# 12 volt battery wireing for lights??



## outsidergr8

I know i can use a car battery and head light,direct connection but is this safe? Would like to have for camp site or on hand for any time i need light and have no power. Not sure how to wire it?.And would the battery last longer useing say tail light bulbs??? CAN any one help.


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## bunkerbob

outsidergr8 said:


> I know i can use a car battery and head light,direct connection but is this safe? Would like to have for camp site or on hand for any time i need light and have no power. Not sure how to wire it?.And would the battery last longer useing say tail light bulbs??? CAN any one help.


 Pretty safe to hook up a small 12v dc lamp to the battery, can't really damage the lamp by reverse polarity, ie. wires hooked up on wrong side of battery. You can find 12v dc shop lamps at most auto stores, these have large clips or clamps on the ends to hook up to a auto battery. Watch out for tail lights they tend to be very hot when operating, will burn you skin.


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## horseman09

Depending on your application, you might want to consider LEDs. More expensive, but a far lower power demand. Your battery will last longer.


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## ZoomZoom

Welcome to the forum.

The advise given so far is sound. You can't mess up much with 12V in terms of wiring and LED's are much more efficient.

I do wonder your intent though. If you're talking about a campsite, no power... are you thinking of wiring in your car battery instead of having a flashlight or lamp at the ready? That doesn't make sense to me. OK, you use up your car battery on headlights to light up your camp. How are you going to get home when your car battery is dead?


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## mosquitomountainman

led's must be hooked up with correct polarity or they'll burn out instantly.


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## Tirediron

Good advice so far, a couple of things to consider, car / truck batteries are designed for a deep hard load , then an imediate recharge, rv / deepcycle batteries can handle a longer discharge etc, I would also recommend that you put an Ato type plug in fuse/ holder in the curcuit leds are getting cheaper and are tougher and last well, add to these components a solar panel and your lit


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## NaeKid

If I might make a suggestion as well. Purchase a battery-box from an RV store and modify it with wing-nut battery connectors and a couple of 12-volt power-ports, and, while you are at it, throw on some solar-power connections as well to charge up the battery.

Place a gel-cell battery into that box. Optima makes a great model, Sears has one and so on. Look for the words spiral-core-technology and make sure that the battery can be layed down on its side without leaking.

Now, when you are putting it all together, make sure that you use nothing less than 10g multi-strand wire and fuse every single connection.

You can see web-found pictures below of what I used to do it (I can take a picture of my box in "action" when I get home).

An alternate to that would be to purchase a ready-made battery-box with the connections on it from places like BassProShops - I saw one there about two years after I made my own ... you can find it as item# 38-510-442-00


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## ZoomZoom

I run a battery box as well.

In my setup, there's a deep-cycle marine battery in the box.
On top of the box is an inverter. In the one pictured below, it's a 1200w.
I use a luggage strap to hold it together.
In the one pictured, I have a couple shop lights with CFL's installed. I just flick the power switch on the inverter and I have lights.


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## nj_m715

I have a couple articles about adding an extra battery to a vehicle so you can run down the spare battery but still start your vehicle. I also have info about small solar chargers and home made 12 volt generators. I have used an inverter with jumper cables to run my lights and tv during extended power failures. I can also run my fridge or sump pump, but I need to switch between the high load items, because my inverter was only a mid sized unit. 

As stated already leds are the way to go. they use a fraction of the power that a standard bulb uses. If funds are tight you can get a standard looking 12v light bulb that fits normal sockets. Of course the sockets must be wired to a 12v source.


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## outsidergr8

Hello every one,and thanx for the info. My camp site is a walk in abt 1/4 mile so i would be walkin anyway (dead battery) and i dont have a problem with luggin it in or out. I want this for extra light when i need or want it. The plan is to have it set up as a over head light not to be used all the time. When i have the extra $$ a deep cycle battery i will have.and LEDs sounds like the way to go. For now i think the car battery and 12 volt bulbs will work. In the future i would like a solar system just for this purpouse. again thanx to you all and im always open for advice or ideas


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## HozayBuck

*MY Turn to ask!!!*

I have 4 deep cycle battery's on my TT, would a solar charger for an elect fence work to keep them charged? be a hell of a lot cheaper then what I was quoted for the roof top unit...

Also it's my understanding that while I'm driving my truck is charging the RV batter's ..yes?...I'm actually almost sure it does..

Some of the lights in the trailer are like tail light bulbs and yes they get really hot... will the LED's fit in the same socket as the tail light type bulbs..

My biggest worry with LED's is that I read a lot at night and they seem to put out a dimmer bluish light???.. and I don't need to mess with my eyes at all..


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## Tirediron

If things are wired correctly your truck should add some charge to the batteries, but due to the distance from the alternator they never reach full charge, 
the electric fence charger will also add some power , but probbably not enough to make up for the usage, compare the output wattage. a watt is 1 volt flowing at 1 amp so it takes 120 watts to run a 10 amp load at 12 volts.
There are some led replacement bulbs for socket type tail lamps , but you have to make sure that they are oriented correctly


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## labotomi

Tirediron said:


> If things are wired correctly your truck should add some charge to the batteries, but due to the distance from the alternator they never reach full charge,


They will reach full charge fine, just ever so slightly slower.


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## NaeKid

Hozay - you probably have heard the saying "There is no replacement for displacement". It was said when comparing a tiny little sewing-machine motor (1 litre 4-banger) against a Chevy 454 big-block put into a 1-ton truck, or, maybe a monster diesel in a Dodge ... :dunno:

Anyway, you get what you pay for in solar-panels. I have an 80-watt panel on my trailer to charge up my dual 6-volt batteries. If the weather is not great (cloudy) and the sun isn't catching the panels properly (trees, mountains), then I find that the panel does not recharge the batteries fully/completely if I am using the trailer hard during the day.

Another way to think of a panel.

Each battery is a 55 gallon drum. You take a garden hose and allow it to drip water into the drum and you might fill up the drums in a week (remember, the batteries are tied to each other, so, the drums would have to be tied to each other as well).

That "drip" would be equal to a solar-panel for an electric fence.

Now, turn the garden-hose on full-blast to fill your 4 drums. They will fill in an hour instead of in a week. That would be like an 80 watt panel recharging your batteries.

Now - overkill is the word of the day. Drop 4 panels at 120 watt each on your trailer and it would be like a fire-hydrant being turned on to fill your barrels.

If you only have an hour of good light, wouldn't you want to maximize that hour by making sure that the flow was at the maxium possible?


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## nj_m715

I have an article on my blog about upgrading the wire to the extra batteries and using an isolator to keep the lights from killing your starting battery. Also have some solar panel and solar charger info too. I can send 90 amps from my alternator to the house batteries if needed. I can also use my solar panels and house battery to charge/jump start the truck if the truck battery is dead. It's a handy little set up.


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## HozayBuck

I do have shore power at the homestead, and I ?"assume" that when I'm plugged into it that this also keeps the battery's charged fully at the same time.. these conversations really make me feel dumb even more then I am...

Lets talk about guns!!!! ...

I guess since my on going plan is to live in my TT until I can afford to pay cash for the cabin I want to build, which may be a couple of years I might want to have a panel set out for my trailer for now and then switch over to the cabin later... that makes sense...

I stayed up until 0130 watching the entire "Band of Brothers" I'm beat...but proud to say.."WE WON" !!!


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## nj_m715

HozayBuck said:


> I do have shore power at the homestead, and I ?"assume" that when I'm plugged into it that this also keeps the battery's charged fully at the same time..
> !


Yes, if your tailer has a battery charger and it still works. There's no way for us to know how your trailer is set up and if the original gear still works.

You can take a voltage reading, plug in the cord and take another reading to see if it's charging. Same as you would test an alternator on a car.


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## LincTex

mosquitomountainman said:


> led's must be hooked up with correct polarity or they'll burn out instantly.


I have not yet experienced this... typically, they just don't flow any current at all. I have yet to "zap" a LED by reversing the polarity on it.

I suppose if you are using a high voltage source (120 volts) with a small 1/4 watt resistor bringing the power down to 3 volts, you might over-bias the LED if it is a really cheap one. But even still, the current should be limited enough. I have never, ever damaged one in reverse polarity.


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## frankd4

*The 12 Volt Bible*

The best book ever on 12 volt issues is the 12 volt Bible a paper back has all you need to know about 12 volt stuff, I use this book when I started to live on my sail boat it was a life saver I highly recommend it.


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## BillS

outsidergr8 said:


> I know i can use a car battery and head light,direct connection but is this safe? Would like to have for camp site or on hand for any time i need light and have no power. Not sure how to wire it?.And would the battery last longer useing say tail light bulbs??? CAN any one help.


I'd get some Coleman d-cell powered lanterns. I saw one kind on Wal-Mart's website where you get 10 to 15 hours of lighting per d-cell battery. You can get any kind of battery really cheap if you have a Sam's Club membership.


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## YouNeedBatteries

Deep cycle batteries would work. If you're looking to power a simple lantern, you can get one for pretty cheap. If you're looking for something more luminous, a simple U1 battery should do the trick. It's a 12V 35Ah (depending on where you get it from, ranges from 30Ah to 40Ah) battery.


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## labotomi

LincTex said:


> I have not yet experienced this... typically, they just don't flow any current at all. I have yet to "zap" a LED by reversing the polarity on it.
> 
> I suppose if you are using a high voltage source (120 volts) with a small 1/4 watt resistor bringing the power down to 3 volts, you might over-bias the LED if it is a really cheap one. But even still, the current should be limited enough. I have never, ever damaged one in reverse polarity.


As seen below, they do have a point of reverse biasing that will cause breakdown and failure. there's no values on this chart as its just a representation of the majority of diodes, but one designed to handle a few watts will not stand up to much more power in the other direction before it fails (the exception being a zener diode that operates in this breakdown range to somewhat regulate voltage, but zener diodes do not emit light.


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## Tex

Since you're dealing with a 12V system in a portable environment, look in automotive and RV stores. Lean toward LED lighting and flourescent if you can't find LED.


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## TopTop

For simplicity & reliability you can't beat something like a jump box with a built in light. Easy to carry with a built in charger.

http://www.amazon.com/Jump-N-Carry-JNC300XL-Ultraportable-12-Volt-Starter/dp/B000XQ9MGE

If you are looking for more light or longer duration I would probably opt for the old Coleman gas lantern. A lot easier to carry a gallon of fuel than a heavy lead acid battery & it last a lot longer plus it can be used for heat if needed.


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## ram91648

*AC power from batteries.*

I am in the process of installing an off grid/off generator system to run a few items like a TV and a few lights. It consists of 2 deep cycle marine batteries and a 1500/2000 watt inverter. I've wired the house in a few locations with 14 gauge wire and red receptacles so I know which is which. Hence the power goes down, I flip a switch on the inverter and "VOILA" I've got the TV, satellite dish and some lights. When I'm on grid or generator the batteries are on constant maintenance charge. Simple and reasonably priced.


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