The fingertip pulse oximeters here, from Masimo, Nonin, Zacurate, Innovo and Beijing Choice, each take two AAA batteries.
Who made it?
Which model?
The battery it takes
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How long a set of batteries lasts
The user manuals for the Zacurate 500DL and the Innovo iP900AP each give about 30 hours on two AAA batteries. Beijing Choice gives up to 30 hours of continuous use for the MD300C22 on two 600 mAh alkaline AAA, and Masimo 15 hours or more for the MightySat Rx at half screen brightness.
Nonin counts spot checks instead: up to 6,000 for the Onyx Vantage 9590, up to 2,200 for the TruO2 3250, and about 2,500 for the Onyx II 9550, which Nonin puts at 21 hours of use. Each maker measures differently, so the figures don’t compare one to one.
The iP900AP’s screen has five brightness settings and leaves the factory on 4. Innovo Medical says a brighter setting drains the batteries faster.
The low battery sign
On the Zacurate 500DL, a battery outline at the top left of the screen flickers continuously when the batteries are low. On the Innovo iP900AP, an empty battery symbol flickers on the screen. Both manuals say to replace the batteries when it does.
Beijing Choice’s MD300C22 manual draws its low power sign as a battery with one low bar, and says to replace the batteries in time once it lights. On that model, an Error7 message lists low power as its first cause, and changing the batteries as the fix.
If it won’t turn on
The Zacurate, Innovo and Beijing Choice manuals each give drained batteries, or batteries put in the wrong way round, as causes of an oximeter that won’t power on. All three warn that wrongly fitted batteries can damage it.
Charging and other battery warnings
The Zacurate 500DL and Innovo iP900AP manuals warn against trying to charge the batteries that come with them, since that could cause leakage, fire or even an explosion. They also say not to throw the batteries into a fire, and to keep the battery cover closed while the oximeter is in use.
Masimo says to replace both of the MightySat Rx’s batteries at the same time, so a fresh one never sits with a part-used one.
The Zacurate, Innovo and Beijing Choice manuals say to dispose of used batteries as your local laws require.
Storing an oximeter
Masimo says to take the batteries out of a MightySat Rx that won’t be used for more than 30 days. The Zacurate, Innovo and Beijing Choice manuals say to take them out when the oximeter won’t be used for a long time, without giving a number of days.