Unless you have a DC-DC converter in line that can take 10v and output regulated 24v.
> On Dec 2, 2015, at 3:53 PM, Mathew Howard <[email protected]> wrote: > > I don't see that there's really a lot of value in running batteries below > 10.5 volts or so, at that point the voltage is going to be low enough that a > lot of radios aren't going to run anyway (for example, ePMPs will die just a > little under 22v), which means your going to just be wearing out the > batteries for nothing. > > One time I had a Mikrotik router lock up after a power outage - apparently, > when the voltage dropped to low (and all the radios had long since died), the > Mikrotik locked up, but it never actually got low enough for it to completely > shut down, so when the power came back on, it stayed in it's locked up state > until I went out there and unplugged it. it would've saved me a trip out > there if there had been an LVD on the batteries. > >> On Wed, Dec 2, 2015 at 2:12 PM, Ken Hohhof <[email protected]> wrote: >> I have anywhere from 2 to 8 x 100Ah AGM batteries at a bunch of sites. >> That’s a lot of money. They are not throwaways. It does help somewhat that >> more expensive batteries tend to survive more discharge cycles. >> >> But it seems to me from graphs that once you get down to 11 volts, it >> declines pretty rapidly from there. I could be wrong, but I don’t think >> you’re getting that much extra runtime continuing to drain the batteries >> below let’s say 10.5 volts. >> >> I try to have at least 8 hours of runtime, some sites that are hard to get >> to in winter more like 2-4 days of runtime. The idea is to bring out a >> portable generator before the batteries are dead. If you have mountaintop >> sites, maybe that’s different. >> >> Smaller sites we often see zero customers registered while running on >> batteries because none of them have power or generators. It might make >> sense to have remote per-radio power control, to shut off the APs but keep >> the backhauls running for downstream towers. But if they are licensed >> backhauls, they may consume most of the power anyway. >> >> >> From: That One Guy /sarcasm >> Sent: Wednesday, December 02, 2015 1:56 PM >> To: [email protected] >> Subject: Re: [AFMUG] Calculating battery bank size >> >> so how dead does it make the battery for fully discharge, the rhetoric, is >> run em down, throw them away, is there a rule of thumb for damage? >> >>> On Wed, Dec 2, 2015 at 12:49 PM, Bill Prince <[email protected]> wrote: >>> He didn't indicate how the 400 ah were configured. Is it one 12V 400 ah >>> battery, or one 24v 400 ah battery, etc. But as you noted, once you convert >>> the battery voltage and amp-hours to watts, it eliminates any confusion. >>> >>> If I had 4800 watt-hours of battery (assuming 12V X 4 at 100 amp-hours), >>> I would estimate 9 hours of run time until the batteries are dead as a >>> doornail. If you want to use them again (and most people do), then cut that >>> time in half. >>> >>> On the other hand, if you have a 48 volt battery with a 400 amp-hour >>> rating, then you actually have 19,200 watt-hours of capacity, and you could >>> multiply the above by 4. >>> >>> If you configure the four 12V/100 ah batteries in series, then you don't >>> have 400 ah, you have 48V/100 ah. The watt-hours are the same. >>> >>> bp >>> <part15sbs{at}gmail{dot}com> >>> >>>> On 12/2/2015 10:23 AM, Mathew Howard wrote: >>>> watt-hours stay the same - 200x24 and 100x48 both equal 4800 watt hours. >>>> In other words, unless you have some horribly inefficient voltage >>>> converters in the mix, it makes little difference. >>>> >>>>> On Wed, Dec 2, 2015 at 12:05 PM, Bill Prince <[email protected]> wrote: >>>>> wrong. >>>>> bp >>>>> <part15sbs{at}gmail{dot}com> >>>>> >>>>>> On 12/2/2015 10:04 AM, Josh Luthman wrote: >>>>>> If you do 4x 12v 100ah batteries and do 24v it's twice the time as 48v >>>>>> >>>>>> Josh Luthman >>>>>> Office: 937-552-2340 >>>>>> Direct: 937-552-2343 >>>>>> 1100 Wayne St >>>>>> Suite 1337 >>>>>> Troy, OH 45373 >>>>>> >>>>>>> On Dec 2, 2015 1:01 PM, "Bill Prince" <[email protected]> wrote: >>>>>>> What voltage? >>>>>>> >>>>>>> bp >>>>>>> <part15sbs{at}gmail{dot}com> >>>>>>> >>>>>>>> On 12/2/2015 10:00 AM, TJ Trout wrote: >>>>>>>> >>>>>>>> How long will 500w load last on 400ah? >> >> >> >> -- >> If you only see yourself as part of the team but you don't see your team as >> part of yourself you have already failed as part of the team. >
