I agree with Cdr Gibs about the 100% charge definition.
In fact the batteries of the XXI act on a strange way in the game : they charge really fast at the beggining then they start slowing down and when they reach the last 10% they take something like 10 hours to reach the 98%. It seems that the charging is based on a exponential time formula that points to infinite time to reach 100%
So some questions and some answers to try to help :
- It would be interesting to test if the other boats have a linear rythm of charge or if they charge quicker when the voltmeter is on the yellow zone than on the end of the green zone.
- It's very hard to have accurate information about the XXI. Most sources copy themselves and say the same thing with almost the same words. The only reliable information i found are the tests that the German Navy did on the "Wilhelm Bauer" a type XXI. Searching on this forum i found also a post from catfish who gives very accurate informations about the XXI batteries. The conclusion reading this is that the type XXI on the game doesn't behave like the "Wilhelm Bauer" :
From Catfish
Quote:
Hello,
don't want to be a wisea**, but because i have been on the U-2540 and also have a book (Eckard Wetzel: "U 2540", ISBN 3-86070-556-3) about it, i only add some facts - do with it what you want .
The U-2540, later named "Wilhelm Bauer" after being raised in 1957 is a type XXI boat that was thoroughly tested by the german Navy from 1960 to 1982. It is now moored at the port of Bremen (Bremerhaven) as a museum. The batteries have recently been removed, so it does not have its original waterline:
http://www.dsm.de/3ubor.htm
Ok, to the facts as listed in the book:
Surfaced drive with Diesel propulsion (2 propshafts)
Range at cruise speed:
17000 seamiles at 8 knots
15000 sm at 9 knots
14000 sm at 10 knots
11000 sm at 12 knots
Range at high speed:
5000 sm at 15,6 knots
Submerged drive with electric propulsion (2 propshafts)
Range at slow speed:
480 seamiles at 3 knots
420 sm at 4 knots
330 sm at 5 knots
250 sm at 6 knots
Range at high speed:
130 sm at 8 knots
90 sm at 10 knots
30 sm at 15 knots
(top speed submerged 18 knots, no range tested. Some boats only able to run at 16,2 knots due to production and fitting problems)
Submerged drive with snorkel (2 propshafts)
15500 seamiles at 6 knots
11000 sm at 8 knots
An increase of range at slow speed (~6 knots) was possible with Diesel-electric drive, meaning one Diesel charging, and propulsion by both electrical "creep" engines.
All other combinations were certainly possible like in the other "conventional" U-boats.
Battery charging:
Problem is the boat had six engines: Two Diesels, two main electric engines and two "creep" engines which were "rafted" and coupled to the propshafts via belt gears, so vibrations would not be transferred to the hull. The latter used very few energy, thus the long endurance at slow speeds.
The charging times differed depending on how much discharged the batteries were, and if there were the Diesel-driven Junkers compressor or the other electric compressors switched to "load" the pressure tanks, or better compress air. If the boat was at full stop submerged, the Askania automatic hovering device that held the boat at an exact depth would also use some electricity as did other minor engines and devices. If the boat ran submerged with snorkel, using only it's creep engines for propulsion, and one Diesel charging (the other at full stop) it would take appx. 5 hours to recharge.
As well voltage, acid density of the batteries and temperature had an impact on the recharging times.
Normal charge (quick charge did not really change the recharging times):
(previous de-charging/emptying with 2750 A = 8250 Ah)
Full charge:
9488 Ah = 115 % 6 hours 45 minutes
9075 Ah = 110 % 6 hours
8890 Ah = 100,5 % 4 hours 30 minutes
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The fix of Cdr Gibs is the only one that i know (and this is a good oportunity for me to say thanks to him) who allows a player to at least simulate (switching manually between standart/recharge mode) what would have been a patrol in a XXI.