Toddler EV Gets Big Boy Battery Upgrade

No matter the type of vehicle we drive, it has a battery. Those batteries wear out over time. Even high end EV’s have batteries with a finite life. But when your EV uses Lead Acid batteries, that life is measured on a much shorter scale. This is especially true when the EV is driven by a driver that takes up scarcely more space in their EV than a stuffed tiger toy! Thankfully, the little girl in question has a mechanic:

A 3d printed adapter sends go-juice to the DC-DC converter

Her daddy, [Brian Lough], who documented the swift conversion of his daughter’s toy truck from Lead Acid to Li-Ion in the video which you can see below the break.

Facing challenges similar to that of actual road worthy passenger vehicles, [Brian] teamed up with [bitluni] to solve them. The 12 V SLA battery was being replaced with a 20 V Li-Ion pack from a power tool. A 3d printed adapter was enlisted to break out the power pins on the pack. The excessive voltage was handled with a DC-to-DC converter that, after a bit of tweaking, was putting out a solid 12 V.

What we love about the hack is that it’s one anybody can do, and it gives an inkling of what type of engineering goes into even larger projects. And be sure to watch the video to the end for the adorable and giggly results!

Speaking of larger projects, check out the reverse engineering required in this Lead Acid to Li-Ion conversion we covered in 2016.

13 thoughts on “Toddler EV Gets Big Boy Battery Upgrade

    1. I did exactly this to my kids ride on. I used a Makita adapter from AliExpress rather than printing my own as all my tools are Makita. Interestingly Makita batteries, and probably others, have the undervoltage protection in the tool not the packs. Make sure there’s some provision for this or you’ll kill packs.

      1. Ryobi ONE+ has it in the battery to make the lithium ion ones compatible with the old blue and orange tools. Also allows for the new tools to cost less since all they need is a switch and a motor.

        1. Ryobi also have short circuit protection too, I did this hack on our power wheels and had to use a beefy buck converter, but I really like the Ryobi one+ Lithium batteries, its nice that they have a BMS on board.

  1. I recently replaced the SLA batteries in the new-to-us razor mx500 electric dirt bike for my 4 year old. Luckily though Amazon sold LiFePO4 batteries in 12V, so they were direct swap. I considered a hack like this since I have a ton of liion batteries for my power tools, and his older mx350 motorcycle’s SLA are pretty worn… But that bike doesn’t have a front brake or shocks which are necessary on longer hikes (we walk, he rides).

    1. Took the family for an off-road camping adventure this past weekend and had to modify my 7 yr olds Razor Dirt Quad to keep up with our gas powered go-karts, dirt bikes and ATVs. It’s a 24V system with a pair of 12V 7Ah SLA batteries. Found room under the body to add a second battery bank with a pair of 9Ah SLA’s to more than double his range. Selecting banks is done with a body mounted rocket switch. He wanted to keep up with his older brothers 60cc dirt bike so I also added a “Turbo” switch that added a 3S lithium ion (from a Traxxas R/C) in series to boost the system to ~36V without any apparent issues to the stock electronics. Also added a 24V 15A stepup voltage regulator from Amazon with battery clamps which allowed us to remove the 12V lead acid battery from the go-cart and ATV to power his Razor Quad (then used the charging coil in the gas units to recharge his SLA pack on the trail). The Razor Quad is priced like a power wheel but much capable and surprisingly well engineered. I found that the chain drive had a really quality tensioner with ample adjustment so I also added a 2nd smaller drive sprocket along side the factory sprocket. A simple spacer block slides under the motor allowing tool-less switching between low (regular) and high gear ranges. Oh, also stopped by Tractor Supply and picked up a set of “tractor tires” for his back wheels. Worked excellent.

      I’m also considering some additional rewiring to allow the Razor’s motor to charge the units battery packs when it’s towed by our gas units on the trail

  2. Ridgid batteries have an internal BMS, a lifetime warranty, and will work drop in (you will get a bit more speed). I used a spare charger for the battery adapter. Also, the only difference between 18v batteries and 20v batteries is marketing. As a side note (and for extra points) you can pick up 18v scooter controller and a pedal for fairly cheap, then you don’t have the annoying all on or off issue of the stock pedal. I also got a cheap remote on/off module that has a keyless entry like fob so I could remotely deactivate it if the driver was about to do something dumb.

  3. I did this after seeing it on dude dad, a couple years ago. I put my DeWalt battey pack in my sons truck. I also wired up headlights:) I used one of the motor controllers to limit the speed.

  4. I replaced the 4 stroke engine in my daughter’s quad with a 1000 watt electric motor using my 48 volt ebike battery as power source . It’s way way way too strong and fast now. Now i have to find a way to make it child friendly again

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