The short answer
- No, don’t do it. A 12V battery on a 6V Power Wheels, or on any 6V ride-on, doubles the voltage on motors, gearboxes, switches and wires built for 6V. Two 6V batteries wired in series do the same, and a drill battery is worse.
- What happens: a car made for a toddler or preschooler goes about twice as fast, the motors run hot and can burn out, the plastic gears can strip, and switches, plugs and wires can overheat. Mattel’s manual says never to modify the electrical system because it could cause a fire, and doing it voids the warranty.
- Want more speed? Try the safer ways to get more speed first, starting with a full charge. If your child has outgrown the 6V car, move up to a 12V ride-on.
Safety first: use only the battery and charger made for the car. Mattel’s 6V manual says other batteries or chargers “could cause a fire or explosion”, and that only adults should handle and charge the battery. Before any battery or wiring work on a ride-on, read the safety rules in the speed-mod guide and are ride-on cars safe.
Outgrown the 6V car? See the best Power Wheels for ages 3 to 7 and the best 12V two-seaters. For big kids, see the best 24V ride-on cars and the fastest Power Wheels.
On this page
Can you use a 12-Volt Battery on a 6-Volt Power Wheels Car?
Not safely, and I don’t recommend it on any 6V ride-on. A 12V battery will make a 6V car move, and at first it moves about twice as fast.
But everything between the battery and the wheels was built for 6V: the motors, the plastic gearboxes, the pedal or push-button switch, the wires and the plugs. At 12V they all work far harder than they were made to, and something gives.
Most 6V ride-ons are made for toddlers and preschoolers. Of the 19 6V ride-ons in my spec database, 16 top out at 2.2 mph or less, and they’re rated for kids somewhere between 1 and 6.
Mattel’s 6V Kawasaki Lil’ Quad, for example, is made for ages 12 to 36 months and up to 40 lb, and it goes 2 mph, forward only. That’s walking pace on purpose, so you can keep up with a child who’s still learning to steer and stop.
Unless the new battery plugs straight in, it also means cutting into the wiring or adding an adapter. Mattel’s 6V manual is clear about that: “Never modify the electrical system.
Alterations could cause a fire.” Other makers agree: Aosom’s manual says never to swap in another brand’s battery or charger, and Peg Perego’s says to repair its cars only with its own parts.
Two 6V batteries wired in series (the + of one to the − of the other) add up to 12V, so the car’s parts get exactly what a 12V battery would give them. Some older 12V Power Wheels, Mattel’s Preschool and Advanced Series, did run on two 6V batteries from the factory, but those were 12V cars with parts to match. A 6V car isn’t.
A drill battery is worse. An 18V (20V MAX) tool pack is three times the voltage a 6V car was built for.
What Happens When You Put 12V on a 6V Power Wheels
Here’s what doubling the voltage does, part by part.
How much speed and power do you want?
Using a 12-volt battery on a 6-volt toy will most likely double its power and top speed. Most 6V ride-ons go about 2 mph from the factory (here’s how fast 6V and 12V Power Wheels go). So is this something you would like to have? For a 6V car, my answer is no. Twice 2 mph is roughly 4 mph, close to a 12V Power Wheels in high (5 mph), in a car made for toddlers and preschoolers. Mattel’s 12V Power Wheels are for ages 3 and up, and many ship locked in low (2.5 mph). Mattel says to unlock high only once your child can steer, start and stop.
“Double the power” also undersells it. Every time the car starts, or a wheel stalls against grass or a curb, twice the voltage pushes twice the current through the motors, and that’s up to four times the heat in parts made for 6V.
A 6V car is made to stop from about 2 mph when your child lets go of the pedal or button. At twice the speed, it needs more room to stop.
The motor rating
A ride-on motor’s speed rises roughly in step with its voltage, so a 6V motor on 12V spins about twice as fast. It also runs much hotter, the brushes and windings wear quickly, and it can overheat and burn out. Doing this properly would take motors rated for 12V that fit your car’s gearboxes (see what a real conversion takes).
The gearboxes
Ride-on gearboxes use plastic gears sized for the motor they came with. More speed and harder starts can strip them. Mattel’s 12V manuals list a loud clacking or grinding noise from a motor gearbox as broken gears, and the motors and gearboxes section of the speed-mod guide explains why overpowered cars break them.
The switches, wires and plugs
The pedal or push-button switch, the thin wires and the plastic plugs were sized for a 6V car’s current. At 12V they carry more of it, most of all at every start, so contacts and plugs heat up.
One ride-on builder’s wiring guide reports melted connectors and failed pedal switches after motor upgrades that pull more current, and heat in a switch or plug is a fire risk, not just a repair. Even factory wiring can overheat: in 1998, Fisher-Price and the CPSC recalled about 10 million Power Wheels over overheating electrical parts, after about 150 fires were reported.
A 6V car with a parent remote runs its motors through a small receiver board, and that board is a 6V part too (replacement boards are sold by voltage). At 12V it gets twice what it was built for, and it’s the part you count on to stop the car from the remote.
The thermal fuse
A genuine Power Wheels 6V battery has a built-in thermal fuse. Mattel’s manual says it trips and shuts the car down when it’s overloaded, and resets after about 25 seconds.
Swap in a generic 12V battery, or two generic 6V batteries, and that protection is gone. A 12V Power Wheels battery has its own fuse, but it’s made for a 12V car’s motors and wiring, not a toddler car’s.
A fuse doesn’t make 12V safe anyway. It cuts the power on a short or a heavy overload, but motors and gears can wear out at twice their voltage without ever tripping it. Never bypass a fuse or fit a bigger one.
Size of the battery
A 12V battery is bigger and heavier than a toddler car’s 6V battery. Mattel’s blue 6V toddler battery is 4Ah and weighs about 2.2 lb, so a 12V battery usually won’t fit the battery bay or the retainer, and two 6V batteries take up even more room.
That matters: Mattel warns that a battery can fall out and hurt a child if the car tips over, and says to always use the battery retainer. A drill battery is small, but it’s 18V.
The charger
A 12V battery needs its own 12V charger. The car’s 6V charger can’t charge it, and a 12V charger on a 6V battery overcharges it. Mattel says other batteries or chargers could cause a fire or explosion.
Even the red and blue Power Wheels 6V batteries use different chargers. See how to charge Power Wheels batteries.
The warranty
The Power Wheels warranty (one year on the car, six months on the battery) covers normal use only. It doesn’t cover damage from misuse or improper service, and Mattel’s manual says any sign of a consumer repair voids it. Peg Perego’s manual says it assumes no liability if the electrical system is tampered with.
Converting a 6-Volt Power Wheels to 12-Volt: What It Really Takes
A real conversion isn’t a battery swap. It’s the same kind of job the speed-mod guide describes for taking a 12V car to 24V, with every part matched to the new voltage. On a 6V car that means:
- 12V motors and gearboxes that fit your exact model.
- A pedal or button switch and wiring rated for the higher current, and a 12V receiver board if the car has a parent remote.
- A fuse on the + wire, close to the battery, with the wire gauge and fuse sized together (see where the fuse goes).
- A 12V battery that fits the bay and is held down by the retainer or a strap.
- The charger made for that battery.
- An adult doing all of the work, and the Power Wheels warranty gone.
My take: for a 6V toddler car it isn’t worth it. You’d replace most of the car’s working parts, and the frame, seat, wheels, weight limit and age rating would still be the 6V car’s. A 12V ride-on comes with all of it matched, a warranty, and usually a low speed for learning.
Is there a DC-DC converter?
No. A Power Wheels doesn’t have a DC-DC converter that steps the battery voltage down for the motors. On most models the battery feeds the motors through the pedal and the shifter or push button, so there’s nothing in there that could make 12V safe for 6V parts.
You could add a step-down converter that turns 12V into 6V, but then the motors get 6V again and the car goes no faster. On ride-ons, a step-down converter’s real job is running 12V lights or a sound module on an 18V or 24V car. It’s for accessories, not the drive motors.
Read the Power Wheels specifications.
Your manual and the label on the battery tell you what the car was built for: the voltage, the battery and charger part numbers, the age range and the weight limit. Mattel’s Lil’ Quad manual, for example, lists a 6V 4Ah battery, a 6V charger, ages 12 to 36 months and 40 lb. Those limits don’t change when the battery does. The battery guide lists the Power Wheels batteries and chargers by part number.
Safer Ways to Get More Speed
Charge or replace the 6V battery first
A 6V car that feels slower than it used to usually has a tired battery. Charge it fully on its own charger for the hours in your manual.
For a Power Wheels, Mattel says at least 18 hours before the first ride, at least 14 hours after each ride, and never more than 30. Mattel puts average battery life at one to three years, so if yours is older, test the charger and battery or replace the battery with the same type (red with red, blue with blue). The battery guide has the Power Wheels 6V batteries and a 6V battery for other small ride-ons.
Check the speed switch
If your 6V car has a high/low switch, make sure it’s set to high. Many 6V toddler cars have one forward speed, so there’s nothing to unlock. On many 12V Power Wheels, the high-speed lock-out screw is the free fix: it takes the car from 2.5 to 5 mph.
Move up to a 12V ride-on
If your child has outgrown 2 mph, that’s the real answer. A 12V Power Wheels is rated for ages 3 and up and goes 2.5 mph in low and 5 mph in high, and the two-seaters carry up to 130 lb. Many other 12V ride-ons come with a parent remote, which helps while a new driver learns. See my Power Wheels picks for ages 3 to 7 and the best 12V two-seaters.
Already have a 12V car?
Start with the lock-out screw. After that, the speed-mod guide shows the 18V upgrade for 12V cars, with a matched 6V battery added in series or a drill battery on an adapter with a low-voltage cut-off.
It makes a 12V car roughly 50% faster, with a fuse on the + wire every time. It’s a real modification: an adult does the work and watches every ride, your child wears a helmet, the stock motors and gears wear faster, and it voids the warranty.
Buy speed instead of building it
For an older kid, a ride-on built for more speed comes with the motors, gearboxes, wiring and age rating to match. See the fastest Power Wheels, the best 24V ride-on cars and Power Wheels for big kids.
FAQs For 6 Volt to 12 Volt Power Wheels
Which is faster, a 12V or 6V Power Wheels car?
A 12V. Mattel’s 6V Lil’ Quad goes 2 mph, forward only, and its 12V cars go 2.5 mph in low and 5 mph in high. Most other 12V ride-ons in my spec database top out between 2.5 and 4 mph, so check the listing. Here’s more on the difference between 12V and 24V cars.
Can changing from 6V to 12V damage my Power Wheels car?
Yes. A 12V battery, or two 6V batteries in series, doubles the voltage on motors, gearboxes, switches and wiring built for 6V. Motors can burn out, gears can strip and wiring can overheat. Mattel’s manuals say never to modify the electrical system because it could cause a fire, and any sign of a consumer repair voids the Power Wheels warranty. Don’t do it on a 6V car.
What if I have a 12V car but want more speed?
Check for a high-speed lock-out screw first. On many 12V Power Wheels, removing it takes the car from 2.5 to 5 mph. After that, the speed-mod guide covers the 18V upgrade (a 6V battery added in series, or a drill battery conversion), which is roughly 50% faster. It needs a fuse on the + wire, an adult doing the work and a helmet on every ride. Batteries in series must match and need the right charger, and a drill pack needs a low-voltage cut-off and its own tool charger. If the battery is just old, a same-voltage replacement battery can bring back the speed it had when new.
How do DC-DC converters work?
A DC-DC converter changes one DC voltage into another. A step-down (buck) converter lowers the voltage, like 12V to 6V, and a step-up (boost) converter raises it. Neither makes a 6V car faster: step 12V down to 6V and the motors just get 6V again. Power Wheels don’t use one to run the motors.
How do you upgrade a 6V Power Wheels car?
Not with more voltage. Charge the battery fully, replace it with the same type if it’s old, and set the high/low switch to high if the car has one. The speed-mod guide’s 6V section covers the same checks. If your child has outgrown the car, the upgrade is a 12V ride-on.
Why does my car move slow when I put in new batteries?
Check the charge first: Mattel says to charge a new Power Wheels battery for at least 18 hours on its own charger before the first ride, and a meter check tells you if it’s really full. Then check that it’s the right battery for the car and the plug is pushed all the way in. If the car stops and runs again after about 25 seconds, the thermal fuse is tripping from too much load, like extra weight, hills or soft ground. Many new 12V Power Wheels also ship locked in low (2.5 mph) until you remove the lock-out screw. More in how to fix a ride-on car that’s not working.
Are there 12V Power Wheels cars you can buy?
Yes. See the best 12V two-seaters and my Power Wheels picks for ages 3 to 7. For bigger kids, the 24V ride-on cars are faster.
Conclusion
Keep a 6V car on its own 6V battery and charger. If your child has outgrown 2 mph, move up to a 12V ride-on. If you already have a 12V car, our guide on how to make a Power Wheels faster shows how to add speed with a fuse and the right parts.
Kevinsmak
Power Wheels dad. Writing RC Ride On Cars since the start.
Hello! I'm Kevinsmak; I have been a content producer of RC Ride On Cars since the start of this site. I have always enjoyed Power Wheels with my family. My two boys love them, and seeing this helps me make sure this website is very accurate for the safety and enjoyment of your family.
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