The Underpowered Battery

Absorbent Glass Mat (AGM) batteries including Optima, Odyssey, Duracell Platinum, AC Delco Gold/AGM, Northstar, and XS Power, typically require a slightly higher charging voltage compared to flooded lead-acid batteries. AGM batteries have a different internal construction and electrolyte containment method compared to traditional flooded lead-acid batteries.

Flooded lead-acid batteries have free-flowing electrolyte, while AGM batteries use a fiberglass mat to hold the electrolyte in place. This design difference impacts the charging process. AGM batteries are generally more sensitive to voltage fluctuations and can be damaged if not charged properly.

AGM batteries usually require a charging voltage of around 14.4 to 14.7 volts for a 12-volt battery, which is slightly higher than the 14.2 to 14.4 volts typically used for flooded lead-acid batteries. It’s important to follow the manufacturer’s recommendations for charging voltage to ensure the longevity and performance of the battery.

 It’s crucial to understand the specific requirements of the AGM battery you are using to avoid overcharging or undercharging, both of which can lead to reduced battery life and performance.

GM Diode (Hint: It’s NOT a fuse)

A common misconception amongst DIY enthusiasts is that a diode commonly referred to as the “GM Diode” can be safely used in place of your alternator sense fuse. However, replacing the OEM fuse with a plain diode is unsafe as it removes the fuse protection of that circuit. NO, the “GM Diode” is not a fuse. And NO, just because it has a 1A load rating does not mean it behaves as a fuse with a 1A rating nor should you use any non-fuse component to act as a fuse. 

PTC Fuse (AKA resettable fuses)

Another popular manufacturer of boosters utilize a PTC fuse with their diode. It has a temperature component such that when a short occurs and this component heats to a predictable temperature, the fuse opens. After the component cools, the fuse closes and power is restored. This is a safer option when compared to the plain “GM Diode” as now you keep a fused circuit design in your vehicle. However, PTC fuses are not ideal for vehicle battery connections. You do not want a fuse to reset in your vehicle automatically due to a circuit fault or short circuit. Just like the a circuit breaker in your house, you do not want a short circuit to trip your breaker, only to have it reset itself an infinite amount of times. You need to find the short in your wiring or electrical device before more damage is done. 

PTC’s are convenient for manufacturers since they are small and cheap, but not ideal for high amperage capable circuits found in your expensive vehicle. That is why there are no PTC’s on any of the high amperage capable circuits in your vehicle!

VoltageBoosterPRO uses standard commonly available automotive ATM fuses that you can find at any store that has fuses. If your fuse blows, the first action to take is to find what is causing the fuse to blow. Once you determine the fault has been corrected, you can simply install a new fuse. Fuses were engineered into every vehicle for a reason, and you should not defeat that purpose by putting a “GM diode” or an inferior resettable fuse in a standard fuse’s place.