I have two Interstate AGM 31 series batteries for electronics, one for a Mercury four-stroke 250 engine, and three additional batteries for the trolling motor. I haven’t had any issues with the trolling motor batteries; however, after two or sometimes three hours of fishing, I often experience low voltage on my Humminbird unit at the dash. My Humminbird unit reads 12.6 to 12.4 volts, and my Garmin LiveScope unit at the front stays at 12.2 volts. I also have a Noco four-bank charger set up for the appropriate batteries.
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I never had any warning signs before taking my boat to B.A.S.S. Pro. They told me I needed new batteries, and I agreed(due to age only) I didn’t want to risk power issues during the season. I told them to install the best option, and they put in two Group 31 AGM Interstate batteries.
Everything seemed fine at first, but about a month later, I started experiencing a consistent loss of power to the point where I couldn’t even crank the engine. They replaced one of the batteries with the same model, and so far, I haven’t had issues. However, I’m still seeing voltage fluctuations similar to what I experienced when I couldn’t start my motor before. The strange part is that before I ever took it to B.A.S.S. Pro, I never had low-voltage warnings.
To make matters worse, in between all of this, they initially wired it incorrectly—running power to the trolling motor from the main motor, which caused electrolysis. They claimed to have fixed that, but now I’m left wondering why these new batteries aren’t performing as expected.
If I hadn’t just bought these, I’d switch to lithium, but for now, I need to figure out why my system isn’t working properly when it was before. The only difference is that I previously ran the same battery setup, just not with the Interstate brand.