which battery should i hook my amp power wire on a diesel truck

 

How many batteries do you have? As long as your hooking to a 12V system you shouldn't have any real issue. As long as the charging system is running to the battery you hook to.

 

It don't really matter. I hooked mine up to the one on the drivers side(left battery) just for ease of instalation. There is a good spot right there to go thru the fire wall at.

 

Most of the time, the driverside is easier to find a spot to get through the firewall. There is a plastic access point in the firewall just under the power steering pump. You will see other wires going through that as well.

 

actually it does matter, you should hook it to the battery that has the dead end of the battery cables that way it will draw from both batteries before it draws from the altenator, resulting in better performance, I like to periodically rotate my batteries to keep my amps from draining to hard on only one of them (about every six months) [the dead end is the end that doesn't lead directly to the altenator which 9 times out of 10 is on the drivers side, but now you know! :P]

 

I don't see how you could drain one battery more then the other.

Batteries in parallel will equalize it's resting charge to the weakest battery in the chain. That is why they suggest replacing both at the same time.

The only time you will see a benefit of having both batteries in line between the alternator and amp is when the quick discharge draw from the amplifier is greater then the first battery can supply, and faster then the alternator can charge. Even then Your current draw would only be limited by the gauge wire between both batteries and to the alt. If you had this much draw, you would need to really beef up your electrical charging system anyway and be upgrading the charging system wire also.

 

The reason being is that the truck would draw from one side and the stereo would be drawing from the other, ever have one battery drain completely while the other was fine? and this happens even without a high end audio system, yes, having these wires connecting to both batteries would drain from both, but high end draws will draw quicker from the shorter the distance. meaning that it would drain the first one quicker. (which is why fosgate strongly suggests installing a compassitor no more than 3 ft from the amps so the wires won't over heat and catch fire, and the fuse no more than 12 inches from the power source so it doesn't have time to draw to heavy on the wire and possibly short out something before the fuse blows)

 

I'm sorry but I'm a little confused?

How does the engine pull from one and the stereo pull from the other? Unless you have an isolator on the 2 batteries, both will drain the same at the same time. This is the whole reason a diesel has 2 batteries. A diesel starting amperage is greater then a single battery will allow. ( a stock battery anyway ) That is why they use 2 batteries. They didn't just put the second one in there to be nice.

How would you charge both batteries from 1 alt unless they are both connected together? Unless you use a battery Isolator you will be pulling off both batteries equally all the time.

I don't even want to get into a capacitor discussion as it is too much to type about. But I will say, in the design you described, using a capacitor in the manner you stated, would be incorrect. Capacitors are one of the most misused items ever used in a stereo install.

Using the wrong size wire will cause wire to fail. Too much current through the wire will cause it to heat up and fail. The wrong size wire will also cause a greater amount of resistance which will cause a voltage drop from point A to B. The only thing I agree on is fusing within 12" of a battery.

 

a diesel will start with just one battery after its warmed up "cold cranking amps" does not just mean in cold weather, diesels are harder to start because they have no ingition system they use compression to sqeeze the fuel intil it explodes a cold engine needs alot of amps to start but are still 12-18 volt systems, fosgate will not warranty a compassitor unless it was installed within 3 ft of the amps that it is feeding (among other things, and I don't care what you think is the correct installation method, think I'll stick with fosgate's for the time being), all the diesels I've driven have a set of wires leading from the drivers side to the passenger side and then the altenator (given though, I have worked on some where the connection was flipped, and even spilt between the batteries, although no pre-99 fords were like this) I'm currently driving a ram 1500 regular cab with about 2200 watts in just two subs (yes a regular cab), for the two years I've owned the truck I've had no trouble at all from my audio system and my 7.3 IDI is only running off one battery atm because the other one failed on me shortly after I bought the truck, it wouldn't start (but being the mechanice that I am) I swapped the bad battery to the dead end side and put the good one on the live side, and it starts fine now, if I drove this truck every day (and didn't have another five sitting around it) I would go ahead and get another battery, but oh well. The fact of the matter is that I am tired of arguing and was going to write alot more last night but lost all enthusiasm to post since I knew I was replying to someone that was going to argue with me even if I told him the sky was blue, good night sir.

 

You sir are wrong. Batteries are in parallel. Whatever one battery gets the other gets. I don't see how you can figure it any other way. LOok at it this way if you hook a wire from one battery (either one) and run it how ever long you want it. Check the other end and see if you don't get the same voltage you get from the other. Now when you start figuring amperage and every thing eles then that makes a difference on what size wire you use how long it is and stuff like that. But not on where it is getting it's power from. I too have had many high end stero systems hooked up and have never had a problem. Dose that matter what battery you hook up too NO! I have installed countless system and this is the first time I have heard that it matters witch one. I was also a tech and was certified in auto electric. I know from my experience that it is bad to replace just one battery at a time (hint ficm fallures). Typicaly the other is not far behind. In your case I guess you are just lucky. There are two batteries on a diesel for a reason when hooked in parallel you get more amps but still just a 12v system. And current will flow through both batteries when wired this way.

 

Just answer me this.

How does one charge the 2 batteries off one alt if they aren't parallel?

If one battery drains faster then the other because of the stereo, then at what part in the electrical system are they separated?


Or.... Try this one and get back to me, Run your stereo for a long extended time with no charge, then test your voltages off both batteries.

If they are separate as you stated, then wouldn't one have a higher voltage then the other? Being you are a mechanic, this should be an easy test for you to perform.

 

firstly, I never said they weren't parallel
secondly, I never said they were separated
thirdly, try this, hook a voltage meter to each battery, turn on your stereo, and watch as one meter jumps, and then the next, whats happening is the stereo will start draining from the first battery, and then the second will surge, trying to stabilize the current flow through the cables, this is the whole primises as to what I'm refering too. It also works in reverse, your altenator will start to charge one battery, and then there will be a surge as the second one starts to charge. The idea of hooking your stereo to the deadend of the battery cables, is to make it easier for the cables to run everything. and example of this would be... 1) trucks ignition system, factory stereo, and other devices drain from one side (the "live side" which is closer to your altenator), 2) your amp (hopefully a compasitor instead) draws from the stronger battery on the dead end side since a minute spare voltage (this will show up on a voltage meter) will be used on the higher output system (i.e. the amp/compasitor), that way both batteries are being used instead of having all your currents flowing from one set of connectors, does that make since? Now, say you stomp the thottle in a gas motor, and a sudden surge of power is needed in the ignition system, if your amp is drawing from the reserve (i.e the battery) the ignition system won't have all the power it needs to ignite the plugs and will give less power, a common problem with high end sound systems, yes (although not as prevelant in a vehicle that has a compasitor for obvious reasons)? Now of course in a diesel, there is no igition system since the motor works off of compression right? Now if there were two batteries (and in this since one would be a spare, which would be the same on a diesel after it was started) the sound system would draw the amps from the spare battery, draining it intil the altenator restored power to the battery, since a hard surge was all ready coming from the ignition system it would in turn drain the other battery intil the altenator restored the power to that one as well. Now if you still wanna argue, at this point there would be nothing further I could try to explain. The reason this isn't an issue on most trucks is because the prefered side (i.e. the dead end side) happens to be on the drivers side of most diesel trucks, the reason in which I brought this whole thing to light was that it -is- in fact applicable on -some- trucks, but hey, you can always just connect the cables straight to the altenator, see if I care, this is the last time I'm replying to this thread, you all have a good day now.