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Now, this might sound like a topic I’d much rather not talk about as someone that sells batteries for a living, but I believe it’s very important to reiterate the potential risks of building batteries, so that we can all take precautions to ensure we all stay safe.
Today, a customer called me. I had sold him some Victron gear (I had not sold him a battery nor cells, but that’s not really relevant) roughly a year ago.
He told me about what happened to him two days ago:
He was working on his DIY 48V 280Ah (using EVE cells) battery, when he accidentally dropped a metal spanner. It created a dead short across the terminals, creating a surge current of well over 1000A. It melted the bus bars and fused the spanner to the battery cells.
Sometimes people say that LiFePO4 cells can’t catch fire. That’s not quite true and while they are much safer than NMC or Lithium Polymer cells, the vapourised electrolyte can catch fire and I believe it has a flash point somewhere between 700 to 800°C.
In this case, the pressure relief valves blew and created quite a directional fire. Thanks to my customer’s quick reaction only ~$600 of gear (other than the cells) was destroyed as he was able to remove the cells from the motorhome.
He got extremely lucky! If it had been NMC or Lithium Polymer cells, there’s simply no way he would have been able to save the motorhome and his life may even have been in danger. But even with the safer LiFePO4, it was still a very precarious situation. It’s something that could happen to most of us in a moment of inattention.
So please stay safe and when building a battery always:
Use insulated tools
Wear eye protection
Minimise distractions
Have a plan of what you’re going to do if things go wrong
Think about every single step before actually doing it
I obviously don’t want to discourage anyone from building batteries. It’s a fantastic hobby and I personally enjoy it greatly (it’s the reason that Muller Energy exists in the first place) and know many of you do too. But I obviously don’t want to see anyone get hurt, so please stay safe.
If you want to minimise the risk even further, you can obviously just buy a battery that has been built for you, given that it contains a BMS (battery management system), if you were to accidentally short out the terminals on one of those, you’d just get a nice spark, but the BMS would then very quickly disconnect the discharge and the flow of current would come to a halt virtually instantaneously, without creating a safety risk.
If you would like to hear other people’s tips on staying safe while building batteries, please feel free to join our Facebook group: https://facebook.com/groups/australianlithiumbatteries
