Battery Replacement

[fordp]

I am now sitting on 5 A501's, and 1 other memory card which should get their NiCd's replaced. It seems from my reading that some people use NiMH replacements, while others have used Lithium coin cells+diode. Does the community have a preference? In general I prefer coin cells, but I've also never replaced an Amiga battery.

[motrucker]

They'll work fine, just don't forget to add a diode.

[freqmax]

Why diode?, and is the voltage drop accounted for in such case?

[fordp]

Why diode?, and is the voltage drop accounted for in such case?

The original NiCds, and NiMH's are rechargeable batteries, and are recharged by the computer when a reverse voltage is applied to them while the machine is on. Lithium batteries are not rechargeable, and can do nasty things when you apply reverse voltages to them.

Most clocks chips I've looked at, I've not looked at the Amiga, tend to work down to 2.2V or so, so its probably better to use a schottkey diode as they have a .3V drop, which gives you a bit more wiggle room on a 3V lithium battery. But a standard diode should be fine, it will just have a shorter battery life.

[zipper]

Most clocks chips I've looked at, I've not looked at the Amiga, tend to work down to 2.2V or so, so its probably better to use a schottkey diode as they have a .3V drop, which gives you a bit more wiggle room on a 3V lithium battery. But a standard diode should be fine, it will just have a shorter battery life.

I think it holds true for Amiga gear,too - aamof my A500 memory board had just a 2.4V NiCad battery.

[motrucker]

Sorry I wasn't more explicate or detailed.  fordp  hit it though.

[orange]

some people use those rechargeable coin batteries. its might be a good solution if your amiga is frequently on.
its probably more expensive than alternatives, though.
using them in parallel might give enough capacity.

if I had 'money to burn', I'd build some massive super-capacitor instead of battery. it would probably require some additional, simple, electronics.

[Retro_71]

I use both types BUT with the NiCd or NiMH i normally put them on long wires and have them sitting out side the case so if i need to replace them its as easy as cut and paste... (lol so to speak)

[J-Golden]

I did the Watch battery mod on my A4000T many moons ago.  It was painless and gave me an easily replaceable battery option.  Obviously, I endorse that way to go.

I've also seen people put in a series of AA batteries (don't know what they are called in other parts of the world) to achieve the same voltage.  I assume you could put in rechargeable batteries but I am NOT an electrical engineer so make sure that is a viable and SAFE solution before you try it.

Again, Watch battery.  Simple, safe, small.

[fordp]

I use both types BUT with the NiCd or NiMH i normally put them on long wires and have them sitting out side the case so if i need to replace them its as easy as cut and paste... (lol so to speak)

Nice. I'd not go so far as outside the case, but I had planned an installing headers instead of directly mounting the battery on the board. Still I'm partial to watch batteries, as they are designed to be removable.

I've also seen people put in a series of AA batteries (don't know what they are called in other parts of the world) to achieve the same voltage.  I assume you could put in rechargeable batteries but I am NOT an electrical engineer so make sure that is a viable and SAFE solution before you try it.

I'd considered the AA/LR6 option, but having done it on old PC's in the past, I never liked having to sort out how and where to mount the pack'o'batteries and dismissed it. As for safety, I would always install the diode, the cost of the diode is far less than the cost of the trouble later if mistakenly declare your mod safe.