Tmj. More Condition_symptoms

BATTERIES, how to calculate consumption

(taken from blogdellavela) http://blog.veleggiando.it
not much change the mode 'of use, even if both supply utilities that are almost identical (but at sea and there 'the enel with an outlet that runs after you) In this first article we will see some basic concepts that will be used to calculate the daily consumption of electricity, in order to determine the autonomy of the installed battery park on board.

of any electrical current can be measured tension and intensity .

The voltage is measured in Volts (abbreviated as V) and for this reason is sometimes called voltage (personally I find it an ugly term).

The current, however, is measured in amperes and even this is sometimes improperly called amperage.

Any electrical device when in use, uses energy and thus determines a power consumption .

On our boat, batteries have a duty to store electrical energy, storing it within them when they are connected to a power source (such as chargers ol ' alternator motor function) and then releasing it to feed the passengers on board.

It's called capacity of a battery that measure the amount of electricity that it is able to store, and is expressed in Ampere hours (abbreviated Ah).

A typical battery with lead elements immersed in a solution of sulfuric acid, can withstand shock not exceeding 50% of its rated capacity , otherwise its irreversible damage. For gel batteries this value is only slightly higher.

This means that if our battery has a capacity of 100 Ah, 50 can only unloaded before it is completely discharged.

When fully charged, the voltage at the poles of a battery is about 12.8V, and when it is completely discharged its voltage reaches 11V. Anyway, we must always be careful not to drop the voltage below 10.8V , otherwise the battery will ruin you forever.

precisely to avoid this irreversible damage, the electrical panels are fitted with an electronic device that provides a disconnect the utilities that consume the most (eg refrigerator) when the voltage reaches this limit value of 10.8 V.

Having said this, it becomes very easy to calculate the autonomy of our battery park, once calculated the consumption of all devices electrical board.

To do this we must first know the current consumption (measured in amperes) of each of these and multiply by their operating hours during the day.

For example, suppose that the refrigerator compressor (one of the most voracious equipment on board) absorbs 5 amperes and that to maintain the set temperature, this works for 20 minutes every hour. In essence we are assuming that it is running for a third of the total time, then for 8 hours a day. Within 24 hours, then, our fridge will suck the batteries for 40 Amps * Time (8h x 5A = 40Ah)

In just 24 hours, then, has consumed almost all of our hypothetical loads 100Ah battery: to be exact will be used for 80% of its payload, remember, is only 50Ah .

But how do we know how many Amps the fridge or any other device? Well, just look at instruction booklet. certainly find the power in watts . From the power we can calculate the intensity (Ampere) by simply dividing the power voltage (in our case the 12 volt battery).

So if the power of the refrigerator was 60W, the current consumption would be 60W / 12V = 5A

The calculation that we made for the fridge, of course must be replicated for all other utilities, such as bulbs, electronic equipment like GPS, etc. .

Remember, each current value in Amps is multiplied by the actual time in hours and the result is in addition to the above, to obtain the total value of the current consumed during the 24 hours.

The same amount of electricity must somehow be supplied each day to the batteries to prevent leakage.

In the next article we will an overview of the various methods used to recharge the batteries , analyzing strengths and weaknesses of each. Stay tuned then