Battery Endurance not good?

[Schnee]

Am I just spoiled by SHIII's Type IIV's performance underwater (ie 12 hr plus at creeping along) or do the US subs have crummier batteries. Seems like the best I can get out of mine so far is 8-9 hrs submerged creeping along.

Its just that I have gotton tired of cruising along on the surface in daylight being a punching bag for aircraft. So I'll spend most of the day cruising underwater, surfacing a bit before sunset.

[mookiemookie]

This has been fixed. Mod is located here: http://www.subsim.com/radioroom/showthread.php?t=109120

[Sailor Steve]

Well, you came to the right place:
http://www.subsim.com/radioroom/showthread.php?t=109120&highlight=battery+life

[GnarPow]

just go to 2.5 knots and you can cruise for a lot longer than 1/3 ahead

[-Pv-]

The default battery performance is historically accurate and only needs moding for the players who want 1950s nuc boats. As has been suggested your "creep along" may not be slow enough to get the endurace you need. Go slower. I have been able to stay submerged over 18 hours at 2 knots and have easily outlasted all attacks to date.
-Pv-

[AVGWarhawk]

Agreed with PV! 2 kts and you can stay down just about all day. I find battery life just about on the money as far as accuracy.

[NEON DEON]

Agreed with PV! 2 kts and you can stay down just about all day. I find battery life just about on the money as far as accuracy.

I get the same results and they seem to fit at 2 Knots with actual boat performance.

What I am wondering, however, does the power consumption ramp up faster than it should given the amount of speed that is applied?

[Krupp]

The default battery performance is historically accurate and only needs moding for the players who want 1950s nuc boats. As has been suggested your "creep along" may not be slow enough to get the endurace you need. Go slower. I have been able to stay submerged over 18 hours at 2 knots and have easily outlasted all attacks to date.
-Pv-



:hmm:, oookey. Then how come the ww2 Fleet sub manual give us these figures?


Based on the following research
data from the Fleet Submarine Manual.

Maximum Time Submerged and Cruising Range vs. Submerged Speed Knots
knots--miles(peace-time)-- miles (war-time) --hours(peace-time) -hours(war-time)
2 ------73 --------------100-110 ------------36 ----------------55
3 ------69 --------------100-105 ------------24 ----------------38
4 ------55 --------------83 -----------------14 -----------------24
5 ------40 --------------64 ------------------8.5 ---------------14.5
6 ------30 --------------48 ------------------5 -----------------9
7 ------20 --------------31 -----------------2.6 ----------------4.8
8 ------14 --------------23 -----------------1.6 ----------------2.6
9 ------9 ---------------15 ------------------1 -----------------1.5
10 -----10 --------------X--------------------X-----------------X

[Redwine]

Most of the sim's subs can, historically, be able to stay 48hs at 2knots.

Balao and Gato has about 34 hs at 3knots in peace time and about 39 hs at 3knots at war time.

:up:

[Rab09]

I don't have an issue with duration of battery life. You can go all day plus in a S-18 class boat and still have 50% battery left. My issue is with the time it takes to recharge them. It seems to take forever to get a full charge.
Is the recharge time close to historical??

[NEON DEON]

The default battery performance is historically accurate and only needs moding for the players who want 1950s nuc boats. As has been suggested your "creep along" may not be slow enough to get the endurace you need. Go slower. I have been able to stay submerged over 18 hours at 2 knots and have easily outlasted all attacks to date.
-Pv-



:hmm:, oookey. Then how come the ww2 Fleet sub manual give us these figures?


Based on the following research
data from the Fleet Submarine Manual.

Maximum Time Submerged and Cruising Range vs. Submerged Speed Knots
knots--miles(peace-time)-- miles (war-time) --hours(peace-time) -hours(war-time)
2 ------73 --------------100-110 ------------36 ----------------55
3 ------69 --------------100-105 ------------24 ----------------38
4 ------55 --------------83 -----------------14 -----------------24
5 ------40 --------------64 ------------------8.5 ---------------14.5
6 ------30 --------------48 ------------------5 -----------------9
7 ------20 --------------31 -----------------2.6 ----------------4.8
8 ------14 --------------23 -----------------1.6 ----------------2.6
9 ------9 ---------------15 ------------------1 -----------------1.5
10 -----10 --------------X--------------------X-----------------X


Nice! :up:

Does the mod use this?

[-Pv-]

"Charge time is based on surfaced speed. In US boats engines not driving the boat are used for charging. At 1/4 you have three engine charging, 1/3 you have two, etc."

I do the same thing. While in heavily patrolled water I submerge an hour before sunrise an surface an hour after sunset. I still have 25-35% battery or more depending on the season and how far N-S of the equator.
-Pv-

[Schnee]

But I've just been moving the arrow on the subs telegraph to 1/3 - you mean there is a manual way to set the speed precisely to 2 or 2.5 knots ? I usually adjust speeds from the map interface - do I have to go into the control room?

[zylark]

Right under the telegraph, there is a small knob. Press that, and you will be able to set a certain speed of your liking.

Oh, and set speed does not equal actual speed. Actual speed depends upon other factors like weather or if you are manouvering. Set speed should be read as speed achieved when going straight ahead on glass-clear water with no wind.

The same concept is used for the other two dials. Press the knob under the bearing dial, and you can manually set rudder angle left or right. The depth dial will change from low depth representation to great depth representation.

[-Pv-]

Endurance test results.

Platforms:
1942 Porpoise leaving Midway using a saved game on my 3rd patrol. I've been carefully building up my crew skill (assuming those graphs and numbers aren't totally meaningless.)
Eng Room Crew Efficiencies- I=.93, II=.94, III=.98
Weather: 5m/s dir 44
Sub Heading 250

1944 Balao Leaving Midway using one of the default patrol missions.
Eng Room Crew Efficiencies- I=.88, I=.88, III.88
Weather: 5m/s dir 0
Sub Heading 270

Procedure:
On Surface set depth to 70 ft 1/3 speed "Ahead Slow" 11 knots.
Passing 50 ft set speed to 1/3.
Upon reaching 70 ft, mark the time, mark the map,, and set speed 2 knots (both text and voice confirm 2 knots.)
Cruise at set depth/speed using 1024 TC until battery reaches 2% or Oxygen warning of 95% CO2 (whichever comes first.)

Game has no diesel, power, battery, or crew mods. No mods to any submarine model or components.

Results using Porpoise:
2% batt, 95% CO2 = 76.95nm, 48 hours

Results using Balao:
4% batt, 95% CO2 = 91.4nm, 48 hours
Continued until battery reached 3% and 98% CO2 (Crew death at 99% CO2)
Distance = 95.1nm

Procedure for battery charge time:
Surfaced at battery depletion times described above. Mark time from charge lcon changing to bright until icon changes to dark.

Recharge times:
Porpoise- Speed set to 1/3 on surface = :49 min
Porpoise- Seed set to Full on surface = 2hr:47 min

Balao (based on 4%/95%CO2)
Speed set to 1/3 = 1hr:16 min
Speed set to full = 2hr:18 min

Ran same tests using Silent Running. No difference. This setting apprently only affects noise/detection/repair and does not affect CO2 generation or machinery/power savings.

My opinion based on these tests lead me to believe there is no significant reason to use power/range-extending mods as the results are close enough for reasonably accurate game play. I've yet to be forced under for longer than 24 hours at a time and usually have nearly half the battery left when I am. In addition, if you are using high speed under water for extended periods while under attack, you are not doing yourself a favor. I've yet to be forced to manouver while under DC attack for more than a few hours at a time which leaves me with very generous battery margines. As I suspected, the game reasonably models the US fleet boat using any of the four engines not used for propulsion for charging battery.

As far as submerged attacks, again technique has a very large contribution to success and endurance. I've yet to sail away from a high speed attack and evasion with less than 30% of my battery remaining.

My typical high speed attack is as follows (with variation depending on lighting, weather and convoy formation):
Surface speed necessary to get within 1/2 mile of outer contact.
Deck awash (22ft keel depth) at necessary speed to within 4,500 yards of closest escort.
47 ft keel depth at full until within 2,500 yards of closest escort (depending on weather, own profile and escort profile.
Continiously decreasing speed and dipping pariscope until within 1000 yards of torpedo target until reaching 1 knot.
Launch torpedos.
Set 1/3 and dive under convoy at 150ft or more.
Arrive out the other side of the convoy, set pariscope depth and attack targets of opportunity with rear tubes.

Repeat two to three times.

Additional end-arounds provide me with ample time to recharge if I don't use ahead full.

-Pv-