Electrical issue with pop-up

[CamperFrank]

Recently purchased a 2002 Forest River Flagstaff 623 popup camper. Setting up for first time and low voltage alarm is beeping. Have checked breaker and fuses which are ok. Any suggestions on what I should be checking next. I am using an extension cord from my house (heavy duty). Looking forward to this new camping experience. Thanks for any suggestions given.

[Herk7769]

If the battery has been dead for a long time it may not be taking a charge. You can try removing it and putting it on a dedicated battery recovery charger.

Autozone will check it out for free (I think).
If it needs to be replaced (I think it will), get a Deep Discharge battery and stay away from a car battery.

Car batteries are designed to give up their charge in a burst (for starting) and don't last long supplying constant current.

TIP: if it says CCA on it run away. Cold Cranking Amps is a "Car Starting Power" measure. Look for words like "Reserve Capacity (RC)" or "Amp Hours (AH)" to denote a Deep Discharge battery. Good 12 Volt ones have capacities from 75AH to 220AH.