Lets say I have one quite large circuit consists of many components including winding and light bulbs.

The positive terminal of the battery goes directly to a winding.

If I disconnect only negative terminal, does this circuit still drain the battery?

  • 3
    \$\begingroup\$ No current will flow through the circuit. The battery might still self-discharge slowly, same as if neither terminal was connected. \$\endgroup\$
    – user253751
    Sep 29, 2015 at 2:19
  • \$\begingroup\$ I know but just doubt since the circuit is large \$\endgroup\$
    – apasajja
    Sep 29, 2015 at 14:27
  • 1
    \$\begingroup\$ Why do you think the size of something that is not connected matters? \$\endgroup\$
    – R Drast
    Sep 29, 2015 at 15:17

2 Answers 2


Current will not drain through the circuit, but if you consider the batteries leakage current, then yes, the battery will drain.

This drain rate varies according to the battery technology (lead acid, lithium, etc..) and may or may not be big enough to impact your project.

This other question has some interesting remarks on battery leakage.


The circuit needs to be closed for current to flow. If you open the circuit (disconnect a battery lead or otherwise), then the battery will not drain.


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