How to know what replacement modern battery to use?

[Bill-kun]

Compaq Prosignia VS from 1996. Has a dead Rayovac type 840 battery. These are actually still commercially available, for $21-$36 each.

But say, just for the sake of argument, that I wanted to instead replace it with a much more common battery type. The 840 battery says 4.5 Volts but doesn't say the current. I can easily buy a replacement battery pack for 3*AA, 3*AAA, or 3*AAAA batteries to add up to 4.5 Volts, but how do I know that I will have the correct current?

 

[Timo W.]

Batteries don't have a current rating. Any standard one will do. Only voltage and type (rechargable or not) must match. Current is given by whatever circuitry you connect to it.

 

[Chuck(G)]

The 840 is rated at 4.5V 1100 mAH. 3 x AA alkaline cells should work nicely. Or even 3 AAA (LR03) cells should work fine.

 

[GiGaBiTe]

Quite a few Powermacs use that battery pile brick. I've had luck replacing them with CR2 Lithium battery. If you scuff up the terminals, you can cut the pigtail off the old brick battery and solder them to the CR2 and wrap the ends in electrical tape to prevent shorts.

 

[Bill-kun]

Thanks for the info, everyone. I chose to simply order a replacement type 840 battery.