Powering the car battery, how much time it takes?
To find the answer to the question of the topic, you need to keep in the mind one rule, that there is no huge matter on the type of battery, as the matter of the way of charging the battery.
Important indicators for the battery:
1. The capacity (ampere per hour) means the amount of load, measurable in current intensity, which can be completely wasted during for one hour. For instance, if the battery capacity is 75A/h, and you give the same load at once, then after an hour the battery will run down. So, if the load value is
2. The voltage is approximately 12.7
The first step for accumulator charging is to remove it out of your car. Before to do it, you need to clean battery terminals (use the water and soda bath). The next step is used to be only with the nonhermetic accumulator, or service battery. When preparing to charge this type of battery, it is important to check the electrolyte level, it should completely cover the plumbic plates. Otherwise, it is necessary to add distilled water to each bank separately, as the banks have no communication with each other. Boiling electrolyte is a signal that the battery is charged. As it was mentioned the service battery can be opened, so it is not recommended to charge it at home, in the case when you have pets or small children there.
Before proceeding, the answer to the main question, how long to charge the battery  will be variable, namely, this process can take from 4 to 12 hours.
It's quite simple, the voltage equal to 10% of the total capacity of the battery is optimal decision. Therefore, if you have a battery capacity of 100 A/h, the amperage is 10 A. in the case where the voltagepower was 11.5 W (the extreme value of the discharge), the battery capacity of 100A/h will be charged for 12 hours.
On average, the battery charge at 75 A/h at a rate of 11.7 W, will take 10 hours.
It is important to mention, that it is undesirable to bring the accumulator into a state of the full discharge. It is more useful to maintain the charge at rates of 50% (12 W), you can charge the battery 68 hours at a voltagepower of 12W, this is optimal to do at night.
There were conditions of the charging at a constant current, above, but more common is the constantvoltage charging, which is adapted for the hermetic accumulator.
The voltage conventionally is in the range of 13.8 — 14.5 Watts. At this voltage, the battery absorbs 60% of the charge for the first hour, then 20%, for the
In such case, 100% of the accumulator charge, in conditions of constantvoltage powering, takes about 10 hours, as well. But you can charge the battery to 90% of power in 4 hours, because of the measured strength of the charge voltage.
While at a constant current, the charge takes 68 hours if the discharge level is about 50% or 1012 hours at a deep discharge.
The voltage and the capacity 
Charging % 
The charging at a constant current 
The constantvoltage charging 
12,7 W 
100 
х 
х 
11,5 W (for 100 A/h) 
2530 
12 hours 
12 hours 
11,7 W (for 75 A/h) 
10hours 
10 hours 

12 W 
50 
68 hours 
45 hours (to 90%) 
68 hours (to 100%) 
*values  are given for batteries with a capacity of 100 and 75 A/h, and the difference for batteries of lower capacity will be less by 11.5 hours of charge from the indicators in the table.