Originally Posted by M Scott
About how long (days) will the battery last on my Scamp
13, using lights
fan, water pump when no hookups are available/dry camping?
Do I recharge battery by hooking up to car and running engine? For how long?
Is there a way to test the life of my battery while dry camping
Thanks for the help.
Just a reminder that this is the question the OP actually asked.
Solar, running the car, or a generator are all ways to extend your battery time. Each having some trade off.
Solar has a finite limit - you can only get how much sun there actually is. Often addressed by having enough capacity in panels that even a few hours of hazy sunlight will charge you back up. Or at least extend you battery time by long enough you run out of water and have to leave anyway. With adequate panels one can camp for an indefinite period as far as electric goes but water, food, fuel, laundry these things can remain limiting factors.
Generators - unlimited power (depending on size) but heavy, require fuel, create noise and may have some limits on where or when they can be operated. Only way to run power hungry devices such as AC or to insure power to health related equipment such as CPAP machine or Oxygen
concentrators. Deep cycle batteries charge best with modest charge over longer time, charging off of generator means running the generator for a longer time. Or in cold weather with young children insuring you can have enough battery to run your furnace
Converter - a charger that runs trailer 12 volt systems while plugged into the parks power and charges the battery at the same time. Fairly standard equipment for campers. A good one will do a good job of maintaining your battery, a junky one will cook it. These can be nice if you do a few days of boondocking
then hit a park with showers where you can plug into shore power for a night. Or when running off of a generator.
Running the car - effective IF you are doing it when driving from one location to another. Requires the tow vehicle and hitch be wired to bring power back to the camper battery.
There are test gadgets to tell you the "state of charge" these range from cheap LED lights
that more lights mean more charge to systems that are tracking actual usage and charge going in. A simple voltage meter works well. Voltage drops as the battery gets discharged so you can watch the battery go from 13 volts down to around 10 volts which is considered too low.
Advantage of a volt meter is you can monitor your battery, test for broken wires or troubleshoot bad tail lights
etc. Sometimes just going from battery and checking for power along the way toward a device that is not working will go a long way toward figuring out what is wrong. Or answering the immortal question. Does it have a connection to ground? Useful in other words. If you don't know how to use one, it is not hard to learn the basics and a skill worth having.
One thing that get overlooked is the "solution" does not have to charge your battery to fully charged. Just put enough charge in to extend you camping time before battery gets drawn down to 50% charge. If you can get 3 days from the battery and only put 1/2 of that back with solar each day. That means you can now do 4 1/2 days instead of 3. Maybe running the generator for a couple of hours would give you enough battery charge to get that "extra" day and a half of camping.
See what I mean? For folks that more often than not do a weekend or long weekend 4 days is all they need, maybe they add a battery and/or more solar and extend that to a week but for those that work getting more than a week in the woods is a rare treat.
For those that camp and travel the car can charge during travel so battery solution only has to last as long as you think you will be in one place. I have done a fair number of trips like that. Go to some area then spend a couple of days, drive to another location further along and see what is there. Done loops through Colorado for example as a way to see the state.