David Cook
Well-known member
As you know, many later models of the LC / Performa and Quadra / Power Macintosh came with 4.5V clock/pram/cuda battery packs. I've seen Rayovac 840, Rayovac 841, and Energy+ 3LF22 alkaline batteries.
Besides a direct aftermarket replacement, the simplest method of replacing the batteries is probably buying a 3 cell AA/A battery holder on eBay and soldering it to the original battery connector wires (snipped off the old battery). My concerns are:
1. Standard battery holders are either open frame or in a loosely fitting case that will not contain future battery leakage.
2. AA and AAA batteries have a lot more volume that can leak.
3. Soldering wires together requires electrical tape or heat-shrink tubing to prevent accidental shorting against the motherboard.
3. AA and AAA batteries are larger than the original. They'll last longer, but take up more space.
To address the first concern, I ran across a 'waterproof' IP65 dust-tight 3-cell battery case. Challenge Electronics CAB75A2-03W-1X $5. There is a more expensive variation with a power switch sold by Keystone Electronics.
It comes with four screws, a rubber seal, raised inner lip, epoxy at the wire entrance, and interior space for leakage to expand. It sure seems like it would constrain leakage to inside the case.
As far as batteries, I think it is best to avoid lithium as the fresh voltage of three cells is around 5.4V (1.8Vx3). This might cause damage (doubtful) or excessive drain (shorter lifespan) because the backup battery voltage may be expected to be less than the power supply voltage (>=4.75V). Instead, maybe use alkaline batteries that are marketed as 'leakproof', such as Voniko's double barrier AA.
Third, if you want to avoid splicing wires, you can obtain the correct part as Amphenol ICC FCI Mini-PV Basics rectangular connector contact crimp socket 48236-000LF. They are several variations based on surface coating and spring force. For a two-pin connector, you want the maximum spring force. As far as coating, I was disappointed that the gold is only present on the mating surface, rather than all exposed metal. Oh well.
Below is a comparison to the original socket. It sure looks like a perfect match.
If you use a slightly wrong socket or you insert the write too far, then the socket may not fully latch in the original plastic receptacle.
A replacement receptacle is Amphenol ICC FCI 4 position 2.54 mm rectangular connector housing receptacle 65039-033ELF. To key it against being inserted in reverse, shove a white plastic polarizing key / post / plug Amphenol ICC FCI 65307-001LF
Yes, a sealed 3-cell AA battery pack is a bit bulky. The advantages are:
* AA batteries will remain available and can be easily replaced
* The charge will last a lot longer in storage
* The sealed holder is significantly less likely to cause computer damage due to battery leakage.
Hope this helps,
David
Besides a direct aftermarket replacement, the simplest method of replacing the batteries is probably buying a 3 cell AA/A battery holder on eBay and soldering it to the original battery connector wires (snipped off the old battery). My concerns are:
1. Standard battery holders are either open frame or in a loosely fitting case that will not contain future battery leakage.
2. AA and AAA batteries have a lot more volume that can leak.
3. Soldering wires together requires electrical tape or heat-shrink tubing to prevent accidental shorting against the motherboard.
3. AA and AAA batteries are larger than the original. They'll last longer, but take up more space.
To address the first concern, I ran across a 'waterproof' IP65 dust-tight 3-cell battery case. Challenge Electronics CAB75A2-03W-1X $5. There is a more expensive variation with a power switch sold by Keystone Electronics.
It comes with four screws, a rubber seal, raised inner lip, epoxy at the wire entrance, and interior space for leakage to expand. It sure seems like it would constrain leakage to inside the case.
As far as batteries, I think it is best to avoid lithium as the fresh voltage of three cells is around 5.4V (1.8Vx3). This might cause damage (doubtful) or excessive drain (shorter lifespan) because the backup battery voltage may be expected to be less than the power supply voltage (>=4.75V). Instead, maybe use alkaline batteries that are marketed as 'leakproof', such as Voniko's double barrier AA.
Third, if you want to avoid splicing wires, you can obtain the correct part as Amphenol ICC FCI Mini-PV Basics rectangular connector contact crimp socket 48236-000LF. They are several variations based on surface coating and spring force. For a two-pin connector, you want the maximum spring force. As far as coating, I was disappointed that the gold is only present on the mating surface, rather than all exposed metal. Oh well.
Below is a comparison to the original socket. It sure looks like a perfect match.
If you use a slightly wrong socket or you insert the write too far, then the socket may not fully latch in the original plastic receptacle.
A replacement receptacle is Amphenol ICC FCI 4 position 2.54 mm rectangular connector housing receptacle 65039-033ELF. To key it against being inserted in reverse, shove a white plastic polarizing key / post / plug Amphenol ICC FCI 65307-001LF
Yes, a sealed 3-cell AA battery pack is a bit bulky. The advantages are:
* AA batteries will remain available and can be easily replaced
* The charge will last a lot longer in storage
* The sealed holder is significantly less likely to cause computer damage due to battery leakage.
Hope this helps,
David
