This is how i made a 12v li-ion battery for free without having to buy any cells or batteries from the internet what so ever. i use these in all of my projects on instructabals that need a battery of some sort, it is cheaper and can usually store more.

Step 1: Source Your Batteries

One of the best places to get batteries that are no longer used but have large capacity and large power output is laptop batteries, these batteries are usually li-ion as they are the lightest per power output and are good in general. if you have any old laptops that are not used anymore then use them, if you have a laptop with a battery that says not charging, what is the point in keeping it, re-use it. phone batteries are good as well but usually don't have good capacity as they are designed for phones and although have the best power to weight ratio they don't output much power as it is small, these batteries are good for smaller projects.

<p>This is <a href="http://batteryrecover.com" rel="nofollow">better alternative</a> for batteries. Thank you William ! :)</p>
<p>correct me if i wrong.</p><p>if i need a 12v battery i can take out the cells from my old laptop battery and use them as is and when i need o charge them i can just connect them + to + and - to -to my laptop charger?</p>
well not necessarily, if you are wanting 12v then the MAXIMUM voltage should be 12.6v as if overcharged lithium ion battery's are not very forgiving, furthermore you will need holders or solder wires to it and also a charging port but theoretically attaching wires works too but is not very user friendly at all. if you could tell me what it is you were wanting the battery for then i may be able to help a bit better.
<p>i wont connect the charger's wires directly to the battery. i will solder connector to the battery and connect the charger to the battery through the connector.</p><p>i will use the battery to power up an amplifier for a portable speaker.</p>
<p>you never ever charge li-ion batterys with out a proper charger a 12 volt unit like pc power supply are wall socket adapter is very very dangerous play it safe get a imax b6 balance charger they are made for charging li-ion packs</p>
When I said I used a pc power supply I used a PCs AIO power suppply which was 12v 5ah and worked in exactly the same way as a li-ion charger, but just to trickle charge them at the end I used a wall charger which was 12v 500mah and this had an overcharge protection circit. If any of the batteries die they would have been throwen out anyway, just making the most out of them.
just as a heads up: the linked kit is the kit only without (!!) the regulator itself.<br>you need to buy an LM317 in a TO220 casing to make it work.<br><br>also, such a linear regulator will discharge way below 2v per cell if you let it.<br>search for 18650 protection online and add one such protector-pcb to each cell if you value your build.

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More by william444555:How to make a 12v battery for free Portable Boombox/Speaker With Bluetooth 
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