- 600lb, 6 kwhr at 6 hour rate. $1050. 
- 1200 lb, 340ah at 6 he at 48v = 17 kwhr, $3000 - 
- 510 ah, 48v , 24 kwhr, $4k new - 
- 12-125-17 - 1000AH, 24V - 24kWhr - $3649 - . About $150/kW.
- 24v system - 12-85-21 is - ReConditioned is 2169.00 USD, including freight & core credit, New is 3887.00 USD, including freight & core credit. . Quote - Most of our Off-grid clients prefer New for the 5 year warranty - which can be extended to 7 years. ReConditioned comes with a 1 year, which can extended to 2yrs. How many years are your off-grid customers using the new batteries before they need a replacement? I do not know the specific data for this question in regards to our Off-grid customers unfortunately, you would need to reach out to us at firstname.lastname@example.org.In general, with proper care & maintenace, our batteries will last 10years+.
- At 10 year life, we have $390/yr battery costs. That is 1/3 the standard cost. Cost is at $32/month, which is better but still not super cheap.
- PV cells are 30 cents/watt. 7 kW system is $2100 hardware cost + inverter. Inverter must be open source for serviceability. Thus, unlimited lifetime. Payback - 7kW*6= 42 kWhr/day or $5/day, or 600 days for payback.
- Efficiency combined with batteries can get you by if you have solar PV.
Do They Make Sense?
- Average USA residential bill - $117 
- Forklift battery costs $4k and lasts 10 years for the 20kWhr battery.
- Get a smaller battery then, 10kWhr - and use a Smart Energy system
- There is plenty of power in the day for cheap
- Run all the loads extra heavy during the day! Cut out at night.
- Or do saturated water storage. That seems like the only sustainable route, outside of hydrogen. Wind can also help, but that is irregular.
- Efficiency is the number one way we can do better. Invest more in walls - such as CEB. Heat electrically during hte day,cool electrically during the day with thermal mass. This is where CEBs would come in, and then you free yourself from $1400/year electrical costs.
- Do a dedicated energy house, with 10kW of cooling and heating during the day. At night, you are simply extracting the heat and cool through hydronic heat exchange.
- But what about simple ground source heat exchange for cooling, if the ground below Texas is 70F? Or here, 60C year round.
Understanding Battery Numbers
Divide last number by 2, multiply by the large number (capacity) to get amp hours. First number is number of cells, at 2v each gets you nominal voltage.
- First is number of cells
- Second is the capacity multiplier
- Third number derives the capacity