baffled by Suunto D4i info while diving vs dive log

[Centrals]

I did not know that! All great reasons for the Suunto to be primary. Plus ... I can't find the IR connector and I'm on a Mac, so I'm SOL when things go wonky with the Uwatec.

Oddly, the way I got such a deal on the Suunto is because the dive shop guaranteed I'd have my Uwatec back in time for my trip and I didn't.

Thanks for all the info and support!

Changing battery(Uwatec) is expensive and time consuming. It is not difficult but tedious because the chamber is filled with paraffin oil. And the battery with tag is not a common type(AA 3.6V) and need to be soldered into the PC board. Finally, there is various trick, depend on model, to wake up the computer afterwards!!!
It is a very good computer but the battery power(3-4 yrs) is the Achilles heel.
How much have you spent over the yr to have the battery replaced?

 

[Dan]

You need to keep eyes on your D4i display more often than your UWATEC SmartCom, especially when you are close to NDL. When you see D10 (Deco obligation at 10 feet ceiling depth) displaying on the screen with how long you need to be at that depth, that means you just pass NDL. It’s time to ascend. As you ascend slowly (> 30 ft/min), the D10 time would slowly decrease down to zero and even disappear if you keep ascending. At that point you can resume your diving at that shallower depth.

If you feel that it’s so conservative and much different than your UWATEC SmartCom, assuming your D4i’ RGBM algorithm setting is like my D4, then change it from RGBM 100 to 50, as shown in page 39, section 5.8.9 of the D4 manual, below

https://ns.suunto.com/Manuals/D4/Userguides/Suunto_D4_users_guide_EN.pdf

 

[Belzelbub]

All good to know, thanks. I will say that I was very surprised by the 48 hour lockout. I was trained that if your computer died, you had to wait 24 hours before getting back in the water. Seems a bit extra conservative to me.

Yeah. That would make sense. 48 hours definitely seems like overkill. Especially when you consider that:
a. The Suunto algorithm is on the conservative side.
b. The Suunto was set to the high conservatism option (presumably).
c. The gas mix was also resulting in less N2 absorbed than the algorithm thought (though this is not the computer's fault)

No doubt, the Suunto will keep you safe, and is fine for most recreational dives. It's just rather picky with certain things and will penalize by reducing NDL on subsequent dives for transgressions that other algorithms are OK with. Reverse profiles, shortish surface intervals, etc.

 

[Dan]

All good to know, thanks. I will say that I was very surprised by the 48 hour lockout. I was trained that if your computer died, you had to wait 24 hours before getting back in the water. Seems a bit extra conservative to me.

That’s SUUNTO.

They preferably for you to wait even longer, up to 100 hours, as stated in page 82 of D4 manual:
“When the battery is changed, all nitrogen and oxygen uptake data is lost. Therefore, the no-fly time shown by the computer should have reached zero or you must wait for 48 hours, or preferably up to 100 hours, before you dive again.”

D4 would warn you about low battery way early. I have never experienced of it running out of battery in the middle of my dive. Also I do carry spare battery (CR2450) for a week or longer liveaboard trip. It’s pretty cheap and easy to get. Any Walmart would have them.

Here’s their battery replacement recommendation (page 85):
“Battery:
• One 3 V lithium battery: CR 2450
• Battery storage time (shelf life): Up to three years
• Replacement: Every two years, or more often depending on dive activity
• Life expectancy at 20°C/68°F:
• 0 dives/y –> 2 years
• 100 dives/year –>1,5 years
• 300 dives/year –>1 year”

 

[eab]

That’s SUUNTO.

They preferably for you to wait even longer, up to 100 hours, as stated in page 82 of D4 manual:
“When the battery is changed, all nitrogen and oxygen uptake data is lost. Therefore, the no-fly time shown by the computer should have reached zero or you must wait for 48 hours, or preferably up to 100 hours, before you dive again.”

100 hours? That would KILL a dive trip! Wow!

Another, I didn't know...

 

[eab]

Changing battery(Uwatec) is expensive and time consuming. It is not difficult but tedious because the chamber is filled with paraffin oil. And the battery with tag is not a common type(AA 3.6V) and need to be soldered into the PC board. Finally, there is various trick, depend on model, to wake up the computer afterwards!!!
It is a very good computer but the battery power(3-4 yrs) is the Achilles heel.
How much have you spent over the yr to have the battery replaced?

Replacement cost is approx. $60. Time sink is usually quoted as 3-4 weeks but ends up being more around the 6 week mark.

When it dies, I'll cry, but I'm not sure I'll buy another one.

Although I should add, my LDS wasn't able to service the Suunto and that one was out for almost 8 weeks!

 

[eab]

You need to keep eyes on your D4i display more often than your UWATEC SmartCom, especially when you are close to NDL. When you see D10 (Deco obligation at 10 feet ceiling depth) displaying on the screen with how long you need to be at that depth, that means you just pass NDL. It’s time to ascend. As you ascend slowly (> 30 ft/min), the D10 time would slowly decrease down to zero and even disappear if you keep ascending. At that point you can resume your diving at that shallower depth.

If you feel that it’s so conservative and much different than your UWATEC SmartCom, assuming your D4i’ RGBM algorithm setting is like my D4, then change it from RGBM 100 to 50, as shown in page 39, section 5.8.9 of the D4 manual, below

https://ns.suunto.com/Manuals/D4/Userguides/Suunto_D4_users_guide_EN.pdf

Really appreciate the tips, thanks! I'm going to comb through the manual and dive computer settings this weekend. Next Cozumel trip is just a couple weeks away!

 

[Dan]

Order this from Amazon & do it yourself (I did it myself & it took me 5 minutes):
For Suunto D4 and D4i Dive Computer Watch Replacement Battery Kit

 

[Dan]

Note:
I actually do even more than him by replacing the o-ring & put silicone grease provided in the kit over the o-ring before snapping the cover back in place. I’ve done it 3-4 times in 9 years of using it (logging over 900 dives with it).

 

[Centrals]

Replacement cost is approx. $60. Time sink is usually quoted as 3-4 weeks but ends up being more around the 6 week mark.

When it dies, I'll cry, but I'm not sure I'll buy another one.

Although I should add, my LDS wasn't able to service the Suunto and that one was out for almost 8 weeks!

US$60.00 for Uwatec battery replacement is not too bad.
DIY for Suunto.

I am never happy with RGBM algorithm. Conservatism is not a big issue, it is the idiosyncratic way with so many "safety" criteria to obey.
You will not be able to buy another brand new Uwatec computer. However, your present one should last at least several more yrs. You can tell if the computer is near the end of it's life when the display gets dimmer ie. difficult to read.

If you have spare cash then an invest it on obsolete Oceanic Voe 2. It has dual algorithms(PZ+ and DSAT) and the former could be similar to RGBM. The DSAT is too liberal.