Forgive me the manufacturers and sellers of chargers.
Especially in winter there are such unpleasant moments, like at inopportune moments, the vehicle battery is razresheniem, or after several attempts to start in the cold, the battery cannot turn the starter.
What to do if you don't have a charger?
Want to share a few ways:
If you have a laptop, you can use its charger.
The dependence of the current from power bulbs for BP which I use to have the following: 
Usually chargers give about 20V and 4A, i.e., the capacity of 80W and are equipped with short circuit protection
with halogen bulb (best pair are connected in parallel) and a laptop charger you can safely charge the battery.
See video
Attention if you decided to repeat this way, it is you do at your own risk, the author cannot be held responsible. The article is written purely for informational purposes!
We will calculate what current will flow when connecting halogen lamp with a power of 110 Watts
under normal voltage 110/12 = 9.2 per And
12/9,2= 1.3 Ohms — resistance lamochki
Take the power supply voltage of 20 To
we assume the battery will fall To 13, glamocko remain 7 In
I=U/R, obtained 7/1,3 = 5,3 And that is quite enough current to charge the battery with a capacity of 53Ач 10 hours
I felt this way about (approx. on video used light bulbs from vases povorotnikov) with 2 parallel soedeniny light bulbs 105 watts each, ammeter postal value 6A, the current protection on the power supply does not work, because there is no short circuit, however, the power supply still limits the current more than 6A and I squeeze him I couldn't.
P. S. the above method of charging a car battery, I use already for many years and don't see any reason to buy the charger.
When a large current to charge the battery can not last long, otherwise you'll just kill your battery. Right to charge with an average current of about 2 – 3 amps, or low strength of the current 1-2 amps, so your battery will be under the charge quite long, about 8 – 10 hours. But you will not cause him any damage.
Since in this case we charge the battery using a current source, it is necessary to control the end of charge voltage at the battery terminals, or at least at the time of the charge, as in the case of overcharging will begin the intensive evolution of hydrogen.
There is another way to charge the battery completely without the charger, with 1 or 4 diodes, conventional incandescent lamp at 220 volts and the socket with the voltage 220V
Making a simple calculation when bridge circuit connection of diodes, a bulb 150 Watt, will receive charging current 0.7 A, respectively, by connecting 2 light bulbs in parallel, the current is 1.4 A, etc. But if instead of light bulbs to use iron, 1 kW, we get a charging current of about 4A!
ATTENTION !!! This charging method is not galvanically isolated from the network, and with respect to (the earth) will be high voltage !!! dangerous for life. Therefore, this method is considered here only theoretical, as one of the possible ways.
