A4000 battery replacement

[Ianoakley]

An Amiga 4000 I purchased a few months ago has had it's clock battery removed and replaced by a caddy which holds 2 AAA rechargeable batteries. I presume this is a solution to the battery problem and it keeps excellent time. However the batteries are showing sign of age. Is it simply a case of changing the existing batteries with new AAA NmH ones. Do they have to be charged first ? Can you also use standard akaline batteries.

Any views on this ?  :-?

[orange]

I'd say you can safely use rechargable AAA NiCd or NiMh. But DO NOT try alkalines, they are NOT designed for charging and might overheat, damage something.. etc
It would be wise to fully charge/discharge those NiMh batts 3 times, just to be safe. BTW, their capacity is probably huge so it doesn't matter if they lose some.
and don't forget to be carefull in orientation.

[X-ray]

We should have a section on battery replacement in System Info : Amiga FAQ/ Amiga Hardware.

It is one of the topics that always comes up. Another one is SCSI chains and device terminations.

[TjLaZer]

YES as this is becoming one of the worst irritating frequently asked questions!    Maybe I will throw together a guide to assist...

To OP, you may want to add a lithium socket to your board so you can simply use 3.0V coin cells, see my picture gallery.

[melott]

Ummmm ... I tried using the Coin Battery hack....
All the coin batteries I found were 3.0 volts.
In my tests on an A2000 rev 4.5 MoBo it didn't work.
I needed 3.6 volts for it to hold time.
I know others here have said they have done the hack
with good results, BUT results will probably vary from
one machine to another.
If the coin battery doesn't hold time you'll have to
go the the Barrel battery.

@TjLaZer
Where did you find 3.6 volt coin batteries ??

[TjLaZer]

Whoops I meant 3.0V.  As long as the battery is new and has a descent charge it will work but if it is a few years old it will not accurately hold the time.  Also make sure to add the diode to the + line or you will be sorry!

[yogisumo]

I just replaced mine with a portable (not cell) phone battery.  Removed the original barrel battery, soldered 2 wires to the motherboard and used 9 volt battery connectors for both battery and motherboard wires so I can easily unplug and change battery.

[Dr_Righteous]

One of the first Ebay purchases I made was a NiMH barrel type battery for my A4000D. Worked like a charm and shouldn't ever leak like its NiCD cousin.

[orange]

don't forget the great option - using super capacitor, it seems like best solution. the only problem might be high inrush current maybe?  :roll:  and they might be hard to find + expensive.

[MrPixel]

Hi, i have read your text may i have some pictures of this experiment.
Thank you