Understanding the AGM Battery System

Understanding the AGM Battery System

Article Objective:

In this article, you will get to know the components that make up the AGM battery system in your van: what they do, what their potential limitations are, and how to maintain/store the system if not being used for long intervals.

Affected Units:

Vandoit vans with the AGM battery system

What components make up the AGM battery system?

The AGM system in your van does not solely include the batteries, but several components that serve to manage power.  The components in the AGM system in your van are:
1. 3-in-1 GoPower IC 2000 Inverter/Charger
2. Automatic Charging Relay (ACR)
3. Three 100 Amp AGM Batteries
4. GoPower Inverter/Charger Remote

What does each component do?
1.  The 3-in-1 GoPower IC 2000 Inverter/Charger performs 3 functions: 1) It converts incoming DC current to 2000 watts of AC current that powers many of the van's devices--namely, those devices plugged into the van's 120 volt wall outlets.  2) It operates as a 100 amp DC charger to charge the batteries from shore power.  3) It operates as an AC transfer switch, which allows the AC-powered devices to be powered directly from shore power when it is plugged in, as opposed to inverting the battery power.


2.  The Automatic Charging Relay (ACR) is a relay that connects and disconnects the Vandoit batteries to the Ford chassis battery based on voltage.  More specifically, when the van engine is turned on, once the chassis battery is fully charged, the ACR connects so that the Vandoit batteries will begin receiving a charge from the chassis battery.  Shortly after the van engine is turned off, battery voltage begins to drop, so the ACR will disconnect so that neither battery system drains the other; both battery systems remain closed and power preserved in them.  The ACR is the large yellow tear-shaped switch in your power box. There should not be a need to change the position of the switch yourself, except if needing to isolation the your rear batteries from your Ford chassis battery; see below.  If you have questions or concerns about the ACR switch in your van, please contact the Vandoit Customer Support team. 


A second part of the ACR is a red override switch, located on the front of the power box, that has 3 positions: ON, AUTO, and OFF.  The AUTO position allows for power to flow between the Ford chassis battery and the Vandoit battery system when high enough voltage is reached in either battery system, i.e. plugging in shore power or starting the engine.  In the event that the Ford chassis battery dies but the Vandoit batteries still have power, switching it to the ON position will allow the Vandoit batteries to send a charge to the Ford chassis battery--in essence, jumping the car battery.  The OFF position prevents the two battery systems from connecting at all. We recommend the AUTO position for normal use.


3.  Three 100-amp hour, deep cycle, lead acid AGM batteries are wired in parallel so they act as one large 300 amp hour system.  AGM batteries are the same kind of batteries used in most vehicles.  The battery system receives a charge from shore power, the Ford van battery, and/or solar panels; stores that charge; and powers to the devices in the van.  These batteries can be maintained and stored much like you would a typical vehicle battery.


4. The GoPower Inverter & Charger Remote allows you to turn the inverter on and off, which allows power to flow to wall outlets and the rooftop Dometic penguin ii air conditioner. Use the INVERTER ON/OFF button on the top left to turn the inverter on (see below), and turn the inverter off when power to the outlets or air conditioner is not needed. The GoPower Remote also allows you to check the battery system's charge state and charge level.  If "CHG" is visible in the bottom row of the remote screen, the system is currently receiving a charge from shore power.  If "INV" is visible in the bottom row of the screen, the system is currently inverting incoming DC power to AC power.  See photos below for reference.

To understand the charge level of your battery system, it is helpful to know that if the remote is reading 12.8 volts or higher, the system is fully charged, when sitting idle.  Readings closer to 11 volts mean that the battery charge is getting low.  In fact, an automatic timer disconnect is set to shut the system off at 11 volts in order to protect battery health.  At 11.8 volts, it is best to begin charging the van from shore power, solar, and/or driving the van. 

A general guide to AGM battery state of charge:
12.8+ volts = 100% state-of-charge
12.05 volts = 50% state-of-charge
11 volts = 0% state-of-charge

As a helpful reference, one of the settings on the GoPower solar remote shows the battery charge as a percentage instead of a voltage reading. This percentage is not always accurate, as there can be variation between the two controllers

Location of Inverter On/Off button, system charging
 
System inverting


What are the limitations of the system?

1.  The Dometic penguin ii rooftop air conditioner cannot be powered from the AGM battery system; it must run while the van is plugged into shore power.

2.  The AGM battery system can power standard electrical devices for 1.5 to 2 days without recharging the batteries.  Standard electrical use includes powering lights, MaxxAir vent, TV, Dometic refrigerator, and moderate use of the AC-powered electrical outlets in the van.  Off-grid camping for more than 2 days or use of electrical devices more than what is described here may be challenging to accomplish with the AGM system.


Maintaining/Storing the AGM System if Not Being Used for Long Intervals

1.  The best option for storing 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.

2.  If keeping the van plugged into shore power is not an option, 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 receives, 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 for information on purchasing suitcase solar panels.

3.   Disconnect the power cables from the battery terminals.



4.  Store the batteries in a warm, dry location such as a 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 10% charge per month.)


Do you have additional questions about your AGM system?

Be sure to read other articles in the Vandoit Knowledge Base library about the AGM system.  If these articles do not provide the answers you are looking for, please submit a ticket through the Customer Support portal or email support@vandoit.com.
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