Simply taking a multimeter and checking battery voltage isn't enough.
We use the latest proven digital load testers to check every cell in the battery. Voltage can lie to you, but doing a heavy amperage draw while measuring voltage is the best way to fully impact a battery and its continued cranking amps. Even if batteries are not 100% charged we can tell you if its time to replace. We work on all batteries, 10, 12 volt or 6, Lead Acid or AGM.