Can I build my own house battery?

In a nutshell, I wouldn't.

Unless you have a real interest in the subject and want to invest an irrational amount of thought and effort, your time can probably be spent better elsewhere, making a few dollars to buy the right battery for the job.


I admire the resourcefulness you see in the lead acid bank in the header image, we really need to be able to make better use of things that aren’t perfectly new, but your insurance company won’t view it in the same light.

There was a time when every house had batteries. They were 2 volt nominal cells built into glass jars, wired into 32 volt banks. An 800watt generator and good supply of distilled water was all that was needed to look after them.


These days, unless it’s installed with deference to AS-NZS-5139-2019, you’ll have a hard time getting anyone with a license to touch it, and those enthusiasts who aren’t licensed are often a Dunnig-Kruger danger to everyone, because they don’t even begin to know what they don’t know. (and if you point that out, you’re just a stooge for big electrical man!) Be aware that youtube and social media are full of people who have enough information to be really dangerous.

This rig pictured below is using a hundred(?) reasonably good domestic chargers to cycle and test individual 18650 lithium cells harvested from many different types of power tool, medical, laptop, scooter, etc. These enthusiasts treat battery recycling and pack building as a hobby and all power to them (pun intended)



They can end up with an interesting looking experiment like this pack arrangement, which to be honest is equal parts scary and steam punk art installation. Some use second hand cells or packs from electric vehicles or simply import large lithium cells to assemble large packs themselves.

Occasionally you see an amazingly executed and really well thought out system. These garner good advice from knowledgeable people. Many are a diabolical mess sadly, and the same knowledgeable people will just point out flaws and advise it be scrapped before someone dies in a fire.

It is not in any way something I would recommend to the novice. Even qualified electricians would in many cases be out of their depth constructing and managing something like this.

The rules around batteries are pretty stringent and we have some explanation in this handy article as well as this informative piece from Renew.

My advice is that if you want to pick up some used EV cells and do some hacking then start with the appropriate Australian standards documents and enrol with someone like GreenRTO to do as much solar design as you’re able, bearing in mind that some training is only open to qualified electricians or engineers.

Beyond that build a proverbial brick sh!thouse in the yard and make sure there are labels all over it so that the fire services know what to do if you’re not home and the battery system is billowing smoke

Some people haven’t been so cautious and they’ve reapt the consequences sadly. These events are a sobering reminder that you shouldn’t put others at risk for the sake of a few dollars.