# Talk:Zinc–bromine battery

WikiProject Energy (Rated Start-class, Low-importance)
This article is within the scope of WikiProject Energy, a collaborative effort to improve the coverage of Energy on Wikipedia. If you would like to participate, please visit the project page, where you can join the discussion and see a list of open tasks.
Start  This article has been rated as Start-Class on the project's quality scale.
Low  This article has been rated as Low-importance on the project's importance scale.
Specific energy {{{EtoW}}} {{{EtoS}}}

## Energy Density

Currently the Article source-lessly expresses "Zinc-bromine batteries have energy densities of 75 to 85 Wh/kg." The Only Battery example given has however a 34.4Wh/kg (50kWh/3200lb). So the given Rating is +200% better that the only example the article gives. I'm changing it to 34.4 but it can be changed back if anyone can give a source or reasoning behind this. Larek (talk) 16:11, 27 July 2009 (UTC)

I Found where "75 to 85 Wh/kg" has been printed in several white papers, And I think may have originated from the Manufacture originally. But it never hurt to check you math. According to Energy_density#True_energy_densities "energy density of a complete system, including all required external components", This "flow" battery has pumps and tanks etc, so one complete functional DC battery (108V) weighs 3200lb (1451.49kg) and stores 50kWh -> 34.4 Wh/kg
I could not find most of the template's specs directly but I did find the required values to calculate them.

Energy/size = 50kWh / (84"x48"x48") = 50kWh / 193 536 in^3 = 50kWh / 3171.48682L = 15.7
Charge/discharge efficiency = 150MW/214MW (for 30 units) =.7
Energy/consumer-price = $600,000 USD / 30 units / 50kWh each =$20,000 / 50,000Wh = \$.4/Wh = 4¢
Nominal Cell Voltage = The Production battery uses 3 stacks in parallel, Each stack is 60 cells in series and each stack has an Open Circuit Voltage of 108 = 108v/60cells = 1.8V/cell
The potential is .76V + 1.087v = 1.847v (in a perfect world), So I don't know where 1.67v is coming from.141.219.144.60 (talk) 20:07, 27 July 2009 (UTC)