User replaceable battery vs rechargeable?

[Bloody Marvelous]

There are benefits and drawbacks to both.

+ A rechargeable battery means you don't have to open your dive computer (if you can charge it through the body).
+ Most will charge through a USB port. A simple charger with a USB connection will charge your computer.
- Over time rechargeable batteries will lose their charge and capacity.
- Li-ion batteries can short out on their internal circuit board, becoming a fire hazard.
- If you forget to charge your computer, or you find your DC without charge while at sea, there is no remedy.

+ A user replaceable battery allows you to buy fresh batteries anywhere (as long as they are a common type of battery, like AA).
+ As long as you have a spare battery in your kit, a depleted battery can be replaced even in the remotest of locations.
- Cheap batteries can leak, and ruin your computer.
- Batteries are bad for the environment.
- You need to open your computer on a regular basis, which can introduce integrity problems for the computer housing.

Pick whichever suits your best, or whichever comes with your preferred dive computer. There are more important things to determine what dive computer you should buy than what type of battery it uses.

 

[dmaziuk]

...
- You need to open your computer on a regular basis, which can introduce integrity problems for the computer housing.

If your computer does not have a separately sealed battery compartment, you should have bought a computer made in this century.

Srsly, I doubt any of the current ones have that problem. It used to exist.

 

[buddhasummer]

I don't believe the Perdix or Petrel have a sealed battery compartment. Both were made in this century.

 

[MarkA]

Is there a dive computer available that has a user replaceable rechargeable battery that can be swapped out for an AA in an emergency?

would cover both bases

 

[Lorenzoid]

I also don't see how unscrewing the battery cap of a Petrel/Perdix, replacing the battery, and then carefully, after inspecting the o-ring for hairs or whatever contaminant, screwing it back in, is likely to cause a problem. I realize leaks have happened to some people, and I can't explain why, but it doesn't seem that likely to me. The threads are coarse, the o-ring is fat--this doesn't require delicacy and a magnifier, the way changing a watch battery might, but rather just a little bit of care. Changing a Petrel/Perdix battery every few months (or every couple of weeks if I'm diving a lot) is not a concern to me, and knowing the battery is fresh gives me a good feeling.

 

[iointerrupt]

I've long since grown tired of throwing out devices with integrated lithium-ion batteries.

In 25 years, every single Teric and Garmin is going to be sitting at the bottom of a landfill, as there won't be replacements for their custom LiOn cells.

Not that I plan to use the same computer for the next 25 years, but the point is that I get to decide when I'm done with it, not the battery. I'm sure even during the apocalypse, I'll be able to find some AAs.

 

[Belzelbub]

The threads are coarse, the o-ring is fat--this doesn't require delicacy and a magnifier, the way changing a watch battery might, but rather just a little bit of care. Changing a Petrel/Perdix battery every few months (or every couple of weeks if I'm diving a lot) is not a concern to me, and knowing the battery is fresh gives me a good feeling.

One minor correction. O-rings. At least on the Perdix, there are two o-rings on the battery cap. As you said, they are thick. They are unlikely to get misaligned. In the remote possibility that one fails, there is a built in backup.

 

[Bloody Marvelous]

Is there a dive computer available that has a user replaceable rechargeable battery that can be swapped out for an AA in an emergency?

would cover both bases

Is the other way around okay? Like when your dive computer runs on AA cells, but you can also put a rechargeable battery in there?
In that case the Shearwater Perdix/AI/2 and Petrel/2/3 would suit your needs.

 

[stuartv]

Is there a dive computer available that has a user replaceable rechargeable battery that can be swapped out for an AA in an emergency?

would cover both bases

A Perdix or Petrel can take a rechargeable AA-sized battery, or a non-rechargeable.

In other words, yes.

I also don't see how unscrewing the battery cap of a Petrel/Perdix, replacing the battery, and then carefully, after inspecting the o-ring for hairs or whatever contaminant, screwing it back in, is likely to cause a problem. I realize leaks have happened to some people, and I can't explain why, but it doesn't seem that likely to me.

It is not that likely. But, it is a million times more likely than flooding a Teric.

The threads are coarse, the o-ring is fat--this doesn't require delicacy and a magnifier, the way changing a watch battery might, but rather just a little bit of care. Changing a Petrel/Perdix battery every few months (or every couple of weeks if I'm diving a lot) is not a concern to me, and knowing the battery is fresh gives me a good feeling.

Every time you open/close the battery port, it is a chance that that is the time one of a number of things could happen that result in flooding the computer. Again, about a million times more likely than flooding a Teric.

As I mentioned earlier, I flooded one of my Predators once, through the battery compartment. The battery door/cap was not screwed in all the way until it was tight. Did I get interrupted and forget to tighten it all the way when changing the battery? Did something happen to turn it back out? I don't know. It was almost certainly me not screwing it in all the way for some stupid reason. But, it CAN happen.

A year or so ago, Michele at Dive-Tronix told me that the most common repair they were doing was repairing Perdixes that had had a battery leak inside the computer.

Yep, you absolutely can use good practices to ensure that doesn't happen to you. You can also use good practices to ensure you don't miss a dive because of a built-in rechargeable, too.

Comparing the two choices:

- with good practices, you can forget to charge a Teric for 2 nights in a row and still be able to dive all the next day without even a fear of running out of battery. You'd have to screw up several days in a row (at least) to end up missing a dive due to a dead battery.

- if you screw up on your good practices ONE time, you can have a battery leak inside your Perdix. One trip where you just need a battery, so you buy the ubiquitous AA alkaline and put it in, then come home and forget to take the battery out (that's your ONE mistake) in your rush to put your gear away and get to work the next day. Go to use it next time and find that the battery leaked and screwed your computer.

- you never have to worry about flooding a Teric.

- Every time you change the battery in a Perdix, there is a chance that you'll create a leak. It's a very small chance, but it is non-zero.

- You can carry a solar battery bank and wireless charger and run a Teric indefinitely. With a Perdix, you can never run it indefinitely. You always have to have a source for AA-sized batteries.

In the end, I don't think either one is really inherently better than the other. So, use what you'd rather be looking at constantly during your dives.

 

[CT-Rich]

I have lost two computers to flooding. The Shearwater Peregrine uses an induction charger. Nothing exposed. No way you or anyone else can mess up the o-ring.after two years it will hold a charge way longer than needed. May I have back up computers that are user replaceable batteries (Zoops). But they were swap meet specials. I wouldn’t have paid retail for them

I have a desk lamp with an induction charger built in. I put it on the charger and it is ready to go the next day (or less).