Rechargeable Battery's

Robert,

I agree with your logic and can extend it a bit.

If one is concerned that a 5 volt board is doomed to premature failure (I don't share that thinking myself, based upon my own experiences), then the replacement for that board will most likely be a PS32 board rather than another 5 volt board.

The PS32 board is a PS3 board and will come with its own Supercapacitors already installed, making any BCR surplus.

Further on the PS2 board failures.................  curious if the failures are oriented toward conventional operation or DCS at constant voltage? 

Just a thought,  maybe the conventional operation may be harder on the electronics?

In the end,  I'm just trying to figure out for the first time in my life,  I wasn't left holding the bag so to speak  <G>.  All good with my MTH engines.........

Mark

Barry, regarding PS2 5-volt board life, I have had 2 go bad with dead short, one that would occasionally take off as soon as power was applied (a factory reset would make it ok for a month or so), and another that I replaced just because I had a replacement 3-volt board available.  I still have 2 with 5-volt boards, and have 2 steam upgrade kits on the shelf waiting for them.

Mark, no you're not holding a bag.

Nativefl, lots of points made above, so I did some basic google fu research on NiMH batteries and super caps.  

GRJ seems right on with super caps having around a 1000 hour useful life.  that works out to about 6 years or so if you run an engine 3 hours a week.  On one hand, that remains intact when you're displaying a shelf piece, on the other hand any time the power is on, the life is depleting.  I would guess that even the 1000 hours is low under the real world conditions.  The information I've found also shows these caps as having a life of about 10,000 cycles, or times power is turned off to the engine.  That's a lot in command, but not really an astronomical number if you are running conventional, what with every direction change being a discharge cycle.  

Next, on to the zener diodes.  These cost less than 2 cents each in production quantities... the plastic case likely costs more. For practical cost consideration in the price of a finished product, they are all but free.    

Why has MTH cone with the super cap design in their products?  Well it is a better design,  and COSTS LESS in production than a battery.  You also get the added effect for marketing of removing one of the long-time annoyances people have had with their products.  ( there is a wide selection of 1 to 5 farad caps  on digi-key for less than $5, many less than $2.  With the advent of 3.3 volt TTL electronics  becoming wide spread, you need but one cap to to the job where you need several to replicate a 9v battery.  

As for the NiMH batteries... when bought ar normal retail the cost for the 9v type is the highest.  the AA and AAA types are about 1/2 that of a 9V for a suitable pair of cells.  you're looking at 1/2 to 1/5 the cost of a store bought BCR for a NiMH replacement.  Even at full retail for a name brand battery you're looking at half of what the Cap replacement retails for... and what do you get for performance?  

Well according to the research, 500 -1000 charge cycles, 1.5 year shelf life between charges without harming the batteries. ( 60 days with older style, not  'low self-discharge' types)  even when left in storage longer, the battery will still work, it will just hurt it's total life. 

To keep in mind, with super caps, they go through a full charge cycle every time track power is removed for about 30 seconds.  With the batteries, the only time they will go through a full cycle charge is coming out of storage.  There is little, or no information I could find on partial charges but it seems that with the little power used by the electronics in normal operation, there is very little charging going on. I would expect to see a good 500 moderate charges, ex not running for a several days or weeks, with the trickle charge having no real effect on life.  That works out to about 9 years in the same 3 hours of running per week described above... It's a little more than the 8 years people have mentioned... but then I can find no mention of a X number of years expiration date on any site that has tested batteries.  they all seem to agree that with proper charging, the only factor is number of charges... not age of the battery.  Basically I'm looking at half the cost(or less) for 50% more documented life expectancy.  Now in the real world how will they match up?  I suppose time will have to tell.  There are not so many heavily used BCR's floating about, nor are there any Low self-discharge NiMH's as the tech is only 5 or 6 years old in the affordable types.  Even if the figures prove to be backwards, and the BCR type product lasts 50% longer than a NiMH battery you still save money on the battery.  

Your resident, long winded, techno-babbler: 

Nicads and Nimh batteries can have a short life due to having no charge in them for long periods of time, ie; shelf queens or long time storage. IF these batteries are charged and discharged properly and on regular basis, they can last for years and years under the PS2 system demands.

I want to raise a peripheral issue:  What happens on starting up when battery is dead or cap is drained?  I have now had a similar event occur twice.  Once when I tried to start up a PS2 with an 11-year old battery after it had been sitting for several weeks, so probably was dead.  Another when I was trying to start a PS2 with a cap.  Both times the loco got befuddled and would not start up.  Restore efforts failed.  Loco wouldn't fully delete from the remote, but retained ID number. 

My question for the tech experts is what function (if any) does the battery/cap play upon powering up the track and hitting startup.

As an aside, one of these locos confuses the loa der program.  Most of the time Loader thinks its a 5-volt loco, but it isn't. (Yes, dear, I know the difference!)

Not entirely true, if you really want to know about NiCad batteries, here's an interesting read from folks that should know, NASA.  They seem to debunk some of the commonly held "wisdom" of NiCad batteries.

Handbook for Handling and Storage of Nickel-Cadmium Batteries: Lessons Learned

There's also many references such as this one: BU-702: How to Store Batteries

See above rambling on how many of the batteries I use are stored for 7-8 months in a box.  Standard NiMH batteries show no ill effects from 2/3 year sitting on a shelf, and the 'low self-discharge' type usually retain 80%+ charge.  I'll grant that several years storage is beyond the scope of my knowledge for standard NiMH for me, but I can add that I've had a set of the low self-discharge type that sat in a flash light for 3 years by mistake, and still worked fine, probably retaining 20% charge even after that time.  From what I've read so far, the batteries are only damaged if you put a high load on them when dead. letting them die sitting on a shelf won't hurt them, so long as they are charged before use.  

I'm only theorizing here... but I think the problem could come if there is no current limiting on the charge circuit.  I don't know how it was done these engines so I could be completely mistaken.  If, there is no current limiting, it could be that a dead battery is drawing too much power, leaving the electronics with low/erratic power, causing glitches and bad data to be written to its memory.  Flash memory in particular is finicky when not supplied enough power.  As for the caps, they will draw a lot of current every start up, but only for a tiny fraction of a second.  I've heard it both ways as to name brand BCR's having current limiting built in, and am unsure at this point.  

Hi john; Yes, not entirely correct. But Without showing off and I am not, I have dealt with hundreds of nicads, Nimhs, Li-pos and Li-Ion in the plane and R/C section and I had failures due to reverse polarity, overcharging, undercharging, wrong storage, batteries at low level discharge stored for long time and one cell go into high impedance and kills the pack. I am sure this is not the norm for ALL quality rechargeable batts that NASA uses, but your quote of "not entirely correct" is entirely correct

Just remember that the battery we use in MTH engine only has to provide about 300ma max for about 10secs.  The circuit board does regulate the current to charge it, but how it attaches to the circuit and the buck circuit that makes 2.5V become 5V for the 10secs of shut down can be sensitive to a battery that is really drained, or has become a low impedance short.  Having said that, I am only now starting to see 2.4V NiCad batteries become low impedance.  Mostly because they are now approaching 12years and older.  2004 engine, with batteries made before 2004 I am sure.

Also, MTH 8.4V batteries use a 2 cell battery.  2 4.2V cells.  This is much better then a battery design using 7 1.2 AAAAAAAA..........cells with much smaller about of chemical per cell.

I have seen 10 year old PS-1 battery's still holding a surface charge close to 8 Volts.

So just saying to be careful applying the facts on High Drain long endurance environments to our low drain short duration train operations.  G

I have used this charger to revive some older Nicads and Nimhs...if you know what to do, it is possible to bring back about 70% capacity to some older batteries.

BTW, this charger works with all four chemistry batts. ($90 charger cost)

I'm confused, how does MTH do an 8.4V battery with two cells?  What battery chemistry gives you 4.2 volts for a cell?

I don't know how they do it, but I posted several years ago.  It is 2 thick 4.2 button style cells.  Vice the 7 smaller series cells you see in other batteries. G

1. I'll take your word for it GGG, but I don't know how nicad or nimh  cells can yield anything but a multiple of 1.2

I'd have to actually see and dissect one to believe this, all the information I can find and have ever seen says that NiCad and NiMh are 1.2v nominal cell chemistry.  When you get to Lithium based cells, all sorts of odd voltages are possible as there are many different types.

Funny thing, I had an old PS/1 on the bench, and it still had a white battery.  Here's my chance to see for myself.  Mystery solved, and the laws of physics have not been repealed.  Turns out that George is right, he just didn't take it far enough.

There are two large cells in there, but all is not what is seems.  One of them is a bit taller than the other, and that's for a good reason.  Each of them are a multi-cell battery internally, one with four cells, and one with three cells.

You can even still buy the individual cell here: Univercell Battery Co. Ltd.

All the skill of a surgeon..

Only if the surgeon uses a Dremel cutoff wheel.

On the univercell link you posted, GRJ, I see several 2.4-volt batteries.  If someone needs a really tiny battery, I'm sure some are usable for PS2.

Probably, I really just did a search on the number on one of the batteries to see if it was described somewhere.  I'm sure there are tons of really small batteries if one chooses to look.

Accepting as correct that there is a  300ma drain for 10 seconds, this means, by my calcs, 0.8 mah is needed.  So 65mah rating should be adequate.  Obviously, a larger battery has advantages of longer usable capacity after sitting awhile, but if you have a very space-cramped application.....

The important specification would be the peak current capacity of the power source since the time of the demand is very short.  It's quite possible some of the really small batteries wouldn't have the capacity to deliver 300ma.  Also, you have to handle the case where there are a number of power interruptions that have to be handled with insufficient time to recharge.

I'm guessing the specification of the capacity of the battery wasn't a total accident.  The BCR is a bit unique as it doesn't require a long time to charge, not so for the battery.

I expect another consideration was that AAA, AA, and 9-volt size are common and therefore cheaper.  But I can't disagree with you GRJ.  Your points are valid.

Cheap is always near the top of the list for consumer goods.

Or, the batteries are made for other applications that require a continuous drain for a period of significant time, and MTH picked the one with a low mahr, because it was more then enough overkill.  RJR, there you go over thinking this again...  G

Retirement means an occasional idle mind, which is the devil's workshop.

Sure, but you don't have to let him have access all the time!

I suspect the original, white, NiCd 9v MTH batteries may have been specially made, or perhaps, repurposed from one someone else had special-made.  This thought is based on the fact that every consumer "9v" NiCd rechargeable battery I've ever seen was a 6-cell, 7.2 volt battery, where as MTH's is 7-cell, 8.4v.  The newer NiMH types appear to be off the shelf types likely chosen for cost, as they appear to deliver particularly low mAH ratings compared to the average consumer products.  

I think I have read these two threads 4 or 5 times, boy am I confused.  I know I need to do something but not sure what!

Most of my engines are from 2000 to 2007, none have had their batteries replaced, I have a mixture of both types.

When I use the Remote (Info, Engine) feature I get all kinds of reactions from the same engine, (HI, OK, & LOW).  I've tried eliminating variables, replacing Remote batteries, cleaning rollers/wheels, cleaning track, even using a test track.  Still random readings.  Even to the point battery OK, then will recheck and get Error Can't Find Engine!  Huh?  I remove track power and sounds stay on for 5 secs or so, and with the track power on I can adjust volume.

So really get confused, last thing I want is an old battery to affect a board.

Decided not to go with the BCR's, I think the payback is to far out.  As to OEM batteries or third party, if I was getting a good third party, I would be good with that.  (ie 9v @ Harbor Freight?).  However I don't want to be "Penny Wise and Dollar Foolish".  IF needed I would order MTH batteries.  What a quandary!

(I would need about 7 of each size).

Would there be an advantage of NI Cad vs NImh?

Is the "voltage" and mah the only things I need to be concerned about?

Thanks for any replies !!

edit,

Oh yeah in looking at batteries that would require soldering leads on, I talked to one manufacturer and they warned very strongly to NOT do that unless you had the correct equipment that essentially does a "flash solder" so as not to expose the battery to too much heat.

Any original 5V batteries you have should be replaced NOW!  Those are way past their usable lifetime. 

I use NiMh batteries for replacements, and that's what MTH supplies nowadays.  Just make sure the 9V replacements are the 7-cell 8.4V nominal voltage batteries and not the 6-cell 7.2V nominal voltage models.

Don, the good news is that bad batteries don't scramble PS2 boards.  At the worst, you lose settings or can't find the loco.

Voltage is key.  You want 2.4 volt batteries for the 3-volt systems and 8.4 for the older 5-volt systems.  Amp-hours or milliamp-hours (mah) is a measure of capacity.  If too small, batteries need to be used.charged more often.

For the 5-volt, use either the MTH battery or some others that are available, like Harbor Freight's.

There are 2 alternatives to BCR or MTH batteries  (note that "BCR" is a brand name):

1. Order 2.4 volt 2/3 AA [these are 2/3 the height of the standard pencell and have the same capacity] from China (www.lightmalls.com) at about $3.50 each in lots of ten.  I posted a picture of these on the other ongoing thread about batteries vs. BCRs.  You will have to clip off the wires and plugs on your old batteries, as solder (watch wire color/polarity) to the leads on the new batteries.

2. Elsewhere GRJ had posted a link to 2.5 farad supercapacitors from Digikey.  They run about $3 each.  Once again you use the plugs from your old batteries. soldering them to the leads of these.  I use heat shrink tubing to cover the bare leads on the Digikeys.  I leave the charging ports in place and just plug these in in place of the old battery.  I have replaced 15 of my many 8-11 year old batteries with these within the last month.  So far, they work fine.

Don, re your edit.  One should never apply solder directly to a battery without special equipment.  I peel the wrapper from the old battery and clip off the wires.

When I solder to the leads of the supercap, I place an aluminum clip on the lead between the supercap and where I'm soldering, and I use a hot Weller soldering gun so heat needs to be applied as little as possible.  I slip heat shrink tubing over the wire lead and then, after soldering, trim the excess lead and slide the tubing all the way up to the supercap, then touch it with the flame of a fireplace lighter.

I use these aluminum clamps as heat sinks whenever I solder electronic components that could be damaged by heat.

A battery that's near death may be able to keep the sounds up for 5-8 seconds, when "fully charged," but not much longer, whereas, if the sounds didn't shut, a new battery would keep them on for a long time

Don't worry about NiCad versus NIHm.  Most 8.4 are now NiHM to replace the toxic cadium.

For the 2.4V MTH still ship NiCad.

As John stated the PS-2 5V engines with the 8.4V should be replaced now.

For the PS-2 3V 2.4V I would say the same since even your youngest engine is 8 years old.  But if the engine still reads OK and performs fine, you can probably stretch it out. G

I think I struck gold!  Thank you so much GRJ, RJR, and GGG for your replies!  It really has cleared things up for me!  I'm going to order the parts for the capacitor alternatives, and see about that.

As I understand the operation of the capacitor alternative, you would apply power to the engine, for a minute or so, allowing the cap to charge.  Then operation as normal.  I'm assuming when the engine is shut down and removed from the track, the caps will hold enough of a charge to retain the memory ID while on the shelf for a period of time.

Thanks again for your replies.

Don

The ID is saved in nonvolatile memory, so even when the cap discharges, it's retained.  All the cap needs to do is to provide enough power for the shutdown sequence when track power is removed.

GRJ, I've had 2 instances recently where the loco got garbled in the system.  Never figured out the cause, nor even how I cured it!!!!  Tried many things, and all of a sudden, it worked.  I do know one was my first upgrade, so the battery must have been pushing 12 years old.  The other had just received a Digikey 2.5F.

I'm guessing lots of things can cause the issue.  I've had it happen a few times, I just reset it and do it again.

GRJ, to factory or feature reset a loco, one has to be able to access it on the remote, true?