Lack of Recharge on type XXI

[Nightowl]

Why doesn't UBISOFT give us a fix on the type XXI lack of Recharge? I mean, that IS a very serious FLAW and it would seem to be such a qiuck and easy fix by the developers with a Patch. Come on, how much would this cost the developers to do? I just don't understand how these companys think, or should I say 'Don't Think" -Nightowl

[Beery]

The XXI is the only boat in the game whose battery works properly. No battery ever made recharges to 100%. It's all the other boats that need a fix, as well as the game mechanic that refuses to switch off recharging until the battery is at 100%.

[wetwarev7]

Originally Posted by Beery

The XXI is the only boat in the game whose battery works properly. No battery ever made recharges to 100%. It's all the other boats that need a fix, as well as the game mechanic that refuses to switch off recharging until the battery is at 100%.

Really? How come? I don't know anything about U-boat batteries, but all my batteries(car/trollermotor/scanner, etc..) charge up to 100% just fine. Did the diesel engines just not put out enough juice?

Did the diesel engines just not put out enough juice?

Well yes and no, yes in that the diesel engines were powerfull enough to drive the generator, no in that they dont directly recharge the battery's, the Generator does (nowdays its an Alternator). They did indeed charged fine to 100%. Any Rechargable battery does in RL. If it didnt you wouldnt get an Amphour rating out of any battery now would you !!!

Mind you tho, the last 10% or so is always the longest cycle to be recharged.

Now as to the fact that the sub's got the TIME they needed to recharge their batteries to 100% is a differant story. That was all subject to daily events.

[JBClark]

I've got to go with Beery on this.

Take your car battery and put it on a charger with an ammeter. Let it charge as long as you like and watch the meter. The battery will continue to suck current for as long as you let it. Not much near the end, but some.

That 100% is an arbritrary number based on a new battery's capacity. From the time the battery is produced the plates start to get covered with sulfates and the acid continually loses it's strength.

The lead-acid battery in my truck is about 4 years old. When it was new, it was rated at 650 cranking amps but can now only provide about 350. Nevertheless, it will charge to its present capacity fairly rapidly, and then continue to draw current for as long as I leave it on the charger.

Another for instance. My laptop battery, which uses much more advanced technology than the old lead-acid types, will never show more than 98% charge, no matter how long it has been plugged in. I think that some of the battery monitoring utilities on some laptops have a "refresh" function that redefines 100% to be the current level of charge. That way, it can report 100% charge, for a while, even though the present capacity is lower than it was when new.

Perhaps something like that refresh function could be used to fool ChEng into believing that it was now time to go to normal running on the engines. That would probably require the SDK though.

JBC

[Marhkimov]

I partly agree with the battery recharge issue. Like Beery and others have said, after prolonged use, the battery should lose it's ability to recharge to 100%. But IMOH the real problem with the XXI battery is the recharge time. Going from 20% to 90% in the type XXI takes much longer than is stated in most websites... I don't have any specific numbers in hand, but someone who knows more about u-boat technology can probably back me up. All I know for sure is that SH3 makes the type XXI recharge rate too slow.

[wetwarev7]

hmmmm..... :hmm:

Just to throw a monkey wrench into this whole thing, does the battery meter on a sub measure current or voltage? I would imagine that it would measure voltage, otherwise you would have a constant drain on the battery(a current meter has to have current run thru it to measure it). If it IS a voltage meter, the current capcity of the battery would have very little effect on it, except in extreme conditions, i.e. extreme cold, extreme old age for the battery, etc, so you would have hit 100% voltage, even before you reached 100% current capacity(like 90-95%).

I think I just confused myself.....

[Beery]

Originally Posted by marhkimov

I partly agree with the battery recharge issue. Like Beery and others have said, after prolonged use, the battery should lose it's ability to recharge to 100%. But IMOH the real problem with the XXI battery is the recharge time. Going from 20% to 90% in the type XXI takes much longer than is stated in most websites... I don't have any specific numbers in hand, but someone who knows more about u-boat technology can probably back me up. All I know for sure is that SH3 makes the type XXI recharge rate too slow.

There was a long discussion about this a couple of months ago. In response to some of the criticisms I did some testing on the Type XXI battery recharge rate and it fit the historical specifications for a Type XXI battery almost perfectly - a 4 hour charge will run the boat for nearly 2 days, although to fully charge the battery takes about 14 hours. The 4-hour for 2 days thing matches all the stats that I've seen on the Type XXI. While I'm sure it's not perfect (I don't know about the 20% to 90% rate of recharge), it's definitely not the horribly modelled system that some would have us believe.

[Marhkimov]

Sorry, 20% to 90% is just an arbitrary figure that I threw into the discussion. I am pretty sure there is no such statistic. It's just a recharge value that I personally go by...

[JBClark]

Originally Posted by wetwarev7

hmmmm..... :hmm:

Just to throw a monkey wrench into this whole thing, does the battery meter on a sub measure current or voltage? I would imagine that it would measure voltage, otherwise you would have a constant drain on the battery(a current meter has to have current run thru it to measure it). If it IS a voltage meter, the current capcity of the battery would have very little effect on it, except in extreme conditions, i.e. extreme cold, extreme old age for the battery, etc, so you would have hit 100% voltage, even before you reached 100% current capacity(like 90-95%).

I think I just confused myself.....

Just to toss the monkey wrench back, and I mean nothing by it, I don't know for sure the answer to your question. I think the stock game displays a voltmeter, and I remember someone's mod replacing that with an ammeter. Surely there would have been both on the boat.

A voltmeter in those days (and well into the 1980's) was just an ammeter with a humongous resister added to the circuit. Both meters relied on current flow through a coil to create a magnetic field that would deflect the needle. The difference was in the way the meter was calibrated.

A voltmeter would draw less current than an ammeter but the difference was trivial to the capacity of the batteries. Turning on one overhead light for 10 seconds would take more power than the battery meters would in the life of the boat.

The voltmeter would tell how much energy was left in the batteries and the ammeter would indicate how fast it was being used. If the electric engines were off, the ammeter should read zero, while the voltmeter would read high. Really the voltage would not tell the whole story, the common test for energy capacity was the specific gravity of the electrolyte.

Ok lets look at the typical 12v car battery.

Its PD is 12V (as we know)

Its Recharge Voltage is 13.8V

The recharge current is usualy a trickel charge of around 2-4 Amps

Whilst its being Charged the Generator/Alternator should be powerful enough to charge the battery and run all required electricl needs, so we get say a 40Amp Generator/Alternator. This as we can see provides us with 40amps to use for running the car.

Now when charging the Volt metre will show 13.8V across the battery and the Amp metre will show the recharge current as stated somewhere between 2-4 Amps. Now as the battery reach's a full charge the Volt metre will still show 13.8V but the Amp metre will slowly start to go down to 0 Amps starting in the last 10% cycle or so. When the Amp metre no longer shows any current moving across the battery its now considered 100% recharged.

Now this is via a trickle recharge system, however most cars also allow a rapid or Boost recharge at the begining to quickly get the battery recharge back to a usable level then taper off to a trickle charge rate so as not to damage the battery. In the rapid/boost stage the recharge current can be as high as 10 Amps.

Now given that your typicl Uboat is NOT the same as a standed car (and the fact that I have worked on many marine electrical systems both big and small), we know that the battery system is a hell of a lot bigger and so is the recharging system. BUT the same basic principles apply. The battery will be considered 100% recharged when the recharge current falls to 0 Amps (or so damn small its not worth noting). There for ergo, all batteries will have reached a 100% recharged state.

Now as to what that state IS compared to the day it was made is another subject.

Is any of this modeled in SH3, NO, so by this very nature it cant be said its realistic, however for the purpose of game play and to get the automatic change over to standed propulsion v's recharge propulsion, the battery Needs to reach 100% recharged. Even tho it may in truth never reach factory specs for recharge, the recharge is still considered completed (100%) when the recharge current is at 0 Amps.

This is something that to my mind is broken on the Type XXI. Yes it may not be at factory specs, but the onboard recharge system is Done, Finished, Over when the recharge current is at 0 amps, we just dont ever get there.

Thats why I adjusted the battery modifier to the Type XXI's battery.

[oRGy]

Originally Posted by Cdr Gibs

Thats why I adjusted the battery modifier to the Type XXI's battery.

Oh?

[Walsung]

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

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

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.

[Beery]

All I know, or care about regarding the Type XXI, is that the real boat could go for two days at 5kts on a four hour charge. So does the game's Type XXI. Its battery also behaves like a real battery. That is enough for me. Since this boat never saw combat, I'm not really going to care too much about the precise accuracy of its batteries, because I'll probably never use it in the game, as my game has it available only when it was historically available - i.e. from mid-March 1945.

This boat appears in the standard game in April 1944 - as such it's a fantasy. If players are willing to accept a sub that never took part in combat, I don't see why they should desperately need it to be 100% accurately modelled. If it was 100% accurate, it wouldn't be in the game. When you accept fantasy, you have to accept a certain lack of realism.

In other words, those who criticise the Type XXI model are, in effect, looking a gift horse in the mouth.

That's my view on it anyway.

[Marhkimov]

Originally Posted by Beery

All I know, or care about regarding the Type XXI, is that the real boat could go for two days at 5kts on a four hour charge. So does the game's Type XXI. Its battery also behaves like a real battery. That is enough for me. Since this boat never saw combat, I'm not really going to care too much about the precise accuracy of its batteries, because I'll probably never use it in the game, as my game has it available only when it was historically available - i.e. from mid-March 1945.

This boat appears in the standard game in April 1944 - as such it's a fantasy. If players are willing to accept a sub that never took part in combat, I don't see why they should desperately need it to be 100% accurately modelled. If it was 100% accurate, it wouldn't be in the game. When you accept fantasy, you have to accept a certain lack of realism.

In other words, those who criticise the Type XXI model are, in effect, looking a gift horse in the mouth.

That's my view on it anyway.

I hate to admit it, but Beery is right about this one... Why do I even care about the Type XXI? The only time I'll ever use it is in a single mission.