FutureTrackStar
New Member
I'm trying to charge my dead car battery (6.8 V) with a laptop charger (output is 19.5 V DC at 3.34 A, max power is 65 W). I figure I need a limiting resistor of about 4 ohms and 40 Watts. Where can I buy one of these?
Follow along with the video below to see how to install our site as a web app on your home screen.
Note: This feature may not be available in some browsers.
I'm trying to charge my dead car battery (6.8 V) with a laptop charger
Wait - STOP. Is this a 12 V car battery - as in a real car battery, with lead plates and liquid sulfuric acid? Meant for starting a car?
If it is, its very likely that battery is toast; possibly the plates are sulphated. The best thing you can do -first- is to put a real car battery charger/conditioner on it, and leave it on it for 24 hours. Then check the voltage; it should be around 14 volts. If it isn't, ditch the battery (take it to a place that will recycle it - you don't say where you are, but if you are in the USA, take it down to Checker/Oreilly/AutoZone and use it as a core) and buy a new one.
Don't continue to mess around with this one; it isn't worth it, and the way you are attempting to go about it might end up in a fire and/or injury...