Floating the 12V battery

*50* amps? Quiescent? No. Flat-out wrong. 50 *milliamps*,
maybe, if smartkey is turned on -- get your orders of magnitude
right, and re-read this.
.
_H*

 

Could one "float" with a 6V battery connected under the hood, with less potential danger than a 12V, and have enough current to retain the presets, etc.?

 

To retain memories, if that is your purpose, the car requires a minimum of 12VDC to support the hardware. Anything less and you may lose your memory, then who would you be?? Ha, Ha.

 

Just looked at your site Hobbit, a really nice job of explaining.

 

There is NO danger, there is always potential danger in everything. So just be cautious, but not scared. Millions of mechanics change batteries every day, it's no big deal. The poster that talked about drawing 50 Amp arcs is full of bovine fecal material. He probably never attempted to change a fuse for fear of electrocution. AND, he never answered my question.

 

The standard operating procedure in the very cold NORTH on a vehicle parked outside in minus temps ( F ) is to short the battery with a large screwdriver, This is of course a emergency procedure when one needs that vehicle. I don't know if this is still done, but I imagine so. Not my cup of tea, but under circumstances, sometimes necessary. It will definitely warm up the battery so those little ole electrons flow!

 

I assumed the 50A comment was referring to peak 12VDC startup currents as here:

Prius Startup Current

As you correctly pointed out its a far cry from the few milliamp draw when the car is off.

 

That is really a great site. But, remember the OP was only talking about changing the battery, not starting the car up. It is reassuring to know that my little 7AH gel can possibly handle momentary current draws. Now I have to research it.

 

Never heard of that. I was also stationed at Thule, and we sure as hell didn't pull a stunt like that either.

 

Your electrons were probably frozen solid.

I have shorted things like that, but never intentionally. You want to be wearing protective equipment if and when you do something that stupid. Several of my tools have notches in them from just such a move.

Tom

 

This is a trick done by people living in a rural area, farmers, hunters, perhaps with older vehicles and weakened batteries to start with. After that silent noise of turning on the ignition switch, the hood is raised and the terminals shorted out ONLY to warm up the battery sufficiently so the starter motor can be turned. I have only read about it, maybe someone who has direct knowledge of it can comment.... No it was never necessary in Thule as the vehicles and batteries were always in good shape. I don't even remember a starter motor turning over with difficulty. Also the weather in Thule is different than say Wisconsin or Minn or ND where the humidity factor might get involved. I was never so cold as one day in Madison, WI when the temp got down to 29 below. It hurt just to run across the street to work. Of course I did not have a Parka or bunny boots at that time. Andy

 

edit

 

Address is wrong, how do I drag correct site address to this thread, I have tried from bookmarks and icon, what is the key? TY

 

Max Lead Acid Discharge Current. at The Alternative Energy Store A short quote from this site states: The difference between power and energy: Watts X <1 second = energy. ( he then gives an example using a 4000Watt inverter. ) 4000 watts times 1 second = lots of power but very little energy. Batteries store energy and will not be effected by this short burst. MY words: If one steps on the brake while at the same time hooking up or disconnecting a 12VDC aux, one might get electrocuted if one is also perfectly grounded. But most likely the surge (if present) will attract immediate to the positive terminal, thru the battery and on to ground. The author of this information is: James Cormican, dated: July 28th. Page 2. There is also a lot of other neat info on this site concerning home power and inverters.

 

Well, the climate I now live in can dip to -40, and I've never heard of such a thing. Asked a few old timers, and they've never heard of such a thing either. Maybe an Urban Legend?

I'm sure you remember the strict rules onsite about plugging in if the vehicle wasn't running. In addition to regular block heaters, and higher power circulating block heaters, they also had electric battery blankets, transmission pan heaters, differential heaters, etc

The heavy equipment at the flight ops line also had heaters for the fuel tanks, if I recall so did all the diesel powered equipment, despite using DFA year round. The loaders had heaters on the hydraulic sumps too. The Huffers on the line also had heaters to ensure they would start

So, do you miss Danish beer?

 

Certainly it is true that warming the battery can increase the cranking amps. An old trick was to turn on the headlamps to draw some current to heat up the battery, then shut off the headlamps and try cranking. Of course the mere act of cranking should provide more heating than the headlamps, so this is probably on old tale. Nevertheless, this is the origin of one of my standard comments: When I see a parked car with headlamps on, my usual comment is to say "They are probably just keeping their battery warm."

Tom

 

Yes I do remember plugging them in, and I do remember the Danish beer, I spent a month in Copenhagen on R&R ( wasn't called that then ) Pre- Viet. I left Thule in 62, but the one very thing I really miss, was a cook they had in the Cafeteria, same bldg as the Service Club. I never met him, but his Danish Pastry was phenominal! Light, not too sweet and of course, cheap .25! At that time I was in CE so I got to go almost everywhere. Later I transferred into AC Black boxes. So the only time I visited the flight line was to fix a gas fired space heater or take a transition flight. I found the clubs a real bore so I would go out exploring, (totally illegal) Mammas little boy might get lost and freeze to death. Actually I liked to party with the Danes, they were all mostly decent and didn't go nuts like the average GI. On shorting out terminals, could be an urban legend OR it could be, people who have done it, don't browse Priuschat. Enough wandering, Good Night Jay

 

Andy

Ok, I was there almost 30 years after you were. Did you spend a lot of time at J site, with AN/FPS 50? Plenty of historical stuff there, I think it was probably more "fun" in your time. It was pretty much a well established base when I was there.

One of the things I was involved in was the BMEWS upgrade to the Raytheon phased array solid state radar system. There have been many significant upgrades to Thule from the mid 1980's timeframe

Nice to reminesce about this. Unfortunately, have to leave tomorrow for another week

jay

 

Hello Jay, I actually never did get to the BMEWS site, I can only assume they had thier own maintenace custodian types. Later I cross trained into that AN/APN stuf. worked in AC Multi-mode radar and Inertial navigation. Everything was just going into solid state at that time. Much more fun working on AC, I could take a one day ride almost anywhere in Europe and be back home for supper. Andy.