Question Where to buy AA lithium batteries for Perdix 2 in Cozumel?

[Joneill]

Yes, I'm fairly new to the Perdix 2 and thought I had plenty of battery left. Turns out I just barely did, as the icon was showing about half full during most dives (oddly, still showed full on start-up). When I could not find the lithium batteries I decided to see how long I could go (had my old Mares Puck Pro+ on all dives also, which is what my son was diving too). Made it through 14 dives on my trip, and right after the last dive it displayed a message across the bottom of the screen. Came home and ordered the lithium batteries.

I have to say, I was not super happy with the inconsistent and vague manner in which the Perdix 2 describes battery life -- was hoping for more of a somewhat accurate percentage display like most cell phones. Is this consistent with others' experiences with these computers?

Are you using Energizer Ultimate Lithium AA’s as they are the very specific AA batteries recommended by Shearwater? See page 66 of the Perdix 2 manual for how different batteries work with the Perdix 2.

I find that the fuel gauge works pretty well but is definitely not as precise as cell phone battery % charge indicators.

 

[Carlos Danger]

Yes, I'm fairly new to the Perdix 2 and thought I had plenty of battery left. Turns out I just barely did, as the icon was showing about half full during most dives (oddly, still showed full on start-up). When I could not find the lithium batteries I decided to see how long I could go (had my old Mares Puck Pro+ on all dives also, which is what my son was diving too). Made it through 14 dives on my trip, and right after the last dive it displayed a message across the bottom of the screen. Came home and ordered the lithium batteries.

I have to say, I was not super happy with the inconsistent and vague manner in which the Perdix 2 describes battery life -- was hoping for more of a somewhat accurate percentage display like most cell phones. Is this consistent with others' experiences with these computers?

My Perdix 2 exhibits similar behavior where it indicates a full battery on the surface, but reads a lower level during dives, then goes back to full again later. I always start with a fresh set of the recommended type and on the latest firmware, and so far it has made it through every trip without dying or yelling at me to change them. Maybe just a quirk of how it operates?

The last couple of trips I started seeing the occasional transmitter dropout, even with new batteries. It never used to do this, but always seems to quickly reconnect. All-n-all, pretty minor issues with what has otherwise been a really great product to use. Perhaps the next firmware release will see some improvements.

 

[Rob9876]

Are you using Energizer Ultimate Lithium AA’s as they are the very specific AA batteries recommended by Shearwater? See page 66 of the Perdix 2 manual for how different batteries work with the Perdix 2.

Yes, but I will look at that manual page for future reference.

 

[ChuckP]

My computers are pretty consistently ****** about the battery meter - but hey they are consistent. When you first see it yellow, you have a few days, maybe a week of two tank diving - I don't really see that as a problem at all. You get a few days warning.......

I can dive two tanks everyday for over a month on a set of batteries, the lithium ones. I would not worry one bit about sticking any good battery in there for a few days, not one bit what so ever - I would not leave the battery in for extended storage but for three days on vacation? I'd be more worried the breakfast buffet started on time.............

 

[ReefHound]

I have to say, I was not super happy with the inconsistent and vague manner in which the Perdix 2 describes battery life -- was hoping for more of a somewhat accurate percentage display like most cell phones. Is this consistent with others' experiences with these computers?

In general, it's harder to measure lithium batteries because the voltage curve is flatter. That is, they tend to maintain full voltage output until they are depleted whereas an alkaline will get progressively weaker. Remember how flashlights with alkaline batteries would get dimmer and dimmer, often lasting quite awhile before not outputting light? Often flashlights with lithium batteries will output full light and either abruptly not output light or have a very brief dim period.

There are different ways to measure the battery state so may be why some devices seem to be more accurate than others. Measuring by voltage can be affected by the load and there is much more load on your DC at depth where it is running decompression calculations.

 

[ChuckP]

I've been a dim light for years - guess that makes me alkaline...

That is a very good point though, never thought of that. Flashlights, old style, definetly go dim, my Dewalt drill goes from functional to nada in a blink of an eye!!!

 

[ReefHound]

Trivia: There was a great baseball player for the Detroit Tigers named Al Kaline.

 

[ggunn]

In general, it's harder to measure lithium batteries because the voltage curve is flatter. That is, they tend to maintain full voltage output until they are depleted whereas an alkaline will get progressively weaker. Remember how flashlights with alkaline batteries would get dimmer and dimmer, often lasting quite awhile before not outputting light? Often flashlights with lithium batteries will output full light and either abruptly not output light or have a very brief dim period.

There are different ways to measure the battery state so may be why some devices seem to be more accurate than others. Measuring by voltage can be affected by the load and there is much more load on your DC at depth where it is running decompression calculations.

There is a very accurate way of determining battery state of charge, which is to monitor the energy leaving and entering the battery and comparing it to the capacity of the battery, but apparently it would be too expensive to implement on portable devices.

 

[broncobowsher]

There is a very accurate way of determining battery state of charge, which is to monitor the energy leaving and entering the battery and comparing it to the capacity of the battery, but apparently it would be too expensive to implement on portable devices.

That would also require starting with a known level of charge. And a battery that actually has the full capacity that it should.

 

[L13]

There is a very accurate way of determining battery state of charge, which is to monitor the energy leaving and entering the battery and comparing it to the capacity of the battery, but apparently it would be too expensive to implement on portable devices.

For replaceable batteries, they have no idea what make and model of battery you installed. It is all a guess, which is why the reported capacity is so variable. The only thing they can reliably say is when you don't have enough for another dive.