast Canuck]

How effective is trying to charge a battery with your TV?  How long should it take at idle to put on a decent charge?

Gas is expensive, but it is still cheaper than a generator.

Depending on your TV, I have a 2004 Dodge Ram 1500 Quadcab with the Hemi and it wouldn't be very cheap to charge my PU battery. I bought a 2000 watt generator from a company called Boss Tools for $329.00 delivered to my door. Unfortunately they only sell it in Canada and don't ship to the U.S. but they import it from Buffalo Tools and it is a chinese knock off but it works very well and it has a 4 stroke motor. It has a decibal rating of 62 which is a little noisier than the Hond EU2000 which sells for $1500.00 in Canada...the EU2000 runs at about 59 decibals. It comes with a 12 volt charge cord for charging batteries. I use it to charge the battery when I am boondocking.

[wavery]

How effective is trying to charge a battery with your TV?  How long should it take at idle to put on a decent charge?

Gas is expensive, but it is still cheaper than a generator.

The alternator on your tow vehicle doesn't start putting out until it reaches about 1000RPM (Far above idle). Then it only puts out less than 10amps unless you have an extremely low battery.

Amp ratings on vehicle alternators are very deceiving. An alternator that is rated at 100amps will put out that much for about 10 seconds then rapidly decrease (or burn-up). The car's starter draws a tremendous amount of amperage (250A-500A) but only for a few seconds. The voltage regulator will sense the high draw and kick the alternator on high for a very few seconds to recover what the battery used to start the car.

It actually takes about 30 minutes of driving to recover from starting so using your vehicles engine, even at 1000RPM will be redundant for that period of time. After that, you would need to leave you TV engine running at 1000RPM for about 5 hours to charge 50 Amps. That's not something that I would ever consider doing. Generators are a lot cheaper than engine replacements.

[AustinBoston]

It actually takes about 30 minutes of driving to recover from starting so using your vehicles engine...

Someone's been feeding you a line...

Plenty of people never drive their car more than 10-15 minutes at a time, and their battery lasts five years or more.

Today's engines often require 1000W or more just to run (about 80 amps).  Add headlights (15-20 amps) rear windshield defroster (15 amps) and other accessories (heater fan, sound system, etc.) and you're in the 120 amp range.

Of course, there may only be 10 amps left to charge the tow vehicle battery, and even less to charge the camper battery.

Engine electrical requirements have risen so much that GM is considering switching from a 12V vehicle electrical system to a 42V vehicle electrical system.

Austin

[chasd60]

Engine electrical requirements have risen so much that GM is considering switching from a 12V vehicle electrical system to a 42V vehicle electrical system.
 
  Austin

The entire automotive industry is thinking about it. They want to be able to reduce amperage by increasing voltage and this will allow for a lighter vehicle with much less wire weight.
 
 The company I work for already makes some 42V semiconductor components. The figure of 42V is actually a 36V system with a peak of 42V much like a 12V system routinely achieves 14V


Back to the topic at hand; I have a current monitor in my camper and I have seen it up as far as 20A from the vehicle charge cable. The current does drop off rapidly but it is dependent upon the state of charge. Your charging system is seeing two 12V battereis in parallel instead of just a low camper battery. The voltage regulation system will react to them accordingly. If you put a battery disconnect on the negative cable of your starting battery and switch it off AFTER you have started the vehicle, I'd bet the current would stay high for a longer duration and give you a much quicker charge because the charging system would only see the camper battery.

[aw738]

I would have to side with wavery on this one. Alternators are not battery chargers.  Popular Mechanics has already tackled this issue. I would in no way try this with a GM vehicle. In PM's article they found that at idle the vehicle actually creates more draw on the system than the alternator produces. They basicly stated that if you were to let the vehicle idle "long" enough it would drain the battery. They didn't say how long it would take but it is possible. Also the power used to maintain the computer memory and for the radio could drain the battery if not driven regularly. They confirmed this from GM and GM stated that this condition was within there specifications and they had no plans to change it. This from the people who couldn't get the first Corvettes to start after they grounded the electical system to the body. Corvette Trivia

[wavery]

AB

The question here was about charging the battery from an idling tow vehicle. I would assume that one would not have turned on every accessory in the vehicle at that point, just to charge the batteries. Even then, the alternator would adjust the charge to the vehicles demand and that would not facilitate extra charging capacity.

Do your homework before you question someone's knowledge about automobiles. The line that I was fed was from spending 3 years At GMI (General Motors Institute) then 15 years in the field as a service Manger at a GM Dealership.

If your car pulls 100amps with everything in it running at full tilt, I'll buy you lunch. Unless, of course, you have some big honkin' (annoying) stereo system or something that draws 50-100amps. If that's the case, I hope that you aren't using your vehicles stock alternator.
--------------------------
The battery disconnect would work, in theory because the voltage regulator would pick up the lower voltage of the camper battery. I wouldn't suggest putting a battery cut-out on a late model vehicle though. On some models, if you disconnect the battery (all together), you can have problems with your on-board computer system. Even then, you would only have a surge of amps that would quickly diminish. No matter what you do, you would surely have to run your engine at a fast idle for 5 hours to get 50 amps in the battery. There's just no getting around it. Besides, if you tried to put more than 10 amps in the battery over a period of 5 hours, the battery would over-heat. Even my 25amp "Smart" battery charger will only put out 25 amps for about 1 hour on 2 discharged batteries, then it drops down to 8 amps and stays there for for about 20 hours, then drops to 2 amps.

[AustinBoston]

AB

Do your homework before you question someone's knowledge about automobiles. The line that I was fed was from spending 3 years At GMI (General Motors Institute) then 15 years in the field as a service Manger at a GM Dealership.

I have only once (yes, just one time) driven my current car (a 1999 Oldsmobile Intrigue) more than 20 minutes.  About 1/3 of the trips are less than 5 minutes.  I have owned it for 2-1/2 years.  It has been through two winters where the headlights are always on, the heater is always on, the defroster is always on.  I drive it nearly every day.  It starts without problems in temperatures below zero.

My experience is no different from thousands of other drivers in my city, and millions of other drivers in the area.

Your statement that:

It actually takes about 30 minutes of driving to recover from starting...

is rubbish.

I don't need to do any more research than that.

Austin

[wavery]

I have only once (yes, just one time) driven my current car (a 1999 Oldsmobile Intrigue) more than 20 minutes.  About 1/3 of the trips are less than 5 minutes.  I have owned it for 2-1/2 years.  It has been through two winters where the headlights are always on, the heater is always on, the defroster is always on.  I drive it nearly every day.  It starts without problems in temperatures below zero.

My experience is no different from thousands of other drivers in my city, and millions of other drivers in the area.

Your statement that:



is rubbish.

I don't need to do any more research than that.

Austin

AB

Chill out my friend. You're arguing about apples and the discussion is about oranges :confused: . That comment was in reference to charging a camper's battery from a tow vehicle and in no way was I discussing normal every day driving (totally off topic IMO). I wasn't trying to be technical as to recovery time of a starting battery. The discussion was about the logic in using a tow vehicle for charging as apposed to using a generator. of course, every vehicle will vary as to recovery time and most will recover in less than 30 minutes but it has little relevance to the poster's question.  

My intent was to be helpful  to the question posed. If you are just reading posts to find things to argue about, that's not being helpful  IMHO.
----------------------back to topic---------------------

Most people think of the longevity of their car's engine in the form of miles driven. In actuality, wear & tear is caused by actual engine run time (with a few other considerations like stress & temp thrown in).

A good quality generator, with proper maintenance, should last 2,000 hours without a major overhaul and 4,000 total. I think that a similar equation could be used for an automobile engine (4,000hrs x 50mph (average) = 200,000 miles). Even if you double the hours for the auto engine, the cost of running, maintaining and replacement is easily 10 times that of a good quality generator.

That is why most RV's and yachts are equipped with on-board generators. It has little to do with supplying power for your 110v appliances. With inverter technology, you can run 110v appliances from your TV, RV, or yacht just as easily as you can from a generator. It's all about saving wear & tear on the main engine. In fact, you can easily buy 3 generators just for the cost of changing your vehicles oil over that 200,000 miles ($40 oil change x 66 changes = $2640. Figuring oil change at 3,000 miles). Generator is $1.50 oil change every 100hrs x 40 oil changes = $60.

The bottom line is, the generator is a much better economical choice for battery charging then the TV, over the long-haul.

Having said all that, if you only camp once or twice a year and replace your TV every 3 years, it is a mute point. Few of us live in their camper  (like I lived on my yacht for 14 years). The difficulty that you may encounter is getting your engine to run at 1,000RPM for 5 hours. In some cases, you may be risking a major melt down. All it would take is the failure of an electrical component to stop your engines cooling fan (assuming that you have electric fans). This could cause catastrophic damage to you TVs engine. Your TVs cooling system is designed to function with the car moving (thus creating air flow through the radiator).  Hardly worth th risk IMHO.

[AustinBoston]

AB

Chill out my friend. You're arguing about apples and the discussion is about oranges :confused: .  That comment was in reference to charging a camper's battery from a tow vehicle and in no way was I discussing normal every day driving (totally off topic IMO).

OK.  My appologies.

I wasn't trying to be technical as to recovery time of a starting battery. The discussion was about the logic in using a tow vehicle for charging as apposed to using a generator.

And I will appologize for not making it clear that I always did agree with you about that.  Even while towing at highway speeds, a typical user will not see much charge go on their camper battery unless they tow all day.  At idle (the OP's question), it might never happen.

of course, every vehicle will vary as to recovery time and most will recover in less than 30 minutes but it has little relevance to the poster's question.  

My intent was to be helpful  to the question posed. If you are just reading posts to find things to argue about, that's not being helpful  IMHO.

I agree.  I misunderstood and went overboard.

Austin

[wavery]

OK.  My appologies.



And I will appologize for not making it clear that I always did agree with you about that.  Even while towing at highway speeds, a typical user will not see much charge go on their camper battery unless they tow all day.  At idle (the OP's question), it might never happen.

 

I agree.  I misunderstood and went overboard.

Austin

Thanks AB , misunderstandings are quite common in this form of media :eyecrazy: . Not good when people get into arguments over them. Best to stay friendly, I think .

Healthy discussion on some issues are good and a lot of people gain from them. I think that the question posed (about charging with TV) was a very good question and worthy of some discussion. I'll bet a lot of the readers here have thought the same thing and were just shy about asking.

The other thing that was not addressed was the possible health risk from the air pollution from the large tow vehicle engine, apposed to the much smaller generator.

We were camping about 3 months ago and the RV next to us was left running for nearly 2 hours and there was no breeze. I had to go ask the guy to turn it off because we were getting gassed out. Very unpleasant camping experience.

[AustinBoston]

The other thing that was not addressed was the possible health risk from the air pollution from the large tow vehicle engine, apposed to the much smaller generator.

Yes, not to mention that unless you have a custom electrical extension, the tow vehicle has to be backed up close to the pop-up.  Wonder where those fumes are going?

Austin

[SpeakEasy]

Bleah to gasoline-powered electrical generation of all types!

[wavery]

Bleah to gasoline-powered electrical generation of all types!

Boy, I couldn't agree more. I had solar panels and a wind generaor on my yacht.

I also had a 9HP Yamaha diesel (axillary) engine on my yacht. I'll stop short of calling it a "Generator" because it wasn't. I had a 150amp alternator, fridge compressor and water maker attached to it. My 110v power came from a 2500w inverter and 2 8D deep cycle batteries (250amp hours each).

I had to run that engine for an hour a day to cool down the "Cold plate" fridge. That also facilitated keeping the batteries full.

We plan to build a house in 2010. I am going to do the entire roof with a solar array. Our property is in Falbrook, CA. It gets a fair amount of wind but not consistant enough to justify a wind generator but it gets a lot of sun.

[SpeakEasy]

I dream of a day when all of us can have solar collectors on our roofs and efficient batteries in our homes in order to provide all the electricity we need for day-to-day operations. I'm no engineer, but I have to believe that day is not too far off. What do you geeks think?