I am wanting to make a power supply to use during storms and

yes to all questions.

better give it a constant trickle charge to make sure it's always topped up. like a 15V 1A transformer in series with a 6V lightbulb.

>>1049058
A phone charger will step down 12v to 5v. If it will still work at 10v is iffy. I'd guess yes but would depend on the charger. Some have low battery shutoff circuits while others are so cheap it is a wonder they don't burn up on first use.

>>1049058
>I only need it to be able to charge phone battery.

You can make a hand-crank emergency generator out of just about anything with a motor that can easily charge a phone. People often recycle old cordless drills for this since it's already geared and a cheap and easy hack.

If you have a car battery that holds a charge, just keep a battery tender on it to keep it constantly trickle-charged and keep a $15 power inverter handy to plug things in. You'll have enough battery capacity to keep a phone charged for months.

>>1049058
Pick a voltage range say 3v-6v and try to keep everything (battery, chargers, devices) to it. Or diversely spend out. I have torches, a 10000mAh 5v bank and a UPS, so no single point of failure

>>1049070

That would be cool I do have a few drills with bad batteries lying around

>>1049058
Order a lm2596 adjustable board. Set it to 5v or what you need. If you can isolate the dead cell in the battery and bypass it that may help too, just charge it at 11.5-12v or so

dont use a car battery, get a 12v sealed lead acid battery that are used in UPS's or better yet just buy a cheap UPS and keep it plugged in. when the power goes out it will stay on to plug your charger into and the ups will stay on battery for a long time only powering a cell phone charge and would last for several hours compared to it powering a computer+monitor

that ay you dont have to deal with nigger rigging batteries, trickle chargers etc

>>1050233

This actually sounds like a better idea

>>1050393

yeah sometimes its better to NOT DIY something where a simpler solution is available. this would be cheaper and safer because you dont have to buy the batteries the SLA batteries can go for like 25+ just for one) not to mention needing to keep it charged, plus hooking up an adapter to power the phone charger. you can buy a cheapo UPS for like 40 bucks and dont have to worry

>>1049058
literally go on amazon and get a 12v battery charger to bring it back to life and then get a 12v to 5v usb board for like 5 bucks

>>1050605


Already charged it, It only holds 10.5 volts

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Buy/make one of these bad boys for maximum convenience (pic obviously related)

>>1049069

A standard dumb as a brick car charger shouldn't have a problem at 10V. All it means the switch has to be on a little longer, so it might get a little hotter.

File: images-1.jpg (3KB, 259x194px) Image search: [Google]

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If only there was a simple solution. ..

>>1050873

And how will you charge that when its run out and the power has been out for longer than 12 hours?

>>1050233
>>1049058
>UPS
See related:
https://youtu.be/-Ur-D37-juo

>>1050883
I do feel the need to ask what you are doing on your phone. My internal battery on my phone easily lasts me 24 hours if I'm not watching videos and shit. I have two external batteries, one cheapy I got for free that can charge my battery once easily and have a little to spare, and a nicer one that can charge my battery twice.

I mean go ahead and use the battery if you have it, but seems like an external battery pack should work for you.

You can also look at restoring the battery since it might not be a bad cell. Could possibly restore some functionality to it if you don't mind messing with it.

>>1050883
Look kid, it's great your trying to be all macgyver. But the practical thing to do would be to turn the old car battery in to a recycling center. Than take that money and buy a few rechargeable usb bricks. There cheap.
Some old dodgy car battery is going to be low on capacity anyways. Might as well get something that will fit in your pocket.