DaveGS4

iTrader: (2)

When I upgraded my trunk setup, I had a set of Monster 1 Farad Digicap (DCAP-1FDS) put into my GS stereo. I had a brief discussion with my installer on the appropriate way to charge / discharge the caps when I need to disconnect the battery, but I haven't had a chance to talk to him to write it down OR to order the tool he had (discharge tool with a small bulb on it).

If I DIDN't Discharge the caps he said I ran the risk of fusing my battery terminals or worse when I reconnected the battery.

Does anyone have:

1) a good step-by-step description or writeup (or link) on how to safely discharge and recharge capacitors?

2) recommendations for the appropriate tool to use?

Thanks in advance
D

Oh, if it makes a difference the caps are not accessible.

DaveGS4

iTrader: (2)

"Hello (tap tap tap), McFly"

I know many of you guys on here have caps in your aftermarket setup. Do you just not discharge / recharge them?

Blue98Gs3

iTrader: (1)

Personally Ive taken my batter off the terminals many times with the Caps charged, and I have the same set up as you, both in parallel.

Didnt know there was a risk....

johnee78

iTrader: (4)

I have the CAP by alumapro and it discharges when the radio is off, thanks to a relay.. I would assume that you can simply remove the fuse by the battery and the caps won't interfere with anything that your doing under the hood..By removing the fuse the caps have no electrical connection with the battery in the front..To my knowledge it was only neccesary to discharge your capacitor when you are removing it from your system..

CleanSC

To charge: Connect positive cable to cap and connect light bulb between negative cap terminal and ground. When the light goes out (or about 30 seconds), you're charged.

To discharge: Connect light bulb to + and - terminals on the cap. When it goes out, it's discharged.

If you lost the light that came with the cap, a 30 ohm 1/4 watt resistor will too. Hold it to the cap for 30 seconds.

This is done to prevent nasty sparks from high current arcs. Some caps do not require a charging procedure if they are equipped with smart charger electrics on the top like some of the digital display models. Not all digital readout models will have this! If you are not sure, use the light bulb or the resistor to be safe.

engin_ear

iTrader: (1)

Doc Brown here: (Back 2 The Future is one of my favorite movies, after you take away the ****, that is)
A 1F cap holds many Joules of energy when charged. It must be charged or discharged thru a resistor to keep the current level reasonable, as previously mentioned. Since your caps are not accessible, you can just let them discharge themselves, there's usually some leakage that will drain charge slowly. When you're reconnecting, the best thing to do is connect your battery back up thru a 100 ohm resistor (current is 12/100 = about 120 mA max) and allow the cap to charge back up close to the battery voltage, then reconnect the direct connection. The problem with connecting the battery back up directly is that the current surge, from the lack of any resistance limiting it, will either blow your fuse/circuit breaker, or worse, will toast the structure of the cap and cause it to leak electrolyte, or if it heats too badly, kaboom (minor). Usually blowing the fuse is the main problem, since the amount of time the current surges is short and caps today are built pretty well.
Gotta go get more garbage for the flux capacitor now.
(PS: A guy I work with actually has one of those DeLoreans - what a piece of crap.)

e-man

1.21 jigawatts, 1.21 jigawatts. How could I be so irresponsible?

SPORTcoupe

iTrader: (2)

I take my 15F CAP fishing with me.

Instructions for discharging:
1) find small pond full of fish
2) attach cables to positive and negative sides of the CAP(make sure the cables are long enough to reach the water tithout you touching it)
3) put the cable ends in the water
4) *OPTIONAL* collect fish

=)

joshoowa

iTrader: (1)

hahah i could see someone do this.

cacrawfo

Hello,
Another safe way to discharge a big car stereo cap is to remove a battery terminal, then turn on the parking lights or headlights. The cap will power them for a few seconds and then they will dim and go out.
To charge, you can use a test light like you would use to diagnose a wiring problem.... just clip it to the battery terminal, (the one that you previously disconected) and touch the probe to the battery post. The light will come on. This will limit the amount of current that can flow into the cap and charge it safely in about 10 seconds.
Charged caps can be dangerous! They can discharge an amazing amount of energy in a very short time.


Carl c

engin_ear

iTrader: (1)

Thanks, cacrawfo, good info.