Keeping devices charged on a long camping trip
Cool stuff ! I researched CPAP power supplies and found that they’re typically rated around 90 watts. Chargers for iPads are rated at about 25 watts. Multiplying the watts of each device by the number of hours of use provides an estimate of the amount of energy your wife needs each day. Eight hours of CPAP and five hours of iPad use per day comes out to 845 watt hours.
The Outback’s alternator is rated at 130 amps. Multiplying amps by volts gives us watts. At idle, the alternator produces perhaps half its rated output: 942 watts. Subtracting the energy needed to run the engine and top-off the battery, and assuming an efficient hook-up to your devices (direct battery connection for the CPAP, lighter socket for the iPad), a little over an hour of run time should be sufficient to get the job done.
Idling the engine for an hour or two per day won’t hurt the engine or battery but it’s an inefficient way to convert gasoline into electricity. And that’s not to mention the emissions produced.
If you’ll be camping frequently enough to justify the expense, a solar panel and battery booster pack, used as a buffer, could significantly reduce or totally eliminate your needed Outback runtime. Assuming eight hours of
BRAD BERGHOLDT
well-aimed sunlight per day, a 100-watt solar panel (about 27by-40 inches, roughly $100) could provide close to all the watt hours needed. You’d want to add an inexpensive charge controller and connect it to the jumper pack rather than the Outback’s battery. The jumper pack (look for one with an accessory socket and an honest 16 amp-hours capacity or greater) is also useful for its intended purpose. The combo could also provide peace of mind for your wife at home should there ever be an extended power outage.
I agree this is creepy. I’m thinking the cause is an electrical fault rather than a mechanical one, but this needs to be confirmed. Assuming proper oil level and condition, an emerging mechanical problem such as excessive bearing clearance or a worn oil pump would usually cause the light to illuminate first at idle, when the engine’s warm or hot, and perhaps also at higher speed as the fault worsened. A severe fault could cause the light to be on at all times. An inexpensive mechanical oil pressure gauge can be connected to the engine with a hose sufficient in length so it can be viewed while the vehicle is driven. This will provide the truth, allowing a proper course of action to be followed.