Inductive charging of dive computers

[Hatul]

Just because a battery is “sealed in” does not mean it can’t be replaced. Witness the battery of the iPhone and Samsung which can be replaced for a reasonable price and the unit resealed.

There really is no need for fast charging a dive computer. My G2 dive computer needs short charge every few dives to top off, but before I can connect the cable I need to make sure the device is rinsed and dried.

My iPhone X gets slightly warm with wireless charging but it’s no big deal.

While Perdix with the ubiquitous AA battery draws a lot of praise, you have to be aware of the state of your used battery before each dive and the unit needs to be rinsed and dried before the battery is changed out. Each time there is a risk damage or wear and tear on the o ring which can flood the battery compartment and ruin your dives.

 

[victorzamora]

Just because a battery is “sealed in” does not mean it can’t be replaced. Witness the battery of the iPhone and Samsung which can be replaced for a reasonable price and the unit resealed.

Except in lots of waterproof examples like the Liquivision X1 where the battery is potted in. Samsung Galaxy S7 doesn't need to be 200m rated, so it can have air spaces and wouldn't really benefit from potting.

As for replacement batteries being "reasonably price"....I'm assuming you're talking about the limited-time-only iPhone offer of $29. It'll go back to >$200 like it was after the PR pain of them limiting performance goes away.

My iPhone X gets slightly warm with wireless charging but it’s no big deal.

You say "no big deal" but you would do well to look up the fact that Qi charging DOES shorten battery lifespans. This is indisputable. Not that big of a deal when you replace your phone every 18months, but a seriously big deal on a $1000 dive computer.

While Perdix with the ubiquitous AA battery draws a lot of praise, you have to be aware of the state of your used battery before each dive and the unit needs to be rinsed and dried before the battery is changed out. Each time there is a risk damage or wear and tear on the o ring which can flood the battery compartment and ruin your dives.

The Perdix and Petrel have the ability to use SAFT batteries for greatly increased duration if checking your battery is a concern (which you would also have to do with rechargeable computers). As for the o-ring damage, it needing to be dry, etc: The o-ring is the standard o-ring used in DIN regs, so they're available everywhere, cheap, and durable. Needing the computer to be dry to change batteries is much less of an issue than needing it to be dry for charging (see below). I've swapped Petrel batteries in the water (holding the computer up) several times.

There really is no need for fast charging a dive computer. My G2 dive computer needs short charge every few dives to top off, but before I can connect the cable I need to make sure the device is rinsed and dried.

It's tradeoffs, really, like anything else. If I can get a slimmer dive computer with a reasonable battery replacement cost and Qi charging in a slow manner that doesn't heat up and destroy the battery...I'm cool with it. The Shearwater NERD2 has a built-in rechargeable battery with a $100 replacement cost every 5+ years, which is totally fine with me on a computer of that scale ($2k+).

I really enjoy the no-brainer of the Petrel/Perdix and using an Eneloop rechargeable with a backup alkaline AA plus a SAFT for international trips (with alkaline backup) over having to remember to charge something else....but if the form factor was right, I'd gladly buy a qi-charged computer.​

 

[tbone1004]

I wonder if @Shearwater will pipe in on why they chose to use contacts instead of inductive charging on the NERD2

 

[fmerkel]

There's 'sealed in', and there's SEALED IN.
Given that it would be a DIVE computer you can bet your wallet changing it would be proprietary and $$$. Even the 'kits' dive shops sell for stock 2450 battery + maybe O-ring are about 10x what they are worth at the retail level for the parts.

Like any computer, the more features you put into it, the more energy you will need to pull out of it. That either means, bigger batteries (bulk), more frequent charges (by whatever method), or more frequent changes. Sure, progress is definitely being made with efficiency but there's only so far you can push that envelope. The Shearwater Perdix supposedly gets 130 hours on a Saft Lithium. The same battery in a old simple DC I had lasted so many years I don't recall when I changed it. It needed to be soldered in, theoretically was a proprietary change because of that, but was simple to change.

 

[Shearwater]

I wonder if @Shearwater will pipe in on why they chose to use contacts instead of inductive charging on the NERD2

Good morning @tbone1004 et al. Some of the reasons for our choice had to do with secure charging in less than stable environments, like on a live aboard. The NERD 2 charger attaches very securely and gives you certainty and peace of mind that your unit is charging even when the boat is moving. Inductive charging requires an antenna, and we wanted a compact unit within certain dimensions. The cable charging that we chose worked better for the design intent that we had. Hope this clears some questions.

-Gabriel

 

[tbone1004]

Good morning @tbone1004 et al. Some of the reasons for our choice had to do with secure charging in less than stable environments, like on a live aboard. The NERD 2 charger attaches very securely and gives you certainty and peace of mind that your unit is charging even when the boat is moving. Inductive charging requires an antenna, and we wanted a compact unit within certain dimensions. The cable charging that we chose worked better for the design intent that we had. Hope this clears some questions.

-Gabriel

curious why not use a strapped charge port though and use the same design but with the Qi antenna vs. pins. would it have made it that much bigger?

 

[Shearwater]

There are other factors to consider along with big. We decided the strapped charge port for a battery that will last 18 hours on medium brightness and supplemented with a portable power pack that's good enough for 5 charges would provide a good offering for divers out on the field. Carrying additional 3rd party power packs or other USB charging alternatives would further extend the range. While you can use different 3rd party Qi chargers to charge a battery with inductive antennas, these will have different efficiencies depending on their layout. Different efficiencies will affect overall battery life to different degrees. In the case of the NERD 2, when we comprehensively considered multiple factors, the simplicity and reliability of the pins worked better for us.

We are not against Qi charging. My toothbrush is inductively charged . We just decided the NERD 2 was better with pins.

- Gabriel

 

[tbone1004]

@Shearwater good to know. Couldn't find it anywhere on the dealers in the US, what's the MSRP of the charging clip when we lose it?

 

[Shearwater]

The retail price is CAD$85. At the moment Google says that is equivalent to USD$69.

 

[kelemvor]

Someone had the solution at the last CES. A company called Ossia has AA batteries with built in QI type charging. Stick one of those into a perdix, and you're good to go. Rechargeable without opening the computer. But you CAN open it if you need to replace it just in case.



I'm surprised I couldn't find regular AA form factor cells with built-in QI