85 amp battery how long will it last

[Moth_5041363]

Hi I'm off for a two week holiday in a 470/4 ranger without electric, how long have you managed on one battery.

 

[rayc]

Moth, from past experience with a fully charged battery running water pump and flourescent light only and at this time of year I have got 10 days. It depends on the current drawn.

 

[ProfJohnL]

Hi Moth

There are several reasons why an 85Ah battery will hold 85Ah of energy, Age, how well charged it is. So assume only about 70Ah,

You then need to add up the energy needs of all the 12V items you intend to use, and work out how long they will be using power

E.g. Pump 15Min (1/4 hr) per day at 4A = 1Ah

Light 3 hr per day at 1A = 3Ah

etc.

Add together all the Ah's and that will be the power you need for 1 day.

Take the battery capacity (70Ah) and divide it by the daily needs to give the estimated life of the battery in days.

 

[RogerL_5041474]

If you discharge a leisure battery below about 20%, it'll deterioate much more quickly. So assume that a 85AH battery gives 68AH useable. This would last 68 hours at 1A or 6.8 hours at 10A. I find that we use 4AH per day without a TV. Adding 5 hours TV a day would add 20AH to the consumption rate. If we used an 85AH battery, it would last 17 days without TV or 2.5 days with TV! You need to assess your own consumption pattern.

 

[ProfJohnL]

Hi Moth

There are several reasons why an 85Ah battery will hold 85Ah of energy, Age, how well charged it is. So assume only about 70Ah,

You then need to add up the energy needs of all the 12V items you intend to use, and work out how long they will be using power

E.g. Pump 15Min (1/4 hr) per day at 4A = 1Ah

Light 3 hr per day at 1A = 3Ah

etc.

Add together all the Ah's and that will be the power you need for 1 day.

Take the battery capacity (70Ah) and divide it by the daily needs to give the estimated life of the battery in days.

Error! top line should read "NOT hold 85Ah"