Battery already crapping out, ideas?

[Amiduffer]

I can't believe this. I got a barrel type battery (very similar to the stock battery) from a local electronic store about 6 months ago for my A3000 and already its starting to fail. When I installed the 3640 "accelerator" last week I noticed a very small amount of white stuff around the wire connector on the + side. :-x And the clock and calender are reseting to 1991 for cripes sake. What a gyp.

Well, time for a new one.

I have a question for anyone who can answer. I've heard about the hack to put the watch battery in your ami. As I have it now, when I took out my last battery, I managed to separate the battery from the "rabbit ears", so could I use those to hold the battery? Fold one side down flat, put the battery on it, and fold the other side on top and wrap it with a rubber band to keep it tight. What do you think?

[smiley1635]

why dont you use a coin battery clock.

All you need is:

Battery clip
coin battery
diode

Instructions on aminet

[Hyperspeed]

I'm looking to replace a dead battery on an SX32-Pro accelerator for the CD32. It's a DCE board and the battery is more chunky than a CR2032 but I too am thinking of doing the Aminet hack.

First I need to find out if the SX32-Pro's battery is self recharging (VL2020 style) or whether it uses a 'mortal' battery like the CR2032.

[AmigaPete]

Does anyone know if there is something a bit more technical available regarding this replacement? Specifically (for the A2000) I would like to know the charging voltage and amperage. Did these specifications change with different board revisions? Is the diode specified strong enough to block that charge? I have some diodes but would like to know if they are suitable. Any more info would be appreciated. I used to have the A2000 Hardware Reference Manual but sold it long ago.

Thanks,
Pete

[Generale]

Hyperspeed wrote:
First I need to find out if the SX32-Pro's battery is self recharging (VL2020 style) or whether it uses a 'mortal' battery like the CR2032.

Why?
If you do it with a battery and diode, it doesn't matter if the board circuitry tries to recharge the battery. The diode stops the current.

[Ral-Clan]

Easiest way to replace this is with a cordless phone battery.  I did this to my A2000.  They can be purchase for about $10 and are everywhere.  There is a particular rating you will need (sorry I cannot remember, but I found the documentation online easily for this), and you have to make sure you solder the correct coloured wires to the proper place on the motherboard for positive and negative.  But it has worked well for me (I could not find any place that sold those coin battery holders in my small town).  Also the coin batteries do not recharge, while the phone batteries do.

As for why your replacement battery failed so soon: some of these are old-stock.  They may have sat on the shelf for years before being sold to you.

[Tesral]

I have heard of using a capasitor to replace the battery.  Sorry, but no details.  It does solve the problem of dying batteries however.

I am running my A4000 without a battery.  I put the clock into the user startup to remind me ot set it on boot.  Since I don't turn it off that often it isn't a problem.

[Amiduffer]

ral-clan wrote:
Easiest way to replace this is with a cordless phone battery.  I did this to my A2000.  They can be purchase for about $10 and are everywhere.  There is a particular rating you will need (sorry I cannot remember, but I found the documentation online easily for this), and you have to make sure you solder the correct coloured wires to the proper place on the motherboard for positive and negative.

As for why your replacement battery failed so soon: some of these are old-stock.  They may have sat on the shelf for years before being sold to you.

Could be. Al Lashers Electronics is an old store in Berkeley, so its quite possible. Check them out online if you need the odd gadget, which they probably have.

I've never heard of the cordless phone battery in an Amiga, but I suppose its possible. I wonder who's got the site with that info?

edit: Ah! After the 8th google, this page showed up.

phone battery in Amiga

And, good advice on dealing with battery acid.

[rkauer]

The only thing who you need to use cordless phone batts is they MUST BE 3.6 Volts. Any maH (mili àmpere hour) could be use.

[]s
Kauer

Brazilian Amigan since 1989
Known drunk since 1982 (don't remember quite well, I was drunk) :-D

[orange]

I think lithium battery hack looks much better than cordless telephone. Its smaller.. besides, what if the new rechargeable battery leaks too.
If you do the lithium batt hack, use Schottky diode like someone here said, its better (though an ordinary one will work too)

[Amiga4k]

Whether using a Varta or Phone battery, the solution I found to future worries 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) 32000- 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 upright, with plastic tie.

[tonyvdb]

I myself bought a 3.6 volt lithium Ion rechargable coin battery and then its just a matter of soldering a proper coin battery holder to the spot where the old one was and works great without having to worry about replacing it again. Do a search for "Rechargable Coin battery" and you will find several places that sell them.

[Castellen]

Rechargeable lithiums are a good idea, but unfortunately the charge requirements of these cells are not compatible with the Ni-Cad charging on the Amiga motherboard.

Take the Panasonic manganese-lithium cell ML2032 for example.  The application note specifically says not to use the float charging techniques used with Ni-Cad, i.e. a trickle charge resistor connected to +5V.  The reason is that the battery needs to be charged with a terminal voltage of 3.0 to 3.3V, if this voltage is exceeded, the battery will be damaged.

An obvious way around this is to put a 3.3V zener diode across the battery so that the charge voltage is limited to 3.3V.

For the ML2032, it's recommended charge current is 2-3mA.
In the A4000D for example, the battery charge current is limited by R179, 1.2k ohms.
So charge current would be ((5V-3.3V)/1200) = 1.3mA which is a bit on the low side.
So if you were to decrease R179 to 560 ohms, this would then give a charge current of ((5V-3.3V)/560) = 3mA.

The cell's capacity is 60mA from memory, so if it was completely flat, it would take (60mAh/3mA) = 20 hours approx to charge.

The minimum data retention voltage of the RP5C01 real time clock is 2.2V and backup current is 15µA.
The ML2032 reaches this terminal voltage when it's discharged to approx 50% of it's capacity, so this gives an affective capacity of (60mAh/2) = 30mAh.
At a discharge current of 15µA, the battery backup time for a fully charged battery is (30mAh/15µA) = 2000 hours (/24) = 83 days (/30) = 2.7 months.

i.e. To use the ML2032 rechargeable manganese-lithium in the A4000D:
1. Replace R179 with a 560 ohm resistor (or just solder another 1.2k ohm resistor across the existing one to give you 600 ohms).
2. Connect a 3.3V zener diode across the battery terminals, obviously the cathode connects to battery+ and anode to battery-.
3. Connect the ML2032 cell in place of the old Ni-Cad or Ni-MH battery.

I might write an application note on this one day, maybe make up a kit & instructions with all the parts needed.  There's probably a slightly better way to do it as well, as there are problems using zener diodes at really low currents.  Unfortunately that requires me to think, so will maybe research it properly some other time.

In the meantime, you may have already seen some other notes on Amiga batteries and other things I've written here.

[Amiduffer]

Thank you very much Castellen!  :laugh:

What a very usefull website. You get a gold star for hard work.

If you're making a kit, can I buy the first one now that I'm tossing my "current" (get it?:crazy: ) battery.

[Dr_Righteous]

Eh, I replaced the one in my A4K with a barrel type Ni-MH battery. I've never had any issues with it.