My friends car has a dead battery. We don't know anyone around here who could help us immediately, but need the car asap.
I have a 12V, 17Ah Lead Acid battery, which someone left at my place about 18 months ago. It may or may not be charged. The only multimeter I have is rated for 13A, so I cant check it.
Should I just hook up the batteries and see what happens? Is there any way I can check the charge of the battery? I have a ton of electrical equipment lying around, but none of it is rated for high currents, and I am a bit skeptical of experimenting...
I think a 17Ah battery is a little underpowered compared to typical car batteries (I think they're in the ~50Ah range). But if it's fully charged it might work.
Your multimeter's current rating is not important, just set it to voltage measuring mode and measure the open-circuit voltage of your maybe-good battery. If it's not near 12V it has an even lower chance of working, as that indicates a non-fully-charged battery.
If you're careful, then yes, you can just hook up the batteries and see what happens. You do need big thick booster cables (else you'll lose a lot of whatever power you already have in the wiring, and in the worst case it will catch on fire). And make doubly sure you connect + to + and - to - (preferably, the dead battery - is not connected, but instead you connect the booster cable to a metal chassis point, like on the engine block, which is also -).
Wear eye protection, etc. etc.
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The Ruggeduino: compatible with Arduino UNO, 24V operation, all I/O's fused and protected
I agree with RuggedCircuits.
I would add: If the battery has been lying around for 18 months it has to be of a very good quality battery to still be charged.
Good luck
Jantje
I have two friends that independently have had a car battery explode. Fortunately, the end result in both cases was damaged clothing. The point of my post is...
thanks for the suggestions guys. seems like the discussion is mute, as the battery is dead.
yeah... eye protection... its important. i learned that one the hard way...
I still remember the face of the lady at the reception when I told her that I had hydro-chloride acid in my eye
I got lucky, but it changed my perspective on freak accidents...
