Trunk mounted battery is history. BACK to the front !

[Kern Dog]

Sometime around 2013, I moved the battery to the trunk.



I had a blue top Optima that weighed 44 lbs. I had read that moving the battery to the trunk helped with traction and weight transfer though I never cared much for drag racing. I did like the extra room in the engine bay.
Over the years, I've gone through a few batteries. I just attributed that to the fact that the car sits idle for most of the time. It was wired correctly and well grounded. I ran the positive cable to a FORD starter relay, then other other side of the relay had the 1/0 positive cable running right to the starter. It was only live when cranking since I had a trigger wire going to the stock starter relay on the firewall. I had 2 ground cables to the negative side of the battery and the engine itself had 3 ground cables to it.
Lately I've noticed the most recent battery won't stay charged up. Even when disconnected, it would discharge at a rate of .035 volts a day which adds up to .45 volts in 2 weeks. The battery is on it's way out.
Why do these batteries fail so often?
I don't blame the trunk location for the issue but it is inconvenient to have to open the trunk to test voltage, then charge it. I started thinking about changing to a different type of battery.



I had two different Optimas, the AGM shown above and most recently, a standard lead/acid battery from maybe 2 1/2-3 years ago.



Awhile back I started looking at the weight of the car and thinking of ways to lighten up where I could. When I replaced parts, I looked for stuff that might weigh less than what I am replacing. I was pushing 4000 lbs with the car a couple years ago.



I added modern A/C and removed the original HVAC box. The front brakes were upgraded with a Dr Diff 13" kit that shed 24 lbs compared to the Cordoba 12" discs. Tubular front sway bar shed 8, the spacesaver spare tire shed 21. Borgeson steering box was 12 lbs lighter. Now that I'm looking at a battery replacement, I'm looking at these:



Mopar Action magazine did an article on these Lithium batteries. A friend of mine has one in a '68 Plymouth. His car cranks over FAST and the battery only weighs 7 lbs!
I recently removed all the trunk mounted battery stuff. Battery box and hardware, holddown, solenoid, all cables and wires. It added up to almost 18 lbs. The engine bay location adds up to 4 lbs including battery tray and holddown and battery cables. The trunk relocation costs you 14 lbs of extra weight. If I do go with the Lithium battery, that is a 33 lb reduction from my 40 1/2 lb battery that I have now. I could be close to 3900 lbs with the lightweight battery mounted up front!

[Nacho-RT74]

Eating less biscuits will help on less weight while driving too

        

[Kern Dog]

Eating less biscuits will help on less weight while driving too

        

Ha, no kidding.
Since I retired, I've put on 20 lbs. I used to be a Carpenter, carrying lumber, climbing up stairs, framing roofs, hauling plywood...
Not much of that now but at least I'm not stuck in traffic commuting anymore.
I know that chasing a lighter overall curb weight won't make a huge difference in anything. I'm a decent driver but I'm not so good that I could tell a difference when the car is 40 lbs lighter.
The trunk battery was sort of cool when I did it because it was different and the engine bay looked less cluttered. Having the battery up front is more convenient though.

[Kern Dog]

The return is complete. The trunk mount is out, it it's place is the bag of tools and ignition parts for road trips:



One of the weight saving moves was this space saver spare from a 2016 Charger. The late model bolt pattern is not exactly the same but will work for short distances.



I made a shorter holddown stud. The stock one was about 10 inches long.



Back up front.



This battery is a side terminal design so I used matching cable ends. They are temporary, I'll explain in a moment.




The headlight relays used to sit on a flat steel plate that was bolted to the stock battery recess in the fender apron. I had to relocate them within the range of movement the wires had. They look decent right here.



Now, regarding THIS battery....
It has something weird going on with it. It loses charge on it's own even when it is not connected to anything. Sometimes when I am charging it with a small charging unit, the unit shuts off before the battery reaches 12.6 volts. For example....I connected the charger last night when the battery was at, say....12.3v. This morning it was maybe 12.46 and the charging unit had the GREEN light which indicates that it is fully charged Or at the least, it thinks that it has. I disconnected the power from it, waited 20 seconds and then reattached the plug to the wall socket and it started charging again. A half hour later it was up to 12.67.
Great!
I started it up and ran the engine a few minutes, then went off to do some things. Later I went to start it and it cranked like it had no spark. It spun 25-30 seconds, tops. The starter struggled to spin the engine and in that short time, it quickly got slower...enough to not even spin the engine over fast enough to start.
I'd bumped a wire loose from the ballast resistor. That was the reason for no spark. I checked the battery and it was ay 12.10v. Yeah, it somehow lost half a volt in around 30 seconds of cranking. I hooked up the charger again and within a half hour, it went from 12.10 to 12.56. If this turd charges this fast, it also discharges even faster. I am going to go ahead and order a Lithium battery tomorrow.