I found batteries online (not original but will last for couple years), got new chargers, and realized that finding RAM for these is almost impossible in New Zealand! Macbooks are very picky when it comes to RAM and I had to order it from overseas. Some people managed to get 6GB of RAM in these old laptops but it was too expensive so I settled on getting 2 sticks of 2GB each. That will make 4GB total, so plenty for older OS X. The RAM must be DDR2, 667Mhz, PC2-5300. I tried faster sticks but they didn't work.
These laptops only support OS X Lion, which was first released in 2011 and got its last update in October 2012, more than 5 years ago! Compare it with Windows 7, that was released in 2009 and will still be supported until 2020... Getting the installer for Lion was another challenge... A long time ago, Apple used to charge for its Operating System upgrades and such is the case with Lion. It was $29.99 in the Mac store but I wasn't the original owner so I couldn't buy it. Luckily, I had one from a long time ago on my server (can't recall where I got it from but probably torrents) and I used my MacBook Air to make a USB drive with Lion.
Yet another challenge... I inserted a 16GB stick, launched Disk Utility, erased the USB drive (not the partition below), and tried to restore the installer from the image. I kept getting the same error message, something like "Failed to restore, the resource is busy". You don't expect things like this from Apple, do you? Neither did I. Turns out that I had to eject the USB drive volume (but not the drive itself, or else it wouldn't be visible) and then the restore proceeded without a hitch. With a relatively fast USB 3.0 drive, it took just 4 minutes.
I replaced the original hard drive with a 120GB SSD and powered on the 1st Mac while holding the Option key. My installer showed up right away and after a minute or so, I was greeted with the Lion welcome screen. I first erased the SSD with the disk utility (otherwise installer wouldn't work) and started the installation. The 1st phase took just 5 minutes and I thought that was it - what a surprise. No, the Macbook restarted and continued with the install. Said it would take 20 minutes but actually took less than 5. After yet another restart, it was almost ready. OS X asked me to connect to a network, choose a user account name and a few more things and it was ready.
I immediately checked for updates, and it found the combo update (10.7.5). It's actually available as a download from Apple here. The whole update is just 2GB and took about 15 minutes to install. I dread having to install Windows 7 from scratch and then waiting a couple of days for the updates to finish, so I was glad it went fast and painlessly.
Being the old version, I found Safari painful to use and replaced it with Firefox. The last version to support OS X Lion is ESR 48, so that's what I downloaded from here. I didn't try Google Chrome as it stopped supporting Lion a very long time ago, unlike Firefox, that was updated sometime in 2016... Firefox updated to 48.0.2 and then complained that the most recent version isn't compatible with my system. Oh well.
I also installed LibreOffice for Mac and it's a free alternative to Microsoft Office. The latest supported version is 4.3.7.2, can be downloaded from here. It opened several files created by Microsoft Office 2016 and saved in docx and xslx formats, so, probably, will be good enough for many users.
I tried browsing, watching Youtube videos, opening programs - and it feels pretty smooth, even despite having just 2GB of RAM (I'm still waiting for 4!). Youtube played trailers in 1080p without any noticeable lags, buffering and skipping frames. Actually, somebody did a detailed video on whether Lion is still usable in 2019. TLDR - yes, it is.
Was it really worth the trouble, considering these computers age and prices? I honestly don't know. However, fewer laptops in the landfill are always better for the environment and having something old but still useful is definitely good for not-so-demanding budget users.
Still, if you have an older Macbook and deciding whether it's worth fixing - the answer is both yes and no. If it has a broken screen, failed motherboard, or wouldn't turn on - it's time to move on. If it works ok but just a bit slow, or doesn't hold the battery charge, extra RAM and SSD make a huge difference.
