Solid State Guitar Amp Forum | DIY Guitar Amplifiers
Solid State Amplifiers => The Newcomer's Forum => Topic started by: flester on January 23, 2018, 07:36:59 PM
What charging voltage is generally used for batteries of different voltages? for example I'd like to be able to charge a 9v PP3 while a power supply is plugged in ro my LM386 amp. Also my 12V Black and Decker drill needs a new charger as the original one is only giving me 5V when plugged in to the mains whereas it used to be 15V as far as I know. I am charging it now using a 12v power supply.
AFAIK most chargers supply pulses at a certain frequency, varying the amount of current and voltage that goes into the battery in relation to the charge. Connecting a battery straight to DC might damage it. If you do decide to put a charger inside an amp, be wary of possible EMI issues, as the pulsating high current will probably radiate a lot of interference.
Quote from: Katoda on January 24, 2018, 04:31:11 AM
AFAIK most chargers supply pulses at a certain frequency, varying the amount of current and voltage that goes into the battery in relation to the charge. Connecting a battery straight to DC might damage it. If you do decide to put a charger inside an amp, be wary of possible EMI issues, as the pulsating high current will probably radiate a lot of interference.
OK will watch for that. I did take my drill charger apart and it seemed to just have a transformer, some resistors and diodes i.e. its basically a rectifier but who knows what circuitry is in the drill itself. The 12v supply did charge the drill but might get an aftermarket charger for it. And will stay away from chargeable amps for now
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You might look up "battery charging". Two kinds of chargers, constant voltage - like the one for your car lead-acid battery, and constant current - like for the nicads in your power drill.
I doubt the drill has any circuitry for charging, the real basic DC supply in the charger has a resistor in series with the drill connector, the current into the battery causes a drop across the resistor. As the battery charges, the voltage across the resistor drops.