How to charge a car battery with a laptop power supply

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This article is from the category - every motorist needs to know. Very soon, winter and many owners of a car with an old battery will be waiting for a surprise: when attempts to get their own steel horse are unsuccessful. As a result, the battery will be completely discharged due to these actions. Such a failure may well happen with the owners of completely new batteries. No one is safe from this.

It’s good if you have a car charger on hand. But often life brings such situations when this device may not be at hand or it will fail as if by evil.
If you encounter a similar problem, then savvy will help you.
We need a power supply from a laptop, which is common in every house and sometimes not in a single amount. They are almost all of the same type and go to a voltage of 19 volts. Car light 21 watts (12V 21V). If you want to speed up the charging, you can take two of these bulbs, connected in parallel to each other, or take one lamp high or low beam at 55 watts. If suddenly you do not have an extra light bulb - pull it out of any available flashlight while charging.

We take the battery, unscrew the lids of the cans, for better ventilation.
Then we take the block from the laptop and the light bulb and all these three elements, including the battery, using a wire we connect in series.

Wiring diagram.


Connection to the power unit.

The minus block is connected to the minus of the battery.

Charging, of course, is a long thing, but it takes a couple of hours to refresh the battery a little.
In general, when my charger burned out, I left this circuit for the night - and in the morning I received an almost fully charged battery, provided that, of course, it was not discharged to zero.
The current through one 21-watt bulb goes about 1 ampere. If you take two of them, then there will be about 2 Amperes. In general, it’s quite possible to charge the battery per day even from scratch.
If you will be able to measure the battery voltage, then 14.2 is the voltage of a fully charged battery.
Yes, note that the load current of the unit, look at the housing and do not exceed it. Usually it is 3 amperes.
Do not forget that hydrogen is emitted from the battery cans when charging - do not forget about the ventilation of the room.
Use your savvy friends, and you can get out of most seemingly hopeless situations.

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Watch the video: How to Charge 12V Car Battery with 19V Laptop charger. DIY Car Battery Charger (March 2024).