Chronic undercharging of batteries leads to premature failure. Deeply discharging batteries or leaving them undercharged for weeks will lead to sulfation.
In general, sulfation starts when a battery’s state of charge drops below 80%, or 12.4 volts. Recharging a battery in a timely manner helps prevent sulfation.
A properly sized and designed system should provide sufficient power to fully recharge your battery bank everyday. That may be a combination of solar, alternator or grid power depending on your particular use habits. If you occasionally draw down your battery bank over successive days for some reason (weather, heavier than normal use, etc) it is not as big of a concern as if you frequently draw down your battery bank over successive days.
Never let a 12 volt battery discharge below 12 volts. A fully charged battery is 12.7 volts. When a battery reads below 12.2 volts it is at or below a 50% state of charge. A 12 volt battery is essentially fully discharged below 11.9 volt
The following chart is conservative
Here is another chart that is less conservative
Reducing the batteries depth-of-discharge increases the life of the battery. A battery discharged to 50% everyday will last twice as long as a battery cycled down to 20% everyday. The following table is for Concord high quality deep cycle batteries (Rolls-Surrette, Crown and other high quality batteries will be similar). Note that these are best case numbers based on lab testing. It is reasonable to assume actual performance may be 2x worse (i.e. only 500 cycles at 50% SOC).
Also it is very important to fully recharge your battery bank between trips or before storing your camper.
In summary, Yes I think you need to increase your solar capacity.
I recommend that you create a power usage table. Use your battery monitor (Victron BVM, or equivalent) to determine the power draw from each item in your camper. Determine how long you use each item and calculate your typical daily power needs. Then size your system (Solar, or combination ) to provide at least that much power so that your batteries can be fully recharged everyday.
Edited by ckent323, 24 October 2019 - 09:07 AM.