Hi Roger, Just to clarify...this is not a personal project (though I do take it personally), but it is also not commercial - in the profit taking sense.
The NC Clean Energy Technology Center is a not for profit (in fact the lab barely survives on fee for service work, grants, and some small state funding). We are a non-academic Center that is part of the land grant North Carolina State University, in Raleigh NC. We don't do research, but we find ways to provide hands on experience for interested engineering students. Presently, I am trying to learn what non-automotive EV manufacturers lack in the way of testing, and other supplier management activities. The ideas range from regular - testing of cells packs, etc.; to unusual; for example, we have a lot of Mandarin speaking students, who might be useful communicating with Chinese manufacturers about technical issues. We might do postmortems and forensic evaluations of failed units. We might test and report on BMS and charger function. And of course evaluate batteries and packs. I wonder if I should be looking at lead acid batteries also. There is a presumption that lithium and the next big thing will supplant lead acid, but it might take a while. We need to serve that sector, too, if it makes sense. I am setting up a survey to collect bounds of the testing, and ideas of other activities where we might be useful. I will make it available to the EVDL list and hope some for you will contribute to it. Your messages have been very helpful, I am grateful. Best regards, Mike Ross On Fri, Nov 7, 2014 at 7:07 PM, Roger Stockton via EV <[email protected]> wrote: > Michael Ross wrote: > > > I think I need to be a notch or two above garage testing. To provide > > results worth referencing. I do have to be frugal and not spend where > > good things can be fabricated. We want to be cost effective for clients > > that aren't at the million$ a year in sales level. > > Thanks for clarifying that this is NOT a personal project, but a > commercial one. > > I think you will find that if you are doing testing for hire, that there > is significant value in the credibility that comes with using professional > grade commercial equipment versus explaining to the client that the coat > hanger in that garbage can full of water really is a sensible piece of > equipment for the test they are paying you to execute ;^> > > The cost effectiveness for smaller clients comes from *you* bearing the > multi-$1000 investment in a proper active load and data acquisition and > control equipment and possibly power supplies (for charging), and then > recovering the cost over multiple clients and over time so that they have > access to this level of test capability, when needed, for a much smaller > up-front or per-instance expenditure. > > If you are able to consider sufficiently large electronic loads, then ones > that can push the energy back into the grid rather than dissipating it as > heat become an option. This capability doesn’t really become available > until you are looking at loads of at least 6kW, and you should check with > your local utility to see what sort of barriers will face you in trying to > connect such a load before buying. > > > I have a pretty comprehensive data acquisition system, National > > Instruments cRIO controller, 32, 5V biderectional DIO channels, 8 > channels > > of high speed 5V bidirectional DIO, 16 channels of 24V DO, 8 channels of > > analog input. I have a couple 6 1/2 digit DMMs and 3 20 channel cards > > to use in them (slow but accurate). All that can be programmed with some > > sophistication using LabVIEW. > > Great! For battery testing you generally don't need particularly fast > scan speeds. I'm not sure just what your 6.5-digit DMMs are, but they > sound similar to the Agilent units I use for battery testing. It is > particularly nice that they can directly measure pack and cell voltages as > well as shunts and thermocouples for monitoring temperature. As long as > the number of channels you are scanning isn't too great, it is possible to > get at least a few readings per second in the uncommon event that your test > requires it. More typically, recording data at 1-10 second intervals is > plenty fast for battery cycle testing. > > > I won't need PLCs. > > Also great, though I referred to use of a *PC*, same as you will use to > run your LabVIEW application to control things ;^> > > > For cell testing I have an EMS 7.5V 300A 1700W supply. I have not really > > used it, so I don't know exactly how to control it automatically. It > > could do cell modules, but not packs. > > > > Then I have a couple of transformers in Lestronic II PbSO4 chargers 24V > > 25Amp, and 36V 30A. And I have a 480V:120V 7.5KVA transformer that ought > > to be useful somehow. > > The power supply sounds like it could be useful, especially if equipped > with IEEE-488 and if a LabVIEW driver is available for it. The > transformers sound less promising, at least for this purpose. > > Really, it comes down to the sort of clientele you will serve and what > sort of testing they require. They may want you to test specific > cells/modules, either recharging them using a provided charger or using > your programmable supply to implement some specified charge regimen. > > You may need to consider investing in water baths to maintain consistent > temperatures throughout the test pack, and/or an environmental chamber to > allow testing at elevated or reduced temperatures. If you are going to > test Li chemistries, especially at high rates and/or elevated temperatures, > investigate the safety requirements for appropriate fire suppression and > ventilation, etc. If you will be testing flooded lead acid, investigate > the spill containment and personal safety requirements (eye wash, emergency > shower, etc.), as well as hydrogen sensing equipment and ventilation > requirements. > > A properly equipped (inert gas purge, explosion proof locking door, > suitable pressure relief fearture, possibly reinforced to handle the weight > of larger (especially lead-acid) packs, etc.) environmental chamber runs > about $60K, so once again part of the value provided for smaller clients is > the ability for them to avoid the need to make this sort of investment in > test equipment. > > > I think I also want some reference standards. But, I > > might make them, or settle for the calibrated DMMs. > > The route you choose may depend on what you already do for other equipment > in your lab, however, the approach we've taken is to maintain the > calibration on the DMM/data acquisition units and rely on them to control > the loads and power supplies so that the loads and power supplies > themselves don't need to be kept calibrated. > > Cheers and good luck! > > Roger. > > _______________________________________________ > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > http://lists.evdl.org/listinfo.cgi/ev-evdl.org > For EV drag racing discussion, please use NEDRA ( > http://groups.yahoo.com/group/NEDRA) > > -- Put this question to yourself: should I use everyone else to attain happiness, or should I help others gain happiness? *Dalai Lama * Tell me what it is you plan to do With your one wild and precious life? Mary Oliver, "The summer day." To invent, you need a good imagination and a pile of junk. Thomas A. Edison <http://www.brainyquote.com/quotes/quotes/t/thomasaed125362.html> A public-opinion poll is no substitute for thought. *Warren Buffet* Michael E. Ross (919) 550-2430 Land (919) 576-0824 <https://www.google.com/voice/b/0?pli=1#phones> Google Phone (919) 631-1451 Cell (919) 513-0418 Desk [email protected] <[email protected]> -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20141107/145c7c37/attachment.htm> _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)
