I design electronics for a living. It’s not that hard you just have to do a lot of testing. I can design one for you but it would not be free. TI has some really good parts for BMS systems and the have videos and app notes. I don’t think it would be worthwhile for a one time project but it sounds like he’s developing a product in which case engineering may pay off.
The hoverboard BTW had faulty batteries not a faulty BMS. Sent from my iPhone > On Apr 14, 2020, at 8:12 PM, Peri Hartman via EV <[email protected]> wrote: > > Ok, Paul, I challenge you. You get to design my cell monitoring boards and > the BMS. Then you get to put it in a closet in your house while it charges > and discharges over and over. If you're living in the same house a year > later, you win ! > > Point being, there are commercial products whose BMS has been designed by > competent engineers and they work nearly 100% without catastrophic failure. > > On the other hand, there are shadier companies that have poorly designed > systems. Remember the hoverboard fires ? There's nothing wrong with > hoverboards, but some company made a popular one and it caught fire on a > number of occasions. > > If I were to design the monitor circuit, I'd be in the latter category, > though not with the intention of selling a faulty product :) > > Peri > > ------ Original Message ------ > From: "paul dove via EV" <[email protected]> > To: "Electric Vehicle Discussion List" <[email protected]> > Cc: "paul dove" <[email protected]> > Sent: 14-Apr-20 12:35:14 PM > Subject: Re: [EVDL] custom battery > >> There are literally hundreds of products out there using these batteries. >> It is rare to see a fire caused by one. I have computers, phones, tools cars >> etc. none have ever blown up or caught on fire. >> >> >> On Tuesday, April 14, 2020, 1:36:12 PM CDT, Lee Hart via EV >> <[email protected]> wrote: >> >> 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, http://www.sunrise-ev.com >> _______________________________________________ >> UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub >> ARCHIVE: http://www.evdl.org/archive/index.html >> INFO: http://lists.evdl.org/listinfo.cgi/ev-evdl.org >> Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA) >> >> >> -------------- next part -------------- >> An HTML attachment was scrubbed... >> URL: >> <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20200414/d0c1549f/attachment.html> >> _______________________________________________ >> UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub >> ARCHIVE: http://www.evdl.org/archive/index.html >> INFO: http://lists.evdl.org/listinfo.cgi/ev-evdl.org >> Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA) >> > > _______________________________________________ > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > ARCHIVE: http://www.evdl.org/archive/index.html > INFO: http://lists.evdl.org/listinfo.cgi/ev-evdl.org > Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA) > _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub ARCHIVE: http://www.evdl.org/archive/index.html INFO: http://lists.evdl.org/listinfo.cgi/ev-evdl.org Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA)
