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| Thread ID: 85885 | 2007-12-25 21:40:00 | Replace batteries with power-pack | Mike (15) | PC World Chat |
| Post ID | Timestamp | Content | User | ||
| 624567 | 2007-12-26 07:17:00 | . . . As far as not using any rechargeable batteries, I don't follow the logic..but it might be that rechargeables aren't as "hot" as regular batteries or that the voltage is very important..and many rechargeables don't have the power of a good set of D-cells. . . Ni-Cad's have a much lower internal resistance than carbon zinc, and can destroy circuits that use the battery resistance as a current limiter. (The old Panasonic electronic flash would do a terminal smoke show when loaded with Ni-Cads - spectacular, but the flash that accompanied it was weak, untimed, and not colour corrected. Even with the junk pld Zinc-Carbons we got in those days, the AA cells would supply over 1.25 amp - modern cells would vapourise the entire flash unit :) |
R2x1 (4628) | ||
| 624568 | 2007-12-26 15:34:00 | Ni-Cad's have a much lower internal resistance than carbon zinc, and can destroy circuits that use the battery resistance as a current limiter. (The old Panasonic electronic flash would do a terminal smoke show when loaded with Ni-Cads - spectacular, but the flash that accompanied it was weak, untimed, and not colour corrected. Even with the junk pld Zinc-Carbons we got in those days, the AA cells would supply over 1.25 amp - modern cells would vapourise the entire flash unit :) Never thought in terms of resistance...that's something I need to file away for another time when this subject rises again.......... Thanks.... |
SurferJoe46 (51) | ||
| 624569 | 2007-12-27 00:23:00 | The argument against rechargeables is just the terminal voltage. 3 NiXX cells give a nominal 3.6V, 3 zinc cells give 4.5V. A music device is likely to make horrible sounds if the voltage is too low and the distortion rises. (Quite apart from the horrible noises produced when the new users get at the keyboard). The low internal resistance is an advantage. I doubt that any equipment would be designed to rely on internal resistance for current limiting; that's not "design". It's more likely that the flash unit was reacting to the low voltage by pulling more average current to get the watts it needed. The problem I see is that the power bricks tend to be quite expensive; it's often worth looking in the bin of orphan bricks at a Cash Converters for a suitable one. Make sure you get a DC supply; preferably a regulated one, though 5 volts would certainly be OK. Be very careful with the polarity when wiring it in. |
Graham L (2) | ||
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