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I have a new, never run steamer that I have listed on e-Bay.  Most of the trains I own are early 5v PS2 locos.   I have gotten in the habit of testing them before shipping.

I test the steam engine and it operates great and the sounds are perfect.  Then, I select "shut down" and immediately cut the transformer power and the sounds abruptly end.  I then recharged the battery with the external charger from MTH for 12 hours.  Afterwards, the loco once again shuts down abruptly after cutting the transformer power.  Okay, this means the battery is bad, right?

So, I order and receive a new battery that is green rather than white.  Several questions come to mind:

  1.)  Why did a white rechargeable battery fail in an engine released in the year 2000 that has never been run?  Does the connection in the dormant engine somehow degrade the battery?  Or, is it a "shelf live" issue?

  2.)  If it is a shelf live issue, what is the battery shelf life and how does one know the manufacture date of the replacement green battery?

  3.)  Should I abandon the rechargeable battery approach and go with the BCR?


Tom Jasper

Last edited by Rich Melvin
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first of all no battery will last 20 plus years and that's how old the old white batteries are ,first thing take out the white battery and immediately throw it out before you destroy the board. NEVER TRY A ENGINE WITH A WHITE BATTERY! second of all you can temporally buy a regular 9 volt battery and install in your five volt board, it is ok to try with a regular battery but only for a test do not leave the regular battery only use it and see if your engine works correctly and when you momentarily shut ff the voltage to your track the sounds should continue for 7 seconds or so, then you know you had a battery issue and can then buy the green battery from mth !


I'm using GRJ's iteration of a battery replacement in a ps2 /3volt  ( 30-1305 ) Mallet .  Similar to the BCRs I've used but less cost.   It plugs right into the board and has worked flawlessly.

What would be the difference between the 3 volt and 5 volt that would be be of concern ? 🤔

The 5v boards were pushed to the limit on basically everything. A tech can help fill in the blanks but the long and short of it is they were pushed to the limit with electronics.

The recommendation for using a BCR as a permanent replacement for the 9-volt battery in PS1 and PS2 engines comes from the device manufacturer. I'm not aware of MTH having recommended the BCR, but their objective may just have been to promote sales of their batteries. Recommending a BCR type device would be an admission that the device was better than the battery.

One more comment. In turning on track power, I initially set the transformer voltage to the "LOW" position of the the throttle on the Z4000, which produces an indication of about 6 volts. My thinking is that this produces lower initial current than if the throttle is initially opened quickly to 10 or 12 volts. I then wait a few seconds, let the current stabilize (and the BCR begin to charge) and then slowly increase to 12 volts before pressing the direction button. It seems to me that it's at least better for the BCR and would also apply to a PS3 system. Do you think it's beneficial for the circuitry?


Do batteries have a shelf life?  Yes.  I have only seen one MTH battery leak, but this one was only 6 years old when I replaced it.  After I saw that, whenever I buy a PS2 loco, one of the first things I do is install a BCR or SBR.

I agree with Oman.  If you are going to sell it, install a new MTH battery.  But if you do install a BCR, up the price.

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I have seen far more PS-2 3V charging failures then I have seen PS-2 5V charging failures.  There is a lot of old wives tales about various failures.  MTH never did failure analysis I was told.  Just anecdotal.  Plenty of engines using BCR without engine failures.  I have also received plenty of PS-1 and 2 with white batteries that still worked.  Was the board at design limits?  YES.  Did the design use components requiring higher power needs?  Yes.  Just watch a startup on  Z-4000.  Jumps between 1 and 2 amps.  Sometimes higher especially to drive audio.

So my experience is 9V batteries last about 4-5 years.  Don't store well.  Do gas out at terminal occasionally.  Really rare to leak.  So why.  7 small 1.2V cells with limited chemical energy in each cell.  Used in series.  So once one cell fails it kills overall voltage.  Plus the board needs 5V for processor already drawing more current then later designs, so once a battery tips over in voltage harder to keep up.  Plus the voltage is dropped to support the board.

So 3V the board uses much less current with modern chips.  Has a 3.3V processor.  The battery is now a 2 cell 2.4V battery with more chemical energy per cell.  They seem to last 7-9 years with moderate use.  Store well, don't seem to gas out or leak.  2 versus 7 cells.  Plus board design has boost circuit that provides 2.5V via an inductor at shut off independent of the battery.  So battery is 2.5, inductor 2.5 for 5V.  Even when battery gets down low you still have power for the power supply (well designed 5V TI version) to feed the 3.3 V power supply for the processor.  Plus board design kills audio volume to reduce load when voltage dips too low.  Plenty of self protection features.

The real killer of the PS-2 3V is high voltage spike and shorts in the DC wiring (pinches, operator error).  For the 5V age and component break down.  Some die without even a short.  Just won't power up anymore?

Thanks G3 for your thorough explanation.  A few follow-up questions if I may:

1.) When purchasing a new "green" battery for the 5v PS2 system one doesn't know when the battery was manufactured.  If a green battery really is new, does it matter (i.e.; one produced 10 years ago will be as good as one produced 1 year ago because they have a very long shelf life)?

2.) Is the design of the green battery different/better than that of the original white battery?



@Tom Jasper posted:

Is the design of the green battery different/better than that of the original white battery?


The chemistry of the white and green batteries is different. The white battery is Nickel-Cadmium (NiCad) and the green battery is Nickel-Metal-Hydride (NiMH). The Cadmium in the NiCad is toxic and presents an environmental problem when the battery is discarded. The NiMH has a higher energy density and stores more charge in a given volume.


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