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Registered Member #1924
Joined: Sun Jan 11 2009, 09:30PM
Location:
Posts: 12
In my infinite laziness, I decided not to use a transformer, but instead hook up a bunch (10 or so) 9v batteries in series to charge a capacitor bank and then discharge it in a massive pulse. The discharge pulse won't go through the batteries.
Will this make my batteries explode having 90V? Or will I be okay as long as I keep the charging current down with a big resistor?
Registered Member #540
Joined: Mon Feb 19 2007, 07:49PM
Location: MIT
Posts: 969
I think one problem with multiple batteries connected in series is that the case to case and case to cell voltage is too great for the insulation to hold. You will need a current limiting resistor in series with the batteries/supply so that it doesn't draw too much current when you start charging the empty caps. You should disconnect the supply from the caps before discharging them into some load. The thing about using 9V batteries is that they don't have a very high Ah rating so they might not last very long.
Don't forget bleeder resistors on your caps so that you don't get a nasty surprise when messing around with the caps. You should take the time to make it safe so that you don't accidentally find yourself connected to the supply or connected to the charged caps.
Registered Member #152
Joined: Sun Feb 12 2006, 03:36PM
Location: Czech Rep.
Posts: 3384
If you use a resistor, you can be relatively safe. The problem can be, if one of the batteries is discharged more than the others, it can see reverse voltage which might even cause it to explode (see "Arcing 9V battery bank" on youtube ) This can be fixed by adding reverse diodes across the batteries.
I would aim for around 100mA current from the batteries...
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How much V can a 9v tolerate?
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