On 21.05.19 16:17, grumpy--- via Emc-users wrote:
> i have no knowledge to add to this subject but it is all very good
> info for possible future projects i have been waiting for someone to
> add saltwater batteries to the discussion
The battery survey at one of the two links in my post on another
subthread of this thread shows the Aquion saltwater battery. They've
unfortunately bowed out of the market. While these (yes 48v) batteries
were rated for 3000 cycles at 100% DoD, they were very large, very
heavy, and could only be slowly charged/discharged. Once enough were
parallelled to provide adequate power delivery, they were then very
expensive.
When looking at them back then, I made these notes:
-----------------------------------------------------------
Not really suitable for off-grid, as it charges too slowly!
-----------------------------------------------------------
Approximate Price: $2500/stack
Nominal Voltage: 48 V
Energy: 2.2 kWh if charged for 10 hrs, then 20 hr discharge = only 110W !!! )
1.4 kWh if charged for 4 hrs, then 12 hr discharge = only 117W !!!
)
Discharge Limitation: Recommended: 14 A (672 W); Max: 17 A
Round Trip Efficiency: 80% at 10A in/out, 90% at 2A in/out
Usable Depth of Discharge: 90%
Cycle Life: 3,000 cycles (to 70% retained capacity)
Operating Temperature: -5 to 40°C ambient
Chemistry: Aqueous Hybrid Ion (AHI™)
Limited Warranty: 5-year full plus 3-year prorated
Physical Characteristics
Dimensions: 935 x 330 x 310 mm (36.8 x 13.0 x 12.2″)
Weight: 188 kg (260 lbs)
To "integrate" capacity decay over time, I'd just take it as straight
line, allowing an average lifetime capacity of (100 - 70)/2 + 70 = 85%
to be used.
Erik
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