Dual AGM Battery system

[Doug1]

As promised, I am passing on what I learned from the optima tech support person. While we know that not all AGM batteries are alike, some use lithium ion technology, etc, it goes deeper than that. In fact, even using the same storage technology, the best way to charge and maintain them varies. Here are the main takeaways from optima regarding their batteries.



1. If you have an Optima battery, you should have an Optima charger on hand. Just because a charger is designed to charge AGM batteries doesn't mean it charges an Optima battery the best. For Optima they only recommend charging when a battery is 20% discharged which they consider a deep discharge. For keeping the battery topped off they need a constant voltage of between 14.4 volts to 14.8 volts with 14.7 volts being ideal.

2. The battery should never really discharge while in the car if the alternator and regulator are working properly. The alternator should just do a topping off since the power to run the car is from the alternator while it is running. So it is important to start with a battery that has been charged with the proper charger to 100%. An alternator / regulator combination that supplies a constant 14.4-14.8 voltage at the battery is also needed to keep the battery in top condition.

2. The staged charging is more important if the battery is down to 80% or less and then you need to use their specific charger. The tech advised that on other brand of chargers, sometimes the Gel setting or the Flooded setting could be a better solution than the AGM setting! So they don't recommend using any other charger for that reason.

3. If you have two batteries then you should use a device that can make sure the batteries independently get exactly the 14.4 -14.8 volts each that they need. The tech stated she didn't have much expertise in this area but thought a DC-DC charger was a good idea if the alternator could support it.

4. If the car isn't driven regularly, an Optima maintainer should be connected to the car when it is not in use. This will pro-long the life of the battery.

So kudo's to Optima for addressing the question and limiting their answers to what they definitely know. So I need to find someone who is an expert multi-bank charging to address that specific area but the rest of the questions posed were well answered.