WORKING IT OUT
I think you can see where this is going …
To determine how much battery capacity you need , you have to estimate how many devices you will run and for how long each day . Add all that together and then multiply the figure by the number of days you want to run everything for . Here ’ s a typical example :
Appliance and number in use
6 x white interior ceiling LED lamps
3 x exterior LED floodlights
1 x 24in 12V flatscreen TV
1 x 12V compressor fridge at 50 % duty cycle
Current draw per hour
Number of hours of use over a 24- hour period
3Ah per hour 4 12Ah
3Ah per hour 3 9Ah
5Ah per hour 4 20Ah
3Ah per hour 24 72Ah
1 x water pump 6Ah per hour 0.5 3Ah
4 x USB charger outlets
1 x car / marine stereo system ¼ of peak
Total amp hours per day Total amp hours over three days
6Ah per hour 4 24Ah
5Ah per hour 2 10Ah
Total amp hours consumed
150Ah 450Ah
Now , you might look at the above table and think a 100Ah battery will not last a day , let alone three days . And you would be right , but remember we haven ’ t yet factored in any recharging .
You may have a decent solar charging system in your caravan but if you get two or three days in a row of rainy weather , you ’ re not going to get a lot of recharging , if any at all .
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