Have you run the numbers? What do they cost per KWH over 10 years? The cost of each battery is meaningless. The "price to beat" right now is about $500 (the cost to buy and maintain over 10 years in dollars/KWH)
THose Telco batteries do last a LONG time because the telcos NEVER discharge them but at 50% discharge they get about 500 cycles which is REALLY good compared to most LA batteries. But in this use case -- storing solar power they will see one cycle per day and a 500 cycle battery will not last two years. So you look at the chart and see that if you discharge only to 10% or 5% thy can last thousands of cycles. No kidding that is the intended use case on the telco industry. But at 10% discharge limit you need five times more batteries so the initial cost is to high. The key to economy with LA is to selects a discharge limits that maximise KWH per lifetime. Here is how to design a lead-acid system for the best long term economy.... Figure out your total usage of KWH per day. Look at you utility bill in a peak usage month. Perhaps you use air conditioning in summer so use a summer month. Divide by the number of days. IN the US 850 KWH per monnth is average, so figure you use 28 KWH per day. FOr best economy size the system for two days of usage and this will reduce the number and depth of charge cycles per years. SO we need a 60 KHW system for the average house in the US. Next, choose a discharge limit for your battery. 50% is good. This means you can only use 50AH from a 100AH battry. convert KWH to AH by dividing by 10. (not 12, as that is way to optimistic. 10 accounts for losses) OK you still with me? 60KHW / 10 = 6,000 AH of usable power. But our 50% limit means we need 12,000 AH of lead-acid batteries Lets assume you use the generic brand "deep cyce" batteries. These at about 100AH and $200 each. You need to buy 120 batteries at a cost of $24,000. This is not bad. BUt you still need an inverter/charger that can handle the entire load of the house. Likey a peak at over 100 amps. You need a shed and lots of wire. Lets say $30K. The above is absolute mainstream design for 15 years ago. and results in a minimum cost to own battery system for a home owner. $30K is not bad and it compares to buying an actual "Power Wall" of the same size that would cost $29.6K . About the same price. But what has happened is the new battery management systems combined with new chemistry has knocked down the maintenance price to "zero". The lead-acid systems costs about what you pay up from to operated for 10 years as in that time you will have replaced EVERY battery at least once. On Fri, May 17, 2019 at 1:14 PM Greg Bentzinger via Emc-users < [email protected]> wrote: > {Greg} > > If I were going to install a full off grid potential solar power system > for my ranch I would buy lead acid Telco system batteries. > > They are not true deep cycle, but have such high capacity that it isn't an > issue. They are initially expensive and huge. ( I might buy some 10yr old > units being decommissioned ) > > > On the plus sign they can have up to a 30 year service life and are user > serviceable with rebuild kits which swap out the battery plates. > > Back in the 80's the phone company would look at the budget come 4th > quarter and if there was a surplus they would rebuild older battery banks > of 12 year or older. > > Now with OSHA and Hazmat regs they hire independent battery maintenance to > service these batts. > > New installs are likely going away from lead acid due to acid vapor and > hydrogen issues as well as a much reduced foot print per KWh. > > But EMP proof? - hard to kill a plain lead acid system. > > {/Greg} > > > _______________________________________________ > 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
