In your garage you has a 14.4V drill and a 18V DeWalt battery. While they both appears to be roughly the same shape, they don’t fit together. The two batteries aren’t interchangeable because physical connectors is different, and using them together would of been destructive due to voltage difference.
They’re physically separate and built to accept certain amount of power. Trying to force them together won’t work it’ll probably ruin the device. However, bigger problem is voltage mismatch.
Why You Cannot Mix DeWalt Voltages
Why 14.4V and 18V Batteries Are Not Interchangeable
Your 18V battery has more voltage then your 14.4V tool can support. Because it’s a lower voltage tool, it have its windings and insulation designed to take less abuse. When you send an increased amount of voltage down those wires it will cause them to overheat and they’ll do so fast because current draw from the motor is exceeding what the components is rated for.
Dangers of Voltage Mismatch and Overheating
That heat builds within housing, melting plastic and creating potential fire hazard.
Physical Safeguards Against Wrong Battery Use
As an added layer off protection, batteries are also physically incompatible. The 18V pack has differently spaced contact pins and is longer then shorter 14.4V pack.
It will not fit in smaller tool because the housing prevents it. It’s a mechanical safeguard to keep user from accidentally plugging in incorrect power source. We have seen some customers try to reshape the contacts, use zip ties to get it to fit or even modify battery pack in an effort to make them fit.
That not only voids your warranty but poses massive safety concerns. You never want to bypass safety mechanisms from manufacturer. Electrical arcing will melt plastic contacts and destroy battery as well as tool itself.
Convenience isn’t worth the fire risk.
Understanding DeWalt Battery Generations
Confusion exists because older models of DeWalt tools came with 14.4V batteries. The old ones was made in the late nineties and early two thousands.
However, you need same generation battery pack that came on those tools. You can continue using these older units, but only with their respective battery packs. Don’t mix up generations of batteries, it won’t work.
Keep old batteries charged. Newer is the 12V MAX, which DeWalt shifted toward from old 14.4V system. It’s smaller tools, it’s a newer system with DeWalt switching over to that voltage.
You can swap 12V batteries between all of their tools, making it consistent system. If you have 14.4V tools, you can switch them to the 12V line and use their battery on your other tools too.
Benefits of Modern 18V System Compatibility
The beauty of moddern-day 18V batteries is that they are made to work on everything throughout the DeWalt line.
Saws, impact drivers, drills… all these takes the same 18V battery. That is why this system is so great now. And sticking with the 18V means all tools works together.
Safety Rules for Matching Voltage and Tools
Never mix voltages. If you have an 18V tool, use it with an 18V battery; if it’s a 14.4V tool, then use it with a 14.4V battery. Why?
It will save wear and tear on both your tools and extend there life. And more importantly, it will keep everyone in the work area safe. Naturaly we want to avoid luxurius mistakes like this so dont let it dissapear from mind or make a mistake based off wrong voltage.