Too much voltage becomes too much pressure, and pop. That one-way valve is supposed to relieve excess pressure from the harmless gases that come when a battery’s charging. However, voltage greater than 15 volts can overheat an AGM and generate enough pressure to pop its safety valve. Regular batteries need 15-17 volts to get the same amps.

Regular battery charging can break AGM batteries. This is also why an AGM battery needs special charging. They need slow, low-amp charging to prevent overheating - and they need more volts to push through their internal resistance.ĪGM batteries don’t have nearly as much internal resistance, which is how they absorb 30, 40, even 50 amps at a time instead of a regular battery getting stressed out at more than 10 amps. It takes time to charge regular batteries. Pick up the smart charger that guards your car battery’s life, the 4-amp Interstate Guardian battery charger, available on Amazon.ĪGM batteries can absorb more current than a regular car battery, which is why they can recharge faster. The Guardian battery charger is safe for AGMs! However, a regular charger could exceed 17 volts when charging a battery. AGM chargers go through the three charging phases (bulk, absorption and float) just like a regular charger. Some battery chargers offer an AGM or Absorbed setting to meet those special charging requirements.Īn AGM-compatible battery charger sends more amps into a lead-acid battery while keeping the voltage less than 14-15 volts. You want to raise its charge without raising its temperature.ĪGM batteries have special charging needs. The solution is to charge your battery slowly.

That means the battery’s insides corrode much faster. In turn, the liquid inside gets more acidic.

If it gets too hot, the water inside the battery evaporates. Now you’re ready to hit the road with a fresh start.Ĭharging your car battery will warm it up.

Reconnect the car’s negative terminal to the battery.

Again, avoid letting the charger’s clamps touch the battery’s loose negative clamp. Your charger’s indicator light will signal when it’s done charging the battery.

Disconnect the charger from the battery when it’s done.

Start the charger and wait two to eight hours to fully charge your AGM battery.

Again, check the indicator lights and make sure they’re set to AGM or Absorbed.

Connect the charger to your car battery posts.

Select 12 volts to match the voltage of your AGM battery.

A smart charger may detect the voltage and battery type when you connect it, but don’t leave it to chance. IMPORTANT: Select AGM or Absorbed for the battery type on your charger.The negative cable is usually black, but you can also look for a minus (-) symbol on the cable as well. Disconnect the car’s negative terminal and wrap it with a glove, rag or anything to prevent it from touching any metal.Connect a backup power supply to the onboard diagnostics OBD-II Port.Follow any other instructions for your specific charger. Plug in your AGM-compatible battery charger.Pick a battery charger from the battery expertsĪvailable now on Amazon, Interstate Batteries offers smart battery chargers with models ideal for maintaining or full-power recharging.īefore anything, take off any jewelry, put on safety glasses and go to a well-ventilated area or outdoors.

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