Technical How to wire a battery to the trunk

..........................Never heard that, but then there's a lot that I haven't heard. What's the "science" behind that?

 

Read it in an article by one of those wiring companies explaining how to wire a battery in the trunk. That`s the only info that I remembered from the article. Because it stood out as logical. Something to do with movement or I don`t know.

 

Mount the battery so the fluid, if it has some, flows through the plates, not up against them. Mount with the terminals side to side instead of front to back. Under a hard launch, the battery acid hits the plates pretty hard, if the battery is side ways, the acid can flow between the plates.
Dry cells or jell cells don't have the same problem.

If you never plan on racing the car, the no worries about the engine shutting off with kill switch. I use my switch just to kill power while setting and as a theft deterrent. I have gone through two batteries in 18 years, I believe shutting it off all the time saves them.

Joe

 

Maybe that mattered when batteries were filled with acid? I never heard that one. With the new AGM Batteries that can be mounted upside down I doubt it matters anymore.

 

Yeah I remember that, they said the acid hitting the plates would slowly move them and sooner or later 2 of the plates would touch and you'd have a internal short and weak battery.

 

I use 00 welding cable for a length of around 15 feet. Mount the battery in a marine boating box solid to the floor or the side of the trunk. I always worry about gas flumes and sparking from the battery due to poor connections.

 

I`ve had 2 extra batteries in my trunk with no boxes covering them for 30 years with no problems.

 

I was thinking of steeling your set up but using a cut off switch on the neg side (already there) and adding your trunk mounted solenoid idea. Can I use a Cole Hersee 24213 12V 200A. Normally open contacts Continuous Solenoid for the remote solenoid. I'm not sure off the amp rating required at the battery.
Thanks

 

I like 0 or 00 welder cable for battery cable.

You cannot use the starter hot post to land your alternator and hot wire to your switch if you are using a Ford Style starting system as the hot to the starter is only hot when you have the switch in start mode.

The only time that running your battery in the trunk needs to be complicated is when you need to be able to shut all power off to the engine bay. That is usually either attributed to racing (your cutoff will be out in the open) or paranoia. Now this is the time for at least one of you to get your panties in a bunch. LOL

 

Not bunched, "but I'm really not as cool as I'd like to be". It may be paranoia (need destroyer), but it wasn't difficult to drag the hot leads through the disconnect switch on the back of my car. Even Lola could do it.

6 gauge heater circ./6 gauge fuse panel/2 gauge to breaker/4 gauge alt cable (so engine will turn off at this switch)

all power from switch through this thing on the way to the battery so one day you don't self-destruct

On/off, all power, running motor or not. Also nice for long term storage or anytime battery disconnect is necessary to service alt, starter, fuse panel, etc.

Feelin' guilty, feelin' scared, hidden cameras everywhere
Stop! hold on. stay in control

 

Well just because your paranoid doesn't mean they're not out to get ya.

I think probably what gets me more then anything else is that everyone gets all excited about how to wire your battery in the trunk and never give it a second thought when it is under the floor or under the hood in its original location. I cannot even count the times in my life that I have seen battery cables lay against a header and short out under the hood. Or just spaghetti wiring on an old heap all laying against the motor etc and no one even gives it a second thought. But the minute the battery goes into the truck it becomes a real wiring nightmare.

Nothing wrong with redundant safety equipment in the system, but, if it is really necessary shouldn't we be giving the same consideration to cars in their stock condition?

Now for a funny story.

I had an OT mini in the 90s with a big engine in a small space. There was room for the battery in its stock location so it stayed right there. I made the mistake of running an AMP Meter instead of a Volt meter and coming home one night from work about 5 blocks from the house I saw a glow on my dash. I looked and it was my AMP meter and the electrical fire ensued. I was close to the house, the cab was full of smoke and I rolled my window down and stuck my head out Fireball Roberts style. About a block from the house I started hollering, "Open the door open the door." For whatever reason ( call it female intuition) Mrs. Beaner was running out the door with a fire extinguisher in one hand and a pair of channel lock in the other. She shouted ,"Pop the hood" as I killed it in the driveway. I did she reached under the hood with the channel locks and snagged the ground wire off the battery, The fire went out. I did have to replace some wires.

Has nothing to do with the conversation but it was running in my head and now its your problem.

By the way @Bandit Billy nice clean setup my friend

 

Mrs. 'Beaner was on her game.

 

Thanks and thanks for the story, had to laugh. I hate Amp meters! Almost lost my first Camaro to one. I have torn them out ever since and replaced them with volt meters.

Your wife saved the day, if I had been yelling like that my wife would have had a crown and cola in her hand for me.

 

Lola never lost her head!

 

You don't need a continuous solenoid [on my schematic] , the solenoid is only activated by the starter button.

 

Thanks. Is 200 amps enough or should I pick up something stronger? The Ford solenoids don’t provide a lot of information.
Thanks again

 

Rather than using a manual cutoff switch, I used a latching solenoid with a hidden on/off switch. Disengaged, the only thing that gets power is the clock. Makes a great anti theft system. Ron Francis sells them but you can get them much cheaper online.

 

If you want to get really creative [refer back to my original schematic , posted here again]


Replace the isolator switch with one of these single channel 12V 27A remote relays. You can disable your car from 100 yards away.
https://www.ebay.com/itm/12V-Relay-...-Switch-Transmitter-Receiver-US-/182446258641
I've used these on Garage Door remote repairs, my trailer winch getting updated etc [2 channel]

You could use a 3 channel remote relay [1 as the isolator, 1 as ignition, 1 as the start button. the starter will need to be set as "momentary"] but this get me thumped with the "Ban Hammer" for being too off topic

The isolator switch on my schematic is low current draw , but obviously headlights etc will need their own relays with fusible links

 

The Ford solenoids are good for up to 400+ amps, but only on an intermittent basis; continuous duty will kill them. The Cole-Hersee, while rated for continuous duty, is too light for starter motor loads. There's also the solenoids used on 12V winches and these see very high currents, but solenoid failures aren't uncommon either. Again, these aren't rated (if they are rated at all) for continuous duty either. Motors have 'current inrush' (the power required when initially starting) which can be up to 1200% of their running current instantaneously, with a figure of 300% generally used when sizing switches/relays starting motors under load.

And you need to remember that losing voltage to a motor will increase the amount of current it will draw under a given load. So if a motor draws 250 amps at 12V, drop 1 volt and this will increase amps to 272 amps. Drop 2V and now you're up to 300 amps. This is why sizing battery cables big enough is important.

Once you go above 200 amps, you get into the realm of contactors and prices will rise sharply.