I agree with Bill. The battery itself can be built with today's technology. It's the BMS that's going to give you trouble.

As Bill said, the pack will be used until it breaks. And *when* it breaks, it could easily start a fire that leads to a disaster. It's really hard to design things that are not only foolproof, but DAMN fool proof.

For years I worked for Robertshaw and Honeywell designing furnace controls. A furnace control has to be DAMN fool proof, or it could (for example) open the gas valve without lighting the burner, fill the house with gas, and THEN light it. So the controls had every safety interlock we could think of to prevent this from ever happening.

Nevertheless... A control failed this way, and blew up a house, causing several fatalities. On examination, it turned out that the installer had mis-wired the 24v power transformer across two GND terminals. The high current burned the PCB trace open between them. Then he corrected his mistake, and wired it correctly. The furnace seemed to work, so he left. But the open trace defeated one of the safety circuits. Later, when something else when wrong with the furnace, it set fire to the house.

Despite having only contributory negligence, Honeywell still had to pay millions of dollars in settlements. And, the AGA (the regulatory body that sets standards for gas furnaces) added requirements that all controls must pass a "miswire" test, where no safety issue is created even if the control is mis-wired.

Can you imagine how hard it is to design something so it is *impossible* to hook it up wrong? But those are the kind of lengths you have to go to when there is any chance of it causing a disaster.

Lee Hart
--
Whether we or our politicians know it or not, Nature is party to all
our deals and decisions, and she has more votes, a longer memory,
and a sterner sense of justice than we do. -- Wendell Berry
--
Lee Hart, 814 8th Ave N, Sartell MN 56377, www.sunrise-ev.com
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