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I bought an item that takes 4 D batteries or uses the adapter (sold separately). But they didn't have the adapter. Since I have kept a bunch of adapters from things that have been thrown away, I have a 6 v adapter rated for 150 mA. It's the amperage I am not sure about. The item has a small motor and I'm concerned that the 150 mA is not enough. Advice, suggestions? I know 4 rechargeables will work, but would prefer the adapter.

user45935
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  • Just find another 6v supply with more current capacity... – Passerby Jun 20 '14 at 04:37
  • Unless the motor is really tiny then 150mA is insufficient. Even if the steady state motor current was on the order of 150mA, the starting currents tend to far surpass this value if not otherwise limited. – sherrellbc Jun 20 '14 at 06:26
  • Obligatory reference to [Choosing power supply, how to get the voltage and current ratings?](http://electronics.stackexchange.com/q/34745/2028) – JYelton Jun 20 '14 at 07:36
  • What they say BUT it is unlikely to do any harm trying it briefly as long as it is not a piece of precision equipment. If the motor is at all sluggish stop using it. – Russell McMahon Jun 20 '14 at 13:49

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There are 3 big reasons why a device would use D cells:

  1. Weight/mass (no, really)
  2. Capacity (alkaline D cells start at about 10Ah)
  3. Current draw (alkaline D cells can deliver an ampere easily, nicad several amperes, although Li-ion is starting to take over)

Given that your device has a motor, its reason likely falls somewhere along the last two. As such, your adapter is severely underpowered. I would recommend that you find one capable of delivering at least 2A, with 3.5A preferable to be safe.

Ignacio Vazquez-Abrams
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