Super backpack.
Feb 5, 2010 at 7:18 AM Thread Starter Post #1 of 17
Hybrys

Hybrys

Headphoneus Supremus
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So, I've got this really big backpack that I never use. And I wanna do some odd things to it, and was wondering if I could get some input.

BASICALLY, what I want to do is:

Car battery isolated in an enclosure --> two US outlet panel (with grounds, pref.) --> Charging station for my laptop, or on the go laptop-as-source setup with dac/amp. (300-500w)

Charged via Solar while at home; not in use

Any ideas? Would like to do it for under $200 not including the battery, but, any information would be great. I know what I BASICALLY need (Battery, inverter, outlets, solar charger, battery overcharging limiting thingy (?)) just wondering if you had opinions or specific parts in mind. I can solder pretty well.
 
Feb 5, 2010 at 7:28 AM Post #2 of 17
Could be done. Car batteries are pretty ****in heavy, have you lifted one? You'll probably throw out your back walking around with that.

Your parts are about right. You can buy inverters with built in outlets. Solar panel kits usually come with a half-assed charge regulator. It's up to you whether you want to go for a better one but they cost a fair chunk of change.
 
Feb 5, 2010 at 7:37 AM Post #3 of 17
I used to jog with 15 lbs in my backpack. I'm young, I'm fit, and I'll damn well pay for it when I get old. = D

I've seen in-car inverters with built in outlets, but never one for just a straight battery. Solar kits do usually come with a half-assed charging regulator, but, since it will be a relatively expensive battery, I'm wondering if I can DIY a better one.
 
Feb 5, 2010 at 8:38 AM Post #4 of 17
I can't offer any specifics, but you might want to search around for what some of the obsessively mobile hams (amateur radio) use. There are a number of them who run mobile HF rigs off the grid, and this sounds exactly like something one of them has likely done.

Also, you might want to think about a motorcycle battery. Car batteries weigh a little more than 15 lbs. I spent several years marching with a 45 lbs. sousaphone and have backpacked extensively with 50-60 lbs. packs. It's not something you want to do if you don't have to.
 
Feb 5, 2010 at 10:35 AM Post #6 of 17
BestBuy has some $50 portable batteries that look promising. Amazon has the cheaper though: Amazon.com: Duracell 852-0257 PowerSource Mini: Patio, Lawn & Garden

Or maybe there is something between this and a car battery that you could use. I think there are lots of options out there, I just wouldn't recommend the car battery one. And if for whatever reason, you decide on a car battery, look at some of optima's sustained output ones.
 
Feb 5, 2010 at 4:37 PM Post #7 of 17
Please do not consider anything that is not sealed. Your best bet are any type of medical batteries. They are a little on the pricey side, but they are meant to be carried in portable medical equipment, i/e defibrillators AED's (like the ones you see in the airport). You can even get the correct chargers on ebay and swap them out daily. Here is a link to a 3rd party vendor. R&D Batteries, Inc. or Google medical batteries.

We used to run a car stereo from older defib batteries in one of our shops.

But also remember, if the wiring shorts in your backpack, you will burn a hole in your back(just like the old school car cigarette lighters) and release poisonous gas. I have accidentally shorted a 12v 7ah battery and it melted the tip of my screwdriver.

You know what, on second thought, it is a bad idea!
 
Feb 6, 2010 at 12:13 AM Post #8 of 17
Heh. It is pretty much always a bad idea. I'm just looking to do it as perfect as possible, and thus limiting the chance I'd ruin anything. I do plan on installing some kind of safety harness or enclosure and properly setup/stationary outs, though.
 
Feb 6, 2010 at 2:52 AM Post #10 of 17
You could get some nice lithium batteries out of a prius. Just follow the hippie until they park it and hold them up with a bar of soap. If you want to be really mean put some liquid soap in a super soaker. Hell, even bubble stuff will scare them to death. Do that while eating a steak burrito in front of them and watch them cringe in mortal fear.
smily_headphones1.gif
 
Feb 6, 2010 at 4:36 PM Post #11 of 17
You definitely don't want to use lead-acid batteries for anything portable... they are way too heavy for the amount of power they provide. Look into lithium batteries, great power density, but require complex charging systems and are very expensive.
 
Feb 6, 2010 at 7:02 PM Post #13 of 17
Quote:

Originally Posted by HeyItsBattleKid /img/forum/go_quote.gif
BestBuy has some $50 portable batteries that look promising. Amazon has the cheaper though: Amazon.com: Duracell 852-0257 PowerSource Mini: Patio, Lawn & Garden

Or maybe there is something between this and a car battery that you could use. I think there are lots of options out there, I just wouldn't recommend the car battery one. And if for whatever reason, you decide on a car battery, look at some of optima's sustained output ones.


That thing is awesome! Is says it can be recharged from your car so that means it should be rechargeable by solar panel as long as it isn't overly big. Plus, it is lithium Ion so it will take less panel to charge than a lead acid and it will charge faster. Basically all lithium batteries need a charge controller to be charged properly anyway, so that is already built in and should be good for 11-15v range or so. If you get a big panel for charging, I would charge a stationary lead acid with it all the time and just use that to charge the lithium pack on demand. A large panel open circuit could go to 22v or so and you wouldn't want to toast the charger in it.
 
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