On Mon, May 20, 2019 at 3:25 AM Erik Christiansen <[email protected]> wrote:
> On 20.05.19 02:02, Chris Albertson wrote: > > Total KWH meant if you have a 10 KHW battery and you chrage and > discharge > > it 200 times then you have 2000 "lifetime" KHW > > If you can charge the battery 400 times then you have 4000 "lifetime KWH. > > The second battery as twice as much value. > > As a first approximation, yes, but the value is also affected by > loss of utility through degradation of capacity over cycle life. > Looking at: > Yes, but I wanted to avoid math that requires calculus. I think you need to integratt the power output over time. There are quick ways and exact ways to calculat the number but what you realy would like is to mearuse the total amount of energy the battery supplies over its usfull lifetime. One thing that makes it hard with lead acid is that you get a LOT more cycles it you don't discharge the battery deeply. But then you need a more batteries. So you have to find the optimal discharge level, or just assume it is 50%. What we really should be taloking about is the INVERTER. There are non-trivial what you get th=o the size where you are powering a house > > "In comparison, the Tesla Powerwall is a 6.4 kilowatt-hour battery and > only 5.44 kilowatt-hours of that is actually warranted to be usable. > But after the first 2 years that drops to 4.6 kilowatt-hours. And 3 > years later it drops down to only 3.8 kilowatt-hours of warranted > storage." > > from: > > https://www.solarquotes.com.au/blog/redflows-zinc-bromide-zcell-battery-may-have-the-edge-over-lithium-ion/ > > I'm reminded that phone and laptop battery capacity doesn't take long to > nosedive. That's a much bigger problem with house batteries. > > One outlier is the ZnBr flow battery - it is claimed to maintain > capacity for its full life, with efficiency falling instead. As that can > be compensated by adding cheap solar panels, it's a very interesting > variation in the cost/energy equation. > > OK, reasonable efficiency is still necessary, especially in polar climes > in winter, but in generally sunny Australia, it's just the high initial > cost which detracts. > > Erik > > P.S. That web page is inordinately folksy, but if you skip the waffle, > it does cover some of the battery's properties. > > > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users > -- Chris Albertson Redondo Beach, California _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
