Winterizing the AGM Battery System

Winterizing the AGM Battery System

Confirmed Issue:

Some van owners opt to store their vans over the winter rather than driving and using them.  Long-term storage requires caring for the AGM battery system.

Affected Units:

Any Vandoit van with an AGM battery system

Issue Explanation:

A van that sits unused is always drawing power.  Therefore, if you do not plan to use your van for a week or longer, you will want to take steps to prevent the battery system from draining so low that the batteries are in danger of being damaged.


1.  The best option for winterizing the AGM system is to keep the van plugged into shore power in a location where the rooftop solar panels can receive regular sunlight; this combination will keep the AGM system fully charged. Having both will serve as a backup in case any power issues arise with your shore power source.

2.  If your van is equipped with a Rear Battery Disconnect Switch (a large red switch on the rear-facing panel of the power cabinet), this switch can be used if access to shore power during winterization is not an option.  Be sure to charge the batteries to 100% before turning the switch to "off."

3.  If keeping the van plugged into shore power is not an option, or if your van is not equipped with the Rear Battery Disconnect switch, parking the van in a location where the rooftop solar panels can receive regular sunlight is the next best option.  

Note: You may wish to purchase ground solar panels that plug into the van next to the shore power plug.  Ground solar not only adds to the incoming power the van can receive, but the panels can be placed on the ground near the van or on the windshield.  This option is especially helpful when the van must be parked in shade or under a covering.  Contact the Customer Support team (see below) for information on purchasing ground solar panels.

4.  If keeping the van plugged into shore power or accessing solar power are not options, the Vandoit AGM batteries can be disconnected by removing the power cables from the battery terminals to stop the draw of power.  (This may require removing a panel from the power box using a 4mm allen wrench.)

Note: Make sure shore power is disconnected and the vehicle is turned off before removing Vandoit AGM batteries. 

5.  Disconnect the power cables from the battery terminals starting with the positive first and then the negative. The longer positive red cable should be removed and covered with electrical tape or a rubber cap to prevent contacting metal when repositioning it to get the batteries out. 

Be aware that it may take 2 people to remove the batteries safely due to their weight (approx. 66 lbs each).

6.  Store the batteries in a warm, dry location such as a heated garage, and attach them to a battery tender.  (If batteries are only disconnected and not attached to a battery tender, they will lose up to 3% of charge per month.)

7.  When you are ready to use the van again, make sure it is not plugged into shore power.  Detach the batteries from the battery tender and install back in the van, reconnect the power cables to the battery terminals the same way they were removed, and then wait for the system to kick back on. Voltage readouts in the van should show around 12.8 volts. 

If you used the Rear Battery Disconnect Switch as directed in step 2 above, turn the switch to "on" and then start the vehicle's engine.  If your van is equipped with the Front Isolation Switch (a similar red switch near the driver's seat or under the hood), make sure it is also switched to "on."

If the resolution steps above do not provide the direction you are seeking, please contact the Customer Support team by submitting a ticket through the Customer Support portal or emailing


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