Following Lithium-ion Batteries: South Korean & Chinese Subs of April 9, 2021, Anonymous on April 13, 2021 kindly provided thesecomments and calculations (with some editing by Pete) regarding battery propulsion for China’s Yuan-class submarine:
The advertisement for China's Winston Battery WB-LYP10000AHA Lithium-ion Batteries (LIBs) indicates the average on-board consumption of a Yuan-submarine, when not moving, is some “38kW/h” meaning that its hotel load is 38kW.
The total energy of Lead-acid Batteries (LABs) (assuming they are 400 tonnes in weight) in the Yuan-class seems to be around 11 MWh or more. The Chinese make the incredible claim the Yuan-class using LABs can stay under water for 12 days! [1, 2] Such a LABs-based submarine does not exist. A capacity of 31 MWh, 3300 nm over 33 days for Yuan (LIBs) also looks like perfect nonsense. 580nm over 6 days looks more reasonable [3].
[1] A Japanese ton is the same as a metric tonne, ie. 1,000kg. This calculation example uses data of a Japanese GS-Yuasa LAB, type MSE-3000 (weight = 212kg, capacity = 3000 Ah, voltage = 2V). As the energy of a type MSE-3000 is 6 kWh ( = 3000 Ah x 2V) , then energy of 400 tonne of MSE-3000 is 11.3 MWh ( = 400 ton/212 kg x 6 kWh). Then total hotel load per day is 0.912 MWh/day (= 38 kW x 24h). Endurance is 11.3 (MWh)/0.912(MWh/day) = 12 days.
[2] Generally, the average hotel load of diesel submarine is around 150kW. Maximum (90% discharge depth) and repeatable (30% discharge depth) endurance of a Yuan-class using LABs might be 3 days or less.
[3] On LIBs, if the hotel load and propulsion output at 4 knots are 150kW and 50kW, respectively, total output per day (= (150kW + 50kW) x 24h) is 4.8MWh/day. Then endurance and distance, at 4 knots, is 6 days (90% of discharge depth) and 580nm ( = 4knots x 24h x 6 days). And endurance when not moving (= 0 knots) is 7.8 days (=31MWh / (150kW x 24h) x 0.9).