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  1. Audioguru

    Unwanted powered circuit

    A single Li-PO cell is fully charged at 4.20V and if charged higher then it might explode or catch on fire. A very cheap multi-cell Li-PO charger does not balance-charge and matched cells can change with time and become unmatched. Then the weakest cell overcharges and explodes or catches on...
  2. Audioguru

    1.5 volt bulb won't light in my circuit newbie

    If the 9V battery kept its voltage at 9V (it won't) when overloaded with the high current, then the total resistance is 27 ohms + 5 ohms= 32 ohms and the current is 9V/32 ohms= 281mA. The heating is called Power Dissipation and the formula is (P= I squared x R) so the 27 ohms resistor heated...
  3. Audioguru

    Unwanted powered circuit

    You have the batteries in series but the chargers are in parallel. Then the chargers do not charge and the switch does nothing. You need a charger designed to charge at 8.4V which is two Li-PO cells in series.
  4. Audioguru

    1.5 volt bulb won't light in my circuit newbie

    Remember seeing an old fashioned flashlight? It used a 2.4V incandescent light bulb and two HUGE D cells in series. The high current used by the light bulb reduced the 3V when new battery voltage to 2.4V. The cells in a 9V battery are like tiny AAAA cells.
  5. Audioguru

    1.5 volt bulb won't light in my circuit newbie

    A little 9V alkaline battery is designed for a 20mA load, not 15 times more that you are trying to do! Also the contacts on a solderless breadboard probably have trouble passing such a high current. I think you measured the current draw of the multimeter (not of the light bulb) because you...
  6. Audioguru

    Beginner Amp Hour Question.

    A CPAP is a medical device that keeps you breathing. I looked at Amazon's Details to see if the Rockpals battery powered generator has a medical certification and warranty and Amazon said, "see the Seller". I looked for Rockpals in Google and found a Chinese trademark. I would not trust my life...
  7. Audioguru

    Micro hydro-electric generator help

    A hydro-electric generator uses the boat's power to spin it. So whatever powers the boat will need extra power to spin the generator. The same if you think a windmill will produce charging current. It produces drag than needs extra power from something to overcome it.
  8. Audioguru

    Lead acid battery

    40 or 50 years ago (before Ni-MH) I used Ni-Cad C cells in my sound system for the beach.
  9. Audioguru

    Lead acid battery

    Guess what? An old (pre-Eneloop chemistry) Energizer AA Ni-MH cell was 2500mAh. Their NEW Ni-MH C cells and D cells are also rated at 2500mAh. So they and probably many other battery manufacturers make C and D cells with a little AA cell inside?? A Ternegy Ni-MH D cell weighs much more than an...
  10. Audioguru

    traffic light australian with 2 555 timers

    The second link in Google Images for Traffic Light Circuit shows the horrible circuit you found. The first link is that circuit as a kit from Arizona, USA. Most of all the other circuits use a 555 as a clock driving a CD4017 counter/divider. You found a defective circuit from a website in South...
  11. Audioguru

    Lead acid battery

    I buy Energizer Ni-MH AAA and AA battery cells. Old ones did not hold a charge longer than 2 months and were guaranteed for only 3 years. New ones are made in Japan maybe by Sanyo/Panasonic using their Eneloop chemistry and come pre-charged, hold a charge for 1 year and are guaranteed for 5...
  12. Audioguru

    Lead acid battery

    I use modern Ni-MH and Li-PO batteries and I am too young (73) for this thread about antique lead-acid batteries. Does anybody make an antique 6V charger for an antique 6V lead-acid battery anymore? I think cars used a 6V lead-acid battery a long time ago.
  13. Audioguru

    Lead acid battery

    I think a Lead-acid battery in Google is a huge and heavy car battery that is charged with 10A or more. Your tiny battery is completely different. You should not begin charging a discharged battery with unlimited voltage (something might explode) which is why they say to begin charging with a...
  14. Audioguru

    Lead acid battery

    Then without having a reduced voltage and reduced current for a float charge the battery will not last long because it will have "grid corrosion on the positive plate. This also leads to gassing and water-loss." If the battery is sealed then it will be doomed to fail soon.
  15. Audioguru

    Lead acid battery

    I guess your charging voltage is too low. Your charging current is only 0.5A? The battery must be tiny. When the charging voltage reaches the voltage limit then you must detect it and regulate the voltage to the constant voltage amount. Then the current will gradually reduce and when it is low...
  16. Audioguru

    Lead acid battery

    Again you did not read Battery University about charging a lead-acid battery with 3 stages. Stage 1. Constant current until the upper voltage is reached. Stage 2. Switch to constant voltage until the charging current becomes low. Stage 3. Switch to reduced voltage (as shown on the graph) for...
  17. Audioguru

    Lead acid battery

    You did not read what The Battery University said. Constant current until the upper voltage limit is reached (you must detect it) then keep that voltage with a voltage regulator until you detect that the charging current has dropped low, then switch to a trickle charge.
  18. Audioguru

    Lead acid battery

    The datasheet of an LM317 has a graph showing its "dropout voltage" which is about 1.9V. The dropout is when the input voltage is only 1.9V higher than its output voltage and it is already doing a poor voltage regulation. The datasheet shows at least 3V from input to output for its excellent...
  19. Audioguru

    Lead acid battery

    The LM317 current regulator has a voltage loss of about 3V (the dropout voltage of 1.9V plus the 1.1V across 2.2 ohms) so it should come before the voltage regulator. The voltage regulator also has a dropout voltage of 1.9V so the adapter voltage should be about 12.8VDC. You are charging with...
  20. Audioguru

    Buzzing sound in speakers

    The phone volume is turned down and the amplifier volume is turned up so that another reason why there is lots of interference picked up. Instead, turn up the phone volume (but less than clipping distortion (you call it jarring?) then turn down the amplifier volume so that the music does not...
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