JohnGaltLine posted:Jim 1939 posted:12V for 8 hour. A BCR charges in 1 minute.
1 minute every time you haven't run the engine for an hour or two vs 8 hours once, if the engine has been in storage for more than a year. 8 hours of run time over a week or two will do fine to charge the battery in cases where it was charged less than a year before. ( using a year as a nice simple amount of time, the actual time will vary based on the capacity of the battery, but in the case of all major brands will be somewhere in the 14-20 month range. Also note that even in the case that the engine has been stored long enough to fully discharge the battery, a useable charge will only take 10-20 minutes to allow the engine to operate normally and the remaining charge can be applied while running.
Worth noting that if the new battery is a Low Self-Discharge(Pre-Charged) type as all name brand NiMH batteries are these days, you'll do more harm than good by applying a full charge out of the package. These batteries, when installed before the date marked on the package, come ready to use.
GGG,
It is true that NiCD batteries are perfectly good when used, and charged, correctly... Sadly train engines do neither.
While LSD type NiMH batteries suffer from some of the same issues as NiCD, most notably the issue of voltage depression, they do so to a much lesser extent. In addition, NiMH do not suffer from crystallization which damages the battery.
There ARE two issues with using NiCD batteries in train engines with the charge design that is in use. One of these also affects NiMH, but not to the extent that it does NiCD. First you have voltage depression. This occurs when you routinely charge/over-charge the cell when it still has a good charge. with the small amount of actual discharge that the engines use, they will never become significantly depleted in use in a model train engine. The charge circuit then applied constant over-charge while the engine is running. over time this will cause the battery to report a lower voltage even when fully charged. While it will hold this voltage for just as long, a circuit designed to require 8.4V... Mostly likely, actually 6.7V on the input side of a 5 volt regulator... will not run correctly with a battery that only provides less than 1v per cell, even if that battery will provide that 1V for a significant time. NiMH batteries also suffer from voltage depression, however, depending on what study you look at they appear to be between 5 and 25 times more resistant to it.
Voltage depression is a non issue for NiCD/NiMH batteries given proper exercise, meaning they are fully depleted and recharged at least once a month, and it can often be repaired by a heavy depletion well below the normal "dead" level, then a re-charge. Unfortunately, in train engines they do not see proper maintenance and usage like this.
The second thing that effects NiCD batteries is crystallization. When NiCD batteries are over-charged, AND when they are not charged for long periods of time crystals of cadmium form in the cell. These crystals reduce the surface area of the plates and thus reduce the total capacity of the battery. In addition, as the crystals grow they can puncture the film between layers and cause a short between them. This will drain the battery just as shorting it externally would. Once the battery has been damages in this way, if it is not repaired, it will continue to damage it's self further with every charge cycle.
When NiMH was first introduced, NiCD still held one advantage over it: High current discharge. For use in RC cars and Airplanes NiCD could deliver higher current, even if it could so so for only a short amount of time. ( Even in the early days, NiMH had 2-3 times the capacity of NiCD) As NiMH batteries have improved, however they have relegated this deficiency to the history books. With Li-Ion batteries providing even better current drain, and lighter weight, however, Li-Ion has replaced NiMH for many folks into the RC cars and planes.
Quite honestly there is only one thing NiCD batteries still do better than NiMH. They have a longer lifespan, when charged and discharged correctly, than NiMH. NiHM typically are rated for 350-500 full discharge cycles, and similar NiCD are rated for 750-1500 cycles. So, if you are building something with a proper charge circuit designed to exercise the battery properly, and it is going to be a pain to replace the battery, NiCD may be the way to go... For most things, however, NiMH does everything better than NiCD.
JGL
How many MTH PS-1 engines do you own? How many do you repair? Just yesterday I worked on 4 PS-1/PS-2 5V engine from 1998 to 2000. Pulled 4 original white NiCad batteries out of the engines that still have voltage and did NO harm to the engines. I have one still on my desk holding 8V under load.
So clarify why NiCad is not used or charged correctly for our trains?
Anyone can go to various websites and gather information and misapply it to any circumstance.
Everything has a pro and con, but just because a con exist doesn't mean it is a factor under all operating conditions.
Our trains do not use the battery to operate it, they only use it for sound backup and processor operations when power is turned off. Motor, smoke, light functions all turn off and only the microprocessor and audio amp function for 7 to 15 seconds depending on model. You could probably get away with a alkaline battery for about a year if the charging circuit was disabled. Folks still buy off brand NiCad batteries for their engines. 2.4V NiCad is still a standard.
NiMH is probably more about getting Cadium out of batteries than anything else. Unless you talking about space satellites and deep drain and recharging cycles where you need the full endurance of the battery. At that point the memory effect matters.
And Post War folks hate batteries no matter what, because many PW engines were ruined by wet cell batteries left in engines in the 40's and 50's. The fact that dry cell and sealed batteries exist now will not change their opinion on batteries in trains. G
