GORV - Digital Magazine Issue #43 | Page 44

RECHARGING
Battery chargers , be they solar or mainspowered , are rated in amps . The higher the amps , the quicker they will recharge your batteries . You would think that if you depleted a battery by 30 amp hours ( Ah ), a 30A battery charger would replace that used power in about one hour .
Unfortunately , it doesn ’ t quite work that way . Recharging batteries requires energy to cause a chemical reaction within the battery and that reaction produces heat , which is , essentially , wasted energy .
Battery chargers also regulate the amount of amps and volts they put into the battery during recharge , according to the type of battery . This is called a charge profile . For a variety of reasons , including the charge profile setting as well as the wasted heat energy , it will take three to four hours to recharge that battery . If it ’ s been drained lower , it will take longer .
SOLAR CHARGING LIMITATIONS
Despite years of development , solar panels remain rather inefficient . Even the best quality panels only convert about 24 per cent of the energy falling on them into useful power , and that is under ideal conditions .
In order to maximise power production , solar panels must face the sun directly , with the rays hitting them at a 90-degree angle . This
creates a problem , particularly for roofmounted solar panels .
The sun is not a stationary object . Its position in the sky depends on the time of day , the time of year and where you are located . Because of this , the sun will seldom be in the ideal location for producing maximum power , if at all . Even in the height of summer in central Australia , you may only have four hours a day of good solar charging .
You also have to consider the effects of the
weather on solar panels . Any sort of cloud cover will severely reduce their output .
If all else fails , there ' s always the generator ...
Finally , there ’ s the position of the RV itself . I tend to look for campsites that offer some shelter from the sun , such as a large tree . Ultimately , a 100W solar panel mounted on the roof of an RV could only be expected to produce about 90W or 5A in full sun , midsummer , for only about four hours a day .
In winter in the southern states , you might be lucky to get half that for three hours a day .
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