Replacing Batteries with BCRs in MTH PS1 and PS2 Locomotives

MELGAR - I've read several Posts about 'fried MTH boards' (particularly the 5 volt boards) in PS1 and PS2 equipped engines, and it's usually associated with the MTH batteries, but could you (or someone else reading this) please explain what actually happens to cause the boards to be ruined - in layman's English please.  Thanks very much. 

In simplest terms, the PS1 board needs to "save" a file before the electronics completely power down. When there is not enough energy in the battery, the board can not do this and gets "confused" about where it is and what it is doing the next time it is powered up.

Uber - Hence the 'next' time you try powering up - nothing happens? (at least that's what happened in my case)

Thanks for the explanation, really appreciate it!

That explanation works for PS/1, and was a common issue with early PS/1 boards from 2095 and earlier.  PS/2 doesn't have the scrambled board issue from bad batteries.  The issue with PS/2 is thought to be a possible short across the battery damages the charging circuit, but that may not be the whole story.

GRJ - Thanks to you too.

In my case I'd been running a PS 2 steamer for approximately 0.5 hr, then put it in neutral (and left it idling) while I answered the phone, and after no more than 2 or 3 minutes I heard the power down sounds start (without me touching the remote) and that was it.  I assumed it might be the battery so I popped in a brand new MTH battery the next day (after properly charging it overnight) and tried to power it up but nothing - no sign of life at all. 

The 5V boards are pretty infamous for dying for no apparent reason, hard to say what caused it's demise.  I've put one away running flawlessly and a couple weeks later it was dead as a door-nail!

For PS-1 if the battery is dead enough the processor does not write to memory.  It knows it does not have sufficient power.  It is usually the partially charged battery that causes issues in that it does start writing, but can not finish.

THAT CAN HAPPEN with BCR too.  If BCR only allowed to half charge and turned off same happens.  Or an attempted direction change with insufficient charge.  I have had to do resets on BCR engines.  So let them fully charge.  Normally the newer 1997 up PS-1 stuff is less effected.  G

@GGG posted:

For PS-1 if the battery is dead enough the processor does not write to memory.  It knows it does not have sufficient power.  It is usually the partially charged battery that causes issues in that it does start writing, but can not finish.

THAT CAN HAPPEN with BCR too.  If BCR only allowed to half charge and turned off same happens.  Or an attempted direction change with insufficient charge.  I have had to do resets on BCR engines.  So let them fully charge.  Normally the newer 1997 up PS-1 stuff is less effected.  G

I know of a well-known O-gauge guy who owns a LOT of engines - he swears by using cheap rechargeable batteries from Harbor Freight ($5 each) instead of BCRs.  Personally, I feel more comfortable with the BCR.  Just wondering if you have any thoughts on his practice?

John I have to agree with you 100 % in your analogy of the gun always loaded and the bcr's or cheap batteries. just because someone says its's great to jump off a bridge don't mean I would do it !

Alan

@gunrunnerjohn posted:

I know a guy that owns a lot of guns, and he never checks to see if one is loaded before handling it, probably the same kind of guy.   Just because someone does something foolish, that doesn't make it a good idea.

@Alan Mancus posted:

John I have to agree with you 100 % in your analogy of the gun always loaded and the bcr's or cheap batteries. just because someone says its's great to jump off a bridge don't mean I would do it !

Alan

Don't hold back - let me know how you really feel!   I'm with you - I think BCRs are cheap insurance.

Not going to name him, but you might be surprised.  Or maybe not...

And re the loaded gun reference, it's called Rule #1 for good reason.  Unfortunately, some folks can't count that high.

So you intelligent gentleman are equating a battery with a loaded gun.....wow.  So are the harbor freight batteries known to be bad, or is everyone just jumping on the BCR band wagon now?   How long ago was there a concern that BCR might harm the charge circuit and ruin a board?

6 batteries at $5 is about 6 x 5 years of service or 30 years.   1 BCR is $30 and X years?  Will those capacitors last 30 years?  Maybe the gentleman figures he only has 20 years left running trains.

It is economics and easy of maintenance otherwise 6 or a half dozen.  G

@GGG posted:

So you intelligent gentleman are equating a battery with a loaded gun.....wow.  So are the harbor freight batteries known to be bad, or is everyone just jumping on the BCR band wagon now?   How long ago was there a concern that BCR might harm the charge circuit and ruin a board?

6 batteries at $5 is about 6 x 5 years of service or 30 years.   1 BCR is $30 and X years?  Will those capacitors last 30 years?  Maybe the gentleman figures he only has 20 years left running trains.

It is economics and easy of maintenance otherwise 6 or a half dozen.  G

Well there is the extra hassle of replacing the battery periodically which is not always easy.  

The BCR is a capacitor.  Measure the capacitance.  A 24 to 30v capacitor is probably $3 maybe even $1 depending on the capacitance.  Solder the cap in making sure the terminal are insulated and you have saved yourself some real cash.

Has everyone forgotten high school electronics?

@swrr posted:

The BCR is a capacitor.  Measure the capacitance.  A 24 to 30v capacitor is probably $3 maybe even $1 depending on the capacitance.  Solder the cap in making sure the terminal are insulated and you have saved yourself some real cash.

Has everyone forgotten high school electronics?

Nope, I actually still remember some of the stuff well beyond high school electronics.   We also haven't forgotten how to read the labels on a capacitor either.

The BCR for 5V engines is four 1.5F 2.7 volt capacitors in series with a Zener diode across each cap to equalize the charge voltages.  The cost will be a bit more than $1.

@GGG posted:

So you intelligent gentleman are equating a battery with a loaded gun.....wow.

Don't they look the same?

Did not have electronics in high school.  Took circuits and power engineering courses in college - barely remember anything relevant. Somehow I do not think it is as easy as popping in a cap. Isn't there concern about dropping the voltage down to meet the board's requirements?  Don't you have to limit the discharge rate? Seems to me this involves resistors and inductors and maybe diodes in addition to the cap. Don't you have to figure out how much energy storage is needed in the cap ???

After blowing a PS2 board with a bad battery, everything gets a BCR except PS3s.  Pop it in, lube everything up, and I never need to open it up again and never need to worry about a leaking battery.  For $20 or less - cheap insurance.  Given my EE skill set or lack thereof, why would I risk a $500 and up engine to save $10 or $15 bucks?  Ok to fix the board $200 new board, $100 technician and $75 for RT shipping - assuming you can get the board. 

@ScoutingDad posted:

Did not have electronics in high school.  Took circuits and power engineering courses in college - barely remember anything relevant. Somehow I do not think it is as easy as popping in a cap. Isn't there concern about dropping the voltage down to meet the board's requirements?  Don't you have to limit the discharge rate? Seems to me this involves resistors and inductors and maybe diodes in addition to the cap. Don't you have to figure out how much energy storage is needed in the cap ???

After blowing a PS2 board with a bad battery, everything gets a BCR except PS3s.  Pop it in, lube everything up, and I never need to open it up again and never need to worry about a leaking battery.  For $20 or less - cheap insurance.  Given my EE skill set or lack thereof, why would I risk a $500 and up engine to save $10 or $15 bucks?  Ok to fix the board $200 new board, $100 technician and $75 for RT shipping - assuming you can get the board.

Where are you getting a BCR for $20.  Every place I have seen is $30?  No one will really know what is in there unless you dissect one.  Not a lot volume for caps and other discrete components.  My feeling is that the resistors and inductors are on the ps2 board.

@gunrunnerjohn posted:

Nope, I actually still remember some of the stuff well beyond high school electronics.   We also haven't forgotten how to read the labels on a capacitor either.

The BCR for 5V engines is four 1.5F 2.7 volt capacitors in series with a Zener diode across each cap to equalize the charge voltages.  The cost will be a bit more than $1.

Don't they look the same?

  

Agreed the cost will be more than $1 with Zenars.  The Bcr for 5volt is actually pretty reasonably priced when you take into account time.  Not so convinced on the 9v version at $30.  Have you dissected a 9 volt BCR?

The 9V BCR (for 5V boards), is the one with four caps and four Zener diodes.  The 3V board BCR2 is just a 5V supercap in shrinkwrap.

@swrr posted:

Where are you getting a BCR for $20.  Every place I have seen is $30?  No one will really know what is in there unless you dissect one.  Not a lot volume for caps and other discrete components.  My feeling is that the resistors and inductors are on the ps2 board.

Not that $30 vs. $20 is a big deal when we're dealing with $400-$2000 locomotives, but you can get them for $20 or less each from the source:   https://www.jandwelectronics.com/  Buy 10, get 2 free.  12 BCRs for $250 or 12 BCR2s for $200.  It's a drop-in replacement that requires no soldering, and it supports a cottage industry that has saved many of us a lot of headaches.

@gunrunnerjohn  is that all the BCR2 is?  a single cap and connector plug?  I never thought about taking one apart to see. [I believe you - just stunned that's all there is.]  For what its worth, I am working with a professor who has developed a supercapacitor based on graphene. He prints them with an "ink-jet" to any size and shape needed - all solid state.  When he demo-ed it to me. They touched the leads to a battery to charge, them on to an LED which stayed lit. Nearly as thin as a sheet of paper.  Really interesting.   

CT McCormick Hardware has the BCR2 for $19.95 plus shipping. A bunch of sponsors are close to the same price within a couple of bucks. Like everything - order more than one item and the shipping per unit falls. I thought about going direct to JandW with their great holiday sale, but i will never use that many.