General Purpose Tools

Rechargeable Lead Acid Battery

cheap, durable, rechargeable power source

In this Cool Tools video review I’m going to show you why it’s handy to have a 12v, SLA battery around.

The first time I encountered a sealed lead acid battery was in a Power Wheels kids ride-on car. Instead of having something like this take 100 D-cell batteries that have to be thrown away, the manufacturer mercifully includes a dedicated battery that can be recharged over and over again.

Like your basic car battery, these are an old school rechargeable technology. They’re sealed up completely, so there’s no major risk of spilling or chemical exposure unless you really work to crack these open.

The major downside to these is that they’re heavy. Compared to the LiPo and Lithium Ion packs in most of our gadgets, these things weigh a ton. But they come in a range of shapes and sizes, and a more standard range of voltages.

You do need to exercise some caution not to bridge the terminals accidentally, or they could spark, just like any battery. I’ll often store these with gaffer tape across them as insulation.

They’re very simple to recharge. I have this $17 Battery Buddy charger that I can just clip on and plug in and it charges automatically. Fancier RC battery chargers will typically have a setting for SLA or Pb too.

Now, here’s why I consider these a tool. I have used these multiple times to make plug-in 12v appliances portable. If you have a thing that you typically plug in using an AC adapter, that adapter is often doing the work to translate 110v AC into 9 or 12 volts DC. It will usually say right on the adapter.

For example, my family has this air mattress we use for camping and it came with an inflator that works off an AC adapter or car cigarette lighter adapter. But because I like inflating the bed in the tent, I just wired this up to use with the 12v battery by exposing the wires and putting crimp spade connectors on it.

As another example, I had this portable cathode ray TV that took 8 C-cell batteries or a 12v AC adapter. I just wired a barrel jack cable with crimp spade connectors and glued the battery to the bottom of the TV along with a Raspberry Pi that autoplays videos. It’s a little chunky, but it’s portable and rechargeable.

So that’s a look at SLA batteries. They’re heavy, but they’re cheap, durable, rechargeable and an easy hack for stuff that runs on 12 volts.

-- Donald Bell 06/16/18