Changing Computer Batteries

[resumeman]

My wife's Geo 2.0 is running out of juice, so I'm going to replace the battery (already have a replacement) before our next trip.

There were two things in the instructions I didn't expect:

• To ensure proper sealing, replacing the o-ring is highly recommended each time the battery is replaced
• Lightly lubricate the o-ring with silicone grease...

So, um, are these two steps necessary? Most notably the second. I don't have any silicone grease; is a scuba-acceptable product available in a hardware store, or do I have to go the $9-a-tube route from the dive shop/online dive store?

And in practice, do folks replace the o-rings each time? I'll need to get one if so.


Thanks.

 

[DuboisP]

any silicone grease at the plumber's shop

 

[Bubbletrubble]

Compressed O-rings deform over time. They are cheap to replace, so long as the manufacturer specifies the appropriate size. Most official "battery replacement kits" sold by the computer manufacturer include a new o-ring, a fresh battery, and the appropriate lubricant.

I don't have any experience changing the battery in the Geo. However, with other dive computers, it is possible to damage the o-ring when removing the old battery. This would be one argument against re-using the old o-ring. Also, take care not to damage the sealing surfaces. Follow the manufacturer's instructions.

Make sure that whatever lube you use is compatible with the material composition of the o-ring. Some camera owners have used the wrong lube on their camera housing o-ring...with disastrous consequences. The o-ring stretches out, fails to make a seal, and allows water to infiltrate the housing. Not good. When in doubt, contact the dive computer manufacturer.

The inexpensive o-rings you find in scuba save-a-dive kits are usually made of Buna-N (nitrile).
FYI, the Trident food-grade silicone lube being sold in scuba shops is compatible with Buna-N o-rings.
I bought a small container of the stuff (#LP20; 2 oz.) for $5 about 10 years ago. There's still plenty left.

 

[redacted]

I tend to inspect static o-rings and reuse them if they look OK in all applications including computers. If you damage the o-ring on installation, it does not matter whether it was new or old. O-rings will tend to outlive computers many times. What do you think seals the buttons on your computer that are never changed. While it is a very low probability, there is always a chance of introducing a defective new item when you unnecessarily replace an old working item.

Lubrication is very important to protect the o-ring (help it slide into place) during installation and for proper seating of static seals. The surface film also helps protect the o-ring from degrading elements like oxygen extending their life. If you don't like the price in your LDS, there are many sources such as:Buy Silicone Grease .25 oz Jar from Leisure Pro. Plus silicone lube has many applications so you might try a local camera shop or even the drug store where you might have to read labels carefully. No sprays as the carrier may not be compatible with the o-ring.

 

[mathauck0814]

+1, when you inspect/service your gear (including changing a battery) the manufacturers make recommendations. They're there because it's the best practice for the long life of your product. Sure you don't HAVE to replace the wear and tear parts, but then you'll be spending a lot more than $9 on a replacement computer when the o-ring fails. Sounds like tripping over dollars chasing cents to me...

 

[Spg01]

but then you'll be spending a lot more than $9

That $9 is part of the problem, you can buy a pack of 100 o-rings for like $7 from McMaster. So $9 for a $0.07 o-ring, hmmmmmmm. It would not be bad if the manufacturers would actually tell you what o-ring is required. I tried asking Tusa about the o-ring for my computer and after 4-5 emails of them not knowing how to tell me the correct size of the oring, they finally said to just order a kit from a dealer. I understand that they need to make some money, but the markup on most scuba equipment is horrible.

So the 1st battery change on this computer I used the original o-ring and everything has been fine. Maybe it will get a new o-ring next time???

 

[mathauck0814]

Something similar to this: NBR O-Ring Kit 38 Sizes

Will save you a lot of headache in the long run.

 

[redacted]

If they are standard US (SAE) o-rings, they are fairly easy to measure and inexpensive to buy. For a computer, the cheapest material (nitrile or buna) is good with a hardness of duro 70. This place is a good source. O-rings Online Frameset The only real downside is even $1 worth will last a few divers a long time.

If you can get a small group together and figure out all your diving o-ring needs, it is very cost effective. Many recommend o-ring materials viton or EPDM for regulators used with nitrox but nitrile will work OK for many years before high O2 content may start to degrade it.