# What is the capacity of a WWII Submarine battery in kWh?

After reading about submarines in World War II, I was curious about their battery capacity, specifically in comparison to modern Battery Electric Vehicles (ie Tesla, Bolt, Leaf, i3, etc).

I haven't been able to find a source that either answers the question in kWh or gives me enough information to calculate it myself.

My current guess is about 30 kWh, based on a figure of 12000 Ah in a 120 cell system, and a voltage of 2.75 V - 1.05 V

I would accept an answer for any class of submarine in WWII, but I was looking at the US Balao class.

• What was the chemistry used in the batteries you are looking at? Jan 23 '19 at 20:13
• @SolarMike Lead Acid Jan 23 '19 at 20:58
• Old topic but I am not sure how the maths are done... With lead acid, 2.25V nominal x 120cells in series and 12000Ah cells we get about 3MWh, not 30kWh... maybe Ah rating is wrong. Apr 23 '20 at 17:16
• @ÁlvaroSatuéCrespo my comment to you was lost (mod changing your answer to a comment) so repeating it: are you assuming each cell has a capacity of 12000Ah ? Apr 23 '20 at 20:12
• @ÁlvaroSatuéCrespo It's been a while since I asked this question, I wish I had stated it better.The 12000Ah refers to the whole system, not one cell; so it's 2.25*12000 = 27000 V*Ah = 27000 Wh = 27kWh. I do not recall where I got the figure of 100 Ah per cell in this class of submarine. Apr 24 '20 at 21:49

Collecting bits from sites,

fleetsubmarines

World War II American fleet submarines had two batteries, each composed of 126 cells. By comparison, a 12-volt car battery contains only 6 cells, each producing about 2.25 volts when fully charged, with a maximum power output of about 45-50 amps. Each cell in a submarine battery produces from 1.06 volts when fully discharged, to 2.75 volts at the optimum output, so connecting the 126 cells in each battery in series gives a usable output of from about 210 to 350 volts, and a power output of as much as 15,000 amps with both batteries connected in parallel. (no mention of total amp-hrs)

quora

My submarines (Oberon class of the 1960s-1990s) had two lead acid batteries containing 224 cells each with a nominal voltage of 440 volts.. The cells were rated 74.20 ampere-hours at a 5 hour rate (nominal voltage of each cell was 2.2 V)

448*74*2.2 = 73kWh

uboat.net

The US Navy "Balao" type submarine (1944/45) was fitted with 4 four Elliot Main (Electric Motors) two on each shaft, with a total horsepower of 2,740. While submerged, these motors were powered by two massive (each cell weighing 1650#) 126-cell batteries (in series) capable of delivering 5,320 Amp/Hrs each.

Assuming they meant Amp-hrs, and guessing 2.2 V per cell, 2.2 * 2*5320 = 23.4 kWh