On Fri Feb 03, 2023 at 03:16:28PM -0800, Leo Vegoda wrote: > > Question is, how much battery runtime can I typically expect from ISPs' > > last mile infra. I was hoping some of you here might help estimate from > > own experience. > > Ofcom ran a consultation on this in 2011. They suggested a minimum of > one hour battery backup. My reading is that that is what they went > with but the Ofcom site doesn't make that sparklingly clear, so I > could be wrong. I'm also not sure if whatever obligation they came up > with in 2011 has been updated.
Survey says 1 hour? It is academic what people think when there is an actual plan for <checks notes> rolling 3 hour outages several times per day https://www.gov.uk/government/publications/electricity-supply-emergency-code So not only do you need to plan for the down time you need to consider the recovery time of your system. Lead based systems will take many times the run time to recharge and may not be ready for the next outage. Thus LiFePo4 batteries are the way to go, we can recharge at more than our discharge rate. Without rolling blackouts we have already had this problem with normal rural supply. We had many multi hour outages and concluded we need 6 to 8 hours capacity if we wish to operate through them. That also allows time to find the nature of the fault, the likely resolution time and for someone to take a generator to site (perhaps multiple sites) if needed. Due to the reach of fibre and FWA it is normal for our power to go down while some customers are on a feed that is up, so it is not pointless keeping our sites running. We sent this note to our customers https://www.dropbox.com/s/zvleyj0epqzne5y/20221103_winter_power.pdf?dl=0 so they can choose based on their needs rather than part fixing the problem for them, having just internet may not be sufficient for many. It is a bit late to be worrying about rolling blackouts this winter as the threat has reduced and by the time a solution is deployed at scale it will be spring or summer. brandon
