I need to replace the battery in my A2000. I'm posting this here because the skill and knowledge of members here seems to be greater than anywhere else.
What I am considering is replacing the battery with a battery pack that can hold two AA batteries, then putting two AA NiCad batteries in there. I have the materials for this (a battery pack that holds two AA's, some NiCad's from some old solar moon rays that still work). What I am uncertain of is unforeseeables. All I know about rechargeable batteries is that: 1) I shouldn't mix them with other types of batteries, and 2) regular batteries can blow up if they're put in a NiCad charger.
Any thoughts?
My Amiga 2000
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eslapion
- ultimate expander
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- Joined: Fri Jun 23, 2006 7:50 pm
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We had a discussion about using AA and AAA batteries in Amigas on Amiga.org and my point about it is that its no good because they self discharge faster than the Amiga can recharge them. Also, you would need to have 3 batteries to have the right voltage.
Both NiMH and NiCd batteries have a self discharge rate that is well documented on wikipedia. This discharge rate is proportional to the capacity of the battery. In other words, a large battery takes just as much time to self discharge as a small one.
The original battery clock found in Amigas had a capacity of about 60mA/H and they could take up to 12 hours to recharge from totally empty to maximum power capacity. This implies a charging current provided by the Amiga of about 5-10mA.
Modern NiMH AA batteries have a capacity of around 2500mA/h or about 42 times the original Amiga clock batteries. Therefore the Amiga should take up to 21 days to fully recharge them. They are said to self discharge rate of up to 30% per month which is equivalent to a loss of energy of 833mA/h which is 13.9 times more than the capacity of the original Amiga clock battery.
Since this original battery takes 12 hours to fully recharge, it means your clock battery based on AA batteries will eventually self discharge completely if you don't leave your Amiga on for at least 12*13.9=166.8 hours every month and that's only to compensate for the self discharge loss. You have to add to that the energy consumed by the clock itself.
Please note that NiCD batteries have a self discharge rate that is lower than NiMH batteries combined with a lower capacity. This makes the burden of recharging them much lower.
My own suggestion if you can't easily find rechargeable button batteries of 3.6v then use 3 N type batteries put in series. I suggest you use NiCD batteries instead of NiMH for the reason mentioned above. Also make sure you connect the polarities right.
See eBay item: http://cgi.ebay.ca/N-Cell-220mAh-NiCD-1 ... dZViewItem
With a capacity of only 220mA/H (less than 1/10 of a AA batterie), they should require about 44 hours to fully charge and require that you use your Amiga at least 15 hours a month to maintain their charge.
I think that's much more reasonable.
Both NiMH and NiCd batteries have a self discharge rate that is well documented on wikipedia. This discharge rate is proportional to the capacity of the battery. In other words, a large battery takes just as much time to self discharge as a small one.
The original battery clock found in Amigas had a capacity of about 60mA/H and they could take up to 12 hours to recharge from totally empty to maximum power capacity. This implies a charging current provided by the Amiga of about 5-10mA.
Modern NiMH AA batteries have a capacity of around 2500mA/h or about 42 times the original Amiga clock batteries. Therefore the Amiga should take up to 21 days to fully recharge them. They are said to self discharge rate of up to 30% per month which is equivalent to a loss of energy of 833mA/h which is 13.9 times more than the capacity of the original Amiga clock battery.
Since this original battery takes 12 hours to fully recharge, it means your clock battery based on AA batteries will eventually self discharge completely if you don't leave your Amiga on for at least 12*13.9=166.8 hours every month and that's only to compensate for the self discharge loss. You have to add to that the energy consumed by the clock itself.
Please note that NiCD batteries have a self discharge rate that is lower than NiMH batteries combined with a lower capacity. This makes the burden of recharging them much lower.
My own suggestion if you can't easily find rechargeable button batteries of 3.6v then use 3 N type batteries put in series. I suggest you use NiCD batteries instead of NiMH for the reason mentioned above. Also make sure you connect the polarities right.
See eBay item: http://cgi.ebay.ca/N-Cell-220mAh-NiCD-1 ... dZViewItem
With a capacity of only 220mA/H (less than 1/10 of a AA batterie), they should require about 44 hours to fully charge and require that you use your Amiga at least 15 hours a month to maintain their charge.
I think that's much more reasonable.
Here is the obligatory shot of my leaky battery:
So, as you can see, the matter became rather urgent for me.
I've decided to run without a battery for now. As you can see, I got it out just in time:
The trace running under the 68000 looks like it's just barely making contact. I just desoldered the rearward pin, and broke it off; then brushed off the powdery stuff. Hopefully, things won't decay any further.
So, as you can see, the matter became rather urgent for me.
I've decided to run without a battery for now. As you can see, I got it out just in time:
The trace running under the 68000 looks like it's just barely making contact. I just desoldered the rearward pin, and broke it off; then brushed off the powdery stuff. Hopefully, things won't decay any further.
I've replaced the battery on both my A2000 and A3000.
First thing I'd like to say is make sure you clean that acidic residue off your motherboard! Neutralize it too. Use alcohol on a q-tip to clean the motherboard, and then I think baking soda or vinegar (not sure which you need, a base or an acid) mixed with water to wash all around the area.
There was someone on A.org recently who removed his A4000's battery a few months ago and used only alcohol to clean the motherboard (the battery had leaked like yours). A recent photo of the motherboard showed that the acidic residue remaining in the tiny pits of the motherboard had continued to do damage. It was quite visible.
Now, as for replacing the battery on your motherboard. I used a rechargeable 3.6V(?) cordless telephone battery in both computers. It worked fine. The A3000 is in storage, but the A2000 has been running for two years now with that battery. I can't remember the rating I needed, but it was a very common battery (The Source, or even Zellers sells them). Comes in all sorts of shapes. Just make sure you put it in with the correct polarity and charge it for about 24 hours the first time.
You could also put a common PC type non-regarcheable battery coin battery in there, but you need to put in a simple diode so that the motherboard cannot trickle charge the battery. Most electronics stores sell the little coin battery holder for a few dollars, or you can desolder one from an old PC motherboard.
Here's an old thread about your question:
http://groups.google.ca/group/comp.sys. ... a5db95ffb5
First thing I'd like to say is make sure you clean that acidic residue off your motherboard! Neutralize it too. Use alcohol on a q-tip to clean the motherboard, and then I think baking soda or vinegar (not sure which you need, a base or an acid) mixed with water to wash all around the area.
There was someone on A.org recently who removed his A4000's battery a few months ago and used only alcohol to clean the motherboard (the battery had leaked like yours). A recent photo of the motherboard showed that the acidic residue remaining in the tiny pits of the motherboard had continued to do damage. It was quite visible.
Now, as for replacing the battery on your motherboard. I used a rechargeable 3.6V(?) cordless telephone battery in both computers. It worked fine. The A3000 is in storage, but the A2000 has been running for two years now with that battery. I can't remember the rating I needed, but it was a very common battery (The Source, or even Zellers sells them). Comes in all sorts of shapes. Just make sure you put it in with the correct polarity and charge it for about 24 hours the first time.
You could also put a common PC type non-regarcheable battery coin battery in there, but you need to put in a simple diode so that the motherboard cannot trickle charge the battery. Most electronics stores sell the little coin battery holder for a few dollars, or you can desolder one from an old PC motherboard.
Here's an old thread about your question:
http://groups.google.ca/group/comp.sys. ... a5db95ffb5
Cordless phone battery! What an excellent idea! As for neutralizing the acid, if I remember my science correctly, I'll need a base such as baking soda, perhaps mixed in with a bit of water to make a paste. I doubt it will take much.
As for the use of rubbing alcohol to clean the area, I fear that the fellow on A.org may have actually accelerated the effects of the battery acid with the use of rubbing alcohol. Again, it's been years since I've been in Chemistry class, and what with all the alcohol I've ingested over the years, it's a wonder I remember anything! However, as it turns out, one of my hobbies is my aquarium, and therefore I own a water PH test kit. Isopropyl Rubbing alcohol, even at 70%, comes in at being extremely acidic, as I just confirmed while I wrote this! I also discovered that it's time to change the filter...
As for the use of rubbing alcohol to clean the area, I fear that the fellow on A.org may have actually accelerated the effects of the battery acid with the use of rubbing alcohol. Again, it's been years since I've been in Chemistry class, and what with all the alcohol I've ingested over the years, it's a wonder I remember anything! However, as it turns out, one of my hobbies is my aquarium, and therefore I own a water PH test kit. Isopropyl Rubbing alcohol, even at 70%, comes in at being extremely acidic, as I just confirmed while I wrote this! I also discovered that it's time to change the filter...
That's interesting about the alcohol being acidic. I wouldn't have guessed that.
As for the phone battery idea, I can't take credit for it. There is a document floating around out there on the web (which I am having trouble finding) which tells you the exact rating you need, but I'm pretty sure it's 3.6V and 300 MaH or better (I think that has something to do with the charge strength).
It's an ultra common battery spec, anyway.
As for the phone battery idea, I can't take credit for it. There is a document floating around out there on the web (which I am having trouble finding) which tells you the exact rating you need, but I'm pretty sure it's 3.6V and 300 MaH or better (I think that has something to do with the charge strength).
It's an ultra common battery spec, anyway.
Follow the link below to read the whole, sordid story. I've finally completed the battery replacement tonight.
http://99.253.2.30/amiga/battery.html
http://99.253.2.30/amiga/battery.html
Yes, I have to say that finding that was a great disappointment. However, I know you'll make it up to me with some good deals in the future; like maybe a 300MB SCSI hard drive or something...eslapion wrote:Sorry about the leaky battery!
This nice little web page of yours also provides me with a picture of the triple kickstart I can give people.
Somehow everyone seems to expect it to be a board with stacks of chips on it.
Good stuff and nice small battery you found. The only differnece with my phone battery hack was that I left the connector on the end of the batter (little white thing with two holes) and tinned the ends of the wire coming from the motherboard. Then I just inserted the wires into the holes and secured them with a little eletrical tape. Makes it easy to remove/replace the battery.
I like your use of a plastic tie.
Another A2000 saved from oblivion!
I like your use of a plastic tie.
Another A2000 saved from oblivion!
Thanks!
I wanted to get it as far away from the motherboard as possible; in some place where, if it did leak, it would not cause any damage. There's a lot of space between the metal front side and the front bezel; I'll bet nearly any cordless phone battery would fit in there. I was thinking of putting in some sort of plug, but then realized that I can cut and splice in a battery in a couple of minutes. Considering how infrequent battery changes should be, I just figured to leave plenty of slack in the wire. It runs partway along the front of the motherboard and back again.
The plastic zip tie is one of my favourite inventions.
Here's a picture for those of you who don't feel like clicking on the link:
I wanted to get it as far away from the motherboard as possible; in some place where, if it did leak, it would not cause any damage. There's a lot of space between the metal front side and the front bezel; I'll bet nearly any cordless phone battery would fit in there. I was thinking of putting in some sort of plug, but then realized that I can cut and splice in a battery in a couple of minutes. Considering how infrequent battery changes should be, I just figured to leave plenty of slack in the wire. It runs partway along the front of the motherboard and back again.
The plastic zip tie is one of my favourite inventions.
Here's a picture for those of you who don't feel like clicking on the link:
-
eslapion
- ultimate expander
- Posts: 5458
- Joined: Fri Jun 23, 2006 7:50 pm
- Location: Canada
- Occupation: 8bit addict
I have a 600MB drive that's very busy collecting dust around here somewhere. Would that be good enuf?DigitalQuirk wrote:Yes, I have to say that finding that was a great disappointment. However, I know you'll make it up to me with some good deals in the future; like maybe a 300MB SCSI hard drive or something...
Oh....I didn't know that about the 2090. Again, good reason to pick up an old classic MAC for Amiga SCSI parts!.DigitalQuirk wrote:According to the 2090 FAQ, anything that has more than 524288 logical blocks won't work.
You wouldn't happen to have a different Amiga SCSI controller also collecting dust, would you?