Is it safe to run a 12 volt 3.5 amp pump using a 12volt 7 amp battery.?
Yes. But the battery will run down quickly. The amperage of the battery is its capacity. If you attempted to run a 7 amp pump on a 3.5 amp battery, it couldn’t do it. Wouldn’t hurt anything, but the pump wouldn’t run. And the battery would drain. Always keep the correct voltage and polarity, and remember that the size of the battery is rated in amp hours. Theoretically a 7 amp battery will deliver 7 amps per hour. In reality, you won’t quite get that much because the battery will be loosing power as you go. As the battery warms up, you experience a voltage drop. ADDITIONAL: You could do as mark suggests, but the battery will not force a device to take more current than it can handle. Current is the result of voltage over resistance. The more the pump resists current, the less the current flows. Remember, the battery will PUSH 12 volts but OFFER 7 amps. Using a motor rated for 6 volts will result in an over current situation because the resistance of the 6 volt motor will be lower. The
