In another topic it was advised to use car batteries as power supply for your controllers,
due to their ability to hold a constant voltage.

Trying to keep topics separated, I've started this topic about the dangers of using car batteries indoors or as power supply for MRR controllers.

1: Car batteries can explode if accidentally shorted with a strong enough wire or tool.
My friend Arne Petersen has a glass eye because of dropping a spanner on a car battery, it exploded.

2: When charged, a car battery produces an explosive gas mixture of hydrogen and oxygen, which under normal conditions dissipates.
If the battery is kept in a closed box, the explosive mixture will fill the box, and a spark can ( Will !!! ) make it explode.

3: A 60 Ah car battery are build to deliver > 600 Amps current for starting the car, this current is delivered so fast and strong that most electronic
current limiters don't react fast enough, which in the case with a MS, CS or 6021 / 6015 / 6017 will cause the device to let the expensive smoke out.
Older devices such as Delta 6604 or 66045 has a bimetallic fuse which is far too slow for the current from a car battery.

http://www.google.dk/ima...ql=&oq=&gs_rfai=
http://www.answerbag.com/q_view/2049030
http://forums.x-plane.or...ndex.php?showtopic=14377
http://en.wikipedia.org/...ry_(electricity)#Hazards
http://en.wikipedia.org/...tery#Exploding_batteries

Google can give you many more examples

Per.

There are several companies producing equipment for off grid applications, that use car batteries with solar, wind and hydroelectric generators.
Some have cabinets for outside or garage storage, and come with some type of power inverter for AC applications. Some have 12V, 18V, and 24V DC outputs So there are ways to run a controller off a battery, I plug my cellphone in to my car all the time, it and draws as much amps as needed but has a fuse in the adapter in case of a short.
I would just have a fast acting 2amp fuse in place, that would keep the smoke in and not weld the Wheels to the track if the train derails.
Even better would be a Current limiting circuits http://en.wikipedia.org/wiki/Current_limiting

Edit: This was written while Arconell was posting and not an answer to his post:

You are both right; but in these cases the equipment are build for that purpose, Märklin controllers are not.

Most household UPS batteries are sealed and much smaller than a car battery, and much more suitable for controllers.

The wind turbines I work in also have UPSs, and even though the batteries last much longer,
they are changed every 3rd year for safety reasons, meaning that I have lots of those "in stock"

No matter how fast a "normal" fuse is, it is not fast enough when it comes to protecting electronics.

I also wrote in the other topic where this came up, that current limiting circuits are the way to go, so I agree completely;
but it should be a separate device designed for the task, not the internal circuit in your Märklin controllers.

( It is possible that the current limiter in a MS2/CS2 can handle power from a battery; but in that case they are the only Märklin controllers that can. )

Per.

Let's not make a mountain out of a molehill. I understood Robert using the battery as illustrative of what can be done, not what has to be or should be done. If someone wants to haul a battery into their house and connect it directly to their layout without any safeguards, so be it, their choice.

The seperate threads the last few days dealing with track feeds, transformers, etc. have been informative and engaging, as it should be. Keep it coming. I'm always happy to see people post about their layout or pictures of their rolling stock, but I also want to learn.


Robert,

Sorry for your loss. I see no reason for you to feel you have stepped out of bounds.



Regards,

Thomas

Well, I think most of us are! Not sure if anyone has registered with 'Alien' in their profile yet....although I do wonder about some of those members from the West Island!

You east Islanders are upset because we are the main land and are superior in all things except maybe Mobile Wrestling where the All Balacks (Mainly white) may for a short period of time may win the odd game through Bribery and corruption.

(Into the trenches, flak jackets on)

in other news, hostilities on the Tasman fromt have resumed

A big from clean, green New Zealand (aka paradise)

Actually it is VERY green at the moment.. We have had more rain in the last month than the last five years... How long can you tread water??

You gotta love those greenies - when there is no rain it is global warming and when there is rain it is global warming... They seem to forget that the plant life needs Carbon Dioxide to survive..