Cap for 12volts power supply

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Joined 2009
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Good morning
I have a 12 volts 35 amps power supply that I use to test car amplifier, it works fine, but some amps draw a lot of current when they are first turn on. I need a in line capacitor value that can take care tha problem for me. Can some one recommend me the best in line capacitor value for this problem?
Thank you.
 
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Joined 2007
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Capacitors don't go 'inline', they connect across the supply. If a 35 amp supply is struggling to start some amplifiers then you probably need something pretty large.

68,000uf 16 volt caps aren't that expensive.

There are also dedicated 'car audio' caps available in massive values (3F) but as these never seem to have any technical data attached to them they don't qualify for a recommendation.

The best solution, and probably cheapest as well, is simply to connect a small VRLA battery (gel lead acid battery of say 12v 7ah capacity) in parallel with the PSU for testing the startup behaviour of problem amps. The short term current delivery from these is massive... hundred amps or so.
 
Perhaps the problem is too much starting capacitance on the output thus triggering PS current limit. adding a huge cap on the output will prove this theory but is not the fix.
adding a smallish battery will still trigger CL but should allow time for the problem cap to charge up until CL mode can be cleared.
I would try a slow start resistor (> 12/35 ohms )in series of the output of any problem load to fix. contact the PS OEM sometimes they have a slower start mode option.
 
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