NiMH in my Perdix?

[Chilly_Diver]

I’ve been using NiMH Enloops in my dive lights, though recently read on Panasonic’s website that they should not be used in sealed environments as they may vent hydrogen from their casings. The Perdix manual mentions NiMH batteries as compatible with the computer. Being also a sealed environment, what is Shearwater’s position on their use? -Thanks.

 

[outofofficebrb]

Interesting...as they are also the choice batteries for many photography strobes and those are also very much in a sealed environment....

I have Sea and Sea YSD2 strobes and a Perdix as well. I’ve been using alkaline in my Perdix though am curious about using NiMH since I carry so many of them as it is!

What type of batteries can I use in the Perdix? - Shearwater Research

 

[npole]

I use the Li-Ion because they are (IMO) the best compromise: they can be recharged, they last long enough, they are compatible with the "fuel gauge". NiHM aren't compatible with the fuel gauge, they only give to you two states.

 

[Macan]

On a dive trip, my Petrel 2 was low on battery. I forgot to bring AA's and it wasn't convenient to go and buy them. I had NiMH Eneloops (Black) on hand and used it. I expected a lower total hours (the Alkaline gave me 40 hrs of use) with the NiMH but was surprised when they lasted 40 hours of use as well. I've been using NiMH since then without issues.

Take note that the Battery Indicator will not show the drop in voltage. I just monitor the Battery Info on the System Tools and replace the NiMH when it hits 40 hours or when the voltage reaches 1.2v to be on the safe side.

 

[tbone1004]

I imagine they'd only vent when charging. Shouldn't vent during discharge. I have been using eneloops in my Petrel for 4 years with no issue, and have in my Perdix since I got it *admittedly only a few months ago*, but no issues since.

@Macan if you set it to NiMH with the updated firmware, the battery indicator works decently well with the NiMH batteries. There was a firmware update a few years ago to address that

 

[fmerkel]

The venting is only if something goes 'wrong'; extreme overcharge with heating, or complete/aggressive discharge (to 0 volts) also with lots of heating. You obviously aren't going to get overcharge with use. At the draw level of the Perdix you also aren't going to get an extreme heating discharge scenario.....unless you flood it. Then you have a mess no matter what battery is in it with lithium being the worst. I absolutely wouldn't worry the least about it.

I've been using NiMh in lights and strobes for decades. Never seen it happen except once. Wife left her old UK 4xD NiMh cell light (18W) on after a boat dive. It already had an hour on it, then sat out of the water with no cooling, continuing to draw down the batteries. It blew the light head off after some unknown time frame. Interestingly, threads were not destroyed, and the batteries still worked fine after some careful checking. Both light and batteries continued to be used for several more years.

 

[seeker242]

I imagine they'd only vent when charging.

NiMH generally only vents when overcharged or excessively discharged. They aren't supposed to vent under normal use. It's just a safety mechanism so it doesn't blow up.

 

[KeithG]

Interesting...as they are also the choice batteries for many photography strobes and those are also very much in a sealed environment....

Sea & Sea strobes have an over pressure vent system in the battery compartment cap. My old YS50s have a solid cap while my newer strobes have the vented cap.

CPSC & Sea & Sea Underwater Photography Recall Underwater Strobes

 

[Macan]

@Macan if you set it to NiMH with the updated firmware, the battery indicator works decently well with the NiMH batteries. There was a firmware update a few years ago to address that

@tbone1004 Thanks! That's what I did when I first used the NiMh on the Petrel. Set it to NiMH. What I noticed though is the Battery Indicator stayed FULL even after 40 hours of use. I didn't want to chance it quitting during a dive so I replace the NiMh with a fresh one after 40 hours even if the indicator still showed full. Is yours the same? How many hours are you getting from a fresh NiMh?

 

[kelemvor]

Sea & Sea strobes have an over pressure vent system in the battery compartment cap. My old YS50s have a solid cap while my newer strobes have the vented cap.

CPSC & Sea & Sea Underwater Photography Recall Underwater Strobes

Even sealife strobes have vented caps. I hadn't thought about it until this thread, but a opv is something shearwater could add in order to improve things. They could put it in the little battery cover so users could upgrade to a vented cap, too.

Obviously not many people (if any at all) have had a problem with battery venting or the computers would likely already have a opv.