Another Super Capacitor thread

dragon.breath

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My current setup is a 160 amp alternator (big as I can get, stock alt was 75 amps), Agm battery under the hood, and a XS power d3100 in the rear. I am running a Taramps smart 3 and a Taramps 800.2. While driving the voltage will drop to about 13.0v when the bass first hits. On long bass notes the voltage will rise back up to about 13.5-13.6v before the bass note ends. So I am going to add a super cap bank. My question is this. I figure that they will end up floating at the same voltage as the batteries do, so 12.7v or so. When I start my car in the morning are the caps going to max out my alternator trying to recharge themselves? Or am I overthinking things?
 

metalheadjoe

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Capacitors are fast-charge/low-capacity by nature. They might cause a surge from your alternator, but they charge so fast that they won't hurt your alternator. Electricity generally balances itself.
 
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dragon.breath

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Thanks. That is what I was thinking would happen, but I wanted a little conformation before I installed it.
 

akheathen

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you're overthinking things.... sounds like your voltage regulator is slow reacting. normal caps usually need a very high, like 16-20farad to make up for this, but supercaps just work diffently, and they should fill-in that surge. they arent going to charge up like you think. they are going to stay at battery voltage, then a slight bump in power to reach alternator volatage, but not like a huge short circuit type of event. the second battery is going to tax the alternator far more than the caps will.
 

dragon.breath

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I received my wire and connectors today and installed the cap bank today after work. The bass notes that used to drop from 14.2v to 13.0v and struggle back to 13.5v now drop to 13.8v and hold steady. Then return quickly to 14.2v and is ready for the next bass hit. Most definitely a big improvement. I am sure that if I started playing a test tone I would run out of cap power after a few seconds and the voltage would sag a little lower.

This is the performance that old school 1 farad capacitors were advertised to have, but never did.
 

KicktheSDbasshead

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I received my wire and connectors today and installed the cap bank today after work. The bass notes that used to drop from 14.2v to 13.0v and struggle back to 13.5v now drop to 13.8v and hold steady. Then return quickly to 14.2v and is ready for the next bass hit. Most definitely a big improvement. I am sure that if I started playing a test tone I would run out of cap power after a few seconds and the voltage would sag a little lower.

This is the performance that old school 1 farad capacitors were advertised to have, but never did.
I know a guy who ran 14 banks of this maxwell no batteries at all he said he never dropped voltage but if the headlights were on for more than 15 minutes the car was dead and he had a big boy build those things go
 
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dragon.breath

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I am going to bump up my own old thread to add some more information. My rear battery went bad ( 6 year old XS power d3100 ). So till my new battery comes in I am running just the agm under the hood and the Maxwell capacitor bank.
If I probe the power wires at the amplifier, 12.7 volts at rest. When I start the car the front battery goes immediately to 14 volts, at the amp it slowly ramps the voltage up over about a minute. After the voltage equalizes between the front and rear the voltage goes up to its normal 14.3- 14.4v. The opposite happens when I turn the car off. For a minute or so the voltage at the amplifier ( amplifier off) is higher than the voltage at the battery.
Playing music at full power it obviously depends on the song. Regular music with bass on and off, the caps do pretty well at keeping the voltage up at the amplifier. Music with constant bass, the voltage slowly drops down and after about 40 seconds I turned it down because it was getting to the low 12’s.
Sorry for the long post. Just trying to put some information out there for anyone who is considering going with ultra capacitors.
 

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