RV FEATURE
The winter sun sits very low in the sky . This is midday in July in Queensland .
I acknowledge all of this but , for sizing and operating modern RV electrical systems , breaking everything down to ‘ watts in ’ and ‘ watts out ’ will suffice for most owners .
To address some of these issues , my recommendation is to use this article as a general guide and perhaps make a few assumptions , such as :
• If you have 500W of solar panels on the roof of your RV , make your calculations based on them making 400W and less in the winter months ;
• Battery chargers will lower the charge rate as a battery gets to about 90 per cent state of charge . When calculating recharge times , add an extra hour or two to take this into account ; and
• Remember that , as a rule , batteries do not like being fully discharged , especially older technology batteries like leadacid or AGM batteries . Lithium batteries can sustain deeper discharge rates but will benefit from a limit of 10 per cent state of charge . Most quality battery management systems will include an automatic cut-off to prevent over-discharging . It will help to know what this is and adjust your available capacity calculations accordingly .
To assist , most RVs fitted with modern battery management and electrical systems will be supplied with a power monitor of some description that will display power movement in terms of watts . They may even provide your battery ’ s time remaining based on the size of the battery and any discharge limits set in the system .
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