Hi there,

A while ago I pulled out my A2000 battery to avoid leakage. Can anyone tell me the best way to put a new battery back in? Should it be some sort of SuperCapacitator, or will a watch battery do? Thanks.

I'm sorry but I don't have any batteries currently. Can you recommend one?

Amiga 2k Battery.

If it were my system i'd solder some wires on it, and glue a magnet to the batt, that way I could keep it off the mobo and hanging on the inside of the case somewhere just to be sure.

But on my systems, I don't even bother with it at all. I have never cared what the clock reads.

I have updated my article I wrote many years ago to reflect some changes. Also the Varta battery used in the Amiga can now be purchased for as little as $5.41 USD. (I will comment later when I see my shipment).

Install Amiga battery

Note: The standard battery is a Varta 3.6v 70mAh Ni-MH. This type of battery is more forgiving with over-charging, and does not have the “memory retention” of the more popular Ni-CD battery used in Phone batteries.

The solution I found to future concerns about leaks was the following:
(1) Find a small plastic medicine bottle that the battery fits into. (*See size constraint for A3000).
(2) Attach new leads, approximately 18" long to the motherboard. (I've used flat speaker with, the type with a stripe on one lead. The striped wired is connected on the + side of the motherboard.)
(2a) A2000- Run lead along front edge of motherboard. Then along side edge. Bring lead up at front of PSU. This avoid problems with risers, processors, and allows removal of anything later on, as needed.
(2b) 3000- Run lead along back edge of motherboard. Bring lead up thru cabling access near front of PSU. This avoid problems with risers, processors, etc. The bottle needs to be small enough fit thru the cabling access to allows removal of anything later on, as needed.
(3) Hot glue the leads along the motherboard (3-4 spots does nicely).
(4) Attach lead to battery. Notch bottle to allow leads. Put battery in bottle. Apply cap to bottle. Secure bottle in an upright position with plastic ties.

TheWizard wrote:
Hi there,

A while ago I pulled out my A2000 battery to avoid leakage. Can anyone tell me the best way to put a new battery back in? Should it be some sort of SuperCapacitator, or will a watch battery do? Thanks.

 A "super" capacitor is a good choice, if you use your Amiga in regular basis (once each month is ok). Look for the .47F x 5.5V (note: is 0.47 Farads!, not uF).

Do the Lithium Hack and be done with it!

http://www.amiga.org/gallery/index.php?n=813

@rkauer:
The supercapacitor idea is potentially good, but unfortunately even with 470mF as you suggested, the backup time is less than two days.

Let's do the maths.
As I recall, RP5C01 draws around 15µA at 3.6V (when it operates in backup mode) and it stops working at around 2.2V.  So with a supercapacitor's voltage falling from 3.6V to 2.2V, that's around 61%, so close enough to one capacitor time constant (63.7%).

To work out the equivalent resistance of the RP5C01, where R=V/I, then 3.6V/15µA = 240k ohms

And as we all know that T(seconds) = C x R, then the capacitor discharge time to one time constant is 0.47 x 240k = 112800 seconds, or 31.3 hours.

Supercapacitors are far more suited to modern RTC devices and memory backup applications where only a few nA are drawn from the capacitor.


When replacing RTC batteries, I generally use the original Varta Ni-MH battery which have a rated lifetime of around 6 years.  I put a printed label inside and outside of customer's machines stating when the battery was replaced and whan it should be replaced by.

More details in some of the guides I've written here if anyone wants to know more.