# how to make 12v battery from 18650 li ion batteries?

Hi,

I have this led strip
http://www.supernight.cc/supernight-tm-5m-16-4ft-smd5050-rgb-double-row-600-leds-tube-waterproof-led-flexible-strip-light-12v-120led-m-strip.html
Working Voltage is 12VDC.
Working Current/meter: 0.8-1A
the strip is 5 meter.

18650 x4 = 14.4 v
18650 x3 =10.8 v

How can I make it work with 18650 li ion batteries?
And how many battery must I use and how can I do that?
I think that I need driver or booster to get a stabil 12v!
work-time I need 5 h

Downunder35m10 months ago

Get a proper 12V deep cycle battery, everything else is a total waste IMHO.
Otherwise check Google and Wikipedia on how to combine batteries.
But for your lithium cells you will need either a step up, or a step down converter, best with additional battery undervoltage protection.

Cr77777 (author)  Downunder35m10 months ago

if we did it , can we get more capacity by group of cells and only 12 volts?

each 18650 = 3.6v
18650 x4 = 14.4 v
18650 x3 =10.8 v
I use samsung 3000map each, so if I use 4 cells I will have 4x3000 = 12000map, it will be expensive if i buy it and I love to make these things at home :).
Can I use more cells to get more capacity but only 12v?

which battery undervoltage protection can I use?

which step down can I use?

10 months ago

3.6 volts to 4.2 volts fully charged isn't going to give you 12 volts without some kind of regulator. Plenty of 12 volt regulators around.

Your laptop batteries may already have a protection cct attached to them, many 18650 cells do.

However Ebay or an electronics supplier can give you a suitable under and over voltage protection cct.

Cells in series will add the voltage, cells in parallel will increase capacity. So you need a series / parallel set up.

You will need to arrange for a suitable charger for such a set up though Li ion cells are sensitive to over charging - i.e. they may burst into flames.