I just received my Energizer Ultimate Li-ion batteries that I will swap out for the alkaline this weekend, but I was curious if you notice(d) whether the Li-ion batteries are "compatible" with the new fuel gauge in the Petrel? IOW, does it show a gradually decreasing charge of the battery, or will it only show "full," "low," and "critical"? The Shearwater FAQ for the Li-ion batteries is missing that info, but hopefully with the rechargeable Li-ion batteries being compatible (see below), the non-rechargeable Li-ion batteries are compatible as well.
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There are numerous types of AA sized batteries that will work in your Shearwater Petrel, read below for more details:
Alkaline
We recommend the AA 1.5V alkaline battery (e.g. the Duracell Coppertop) because it is:
A) Inexpensive
B) Available anywhere
C) Reliable
D) Gives about 35 hours of diving
As an added bonus your Petrel provides a useful Fuel Gauge display for these batteries.
Saft
The Saft 3.6V LS14500 battery (used by the Shearwater Predator) is also a good choice, primarily because it has the longest usable life (90 hours on medium brightness). However they are:
A) Expensive
B) Hard to find
C) Sensitive to temperature and storage conditions
In addition they are incompatible with the new Fuel Gauge feature so only three levels are given: Full, Low (Yellow) and Critical (Red).
Li-Ion - Rechargeable
The 3.7V Li-Ion 14500 battery is a good choice that can be purchased online. The AW brand is recommended and typically high quality. The brands Trustfire and Ultrafire can be good, but seem to come from a wider variety of sources and many users report getting duds. The Li-Ion batteries give about 35hours per charge and are compatible with the new Fuel Gauge feature. Note that these batteries are actually about 4.2V when fully charged.
NiMH - Rechargeable
The 1.2V NiMH battery can also be used. These are commonly used in photo flashes and digital cameras, and can be purchased in most electronics stores. About 30 hours per charge can be expected. We recommend using the low self-discharge models typically labeled as pre-charged, ready charged, stay charged etc. and have capacities around 2000mAh. The older style high self-discharge batteries have higher capacities (around 2800mAh) but not recommended. They will work, but will go dead in a few weeks just sitting on the shelf. Also, all NiMH batteries are incompatible with the new Fuel Gauge feature so only three levels are given: Full, Low (Yellow) and Critical (Red). If you have these batteries already from your photo flash, feel free to use them. However we do not recommend buying them for the Petrel as better choices are available.
Photo Lithium 1.5V
These are the best choice for cold water divers. Sold as the Energizer brand Advanced Lithium and Ultimate Lithium batteries. The 1.5V Photo Lithium batteries offer almost double the run time in a Petrel when compared to an alkaline battery. However they can cost about 4X as much as an Alkaline. They are a good choice if you want longer run time than alkaline batteries provide or if diving in waters colder than 8 degrees Celsius (46 degrees Fahrenheit) . They can be found in most department stores or electronics stores and also in many drug stores.
Zinc-Carbon 1.5V
1.5V Zinc-Carbon batteries are el-cheapo batteries commonly found in dollar stores. Although they work, they only provide about 10 to 15 hours and so are not recommended. However if they are all you can get on a tropical island somewhere, feel free to use them.
To summarize:
Type
| Nominal Voltage
| Approx. Med. Battery Life
| Rechargeable
| Availability
| Cost (USD)
| Cost (500 hrs)
|
|---|
Alkaline
| 1.5 V
| 34 hrs
| No
| Excellent
| $0.75
| $11.50
|
Saft LS14500
| 3.6 V
| 90 hrs
| No
| Poor
| $7.50
| $42
|
Li-Ion
| 3.7 V
| 34 hrs
| Yes
| Poor
| $12.00
| $35*
|
NiMH
| 1.2 V
| 30 hrs
| Yes
| Good
| $5.00
| $20*
|
Photo Lithium
| 1.5 V
| 55 hrs
| No
| Good
| $3.00
| $27
|
*For rechargeable batteries, cost for 500 hours of diving is cost of 2 batteries plus charger.
