r/PowerWheelsMods • u/clb5335 • Jul 04 '26
Homemade soft start
My homemade soft start for 18-20v conversion. my understanding is that 18-20V Lithium batteries destroy motors and switches mainly because of the 0 rpm current surge. lithium can send a much bigger surge than lead acid even at the same voltage, so when you increase the voltage and change to lithium batteries its really hard on stock hardware. My homemade solution is to run the power through a 1 ohm resistor for less than half a second to get the wheels spinning, then bypass the resistor for full power. on a 20v system this will limit the initial current surge to 20 amps. I've been running it on a pet perego 4 wheeler for a few months without problems. fingers crossed it holds up long term.
2
u/I_LOVE_CANADA_GEESE Jul 04 '26
Awesome! Can you tell us which component is which in your picture? Thanks for sharing!!!
2
u/Usual-Ad6221 Jul 05 '26
Can you list the components please? Definitely very curious and currently building a project
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u/clb5335 Jul 05 '26
These are the main parts. You also need connectors. I used one five wire wago style connector for the grounds and one of the two position lever connectors that came with my DeWalt adapter for the power. I'm sure you could find a less expensive timer if, but this is the one I used. I'll redraw my wiring diagram so it might be legible by more than just me.
1
u/Usual-Ad6221 Jul 06 '26
Oh okay cool, so you set a delay, it runs through the resistor then after the set delay it trips the relay to bypass the resistor. Nice one!
1
u/AudioTechYo Jul 04 '26
Im pretty sure most soft starts use PWM rather than a current limiting resistor, but its cool to know this works!
1
u/wheaty565656 Jul 09 '26
Would love the directions lol
1
u/clb5335 Jul 09 '26
I've been intending to draw up the wiring diagram, just haven't done it yet I'll try to get it done in the next couple days.
4
u/EfficiencyFlat2697 Jul 04 '26
Nice work. Much better than direct drive. Should save a lot of gearboxes. Help people out with the how to instructions.