Disconnect battery when parked?

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i never leave a car setting with battery hooked up if car is gonna set over a week or so, unless its got sketchy wiring then i un hook battery if itll set over 15 minutes!! lost a 71 ss chevelle to a wire fire, better safe than sorry!
 
And that is bad practice. Positive side is more likely to arc than the ground side. Lead acid battery vapors are flammable/explosive.
Almost every procedure in a FSM first states, "Remove negative battery cable".
I have a modern stereo with programmable channel memory in my 67. I still disconnect neg' cable every time I turn it off. I just shove a cd in the jukebox anyway. No need to program channels.
If you have a factory clock in your car, disconnecting battery is a bad plan for a totally different reason. No need to go into that here I suppose.
Been doing it for 20 years.
 
And that is bad practice. Positive side is more likely to arc than the ground side. Lead acid battery vapors are flammable/explosive.
Almost every procedure in a FSM first states, "Remove negative battery cable".
I have a modern stereo with programmable channel memory in my 67. I still disconnect neg' cable every time I turn it off. I just shove a cd in the jukebox anyway. No need to program channels.
If you have a factory clock in your car, disconnecting battery is a bad plan for a totally different reason. No need to go into that here I suppose.
Yeah that nice positive cable going to the starter no I don't think so and I have no radio.
 
Well i feel wierd

the battery gets disconnected while i'm working on the car....
thats it.....

Car sits for the winter in the garage and starts right up in the spring
current battery 6 years old

we have fuses and fuseable link to cover some of the most likley eventualities

surely the fire risk is way greater when running

Granted i don't live in a zone that has earthqukes or extreme weather that might play a part

Dave
 
I installed an electronic kill switch for the same reason. I know the wiring is all good in the car, went through the harness when I put it back together and replaced a lot of it when upgrading. when I had to move the battery to the trunk I wanted a way to shut it off without opening the trunk or having a visible kill switch. the solenoid has a couple small wires that run up front to activate it and keep radio memory.
 
But just like in your house (all the wires in your house are hot all the time)

Unless current is flowing (ie a load is applied and a complete circuit is made) it poses little to no hazard

If the wiring is in decent shape there is little to no hazard.

For me... I leave the battery attached 24 /7
I do as well. Never had an issue.
 
Yeah that nice positive cable going to the starter no I don't think so and I have no radio.
The cable on the battery doesn't go to the starter. It goes to the starter relay. There is another smaller wire there that makes all sorts of chit hot. Maybe best to just see for yourself. Open the door so dome lamp is on or better yet pull the headlights on. Remove and replace positive cable at battery. See spark jump. Next try same with neg' battery cable. No spark.
 
Been doing it for 20 years.
Maybe so, but @RedFish is right. When only disconnecting one cable, it's best practice to disconnect the negative. At my job, we run car fires ALL THE TIME at wrecking yards where "other" fire departments yanked the positive and left it dangling. After some jostling on the tow truck and shifting from being set down in the yard, the positive makes contact and shorts. Boom. The car is on fire.
 
if I turn off the car and the battery is connected, there's still some load on the wires, right?
Seemingly conflicting answers, but the differences are actually easily resolved.

There is no load in the wires.
LOAD is power being drawn through the wires. With everything turned off, there is no load.

possible to cause a fire when the battery isn't disconnected?
Sure its possible. If there is a short to ground, or a cross wire short from feed to a something that wants electric power there could be sparks.
Those things are things that need to be fixed regardless. Route and secure cables properly. Check insulation for damage, etc.
I have to say, I've had two incidents with the wiring that almost ended in a fire (broken original amp. meter that ended pretty bad and a blown fuse)
The resistance in poor connections result in heat when current is trying to flow through them.
Fuses blow when current flowing through them exceeds their amp rating.
On an old car, when the ignition switch is turned off, then everything is really turned off. There is no draw on the battery- things are OFF!
Murry is correct because he is describing draw, or load.
I don't think that is 100% true. If what you are saying then how would one turn on the four way flashers, lock the car on the side of the road and proceed to get help if say you ran out of gas ?? The interior light, horn, cigarette lighter, headlight and possibly a few other accessories will operate without the key in the ignition.
Those circuits are hot (potential), but there is no flow (current).

There must be a complete circuit for there to be current flowing. It's the current flowing that can be useful or cause damage.
 
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Us humans given a chance to "argue" and we jump at it lol
Can't group me in we (although I am human, I think. Jury is still out on that one).
Just ask my wife. I'll turn and walk away from what might become an argument before it begins. As far as this forum, I will do my best to show someone the error in their ways.
I'll go ahead and share one more reason why the neg' and not the pos' should be removed... A end wrench on a neg' battery terminal can accidently contact a metal chassis ground. No sparks. I saw a battery explode in a guys face because he had his wrench on the pos' cable end. A guy named Curtis and I grabbed the other guy by his legs and dragged his face all around in the sleet and snow. Damage to his face and eyes was minimal.
 
Can't group me in we (although I am human, I think. Jury is still out on that one).
Just ask my wife. I'll turn and walk away from what might become an argument before it begins. As far as this forum, I will do my best to show someone the error in their ways.
I'll go ahead and share one more reason why the neg' and not the pos' should be removed... A end wrench on a neg' battery terminal can accidently contact a metal chassis ground. No sparks. I saw a battery explode in a guys face because he had his wrench on the pos' cable end. A guy named Curtis and I grabbed the other guy by his legs and dragged his face all around in the sleet and snow. Damage to his face and eyes was minimal.
Great example of a danger that doesn't often play out but when it does, is really bad.
In that same category as sparking the battery vapors, is sparking gasoline fumes. Static electicity got Ryan Brown, a well respected and very experienced machinist and tuner. (link goes to Yellow Bullet forum as Speed-talk requires membership to read his post).
I'm sure you all can come up with others .
 
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I’ve been thinking of a battery disconnect for my Scamp, primarily for when I rarely drive it during the winter.

What battery disconnects are you using? When I read reviews on some, half of them indicated they were crap (ie: broke or didn’t fit). Post up yours if yours so I can get a good one!

I run a battery disconnect from an RV and use a Viper alarm to connect and disconnect it using the door lock circuits.


Looks like that one maybe be unavailable now though?

You could use this one instead but the circuit has to be reversed instead of a pulse on one post or another like the one I use.


I don't have a problem leaving it connected, but because it is easy enough I usually disconnected it (without setting the alarm) when I park it in the garage and (usually) if I take it to a show.

When I stop someplace and lock the car, I arm the alarm which also disconnects the battery.

I plan to at some point to go back and add an inertia switch that would trip the disconnect in the event of an accident. But haven't gotten that done yet.
 
A simple disconnect is a cam-loc welding cable disconnect on the battery negative ground wire. Used it in my 69 Charger for years and years. Simple quick twist and your safely unplugged. Simple quick twist and your plugged back in.
 
A simple disconnect is a cam-loc welding cable disconnect on the battery negative ground wire. Used it in my 69 Charger for years and years. Simple quick twist and your safely unplugged. Simple quick twist and your plugged back in.
Moroso makes a really slick one, it a battery terminal, with a knob on the top, just rotate the knob, no power.
 
This might sound weird and I might get laught on, but I'm just wondering if I'm the only one with this "fear".
I always disconnect the battery (I have installed a battery dosconnect switch) when I park my '74, even on meets. I'm worried about a fire caused by the battery. I mean, if I turn off the car and the battery is connected, there's still some load on the wires, right? I just think due to the age of the wiring, isn't it possible to cause a fire when the battery isn't disconnected?
I have to say, I've had two incidents with the wiring that almost ended in a fire (broken original amp. meter that ended pretty bad and a blown fuse)
All the running current except starter go throught the ampmeter. With age corrosion or a poor connection can present their ugly heads to cause a fire. Wiring insulation can break down with age when subjected to underhood heat, UV rays, road salt and vibration. If you carefully inspect the wiring for damage or signs of deterioration, you should not expect a problem. That said we are dealing with Murphy's Law when dealing with lassic and vintage vehicles. But parked at a sshow and shine and disconnecting the battery because you are afraid of a fire is OCD. Preventing theft is a different issue, but I would approach that in a different manner.
Now old ampmeters should be replaced with either a new meter or better would be a voltmeter. Volt meters function in a different way to the amps meters. Volt meters have high internal resistance that cuts current to minimal levels, which cuts heat creating current to very low levels, which reduces fire risk immensely. Now if you have a concours contender a showroom new appearance is of utmost importance so retaining the amp meter is important. In this instance I would look for a NOS meter or have a company like Classic Instruments rebuild the original to new or better status.
It is important to keep a 5# or 10# fire extinguisher in the trunk just in case.
 
On an old car, when the ignition switch is turned off, then everything is really turned off. There is no draw on the battery- things are OFF! New cars are different. With multiple computers and loads of sensors and electrical stuff there is always something ON, maybe on a reduced level but still ON! This is why battery life on new cars is reduced.
Battery life took a powder with the introduction of maintenance free batteries. For a while 2 years was about it for most batteries even when driven daily. Long term storage on old vehicles was basically a matter of removing the key. Now the keep alive memories in ccoccomputer components of modern vehicles require regular use or disconnect the battery. Those draws will drain a battery in a month and when that happens a few times or it is left all winter, that battery is due for a funeral.
Other than tthe lithium batteries which worry crap out of me, newer batteries are getting better and seem to last a fair while if kept charged.
 
I don't think that is 100% true. If what you are saying then how would one turn on the four way flashers, lock the car on the side of the road and proceed to get help if say you ran out of gas ?? The interior light, horn, cigarette lighter, headlight and possibly a few other accessories will operate without the key in the ignition. So to answer the OP's question, it's not a bad practice to have a quick disconnect switch and to use it. Just my thoughts.
Marker lights and 4 way flashers for emergency use bypass the key, as do the head lights and interior light in most cases. As long as their switches are in good condition and turned off, no current flows. There has been some recent recalls due to poor build quality ignition or headlight switches that transfered minute amounts of contact metal that leaves a small current path. Eventually this builds up to the point enough current to get hot transfers. Bean counters cutting corners is the cause. Of course the bean counters finger engineering instead of accepting blame.
Dad had a street rod with a SBC engine in it. He installed a battery disconnect as the battery would be dead in a day or two if he forgot to turn it off. I checked it and the pprevious owner had wired the battery and key power terminals on the Delco alternator backwards. Battery power on the key power terminal leaves the voltage regulator on all the time and drains the battery. I simply popped the the wires out of the terminal connector aand reversed locations. Half hour or a bit less time spend. Dad thought I am a total genius as his battery stayed charged. He would shut the disconnect off in the fall so the radio clock would not drain the battery over the winter.
 
I’ve been thinking of a battery disconnect for my Scamp, primarily for when I rarely drive it during the winter.

What battery disconnects are you using? When I read reviews on some, half of them indicated they were crap (ie: broke or didn’t fit). Post up yours if yours so I can get a good one!
Caterpillar had a disconnect switch that used a key. Any Cat Skinner would have a key but the average person would not. Designed for 24V and diesel starter current. Can probably get a good used one from and equipement wrecker.
 
All the running current except starter go throught the ampmeter.
Simply NOT TRUE
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Alternator output circuit and battery output are joined with the main feeds on the alternator side of the ammeter.
1687618924316.png


Potential is in indicator of energy levels.
There is always voltage (energy available) in all of the wiring connected to the battery positive.
The alternator, when running, produces power at a higher voltage than the battery's energy can be stored.
This is how the alternator is able to recharge the battery.
It is also why lights are dimmer when running on battery (12.8 Volts max) than when the alternator is running (around 14.2 Volts).

Current is electrons moving. Just like the current of a river is water molecules moving.
The ammeter is normally centered because there is no current flowing through it.

The ammeter shows slight discharge during start because the alternator is not running.
The ammeter shows charging after start because the battery is drawing current for recharging
The ammeter has ZERO CURRENT flowing past the needle during normal running.
1687619524008.png
 
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