Amp draining battery?

[Conley 10+ year member]

Voltage between ground terminal and ground wire is a steady 12.88. I've removed the amp fuse and so far my car has started every time I've asked her to. I'm going to rehook the fuse tonight and see if she cranks in the morn. If she's dead then I know it's the amp. I've ordered a cap from Crutchfield and I'll check the amp ground to make sure it's as good as it can be.

 

[Chrispy 10+ year member]

Why'd you order a cap.....

 

[Conley 10+ year member]

Sorry, I guess that was unimportant info. It has nothing to do with the parasitic loss but it will save my alt in the long run...

 

[Chrispy 10+ year member]

Sorry, I guess that was unimportant info. It has nothing to do with the parasitic loss but it will save my alt in the long run...

I asked because a Cap is a waste of money. Do a search on it.

 

[Conley 10+ year member]

It's a waste if you like dimming headlights and dead alternators...

 

[Stalin-ohaulic]

It's a waste if you like dimming headlights and dead alternators...

I agree and so do most of the people who have an intimate knowledge of electronics. This website is full of people who think they know but don't have a clue. They will tell you that your battery charges to your alternator's voltage and discharges a great deal before its resting voltage and all kinds of things they have heard on here that are not true. Then when asked to prove it they cannot obviously because it's not true so they will flame you. Don't even continue this debate. We know caps do a little... not a lot but they charge and discharge at the circuit voltage where a battery cannot and does not so they have a use albeit very limited as the current they discharge while at the circuit voltage is very minimal at best.

 

[Conley 10+ year member]

Update, BTW. I disconnected the amp via the fuse for a couple days and everything was good so last night I decided to reconnect the amp so see if I would have a dead battery in the morning. Car started right up and has worked flawlessly all day. The parasitic drain has mysteriously vanished. I'm very happy but at the same time I wish I could have known what was causing the drain. I guess electricity works in mysterious ways. Thanks to all the users who posted relavent information to help with the problem. Much appreciated!

 

[DammitJames 10+ year member]

Well if this problem comes back just do a parasitic draw test yourself its very simple. Ill give you a quick run down on how to do it.

First off the numbers you will be looking for.

An acceptable parasitic draw is 50 milliamps or less(thats 0.050Amps)

Anything above this will more than likely drain your battery overnight.

Now for the testing part.

Disconnect the negative battery cable from the battery

You will be hooking the DMM in series with the cable to do this you leave that negative battery cable off and put your negative lead from the DMM on the negative battery post.

Take the positive lead to your DMM and hook it to the negitive battery cable with the negative battery cable still disconnected

With this done put your DMM to the Amps scale(use the mA/milliamps scale if the DMM isnt self calibrating). Shut all the doors on your car and wait for the lights to time out, also if you have a underhood light this will need to be disconnected or the bulb taken out. Wait about 3-5 mins for all the inside lights and control modules to go to sleep or time out.

Now you are reading your parasitic draw.

If this reading is higher than 50milliamps(0.050 amps) try taking the fuse on your amps power wire out and see if the reading drops. If it does then your amp is drawing power with the key off. If not then there is an electrical component in your car that is drawing too much key off power. This is checked by process of elimination with your cars fuses but since you are not very comfortable with electrical systems i wont go into that.

Also while doing this before you hook the DMM up it will need to be shunted(the positive lead on the DMM will need to be put into the Amp/mA hole instead of the Volts hole)

If you have anymore questions feel free to pm me

 

[DammitJames 10+ year member]

Now that i thought about this its much easier to test just the drain from the amp lol

Pop your fuse out of the fuse holder on the power wire going to your amp.

Put a lead from your DMM on each side of the fuse holder and set it to Amps/mA scale

There should be no draw at all from this point of testing