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I have a IIgs that I clipped the battery out of a few years back. I'm thinking I want to replace a battery in there, but before I spend money on a product like this one, I'm trying to figure out if I can re-purpose an old AA cell caddy.

I have two questions:

  1. Does the IIgs charge the battery or just draw from it? I'm concerned if I need to install a diode or can I just directly wire the AA cells to the IIgs motherboard.
  2. I know the battery should be more like 3.2v, so should I use a 2 cell or 3 cell caddy for standard 1.5v AA alkalines?

I've always been under the impression that you shouldn't attempt to charge alkaline batteries, but I don't know if the IIgs does that in the first place or perhaps is the charge level too low to matter to the batteries. Looking at the caddy for sale as linked above, I cannot tell if there is a diode or something to make it more special than just a straight-wire job.

thanks

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    I don't understand why you wouldn't use the originally intended battery type? The batteries are easy to find... Perhaps hard to find a holder for it, that replaces the one you clipped... – Brian H Dec 12 '18 at 17:43
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    Why not get a 1/2 AA battery holder? And use a standard lithium cell? Such as B07695SMHG on Amazon – Stavr00 Dec 12 '18 at 21:37
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You can replace with alkaline batteries, but will need a diode to prevent them being charged. Charging alkaline batteries, even very slowly, is risky and can cause them to leak.

If the original battery is a 3.6V lithium cell. You could replace it with 3x NiMH cells which are 1.2V nominal each, and would be charged by the machine just fine. Use Eneloop or other Japan-made cells (all NiMH from Japan are actually Eneloops now, even the IKEA brand ones), because they have lower self-discharge.

If you really want to use alkaline then 2 cells for a nominal 3V might be a bit low, especially with a diode. You could try 3 cells with two diodes, giving about 3.3V if you select a common 1N4001 (0.6V drop at low current, times 2).

  • The original battery would have been a Li-SOCl₂ primary cell. These aren't rechargeable. NiMHs wouldn't charge in this circuit. – scruss Dec 12 '18 at 21:24
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According to https://groups.google.com/forum/#!topic/comp.sys.apple2/3mh5_J2Zl0U yes, you can...but I'd urge caution and would use a protection diode anyway. Or even better, go for the specific product - if a diode is required, it should be included. I'd be going for whatever provides the voltage and current over it's life as close to the original spec as is possible.

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