I am trying to build a home battery like a Tesla Powerbank ( but not so big) I have lots of 18650 batteries and a spot welder some plastic frames and some metal strips but dont dare do it on my own Is anyone knowledgable about battery making ?
Jeremy
What are your questions regarding pack building? I’ve made a couple in the past but definitely not “finished product” pretty. It’s quite risky depending on the individual’s experience and capabilities and unfortunately isn’t something we permit doing in the space due to fire/explosion risks.
I made a pack using 84 cells for a mobility scooter. Instead of buying a spot welder I just made my own using a car battery, copper rods, and solonoid with a timer to dial in the pulse lengths/patterns (double pulse, etc.) until the welds were significantly strong without compromising the cell’s integrity.
Five years later and it still works great. Keep in mind things like chosing a suitable BMS and your layout/design to reduce current bottlenecks and any exposed metal or areas prone to mechanical stress. Use decent sized nickel strips. Use suitable gauge silicone cable. You may want to overspec the BMS for longevity as replacing them is a pain. Kapton tape is your friend.
Obvious/not obvious safety measures: Do it outside, or in well ventilated area with a way to contain the cells should they ignite; even something simple like a metal bucket of sand with a lid. Keep away from combustables for the same reason. Never use water to extinguish a lithium fire. For the love of Zeus don’t puncture, short, or overheat the cells and you should be ok. Definitely wear eye safety, stay aware of fumes from fires, heat from welding, and electrical shorts from tools. Always start with small scale tests beforehand.
If you’re not sure about something during your build, definitely stop and figure it out first. There’s lots of pack building resources online you can refer to. If you have any other queries feel free to ask here. I’m not a professional by any means but I did learn lots of interesting things when I made mine and might be able to guide you with yours.
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Hi
As a qualified electrician, I feel compelled to add to what Dan said above.
In order to connect a battery accumulator to your house wiring, you will need a Battery Management System (an external one in addition to the one embedded in the battery), an inverter, communication to the UK Power Network about having a “parallel supply” and a lot of other bits and bobs.
In addition to all of the above, you will need an electrician to certify the components and the installation, and in all honesty, I don’t think you will ever find someone willing to certify a home-made battery pack.
Sorry to be the bearer of bad news.
thank you so much for your comprehensive reply All of which I agree with . Would you be prepared to come round and give me and my son ( who works for a battery space start up and wants to learn about battery tech as well ) some of your wisdom . I live in Nine ELms near the power station (old power !) Jeremy
totally agree Plan was just to power my kettle and my dishwasher and to plug them directly into the inverter . I have a book that explains all the bits and pieces needed ( DIY Lithium Batteries How to build your own Battery Packs by Micah Toll who is also keen on safety) But I am still too scared to do anything on my own ! Come and do it with us ? JG