Hi, Lipo charge/discharge is not complicated, just keep the current within the bounadies until certain voltage levels are reached. But these cells are quite sensitive to overcharging ( resulting in fire risk) and deep discharge (destroying the cell). When puting cells in series, balancing and/monitoring of each cell is required. So proper testing and reliable circuit (including the watchdog Vasile mentioned) are manatory. I'm note sure about failure prediction, but i guess capacity measurement during a significant charge part of a charge cycle os a good indication for any battery. For nimh, reduced discharge curreny is a failure mode too.
Joep Op donderdag 9 augustus 2012 schreef vasile surducan ([email protected]) het volgende: > Hi Bogdan > In my opinion, failure predicament for Lead Acid accumulators is not too > complicated, but I do know nothing about LiFePO cells so I can't > pronounce... I've designed and manufactured as prototype, about five years > ago (if I don't wrong) a charger-discharger for NiMH with one channel > using a simple PIC12F675 and a PC for analyzing data.. I think you have to > implement two things: a charging algorithm and a discharging algorithm on a > known load. Both are quite simple. You can also measure dV on dt with load, > but this might need more than 10 or 12bit AD resolution. > The biggest problem I've faced over the time since I'm playing with PIC > micro is not the algorithm itself, but the problems of long time running. > For such application you'll have to consider deeply how a watchdog should > help you against bottlenecks. > > best wishes, > Vasile > > On Tue, Aug 7, 2012 at 5:56 PM, Bogdan Mihai Octavian < > [email protected] <javascript:_e({}, 'cvml', > '[email protected]');>> wrote: > >> Hello everybody! I'm not new into microcontrollers, actually all >> my projects, personal or those built for the company I'm working for, were >> built around PIC family. Now I'm working at a project that involves battery >> management and battery failure predicament. It is a industrial process >> automation powered from a Solar panel (UPS with MPPT charger and all the >> other stuff involved). Because it has to work without the Sun, sometimes, >> from the internal UPS powered from one or two LiFePO cells, I have not >> decide yet, I have to know the battery condition. The automation it is >> remotely located and it is visited by the maintenance stuff once a week or >> in case that something goes wrong (radio communication also implemented). I >> have founded some hardware solutions, battery gas gauge, provided by Linear >> Technology or Texas Instruments or Maxim, but those are little too >> complicated. I was thinking do do that myself and this is where I will >> need some help. >> So, does anybody have an idea how to do that? Measure the battery >> capacity and predict battery failure..... >> >> Thanks for your time! >> (Allocated to read this) >> >> -- >> You received this message because you are subscribed to the Google Groups >> "jallib" group. >> To view this discussion on the web visit >> https://groups.google.com/d/msg/jallib/-/vxYiirFkNs4J. >> To post to this group, send email to >> [email protected]<javascript:_e({}, 'cvml', >> '[email protected]');> >> . >> To unsubscribe from this group, send email to >> [email protected] <javascript:_e({}, 'cvml', >> 'jallib%[email protected]');>. >> For more options, visit this group at >> http://groups.google.com/group/jallib?hl=en. >> > > -- > You received this message because you are subscribed to the Google Groups > "jallib" group. > To post to this group, send email to > [email protected]<javascript:_e({}, 'cvml', '[email protected]');> > . > To unsubscribe from this group, send email to > [email protected] <javascript:_e({}, 'cvml', > 'jallib%[email protected]');>. > For more options, visit this group at > http://groups.google.com/group/jallib?hl=en. > -- You received this message because you are subscribed to the Google Groups "jallib" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/jallib?hl=en.
