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what size battery will i need to charge phones have led lights and a small stereo run all weekend?
Go to Walmart and buy the biggest Marine Battery they have, Everstart, it will be like $85-$125. I do not know the math to figure out how much each one of those items or even one of them draws off the battery and low long it will take to "kill" the battery, and I do not know different size batteries, but I do know one of the large Everstart batteries from Walmart will do, for what you need.
EDIT: there is an equation and math to tell you all that and it is on here, I am too lazy to find it.
I'm trying this one out this year, which is 58 Watts (and should last all weekend). Also is much smaller then the AC/DC car charge unit I usually bring to the festival (Which I might still bring because we are rolling out this year with 4 cars/12 people and it would help them charge their stuff too).
USB (always at 5V) and DC out plugs at different voltages (5V-19V variable). Should work well for me because my speakers are USB so this thing should run for 60 hrs or more without a recharge. Literally the size of a hard drive, will report back after it's gotten a little more work out in the field with it. They sell a DC USB connector too so you can have two USB's at once or you could just use a 4x1 USB and I'm sure it will work too.
scrog how do you charge the battery up before hand? will a small12 v battery tenderwork? ive got aneedfora battery tender anyway so might pick one of those up as well
1-1-12 Bassnectar NYE SHOW! 1-21-12 G. Love and Special Sauce 3-1-12 Radiohead 3-9-12 Experience Hendrix 5-15-12 Jack White @ The Ryman 6-7-12 Bonnaroo 6-19-12 Roger Waters presents "THE WALL" 7-7-12 Ringo Starr's 72nd Birthday Party Extravaganza at the Ryman
A battery is rated in Amp-hrs. Say if it is a 100 amp/hr battery it should last 100 hours while drawing 1 amp continuously. Not the case at all though. You never want to get a battery below 70% if you plan on using it again. When it gets to about 20% it may not power the things you want it to like the stereo. Amps = Watts / Volts. So, if you are say using a 12 volt inverter to power your electronics every 100 Watts of power will cost you Amps = 100 / 12 = 8.33 Amps. If you drew exactly 100 watts at 8.33 Amps for the whole life of your battery say 100 amp/hr / 8.33 amps = 12 hours of use from the battery. I would be careful with a stereo though, their wattage can vary widely depending on how loud you have them. They can draw well over 1,000 watts when you have it cranked and that would be 1000 / 12 = 83.33 which is less than an hour and a half. You need to add up the wattage of everything you want to use and see from there how big of a battery you may need. In theory you can also charge your battery while you are there. If you hook your car battery up in parallel with your other battery. You can hook them up + to + and - to - then hook a positive cable to your inverter and the negative cable from the other battery into the inverter. Your car will then share it's amp hours with your marine battery. And your car battery is hooked up to an alternator to charge both of them. Don't have anything on when you do it though. Sorry for the essay. This should get you in the right direction though.
A battery is rated in Amp-hrs. Say if it is a 100 amp/hr battery it should last 100 hours while drawing 1 amp continuously. Not the case at all though. You never want to get a battery below 70% if you plan on using it again. When it gets to about 20% it may not power the things you want it to like the stereo. Amps = Watts / Volts. So, if you are say using a 12 volt inverter to power your electronics every 100 Watts of power will cost you Amps = 100 / 12 = 8.33 Amps. If you drew exactly 100 watts at 8.33 Amps for the whole life of your battery say 100 amp/hr / 8.33 amps = 12 hours of use from the battery. I would be careful with a stereo though, their wattage can vary widely depending on how loud you have them. They can draw well over 1,000 watts when you have it cranked and that would be 1000 / 12 = 83.33 which is less than an hour and a half. You need to add up the wattage of everything you want to use and see from there how big of a battery you may need. In theory you can also charge your battery while you are there. If you hook your car battery up in parallel with your other battery. You can hook them up + to + and - to - then hook a positive cable to your inverter and the negative cable from the other battery into the inverter. Your car will then share it's amp hours with your marine battery. And your car battery is hooked up to an alternator to charge both of them. Don't have anything on when you do it though. Sorry for the essay. This should get you in the right direction though.
What you forgot to mention is that in order for the alternator to do its job and properly alternate the current and keep a fresh charge, the car must be running. Otherwise all you've done is created a close circuit with two power sources, meaning you'll be draining both batteries while doing this. Just get a power inverter and hook it up to a deep cycle battery. I'm not sure how the ranking system goes but deep cycle batteries are intended for boats and RVs, things that use a lot more electricity than a car to run the accessories and start the engines. These should have enough power to run all weekend and bring it back home and charge it up for the next time you need it.
Just get a power inverter and hook it up to a deep cycle battery.
This.
but I will admit, I'm a tree hugging hippie who doesn't want folks to be playing with deep cycle batteries, have it overheat and something not so festive happen. Unlikely but I like things that recharge easy
[/quote] What you forgot to mention is that in order for the alternator to do its job and properly alternate the current and keep a fresh charge, the car must be running. Otherwise all you've done is created a close circuit with two power sources, meaning you'll be draining both batteries while doing this. Just get a power inverter and hook it up to a deep cycle battery. I'm not sure how the ranking system goes but deep cycle batteries are intended for boats and RVs, things that use a lot more electricity than a car to run the accessories and start the engines. These should have enough power to run all weekend and bring it back home and charge it up for the next time you need it. [/quote]
Thought it was common knowledge that your car must be running to charge the battery. You wouldn't be able to do it for to long but you can run it maybe half a day like that without charging it.
What you forgot to mention is that in order for the alternator to do its job and properly alternate the current and keep a fresh charge, the car must be running. Otherwise all you've done is created a close circuit with two power sources, meaning you'll be draining both batteries while doing this. Just get a power inverter and hook it up to a deep cycle battery. I'm not sure how the ranking system goes but deep cycle batteries are intended for boats and RVs, things that use a lot more electricity than a car to run the accessories and start the engines. These should have enough power to run all weekend and bring it back home and charge it up for the next time you need it. [/quote]
Thought it was common knowledge that your car must be running to charge the battery. You wouldn't be able to do it for to long but you can run it maybe half a day like that without charging it.[/quote]
i bet you theres some sad sack out there that thinks the battery drains when the car is running, and charges up when the engine is off.
What you tend to run into is that common sense isn't all that common. I can just see someone thinking it would be straight to plug their rigged electric setup to their car battery and wonder why their car won't start.
