Is A 12 Volt Battery Good Enough?

[den18]

Hey all,<br /><br />As some of you recently saw I just purchased a Class B in good shape. It's electricity is taken from a 12 Volt house battery. There are a few 12 volt outlets around the RV. As I would rather not redo everything my question is would a 12 Volt be enough to run off of?<br /><br />I would mainly be using it to run my Laptop, charge my phone, run a convection oven (If viable) and possibly to run some computer speakers (unless I could hook into the car speakers somehow). <br /><br />Eventually I would like to set up some kind of entertainment system (TV/Projector) with a gaming system but that is very low priority and something I am&nbsp;not&nbsp;worrying about now.<br /><br />Would a 12 Volt be enough for this type of use? How often would I need to recharge it? I am not&nbsp;familiar&nbsp;with electricity usage as before now I never had to measure it.&nbsp;<br /><br />Any and all thoughts appreciated!<br /><br /><br /><br />

 

[peacetara]

Well, the "strength" of batteries it turns out has nothing to do with Volts, but with 'Amps'.&nbsp; or more specifically amps over time, usually called 'amp hours' or ah for short.&nbsp; Voltage is kinda like the kind of battery, and amp hours is like the strength. If you were to change out the 12v battery for a 24v battery, you would either have to change everything that plugs into the battery (i.e. new TV, new everything) or install a bunch of stuff to make it go back to 12v. I'm sure there is some sane reason for doing such a thing, but I couldn't imagine wanting to do such a thing here.<br /><br />I'm sure your battery can run everything, the question is for how long can it run it all before the battery falls over from exhaustion.&nbsp; Of course if you give it support, from a Gas generator, wind generator or solar panels, than you can go a LOT farther before it gets all exhausted because you are giving it food <img src="/images/boards/smilies/smile.gif" border="0" align="absmiddle">.<br /><br />So if you think of your battery like a person.&nbsp; They come in different shapes and sizes, but they can only go so long before they need some food, and the less food you give them, the weaker they get.&nbsp; The best way to keep batteries strong and healthy (is to give them the exact amount of food they want when they get the least bit hungry, and to always keep it there and ready for them if they ever do get hungry!). This is what the 'smart' Battery Chargers do.&nbsp; They talk with the battery, and decide how much food it needs, and then gives it all the food it wants, and then gives it an IV and says, see here, take as much as you want if you are feeling a little peckish <img src="/images/boards/smilies/smile.gif" border="0" align="absmiddle"><br /><br />Anyways, this is my understanding of how batteries work using an analogy that makes sense to me, hopefully it makes sense to you as well!<br /><br />So the question becomes, how far can your little battery run for?&nbsp; That all depends on how much you are asking it to do, which means you have to figure out what you are going to make the battery do, and for how long you are going to make the battery work.<br /><br />so if you really want to know....&nbsp; I'd suggest a little spreadsheet and look at the back or bottom of all the things that use electricity, the Govt requires they all tell you how much energy they take on a little label.&nbsp; Usually they give you Wattage and Voltage, but sometimes they give you Amperage and Wattage, etc.&nbsp; There are 3 possible things it can say: Wattage, Voltage and Amperage.&nbsp; With any 2 of these things, you can figure out the third (with that magic math we mentioned before).&nbsp; <a href="http://www.supercircuits.com/resources/tools/Volts-Watts-Amps-Converter">This handy website </a>will take any 2 of the 3 things above and give you the third thing with no actual math involved by us, which is a win for math idiots like me.&nbsp; Add a column for how long you want to run each device(in hours), and then take the amps column and times it by the hours column.&nbsp; This will give you that same Amp Hours number as the battery will give you.&nbsp; You can then compare them and see if it's enough.&nbsp; If you know it won't be enough, then you need to either get more batteries or find a way to give the batteries food before they get too weak.<br /><br />Of course, if your adventurous,&nbsp; you can just run it all like you want till it stops working, and then you will know exactly how long it will work given your habits, devices, etc.<br /><br />When it stops working, make sure you feed that battery for a good long time, to get it all healthy and fed again.&nbsp; It's bad (just like for people) to run them down to weak to do anything all the time, but I imagine once as a test wouldn't hurt anything.<br /><br />Also, I am by no means an expert in electrical stuff, this is my understanding of all those complicated things the experts talk about. Hopefully the experts around here can fix any mistakes and make us all smarter in the process <img src="/images/boards/smilies/smile.gif" border="0" align="absmiddle"><br /><br />With Love,<br />Tara

 

[wrcsixeight]

Your Van most likely has a converter. This converter takes 120 volt ac grid power when available and puts out battery charging voltages, So you can run all your 12 volt items, and still charge the battery or maintain the battery at full charge. &nbsp;When you do not have grid power, then the house battery powers all your 12 volt items hooked to it.<br /><br />Some Converters will work without a battery to charge. &nbsp;Many will not.<br /><br />Most everybody overestimates the capacity of a battery. &nbsp;Just remove your convection oven from your head right now. &nbsp;No way are you powering that without towing a trailerload of batteries.<br /><br />Most people also overestimate the amount of charge returned into the batteries by the alternator when running the vehicle.<br /><br />If your house battery was fully depleted( something you should avoid doing) &nbsp;If you were to drive for 8 hours straight, on the highway during the day, the battery would only be in the 90% range. &nbsp;That last 10% can take another 4 hours. &nbsp;It is just the nature of battery charging.<br /><br />Many first approach the &nbsp;electrical system in RV's as if the battery is nearly unlimited, when in fact it is severely limited when on battery power. &nbsp;They then deplete the battery too far, too often, and do not sufficiently recharge them. &nbsp;The result is a battery with a very short lifespan, and total failure is&nbsp;guaranteed&nbsp;to happen when most inconvenient.<br /><br />An inverter takes 12 volt battery power and converts it so you can run the 120 volt items you already have. &nbsp;<br /><br />Most chargers for laptops and phones actually run on DC electricity already. &nbsp;Getting DC to DC converters is a much much better way to charge and power these devices. &nbsp;No sense in trying to invert then convert the electricity twice.<br /><br />Get the charger with a ciggy plug for your phone. &nbsp;If it has a USB type cord for charging and data transfer &nbsp;then just recharge your phone from your laptop.<br /><br />For your Laptop, go into amazon, plug in the laptop brand and model number then add the words 'car converter'<br /><br />There should be a product showing a picture with a ciggy plug. &nbsp;This DC to DC converter wilol change the 12.x DC volts from your battery to your laptops ~19.5 DC volts much much more efficiently than if you were to use the inverter to power the original power supply. &nbsp;Mine is 20 to 50% more efficient depending on the task.<br /><br />Also Computer speakers. &nbsp;My Stereo has a MP3 input jack on the front of it. &nbsp;I can plug my mp3/tv/ or computer into it and play the sound through my speakers, but this adds another &nbsp;significant drain to the batteries, and I rarely listen to the TV or Laptop through the stereo unless I'm plugged in. &nbsp;I have plenty of battery power, and Solar, but am simply saving my expensive Deep Cycle batteries for when the diarrhea hits the turbine.<br /><br />One of my all time favorite products is this:<br /><a href="http://www.amazon.com/iHome-iHM60-3-5mm-Portable-Speaker/dp/B002ZAVVHY">http://www.amazon.com/iHome-iHM60-3-5mm-Portable-Speaker/dp/B002ZAVVHY</a>&nbsp;<br /><br />The quality of sound from this tiny thing is absolutely astounding for it's size. I cannot stress this enough. &nbsp;It sounds incredible. &nbsp;You are not going to light up the campsite, but it is more than adequate for inside the Van.<br /><br /> It has it's own Li-ion battery which charges through a USB port. &nbsp;I've gotten over 16 hours at full volume on a single charge, and have been using them regularly for over 18 months now.<br /><br />Do note that most 12 volt " marine/ RV" batteries are not really deep cycle batteries, but are dual purpose batteries, which are starting batteries that are slightly more tolerant of deeper discharges than Starting batteries.<br /><br />If your house battery is unvented, and located inside your living space, Get an AGM battery, and the biggest one, or pair which will fit in the designated area.<br /><br />Sears Diehard Platinums are Rebadged Odysseys and are among the best &nbsp;easily available batteries. &nbsp;Acquiring true deep cycle 12 volt &nbsp;flooded batteries is more challenging and they cost about 30% more.<br /><br />If you are going to be a battery abuser, then get the cheaper ones with a warranty and you get to replace them yearly.<br /><br />If you want plan to treat your batteries with a little respect and not discharge them too deep, and promptly and fully recharge them at least weekly, a true deep cycle battery will perform better for longer.<br /><br />Crown &nbsp;Trojan, and Deka all make &nbsp;quality true deep cycle 12 volt batteries. &nbsp;A few other brands do as well, but most with a deep cycle label are just dual purpose batteries which will give poor service after a few months of hard use.<br /><br />&nbsp;<br /><br /><br />

 

[akrvbob]

Because installing power in your van is such a mystery to so many people, I wrote an article intended to help them get a very basic understanding of 12 volt power. Rather than retyping it all here I suggest you read it first. You can find it here:<br />http://cheapgreenrvliving.com/How_To_Have_Electricity_2.html<br /><br />I also suggest you read this article to get ideas on how to conserve your power:<br />http://cheapgreenrvliving.com/365_January.html<br /><br />Read that and hopefully you will start to get a basic understanding. Then ask specific questions to help clarify what you are learning. Bob<br />

 

[den18]

Thanks everyone!<br /><br />Looks like a lot of good information. Much Appreciated.