Dual Battery Set-Up? (Trunk Location)

[filmsurgeon]

I have read just about every post I could find on this forum site as-well-as many other internet sites, and have bookmarked and made mental/written notes on many factors.  For several years now, I have wanted/planned to do a dual battery set-up in the trunk of my '70 Challenger.  I was advised that based on the Audio Amps I'll be installing, this would be the way to go.  The plan is to use two Optima yellow-tops.  I don't know the wiring configuration yet (as I am a novice at this, but learn quickly).  Luckily, I have friends that do this kinda stuff regularly, and can get help from them.  The ultimate goal is to have a nicely finished trunk (I have no spare or jack, and don't want/need them).  I plan on attempting to make/install the panels myself (sides and rear will be covered to resemble the white seats, the floor of the trunk will hopefully be 80/20 black carpet like the interior floor).  I think the layout will be: Optima battery on each side; amps on the floor or back panel; sub(s) on the back panel or on separate/hidden panel behind the amps.  Anyway,  I'm looking for suggestions, feedback, comments, advice on any aspect of this whole project.  ANYTHING you can share, will be greatly appreciated.  I plan on installing a flat surface on the trunk floor.  I have (2) Wieland Custom Machine Billet Aluminum Battery Hold-Downs for the Optimas (photo attached).  I will be installing (2) JL Audio Amps (1450 Watts total).  I plan to purchase welding cable 1/0 AWG for the negative and positive runs.  Since the plan is to have a battery on each side, I'll probably need about 20' for the positive run across the trunk and to the starter, and about 15' for the negative run across the trunk and to the transmission tail housing mount.

Regarding welding/battery cable:  I found this "Taylor" cable listed on several sites.

http://www.summitracing.com/parts/tay-21540/overview/

Would this be a suitable cable for the pos run? (I can always put my own ends on).  I am also seriously considering making my own cables.  Any advice or thoughts on this?  I think I've already found out whats involved, just don't know if it's really all that much more cost effective over buying assembled cables.

Then there's places companies like this : http://custombatterycables.com/index.htm

BTW - I'd like to see what others have done with there trunks, so please post photos if you can.

Thanks.

[filmsurgeon]

Just wondering if anyone can share any insight on my upcoming project.  Anything about anything in my original post will be appreciated.  I am interested in your opinions, knowledge and experiences.  Thanks.

[Surfmichaels]

When I bought my car it had 2 batteries installed with one in the trunk. The rear battery was a marine deep cycle AGM battery to avoid gas out in the trunk. The was also a breaker installed to protect the circuits. Up front additional power connectors where installed from the alternator as well as a direct to rear battery battery tender that had a plug for easy topping off of the battery. A massive capacitor was also installed but I think it was more aligned with the subs than with power. If you want I can dig out the box of parts to give you more specifics.

Edit: pictures and descriptions added


Shown in the picture are a breaker switch, in line fuse, voltage regulator and power splitter than allows 1 input and multiple outputs to power.

[73EStroker]

Don't use yellow tops as they are deep cycle. Use red tops and do not let them go down too far and you will be good to go. Remember the alternator has to keep up so I recommend you use an AC type alternator which outputs more power. Also the two batteries must be identical.

[Surfmichaels]

Don't use yellow tops as they are deep cycle.

I think battery type needs to be matched to usage, the one installed in my car were deep cycle due to heavier use during shows and other events were the engine were not running, a normal battery would not last long with that type of usage. It should be slightly less complicated if most of your use will be with the engine on.

[Challenger6pak]

If you are going to run batteries in the trunk , make sure you run extra grounds from the motor to the car body.  This gets overlooked and many problems come up because of it.  I have run the same set up with an isolator like motor homes run.  The car was on one battery and the sound equipment was on the other battery.  Run circuit breakers on everything.  There is a lot more in the trunk that can catch fire, due to a short, than what can catch fire under the hood.

[filmsurgeon]

Thanks for the feedback guys.  Any/all other comments still appreciated.

Regarding welding/battery cable:  I found this "Taylor" cable listed on several sites.

http://www.summitracing.com/parts/tay-21540/overview/

Would this be a suitable cable for the pos run? (I can always put my own ends on after adjusting the length if necessary).  I am also seriously considering making my own cables.  Any advice or thoughts on this?  Thanks.

[Travis72]

The Taylor cable should work fine.  I used welding cable.  When I bought mine it was around $80 for 20 feet, however prices vary with the price of copper.  The nice thing about the welding cable is it's has very fine strands so its flexible.  I don't have any experience with the Taylor cable.

I soldered all the terminals with solder slugs and a propane torch. Since then I ran across this method which seems like an even better way of doing it:

http://blog.iimuchfabrication.com/?p=360

I highly recommend a Ford style starter solenoid in the trunk so that the starter cable is only hot when cranking.  The alternator feed back to the battery can be protected with either a fusible link, or with a large capacity ANL fuse.

Travis
72 Cuda

[Topcat]

An option to consider instead of Optimas.
These just came out recently.

MT7
http://www.interstatebatteries.com/cs_eStore/Content.aspx?dsNav=Ntk~SearchGroup|batteries+automotive+mt7|3|,Arpp~12,A~Part+Number,N~21-2147384906

[MEK-Dangerfield]

Can someone explain the reasoning behind 2 batteries?

If you have an alternator big enough as far as Amp output for the load it will see, then why 2 batteries?

[Topcat]

We run 2 batteries in series on offshore boats.

There's a switch that lets you go from one or the other or both.
This allows you to run one down just using accessories like the radio and fishfinder with engine off whiile keeping one fully charged for re starting.

This would be useful on a car similiarly if your engine was off while just running the stereo on one.
Together when tied in series, you have more Amp hours. That's your total reserve runtime with being charged.

[Topcat]

Here's the type of switch block we use.

http://www.westmarine.com/webapp/wcs/stores/servlet/ProductDisplay?productId=17208&catalogId=10001&langId=-1&storeId=11151&storeNum=50523&subdeptNum=50543&classNum=50547

[bert]

Im doing the same as you by putting batteries in the trunk one on each side'
I did run lots of hot and ground wires to the front. Shut off swich in the back and also my starter solenoid .
XV make the trunk kit that you see in the pictures. My amp and subwoofer goes in behind the front panel.