Is a pair of "AA" Ni-cad 1.2V 800mAh an acceptable replacement for a pair of 1.2V 700mAh batteries?

kennybOGR Forum Member

Hello Guys, Well,I'm at it again!!

I recently acquired a 3 volt board MTH Big Boy from 2004.It needed new batteries,and instead of using a BCR this time,I went out and bought the standard replacement "blue" NiCad battery setup,with the plug on the end.

Today,I finally had the time to replace the batteries,and to my amazement,the setup in the tender had just 2 regular 1.2V 700mAh batteries.No Blue wrapping,no plug.

The closest batteries I could find are "AA" 1.2V 800mAh batteries.They are Ni-Cad,rechargeables,intended for use in outdoor solar lights.

I installed them,and everything seems to be working fine,Battery reads out "OK",where it used to say low on the advanced info screen. I have looked everywhere,and these are the closest thing I could find to the exact batteries that where in the tender.

So far,so good.The engine is louder than it was before,but that is the only noticeable change. I just wanted to know from you guys if you think these will be a safe,long term fix,or does anyone know where I can get the SAME exact 1.2 V 700 mAh batteries that were originally in there.

I figured since the replacement ones are 1.2V,and they are only 100 mAh above what was in there,they might be alright.May I please have some advice on this? I spent a lot of money for this engine,and do not want to fry the board,nor do I want to discover what 'magic smoke" is!!!!

Many thanks in advance,Kenny Baughman

8/23/162:56 PM

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The GN ManOGR Forum Member

It will work fine, Kenny. From your comments, it appears you got the replacement battery from MTH; if so, then they should stand behind it, too.

Battery capacity is usually a "nominal" value, stated at a given rate (e.g. C/10 or 70 mA) for 60 minutes. At lower discharge rates, the available capacity may be higher and at higher rates it will be less. It will usually be higher than the "nameplate" capacity when the battery is new. There will be little, if any, difference in performance between a 700mAh and 800 mAh 1.2V NiCd battery.

8/23/163:23 PM

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jonnyspeedOGR Forum Member

You're fine.

8/23/166:04 PM

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TrainLarryOGR Forum Member

As long as the voltage is the same, you are OK. The extra 100mAh will give you extra capacity until the batteries run low and need recharging. The circuit will only draw it's design current irregardless of the battery capacity. You can put enough batteries in the circuit to have 1 amp or more of capacity, and as long as the voltage is 3v to the circuit, the circuit could care less. The board is not in danger of being fried.

More mAh equals more time before recharge.

Larry

8/23/169:25 PM

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kennybOGR Forum Member

Thanks so much you guys for the reassurance.I was aware the train would need a battery when I bought it.The previous owner told me it had not been changed out in a long time.I am kinda new to MTH and DCS,and you can imagine my surprise when I saw that the batteries were different from the ones I was first told I needed.

But your explanations of what mAh actually is,has made me feel much better about the New 800mAh 1.2 V "AA" Ni-cad replacements I put in there today.

This must be a VERY OLD setup and board,seeing it does not even take the "BLUE' wrapped "AA"'s with the plug attached to them. The MTH website says the train is from 2004,and other than that,I don't know much else about it.

Is anyone else familiar at all with this battery bracket setup?Was this the first kind of setup used by MTH with their 3 volt boards?,when ProtoSound 2.0 was first introduced?

Anyhow,the train seems to be responding good to all the commands I give it,and it comes up and starts great from the remote when ever I try to start it. When did MTH move away from this particular setup?.and go to the 'Blue"wrapped "AA's" with the plug on the end? Now I'm curious. Thanks again.-Kenny

8/23/1611:52 PM

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Big_Boy_4005OGR Forum Member

TrainLarry posted:
As long as the voltage is the same, you are OK. The extra 100mAh will give you extra capacity until the batteries run low and need recharging. The circuit will only draw it's design current irregardless of the battery capacity. You can put enough batteries in the circuit to have 1 amp or more of capacity, and as long as the voltage is 3v to the circuit, the circuit could care less. The board is not in danger of being fried.
More mAh equals more time before recharge.
Larry

It's exactly like having a bigger gas tank on your car. cool