Raised on the Erie Lackawanna Mainline- Supt. of the Black River Transfer & Terminal R.R.
No battery should be hot to the touch, unless too much current is being drawn from it. Let it cool down and place the battery in another 400 controller, if it doesn't overheat then your controller might have a short or bad component. Of course as noted earlier make sure it's not in backwards but it probably wouldn't work if it was.
Springfield PA
So when exactly did you notice that the battery was hot?
When this has happened at my club, it's because the throttle user flipped the battery the wrong way. Instead of reversing the polarity (putting the "+" on the "-" and vice versa), the user flipped the battery over so that the batter contacts were up against the metal spring on the other side. This shorts out the battery and causes quite a bit of heat.
Paul A. Cutler III*******************Weather Or No Go New Haven*******************
Yep, you 'flipped' it the wrong way. When peopel talk of flipping the battery in the DT400, they mean putting the + terminal in the - side. This is usually a big no-no with anything electronic, but the DT400 has a diode in the power circuit that prevents this from doing any harm. Opposite the terminals is a metal spring that keeps the battery pushed against the terminals. If you 'flip' the battery so that the battery terminals face this spring, you put a dead short on the battery and especially with rechargables this can generate a lot of heat real fast.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
If this is a known problem I'm surprised that digitrax hasn't corrected it. Sounds like an easy fix.
By the way, what is the battery for? Wireless?
The battery is only needed for wireless. The basic DT400 has IR wireless built in, and then there's the radio DT400R.
This isn;t a 'problem', it's putting the batter in the wrong way with the terminals touching a metal spring. Should be fairly obvious just looking at the battery compartment that putting it in that way would be a Very Bad Thing, but this is not the first time I've see in. Beats having a plastic spring that would fatigue and eventually break and fail to keep the battery pressed against the contacts though.
I doubt you damaged the throttle unless the battery actually exploded or leaked into it. The battery, on the other hand.. I would probably toss that one and get a new one. You can plug in a plain 9V battery, doesn;t have to be a rechargeable type. You need a system to plug the throttle in to really test it, but if you put a battery in the display should light up and show the voltage and version. That's no real proof it's fully functional though. Again, I doubt you damaged the throttle though, unless the battery lost containment. If it wasn't hot enough to set your shirt on fire while it was in your pocket, it wasn't hot enough to melt any components. And if it was because the battery was shorted on the spring, there was no power going into the throttle circuits anyway. The good thing is probably that this happened after a session when the battery was probably mostly discharged already.
This is a known 'design' problem that Digitrax has not corrected? Putting the battery in completely backwards is sort of hard to do(but can be done). The spring 'X-Clip' on the left side is there to hold the battery tight against the +/- contacts on the right side. I suppose Digitrax could redesign the 'X-Clip' attachment, but I suspect that the entire case is some industry standard case and Digitrax just purchases them as blanks in quantity. At least, the throttle electronics are not in that short circuit path! I normally 'pull' the battery when I pack up at the club. At home, the throttles are plugged into a throttle port(even the wireless ones) when not in use, and the Loconet throttles is is powered by 'wall wart' power supplies, even when track power is turned off.
BTW, the battery is in the wireless and non-wireless throttles. It keeps the throttle information 'alive' if you unplug from a throttle port on the non-wireless ones, and provides power for wireless operation as well.
Jim Bernier
Modeling BNSF and Milwaukee Road in SW Wisconsin
HamltnblueIf this is a known problem I'm surprised that digitrax hasn't corrected it. Sounds like an easy fix. By the way, what is the battery for? Wireless?
A design problem? How is putting the battery in bass ackwards a design problem?The same heat can occur if you drop that battery into a pocket full of change.
The battery makes the throttle work when it's unplugged. It also lessens the load on the command bus when plugged in. All system's throttles use the same power principle.
Martin Myers
A little change in describing the process can help. Since I've been describing the process as "rolling" the battery over, rather than "flipping" it, I've had fewer instances of people putting the battery in backwards end-for-end.
-Fritz Milhaupt, Publications Editor, Pere Marquette Historical Society, Inc.http://www.pmhistsoc.org
It's definitely a design problem if it allows the battery to short out. Common practice is to have a blocking diode in line to prevent reverse current, unless the circuit is dual polarity. From the description given it sounds like the one of the battery terminals is shorting out on something. The fact that the batteries overheat is a fire or personal injury hazard and could easily qualify as a recall issue.
From what was posted, you have to put the battery in with the terminals away from the contacts in the DT400. There is a plate that pushes against that base of the battery to maintain contact between the battery terminal and the contacts.
There is a diode to prevent current flow if the battery is installed with reverse polarity. It's fairly common to roll the battery to the reverse polarity position for storage. The potential problem is if the battery is installed with the terminal posts away from the contacts and against the pressure plate.
To avoid the potential short, one could cover the pressure plate with a layer (or two) of capton tape.
I hope this helps.
Vernon in Central Indiana
Hamltnblue It's definitely a design problem if it allows the battery to short out. Common practice is to have a blocking diode in line to prevent reverse current, unless the circuit is dual polarity. From the description given it sounds like the one of the battery terminals is shorting out on something. The fact that the batteries overheat is a fire or personal injury hazard and could easily qualify as a recall issue.
You completely ar emissing the point. Take a tip from the previous post - if you ROLL the battery over and connect it with the polarity reversed, nothing happens because the DT400 does indeed have a diode in it. You can leave a battery like that as long as you want and no harm will come to the battery or throttle.
On the opposite side as the terminals is a metal spring to hold the battery in place. Putting the battery in that way will short it out and I'd love to hear how you could supply the spring action with a non-conducting material that would actually hold up (ie, plastic would NOT work). It's VERY ovcious that the battery is not to be inserted that way, plus it surely takes more effort since the terminals would not be seated in the slots made for them. As was also mentioend, these cases are not custom made by or for Digitrax, the basic case I've seen available at one of the various electronic suppliers. It's an off the shelf item that Digitrax drills out for their buttons and puts a label on.
The battery's terminals go to the left all the time. In the photo, for operation, the positive terminal would be at the top left. For Storage, turn the battery so that the positive terminal is at the bottom left. (polarity reversed)
The metal spring is on the right. At no time should the battery's terminals be in contact with that spring or a short and the resulting hot battery will occur.
If you want to see what the case looks like before Digitrax turns it into a throttle, see this link: http://www.serpac.com/products_m-8.htm
Capt. Grimek It sounds like, from what you guys are saying is that he really meant for me to "roll" the battery over so that the + post is now in the - post position...yes?
That would be correct.
As others have already noted:
There is a diode in the circuit to prevent current from flowing in the "wrong" direction, so it doesn't matter that the positive and negative contacts are reversed.
On the other hand, if you flip the battery end for end, both terminals are pressed against the same spring, and of course that will create a dead short. That dead short, in turn, will cause the battery to heat up which is what you originally experienced.
Steve
@ rrinker, the spring could be made of a suitable plastic/nylon, or could even be two seperate coils springs with no electrical connection, so springing is not really an issue. that said though, i think the difference between flip and roll needed some work.
Yes it could, but because the case is made by Serpac, that would mean a completely new case which means a whole new throttle. That would make our "old" throttles obsolete. Not just DT400's but every Digitrax throttle ever produced since day one. Kind of overkill to keep someone from placing a battery's two terminals against a piece of metal. There is a note and a caution in the manual regarding this.
It never ceases to amaze me what manufacturers have to do to protect us from ourselves.
Ditto
Rather interesting on the case I never realized, it also exactly fits 2 AA batteries with the spring providing a series or parallel contact between the two. Quite clever.
I don;t think the battery roll 'trick' was even in the manual originally, if it is now. Just that somewhere along the line AJ mentioned you could do it because of the diode and suddenly everyone stopped taking out the battery and just rolled it over when not using the throttle.
Well that makes more sense as to what is happening. If there is a chance for someone including a kid to insert it incorrectly and cause physical damage or fire the issue should be corrected. All it will take is one person to get hurt or a few complaints and the consumer product safety commission will be all over them. I only know because I was a product manager and had to deal with them on a couple of occassions.
There is definitely a way to correct it. There have been countless products using 9volt batteries including smoke detectors and they don't use a metal spring.
Removal is always best. If it's a rechargeable battery and you forget to roll it, it ould become excessively discharged and turn into trash. It's been years since I've seen a battery actually leak, but it could happen.
As for leaving it a week shorted out - a nicad rechargeable will dump the current pretty quick (why it got too hot to touch) but once it's discharged, it's done. It won't continue to get hot as little or no current will be flowing (once the amount of charge becomes too low to overcome the internal resistence of the battery).
Yeah, once a battery is 'dead' there's no more power to go through the short and make it hot. An orderinary alkaline battery can dump a lot of current quickly as well. But once the charge is used up, there's nothing more to happen. The difference is that since it's a regualr battery, it's just ready for the recycler anyway. A rechargeable, if you stop using it before it is completely discharged, it can still be recharged. Go too low and, particularly in nicads, one or mor eof the cells can actually reverse polarity. There are conditioning chargers that can sometimes fix this, but usually it means time to get a new battery. Keep in mind an alkaline 9V battery is made up of 6 cells, each putting out 1.5 volts - AA, C, and D batteries are all one cell. Nicad cells are typically 1.2 volts, and there are two types of '9V' repalcements,. Some have 7 cells for 8.4 volts, some have 8 for 9.6 volts.
Whem I swap the batteries (2 AA) in my digital camera, I have a 50/50 chance of getting it right - the polarity is marked, but halfway down inside the dark tube that holds the battery so unless you have bright light it's hard to see. Would it have been so difficult to put a + and - on the battery cover, or on the more then sufficient expanse of plastic under the door, next to the two holes the batteries drop into? The DT400 is betetr marked than many devices out there.