small 12v setup. advice? am I crazy?

stinko · Apr 19, 2013

So I've been thinking lately about rechargeable batteries.  I don't need a whole big deep cycle setup.  The entire back of my van is a bed (for two) so all I need to power is some little things.  I mainly want to power a small fan, just enough to create a cross-breeze, and a few led's.   I've ended up buying one of <a href="http://www.batteriesplus.com/produc...ed-Lead-Acid-Batteries/102645-Werker/12V.aspx" rel="nofollow" target="_blank">these</a>.  My plan is simple. I intend to solder salvaged male and female 12v car plugs to the terminals, as well as a 4 way barrel plug from a universal wall-wart.   Basically this will allow me to charge it from the car's port as well as well from our <a href="http://nextadventure.net/goal-zero-nomad-7-solar-panel.html" rel="nofollow" target="_blank">goal zero nomad 7</a>.  Additionally, it should allow me to use 12v devices for designed for both car and home use. Am I way off?  Should I return it?  Do I have the wrong battery?  Is the wiring more complicated?  Any advice/tips?  Anybody do anything similar?

James AKA Lynx · Apr 19, 2013

No, not way off. Be careful on using the car battery and using it to much. You may find yourself with a dead battery. I suggest that you get a battery charger of some kind, solar or hand crank. A fan is nice but nothing beats cutting on the engine and running the A/C. battery for car of fan? the fan battery can be an Remote Control Aircraft battery. Wiring is not a problem. Careful buying the home 12v appliances. Amp draw is way to much. James AKA Lynx

stinko · Apr 19, 2013

I would only charge it from the van while driving.  Otherwise I would want to use the goal zero solar kit we have.  (this one: <a href="http://nextadventure.net/goal-zero-nomad-7-solar-panel.html" rel="nofollow" target="_blank">http://nextadventure.net/goal-zero-nomad-7-solar-panel.html</a>)  BTW this is the battery: <a href="http://www.batteriesplus.com/produc...ed-Lead-Acid-Batteries/102645-Werker/12V.aspx" rel="nofollow" target="_blank">http://www.batteriesplus.com/produc...ed-Lead-Acid-Batteries/102645-Werker/12V.aspx </a> It's a 12v 2.9amp battery.  good tip on the home 12v appliances.  thanks.

maritimecamper · Apr 19, 2013

I found out the hard way, if l killed the battery on my chev venture...the computer had to be reset. Same if you disconnect the battery, l have to reset it.

wrcsixeight · Apr 20, 2013

I would use a bigger battery.  Look into a UB12120.  ~25 $ and 12 amp hours. For recharging from the alternator, run a dedicated Ciggy plug from the engine battery with 10 awg, fused close as possible to the engine battery.  Use a  dedicated dual male ciggy plug to recharge while driving from this dedicated circuit, but make sure to disconnect when stopped. The 10 awg charging wire should really be fused at both ends.  Ciggy plugs usually have fuses in them.  A depleted AGM battery might blow the fuses when first hooked up, so have a method to see if charging voltages are making it into the smaller distant battery, and fuses are expensive so perhaps a circuit breaker would be better. If fuses keep blowing when hooking up a depleted battery, hook it up to the engine battery  for a short while before starting, 10 to 15 minutes should be enough and not drain the engine battery much.  It will accept much less amps from a 12.6 volt source compared to a 14.~4 when the engine is running and the risk of blowing a fuse on the dedicated circuit, much less.

stinko · Apr 21, 2013

what is the amp hours thing about?  12 is better than 2.9?  Why do I need to wire it to the battery?  Why can't I use the built in lighter to charge from?   thanks for the help.

Les H · Apr 21, 2013

Amp hours is the capacity of the battery to do work. A 2.9 Ah battery will power a .5 amp O2 COOL fan for about 6 hrs if you ran the battery all the way down to nothing. A 12 Ah battery will run the same fan for 24 hours. See? BUT, since completly depleting the battery will damage it, its reccomended to only use half of.the available amp hours. So on your battery, the fan will run for an hour and a half before you have to recharge it. Or 12 hrs on the 12 Ah battery. Honestly, it would be hard to beat a group 29 deep cycle from walmart that is rated for 120 Ah for around $90, which would run the same fan for 120 hours before it needed a charge. Plus, it will have the ability to run lights, a laptop or tablet, a fan and more, all at the same time. Charging can be as simple as the dedicated wire as described above with a manual cut off switch to begin with.

stinko · Apr 22, 2013

thank you.  I will be returning the battery I bought.  I'm not sure if I want one with more amps, or would it possibly make more sense to just get a battery operated fan and 4 rechargeable AAs with car charger.  This is assuming all I want to power is a fan.   Trust me, I've thought about the deep cycle batteries a lot, but it's simply too much money for our extremely tight budget.

Zil · Apr 23, 2013

If only a fan, then rechargeable aa or d cells the answer. Can you get a charger to plug into the 12 volt Cig plug?

Oneleggedcowboy · Jul 14, 2015

This is a old thread but on my first trip out west I had no solar system. I had a battery fan and a electric lantern. Never got hot enough to need the fan. Charged my cell phone and tablet from a car truck battery. For the electric lantern I bought 6 solar driveway marker style lights for a dollarge each at Dollar General. They used AA batteries so I put them in the sun every day outside stuck in the ground or if teaveling in a oatmeal container in front of a window in.my slide in truck camper. They charged great and I used 4 of them in the lantern and two in a flashlite. You get the batteries with the solar lights! It was a great deal and worked flawlesly! They are hard to find now because they are making them with little watch disc style batteries now but look around and you can find them. Hope this helps some newbys.