How To

AGM Battery Management

Does your van have a power system with AGM (Absorbent Glass Mat) batteries? Follow these steps for how to best maintain them for a long and happy lifespan!

If you have any questions about the procedures covered in this video, please reach out to our service and warranty department at See you on the outside!


Absorbent Glass Mat, or AGM, batteries are maintenance free, provide great electrical reliability, and stand up well to below freezing temperatures. AGM batteries have around 900 charge cycles in their lifespan. A cycle is defined as a period of discharge followed by a period of charge, ideally to full capacity.

To maximize your battery’s lifespan, your battery should always be kept above a 60% charge, and be sure to avoid letting your battery ever go below 10 volts: the lower you discharge your batteries and the longer you leave them partially discharged, the shorter their life will be. It’s best to remember that to maximize your battery’s life, you should keep them as close to fully charged as possible. Avoid only partially charging your battery. When you partially charge AGM batteries, with time they will lose their ability to charge to full capacity. If you plan to store your van for long periods of time, be sure to leave your van plugged into shore power, or check on your battery’s state of charge every couple of weeks.

Always remember that even if all the systems in your van are turned off, such as a fridge, lights, and appliances, your overall electrical system will lose about 2% per day. This is due to the diagnostic programs from your Webasto control panel and the inverter control panel that are functioning in the background at all times.

To use shore power to charge your powersystem installed by Outside Van, open the hood and you’ll find the charging socket on the right hand side. Plug the 15 Amp locking shore power cord into the socket and then into the outlet you are drawing power. Then drape the cord out the side and close your hood. These shore power cords are issued by Outside Van and can be plugged in almost everywhere.

Since AGM batteries use lead acid, its best to charge them when temperatures are between 32 and 104 degrees Fahrenheit. Though, AGM batteries can still take a charge in below freezing temperatures, it will only charge slower.

If you follow these tips, you should expect your AGM batteries to last between 5 and 7 years.