In trying to revive an old lead acid battery I have drained the acid solution from the battery and am attempting to clean the plates with an Epsom salt solution however once drained there seems to be a dead short between the two terminals of the battery.

It is my understanding that the plates inside the battery are not connected directly to each other but through the electrolyte solution, if this is the case should I not expect the two terminals to not be connected together and is this a sign that the battery has an internal short, or is there something I'm missing? Thanks.


closed as off-topic by Leon Heller, Dave Tweed Apr 6 '18 at 12:00

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  • \$\begingroup\$ What's a 'dead short' to you? \$\endgroup\$ – Dmitry Grigoryev Apr 6 '18 at 10:46
  • \$\begingroup\$ Continuity detector shows that there is a connection and my multimeter reads 0 ohms resistance so I would assume a "dead short" means two of the plates are connected to one another \$\endgroup\$ – Alessi 42 Apr 6 '18 at 11:06
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    \$\begingroup\$ you can not measure the resistance of a battery with your multimeters resistance measure function, the terminals have voltage across them \$\endgroup\$ – PlasmaHH Apr 6 '18 at 11:07
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    \$\begingroup\$ You obviously didn't drain it completely, so it still acts as a battery. Multimeters are easily fooled by voltage sources in R model, so I wouldn't trust your measurement. \$\endgroup\$ – Dmitry Grigoryev Apr 6 '18 at 11:18
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    \$\begingroup\$ Thank you Dmitry Grigoryev I would have thought leaving it upside down for an hour or so would have completely drained it I must be wrong I'll try to drain it some more \$\endgroup\$ – Alessi 42 Apr 6 '18 at 11:19

The plates have moisture in them which is also on the surface so providing the path to give you the voltage you see.

Why do you wish to see 0V ? What do you think that will achieve?

If you completely dry the battery, then it may not recover after.

If you want to recover the battery, then you should refill it and charge it then test it.

But in my experience any of these treatments rarely work for long periods, and I used to fill dry-charged batteries with the electrolyte which I had to mix from acid...

  • \$\begingroup\$ Thank you for your answer that makes sense, the only reason I wished to see 0v or no connection across the battery was that I suspected there to be an internal short and that would prove or disprove that idea. \$\endgroup\$ – Alessi 42 Apr 6 '18 at 12:13

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