I used DC-DC to get 3.3V supply from my battery with 3.6V capacity. I used large battery (connected number of cells in parallel) for long term operation of device (81Ah).

So my questions are:
-> I used 3.6V, 81Ah battery capacity (non-rechargeable)
Q.: My board required only 100mA to work so is it fine to use this battery?
(Meaning, does it draw large current and damage my board? Or what should I take care to control this current? Or does it taken care by my DC-DC or current drawn depending on my board's load requirement?)

Thanks in advance.


The DC-DC will only output the current required to maintain 3.3v and nothing more. If your load is 100mA then only 100mA will be sourced from the battery regardless of the capacity of the cells. You should consider though that 81aH is a very large amount and this many batteries in parallel likely has the capability to output a considerable current if something were to malfunction with your load or DC-DC converter. Although not required for normal operation a sizeable fuse connected between the battery and the DC-DC will provide some peace of mind and safety if anything does go wrong.

  • \$\begingroup\$ Thanks whiskthecat, So i need to take care for required current protection only If something wrong (short) at my device, right? \$\endgroup\$
    – Deep
    Apr 14 '18 at 7:38
  • \$\begingroup\$ Correct. Odds are the DC-DC itself may have some form of current protection but an inline fuse is always a safe bet just to make sure. \$\endgroup\$
    – lucky bot
    Apr 14 '18 at 7:56

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