I need two rechargeable battery packs that I can charge at any power outlet. I have a pretty good idea about electrical safety and believe that I can fit each into its own backpack for transport to and from power sources. Each batter pack needs to last for around 12 hours at 150-300 watts. I need to be able to charge it in around 8 hours and then it needs to last around that same amount of time if not longer. If need be I can make 3 packs so I can charge two at a time while one is in use.

These battery packs are going to power a thermo electric cooler and a computer fan while I am living in my car. The computer fan circulates air while I'm sleeping since I cant idle the car all night just to circulate air and I dont want to roll my windows down since its a small car and anyone can easily reach inside to rob me. The thermo electric cooler is to keep my supplements cool and keep them from degrading due to getting to hot. Amino acids and other supplements are delicate and decline in potency over time when not kept cool.

I know that home depot sells 6 volt rechargeable lithium light ballast batteries but im not sure if these are suitable for long term daily use.

 

Batteries are measured in Volts and amps per hour , so we need to know what voltage you need, and how much current will be drawn for 12 hrs.?

Example if your current is say 2amps for 8 hours, thats a 16 aH battery .

 

Batteries are measured in Volts and amps per hour , so we need to know what voltage you need, and how much current will be drawn for 12 hrs.?

Example if your current is say 2amps for 8 hours, thats a 16 aH battery .

its probably going to be a 12 volt thermoelectric cooler and most likely wont exceed 300 watts. according to this calculator its 25 amps

 

So 12v @ 25 amps for 12hours , thats a 300aH battery minimum,your looking at a car battery then...

 

cool so ive done a lot of research before when it comes to batteries and solar power. From what ive read the best battery used in solar power storage is the same as in golf carts.

so all i need is a 12 volt batter and a charger that wont short out the wall socket. what would be the best charger for a portable system that can plug into any wall outlet?

 

now to find the right charger. thanks for help / reality check. ill be back when i have want to talk about my other plans.

 

You realise that a 12V 300Ah battery equates to 6x typical car batteries?

Good luck fitting "each into its own backpack".

 

the cruel financial reality will be that a small portable Honda generator would do the job more reliably and for about one third the cost. find a place under the hood of the car to fit it and it will not be easily stolen while you sleep.

 

He won't get much sleep if there's a generator running in the car.

 

that is why I specified Honda. Some of the small portables are almost silent and the soundproofing in a cars engine compartment is enough to cover that.

 

87-92dB(A), according to the Honda website.

 

I considered silent honda generators plenty of times. Part of the reason I don't want to use a generator is because it's going to burn gas (which I don't want to have to deal with) and it's valuable. If anyone knew I had it they would likely want to steal it. With a battery pack I could divide the valuables in half keeping one half with me and the other inside the car where it is relatively safe since no one really has a use for golf cart batteries.

 

Now i may have over estimated the wattage of the thermo electric cooler. There are some high powered cooling units out there but most are going to be below 100 watts. Is a smaller 100 watt unit be feasible?

 

That would require 100Ah but this does not mean that you can use a 100Ah battery as the full energy capacity is never available. So, you would still need a 12V lead-acid battery of around 200Ah as they cannot be fully discharged.

 

ok so lets say I bought a 72 watt peltier pad (heat sink fan wattage aside) and four 6-volt 448 amp hour golf cart batteries? how do you figure I would not be able to have a cold box 24 hours a day with two rechargeable battery packs?

 

sure.. i can hook up other things inside of the batery packs like magnatrons or x-ray tubes but that shouldn't prevent me from being able to have a good system to keep my supplements from degrading while living in my car.

 

ok so lets say I bought a 72 watt peltier pad (heat sink fan wattage aside) and four 6-volt 448 amp hour golf cart batteries? how do you figure I would not be able to have a cold box 24 hours a day with two rechargeable battery packs?

A 72W device requrires 144 Ah@12V over 24 hours so with 896Ah @12V available, that would be no problem. The battery would weigh around 500lb.

 

sick! ok so it is possible. I found some information about battery life cycles. I technically dont need this syetem to last for ever. I would like it to last about a year though. golf cart batteries can endure thousands of cycles when not drained all the way. When they are drained past 90% the life span is reduced dramatically. It's like the percentage you drain it regularity is how long it can potential keep working. so 10% drains mean it will last for over 5000 cycles while at 90% drain it will last less than 1000.

I know from experience car batteries are not very good for draining all the way and that golf cart batteries do way better. lowes, home depot, and walmart sell them so technically it would be easy to replace them if they start to fail.

Im thinking that 144 amp hours for 24 hours would mean the battery is going to drain all the way. but if Im only running it for 12 hours then its going to only drain about 50% which would increase life span a lot.

Thanks a lot for the help guys. Ill be sure to let you everyone know how it goes.

 

how long do you guys think this one would last? at 50% drain per day?

http://www.lowes.com/pd_278043-50656-4U1L_1z0wgca__?productId=4412095&pl=1

 

about 2 to 4 weeks tops.

that is NOT a 175 Amp hour battery. zit is a small STARTING battery capable of supplying a max of 175 amps to a starter motor for a very short time.

a true 150 amp hour golf cart battery of mediocre quality will cost you about $200 for a single 6 volt unit. you will need at least two. These will state they are DEEP CYCLE Batteries, not starting batteries. If the specs contain the words "cranking amps", or "starting amps", they are not going to work as you expect for more than a very short time; days or maybe a week or two at best.

Again the batteries you require to do the year long job you are asking about will be $ EXPENSIVE $ AND LARGE AND VERY HEAVY.