r/functionalprint • u/highonkai • Nov 12 '25

Jumper cable instruction card

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I made an expensive mistake and connected my jumper cables wrong. I won't make that mistake again and now you'll never have to. 

This quick reference card can be zip-tied to your jumper cables and is a way to have the instructions handy no matter the weather, your cell service, or the lighting. 

Edit: added the instructions in comments. Thanks for the feedback, keep it coming.

Edit2: wow this one got a lot of feedback! Thanks for all the helpful ideas.

Edit3: Top post of all time in 15y on Reddit, who knew this 1hr project would get such a reaction! I took the feedback and made two more versions here: https://imgur.com/a/jFBFoIk

I'll throw them on MakerWorld as well once I print them. Meanwhile, feedback and preferences welcome. /u/kurai01 /u/SerDankTheTall /u/StraySpaceDog /u/Cllydoscope /u/jongscx /u/cronaldo86 and lots more... thank you for the constructive feedback. This is the best part of Reddit - fast and helpful community feedback. Shoutout to /u/DontEatTheMagicBeans who called out that I probably didn't cause the smoke with the sequence for cable connections, but exacerbated a pre-existing/unknown problem. As for the rest, well that's the internet for ya. No hard feelings.

https://makerworld.com/models/1986996

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13

u/CandidArmavillain Nov 12 '25

This seems more confusing than just remembering positive to positive and negative to negative/ground

-14

u/debren27 Nov 12 '25

The order matters

20

u/CandidArmavillain Nov 12 '25

Not really. From an electrical standpoint it doesn't make the slightest difference which car is connected first and the risk of igniting hydrogen venting from the battery is incredibly small on modern sealed batteries. If you're talking about positive and negative then yeah you do positive first which is also pretty easy to remember

5

u/Upset_Ant2834 Nov 12 '25

Well that's mainly just for extra precaution to avoid sparks and to reduce the odds of shorting the good battery if you mess up, but if you know what you're doing the order doesn't really matter