Batteries can be had that have a lifetime of 5+ years. Depending on the type of battery you use. Flooded lead acid ( for RE use ) can have a much longer life. Especially if the batteries are conditioned / charged properly.
I've personally bought, and used 10,000 aH D Cells that have lasted 3 years, but failed eventually, because I was using them in a Maglite flashlight, and had dropped it many times. The point is, where there is a will, there is a way. Also, perhaps I am remembering wrongly, but I seem to recall reading that super caps have a limited lifetime as well. Something about only having so many charge cycles similar to a battery. On Wed, May 28, 2014 at 11:06 AM, Dr. Michael J. Chudobiak < m...@avtechpulse.com> wrote: > asked anyone at TI if it is OK to use the PMU like this? Perhaps you >> should post a question on E2E. >> > > From http://e2e.ti.com/support/power_management/pmu/f/200/t/185514.aspx: > > "The battery charger should work fine with a supercap. You'll need to > make sure the TS (battery temp sense) pin is at a proper voltage to allow > charging. If the supercap does not have a temperature sensor, you can > simply put a 10k resistor from TS to GND." > > > If you are charging at 440mA, it will take 50 Seconds to reach full >> charge. What happens when the power fails before that 50 Seconds? I would >> recommend that you monitor the supercap voltage and wait until it is fully >> charged before opening any files. >> > > That is why I use full data+metadata journaling on the filesystem. > > If an unclean shutdown happens before the supercap is charged, the next > boot-up will be delayed for several seconds as the filesystem is repaired > using the full journal. That is annoying, but it is a minor cost for > robustness. Mostly, the supercap is there to eliminate the need for the > repair delay. > > > It is an interesting concept, but I'm still skeptical if this can really >> work. >> > > Well, I do use it, so that's one data point. > > The other main alternative for bullet-proof power-fail robustness is to > rely on on something like unionfs to provide a mix of read-only and > read/write filesystems, but that's not so simple either. It's complex and > not very well supported in general. > > Batteries have a fairly limited lifetime, so I don't consider that a > practical solution (for me). > > I'm interested to hear how other people prevent corruption on power loss, > though. > > > > - Mike > > -- > For more options, visit http://beagleboard.org/discuss > --- You received this message because you are subscribed to the Google > Groups "BeagleBoard" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to beagleboard+unsubscr...@googlegroups.com. > For more options, visit https://groups.google.com/d/optout. > -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to beagleboard+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
