battery

Mar 14, 2005
39
0
0
Visit site
Hi, I have managed to make 12v power last 4 days under normal use, water pump,lights,12v tv (occasional). This was a 85ah battery and still was not anyway near flat but i then connected to the car so i guess it could have done the week easily
 
Mar 14, 2005
17,804
3,202
50,935
Visit site
Hello David,

To get an idea of how long a battery will last,

A battery has a capacity that is quoted in Amps/Hours (Ah). Most leisure batteries are either 85 or 110Ah capacities.

In theory if you divide the battery capacity by the current (Amps) being used you will get an estimate of how long the battery will supply enough current. - so for example, if yo y are drawing 5A from a fully charged 110 battery it should last 110/5= 22 hours, or 110/10= 11 hours etc.

In practice there are a number of other factors that you should be aware of, as these will affect the life of the battery. assume the current draw to be about 10% more, and that should give a more realistic estimate.

The other problem is estimating the current usage.

Each 12V appliance should have a data plate with a current rating on it. This should indicate how much current the appliance uses

For each appliance, work out how many hours it will be running each day. Multiply the time by the current rating to get the amount of power it will use each day.

Add together all these Amp Hour values for the appliances, and that will give you your total daily power usage. For the reasons above add about 10% to cover losses.

Divide the battery capacity by the power usage to give an estimate of how long the battery should last.

Just a small example of daily usage:

Water pump 15Min at 4A = 1Ah

12V Spot lamp 4Hours at 1A = 4Ah

12V Fl Lamp 4Hours at 1A = 4Ah

Tele 3Hours at 3A = 9Ah

Daily consumption (sum of ind.items) 18Ah

+10% (approx) 2Ah

Daily Consumption Inc losses 20Ah

Battery Capacity/daily Usage = Life

110Ah / 20Ah = 5.5 days

Obviously you need to add up all the lamps and other individual items.

With care you could last a week, especially if you turn off items when they are not being used. You will become more aware of conservation through this process.

Best of luck
 
Jul 6, 2005
15
0
0
Visit site
Hello David,

To get an idea of how long a battery will last,

A battery has a capacity that is quoted in Amps/Hours (Ah). Most leisure batteries are either 85 or 110Ah capacities.

In theory if you divide the battery capacity by the current (Amps) being used you will get an estimate of how long the battery will supply enough current. - so for example, if yo y are drawing 5A from a fully charged 110 battery it should last 110/5= 22 hours, or 110/10= 11 hours etc.

In practice there are a number of other factors that you should be aware of, as these will affect the life of the battery. assume the current draw to be about 10% more, and that should give a more realistic estimate.

The other problem is estimating the current usage.

Each 12V appliance should have a data plate with a current rating on it. This should indicate how much current the appliance uses

For each appliance, work out how many hours it will be running each day. Multiply the time by the current rating to get the amount of power it will use each day.

Add together all these Amp Hour values for the appliances, and that will give you your total daily power usage. For the reasons above add about 10% to cover losses.

Divide the battery capacity by the power usage to give an estimate of how long the battery should last.

Just a small example of daily usage:

Water pump 15Min at 4A = 1Ah

12V Spot lamp 4Hours at 1A = 4Ah

12V Fl Lamp 4Hours at 1A = 4Ah

Tele 3Hours at 3A = 9Ah

Daily consumption (sum of ind.items) 18Ah

+10% (approx) 2Ah

Daily Consumption Inc losses 20Ah

Battery Capacity/daily Usage = Life

110Ah / 20Ah = 5.5 days

Obviously you need to add up all the lamps and other individual items.

With care you could last a week, especially if you turn off items when they are not being used. You will become more aware of conservation through this process.

Best of luck
Thank you for your answers.
 

TRENDING THREADS

Latest posts