Wiring A Second Battery.....

[PaulO2288]

Grounding it to the frame is fine. But grounding to the front battery will help with getting more power to the second battery. Instead of one wire transfering the energy from the front to the rear the ground to the front now made it 2 wires. It really helps. My friend has a Kintik 1400 up front a 2 2400's in the back and was lacking getting power to the rear, So had him run a line from the front negative to the rear negatives and made a huge difference. More runs more power to the other batts. Steve has 3 or 4 coming off of his front powermaster for that reason. As will I soon. There also should be less resistance grouding to the front also.

Edited July 4, 2008 by PaulO2288

[Kicker Guy]

This truly depends on the car. If its a unibody then yes you should run it back to the front... because of poor current flow.

But in a normal framed vehicle.... you shouldn't really notice a difference. Either way you look at it the current will have to travel though the metal on the car. Just remember that when dealing with a lot of current to make sure it is to the FRAME and not the body.

And logan... you can't use bill as an example here because it is two different vehicles.

[may03LT]

But in a normal framed vehicle.... you shouldn't really notice a difference. Either way you look at it the current will have to travel though the metal on the car.

i just saved a a bunch of money on 1/0 by reading this post woots

[dmanson]

just make a run of - from the front to back and then ground the battery to the frame for extra.

[snafu]

Thanks Logan, maybe King will post his experience. I never looked for extra batteries on the F250 build.

I got a message from my friend who is a retired pro installer/judge. He said that IASCA used to require some type of isolator in multi battery setups back in the day, and that the Ford solenoid was popular, but newer technology has since surpassed that.

Basically an isolator setup.

I originally wanted the capability of running my stereo with the car off mainly for multimedia. Now I have built it with an extra amp, 2 batteries, and 4 extra subs, so my plan is to never run it without the engine on anymore.

Ford Solenoids are not designed for continuous current duty, but work well for short high current passage - like say, starting a vehicle. We offer both a 80A and 200A solenoid designed for continuous duty in our Install Edge brand - these have been designed for this. (Part numbers are IECS80 and IECS200.)

In regards to your return path question, I've always used the frame as the return path for the under hood battery, case of the alternator, auxiliary battery(s), and amplifiers. Pick one side of the frame, and reference all grounds to it. The frame of a typical truck has far lower resistance than any cable that you could run along side it. In the case of a uni-body vehicle, it doesn't hurt to connect the front and rear frame rails together electrically with a piece of 1/0 (or two) - only necessary on your chosen side. This will provide you with the lowest resistance return path possible.

Equally as important are the integrity of the connections between the wire and ring terminals and between the ring terminals and frame rails. See the post Steve put in this section about soldering large AWG wires:

Soldering Large AWG Wires

When connecting to the frame, I like to use an existing hole. I'll tap it if necessary (taps are CHEAP), grind the paint, use a star washer to get a good long term bite, and use lithium grease to prevent it from rusting. Then, you need to check these connections once every six months or so to be sure they haven't worked their way even a little bit loose.

Good luck!

[MECHMAN]

Ford Solenoids are not designed for continuous current duty, but work well for short high current passage - like say, starting a vehicle. We offer both a 80A and 200A solenoid designed for continuous duty in our Install Edge brand - these have been designed for this. (Part numbers are IECS80 and IECS200.)

In regards to your return path question, I've always used the frame as the return path for the under hood battery, case of the alternator, auxiliary battery(s), and amplifiers. Pick one side of the frame, and reference all grounds to it. The frame of a typical truck has far lower resistance than any cable that you could run along side it. In the case of a uni-body vehicle, it doesn't hurt to connect the front and rear frame rails together electrically with a piece of 1/0 (or two) - only necessary on your chosen side. This will provide you with the lowest resistance return path possible.

Equally as important are the integrity of the connections between the wire and ring terminals and between the ring terminals and frame rails. See the post Steve put in this section about soldering large AWG wires:

Soldering Large AWG Wires

When connecting to the frame, I like to use an existing hole. I'll tap it if necessary (taps are CHEAP), grind the paint, use a star washer to get a good long term bite, and use lithium grease to prevent it from rusting. Then, you need to check these connections once every six months or so to be sure they haven't worked their way even a little bit loose.

Good luck!

Snafy is right, the Ford solenoids are not designed for continuous-closed use, and will burn up in a short period.

Frame rails work well for grounding, on unibody cars we just run a 1/0 copper cable because it's faster than connecting frame rails and has fewer connections. Either method will provide very low resistance.