Are these both Proto2/Proto3 batteries?

The blue 2.4 v battery is for the PS2 3V board, the Green 8.4v battery is for both PS2 5v and original Protosounds.

PS3 does not use batteries, it uses super capacitors in place of batteries

No the blue one is for PS2 3 volt and the green one is for PS2 5 volt and PS1 engines The blue is 2.4 volts and the green is 8.4 volts.

The blue one is for the 3volt system and the green one is for the 5volt system. Proto 3 doesn't have a battery instead they have super caps. 

It's safe to assume the Proto2 upgrade kits always use the blue one?  Based on the type of the connector?  Any other way to differentiate between the upgrade kits?

PS2 upgrades always use the 3V style. MTH stopped using the 5V systems in 2004 or 2005.

Having no idea what prompted the question. There is something called a BCR, which is a battery replacement that is really a capacitor, so you won't have to worry about re-replacing a battery again.

http://www.jandwelectronics.com/

Yes, PS-2 Upgrade kits use the 2.4V battery which can be blue or green, but always like a 2 AAs.  PS-1 and the early PS-2 5V used the 8.4V.  The 8.4V has a round charge port if it has one, and the 2.4V has a rectangular 2 pin connections just like the battery connector.

The 2.4V batteries are normally good for around 7 years.   G

Received a new battery from TrainZ for the MTH EF-2 after the old one wouldn't hold a charge.  It's the big blue one, 2.4V.  When I took the old one out, it was the smaller green 2.4v one so the Big Blue would not fit into the battery holder.  Removed the holder and stuck it in the space with double-sided tape.  Double checked the connection and all seemed correct.   I had charged the new one up over night, about 16 hours, and once installed had the same problems as before with the 10 year old battery.  Engine basically dead to the remote.  It showed but when I pressed start nothing happened, screen hung for a while, then went back to the display of the engine. When I did an INFO check the mileages read out "Infinity" and the battery as "LOW".

Gave up on that after the factory reset etc sequence didn't change anything.  Let it sit on a powered track overnight but that didn't change the problem.  So I removed the new Big Blue battery and put in a BCR2.  That worked and the locomotive is back to normal.  Going to call it good enough.

Checked the output of the charger and it is putting out voltage as per the specification so I'd guess it's working okay?

Might have received a bad battery from TrainZ but don't really have any way to tell.  It is putting out voltage according to the meter.

Next time a battery needs replacement I think I'm going to stick with the BCR2 replacement.

The 2.4 volt battery depicted is NiCad.  MTH later switched to NiMH.  So that is several years old.  Some upgrade kits apparently have been issued with 2/3 AA size 2.4 volt batteries, which have the same amp-hour rating as the old NiCad, but smaller size.  There have also been2.4 batteries made up of 2 AAA size NiMH.

Buying batteries can be iffy, since there is no way to tell age.

NiCad is still current with MTH, in fact they can't get the others.  So ship NiCad.

Some engines use the smaller AAA for space.  Maybe the pins pushed out, but I would say with the low reading that meant that new battery you used had issues.  I think it may be defective. Put a load on it with a bulb and see if it holds the voltage level.

The 2/3AA were a one time event, I only found one in a kit, and I have gone through a lot of kits.  Should have played the lottery that day.    G

MTH had the 2/3AA at York last Oct.

I do have at least one 2.4 NiMH.  I was surprised last night to find the age of some of my locos with their oroginal NiCad 2.4s.  Several over 10 years.

The AA are about a 7 year battery as advertised, but I have posted here before AA in cordless phones over 10 and still working.  Couldn't make a 30min call, but no issues with a 15min call.

Remember these 700ma/hr batteries are only being used to deliver about 200-300ma for 10 secs.  And we only need about 2Volts vice the 2.7V a new freshly charged battery can deliver.

So even though the battery is rated to deliver 2.4V at 700ma at least for an hour, we don't even use 1/100 of it's capacity.

So even with memory effect these batteries are fine.  The engineering application matters.  G

GGG: I posted that info to counter the many on-forum statements deriding batteries.

Thanks for posting the load.  I wondered what it was.  I note that the 2/3AA NiMHs also have 700 mah rating, and take much less room.

Kerrigan:  Once the lead-acid car battery manufacturers eliminated the antimony, battery lives have jumped drastically.

Even the NiMh green AAA battery pack is rated at 700ma/hr.  AFAIK, you can still order them, I got some about a month ago from MTH.

Every time I ordered them the were out of stock.  They did come in the upgrade kits though.  But not anymore!   The Hardware kits have the NiCad.

The consistent NiMh is the 9V.  G

I know there was a lot of misused facts about memory in those post.  Which is true, but effects heavy use.  Driving the train and trying to keep rated voltage. 

Wow one the car battery, mine seem like they want to give up right at the warranty.  G

GGG, what kills car batteries is heat.  In my boat, I have 4 away from the heat, and I usually replace them after 8 years just for peace of mind.  By wife's car has it under the back seat, where it stays cool.

Remember these 700ma/hr batteries are only being used to deliver about 200-300ma for 10 secs.  And we only need about 2Volts vice the 2.7V a new freshly charged battery can deliver.

Thinking about this statement, by my calcs this is about a .08mah drain.  To me this means that a battery can be really shot, and still be able to supply enough power for a shut down.  If the loco has been powered on for a few minutes, even a battery that won't hold a charge for long will probably be able to hack it.

No wonder I have some batteries 12 years old---for a few days anyway.

Exactly, though the instantaneous current draw matters too, so about 200-300ma.  But batteries can source much higher current.

So even those greater than 7yo batteries operated on DCS may still work fine even if they can't hold a normal charge. 

The ones that seem to not handle this are the AAA, but less chemical energy so I think they deplete faster. 

Of course a bad cell and this doesn't hold. 

That is why some of those after market Chinese 8.4V are not so good.  They have 7 1.2V AAAAA? very thin batteries in series.  Very little chemical energy per cell.

MTH, at least the white ones I took apart, were two 4.2 cylindrical button cells.  So more energy per cell and only 2 cells in series.  G

I just received, from China, some 800mah 2/3AA 2.4V batteries from China, that look identical to MTH's 2/3AA, but without the battery connector.

I often leave locos shut down on powered tracks for battery charging purposes.  I started on of these yesterday that hadn't been charged for a week.  Ran it a minute or so, and the shutdown sounds lasted about 2 seconds.  Obviously battery is bad, but it has held up for over 10 years and gave no sign or trouble.