NiMH batteries for the Nonin WristOx 3100

[Nodzy]

Anyone having the Nonin WristOx 3100 wristworn oximeter can rest assured that alkaline batteries are not an absolute necessity for operating the unit - despite that the alkalines are 1.5v and the NiMH are 1.2v.

Weeks ago I ordered rechargeable N-cell batteries and a 4-slot charger having an N-cell 2-up adapter to try. The NiMH charger also accomodates up to four (4) AA and/or AAA batteries when the 2-slot N-cell charging adapter is removed. What I really like is that the charger has fold out prongs and no power brick and cord to hassle with.

The N-cell NiMH batteries work great in the Nonin 3100. But, instead of getting three (3) eight-hour nights with the alkaline batteries, I get only two (2) nights of use with the NiMH N-cells - but that's an acceptable trade-off for the much lower cost per day of use of the Nonin 3100.

The charger and NiMH batteries were bought from MIMIO, a maker of electronic whiteboards and peripherals. Go to MIMIO and scroll to the NiMH charger and batteries.

For more versaility, I also ordered and received four (4) special N-cell battery charging adapters - each holds one (1) N-cell for use in any NiMH charger that'll charge AA NiMH batteries. They were obtained from TNCProducts.

DISCLAIMER: While I have not experienced any problems with data validity or the operation of Nonin 3100 by using NiMH batteries, there is no guarantee that a problem will not occur at some point in the future. You use this information and NiMH rechargeable batteries at your own risk. Follow all safety warnings and precautions, and battery disposal guidelines and regulations for the area in which you reside.

Nodzy said it.... and... get hosed, every night.

[feeling_better]

Nodzy,

I do not know anything first hand about your meter, but I know how electronic equipments work and NiMh and other batteries. The battery voltage of NiMh at full charge is around 1.45v and it will gradually drop to around 1.2 and that is where most of the capacity is delivered. I would guess that your meter operates ok with the reduced voltage until after the two nights. If the meter were designed to operate well with NiMh, they would have made the required voltage a little lower and then you would have got a much longer life from your recharge. As you said it is still a good compromise.

BTW, you battery might increase the capacity a bit after a few full charge discharge cycles (this is is true for NiMh and even more so for NiCad).

The capacity of these batteries are getting better with the newer ones and there is a very wide range of capacities (mAh) for AA and AAA. Also the advertised capacitiy of some brands are false, the actual may be only 70%. You be able to get a higher capacity one to extend it to 3 nights.

[Nodzy]

feeling_better,

Thanks for the reply... but I'm pleased that it works well for two nights with NiMH batteries. As the Nonin is rated for only about 24-hours of operation with a fresh set of N-Alkaline batteries.

Despite the Nonin's short battery life... the N-NiMH batteries significantly will lower usage costs over time... and the Nonin 3100 suits me well for its sensor options, versatility, small size and ruggedness. With a reusable flex sensor, wrapped right with CoFlex to the finger... it's much more comfortable to wear, and less likely for the sensor to be accidentally pulled off the finger when sleeping or out and about.

Nodzy

[feeling_better]

Nodzy,

THe best charger in my research is X1 Super fast charger CHB-7N9. I am sure you would find current vendors for this online. It uses very sophisticated charging methods, yet relatively inexpensive (made and marked by a Chinese company). Since people discovered how good this was compared to others, the price of this has more than doubled in the last 4 years! It can charge AA, AAA, and 9v. They have a number of other models, including auto adapters, with varying features.

Here is a url to the last battery comparison I had. It is old, he might have updated it since then. Even though this is for AA, the same manufacturers AAA will have similar over statement of actual capacity.
http://www.imaging-resource.com/ACCS/BATTS/BATTS.HTM

[Nodzy]

THe best charger in my research is X1 Super fast charger CHB-7N9.

Thank you. I had looked at the X1 charger several years ago and decided to opt for a small MAHA MH-C401FS charger for AA and AAA batteries. The X1 won't charge odd numbers of batteries, but the MAHA does of great job of that - and has a switch to select Normal or Fast charging rates. What I didn't like was the large MAHA power brick, but the charger itself is very small.

For the N-cells I specifically bought the unit mentioned in my original post above through MIMIO, but it is brandless (no name), but has a removable 2-UP N-cell adapter. Afterwards I was able to acquire the single N-cell adapter sleeves I had originally wanted, but which were out of stock... from TNCProducts. They work great in any NiMH charger that accepts AA batteries.

Yes, the X1 is nice, but I have several portable devices that use 3 NiMH AAA batteries at a time... and the MAHA unit allows charging 1 to 4 NiMH AA's at a time in any slot combination. But again, it is tethered to a large power brick which is a drawback.

Thanks again for your insight.

Nodzy

[feeling_better]

THe best charger in my research is X1 Super fast charger CHB-7N9.

Thank you. I had looked at the X1 charger several years ago and decided to opt for a small MAHA MH-C401FS charger for AA and AAA batteries. The X1 won't charge odd numbers of batteries, but the MAHA does of great job of that - and has a switch to select Normal or Fast charging rates. What I didn't like was the large MAHA power brick, but the charger itself is very small.

Yes, odd number charging is a useful feature. Thanks for the feed back. BTW, that big brick means it is not an effecient charger, it uses much more power I would guess. I am surprised how cool the X1 is, which means the switcher power supply is extremely effecient.

For the N-cells I specifically bought the unit mentioned in my original post above through MIMIO, but it is brandless (no name), but has a removable 2-UP N-cell adapter. Afterwards I was able to acquire the single N-cell adapter sleeves I had originally wanted, but which were out of stock... from TNCProducts. They work great in any NiMH charger that accepts AAA batteries.

What is an N-cell? Is it a different dimension one from AA?

[tansey]

I have often wondered why can't they make ni-mh 1.5 volts? I use them in my GPS, camera, and the little radio. In the camera, the flash will only work a few times before it says "battery low". In the Gps, a fully charged Pair of AAs shows up just a little above 1/2 charge.
I avoid any device that uses AAA, they just don't last long enough.

[feeling_better]

I have often wondered why can't they make ni-mh 1.5 volts? I use them in my GPS, camera, and the little radio. In the camera, the flash will only work a few times before it says "battery low". In the Gps, a fully charged Pair of AAs shows up just a little above 1/2 charge.
I avoid any device that uses AAA, they just don't last long enough.

tansey, It is the chemical properties of the electrodes and the electrolyte used. It is not the they simply make it less than 1.5 Many years of research yielded this current NiMh technology, and all the factors that make it good, had the side effect of most of the energy being delivered at about 1.2v.

BTW, another rechargeable technology LiIon, has a volate of about 3.7V.

[tansey]

I have often wondered why can't they make ni-mh 1.5 volts? I use them in my GPS, camera, and the little radio. In the camera, the flash will only work a few times before it says "battery low". In the Gps, a fully charged Pair of AAs shows up just a little above 1/2 charge.
I avoid any device that uses AAA, they just don't last long enough.

tansey, It is the chemical properties of the electrodes and the electrolyte used. It is not the they simply make it less than 1.5 Many years of research yielded this current NiMh technology, and all the factors that make it good, had the side effect of most of the energy being delivered at about 1.2v.

BTW, another rechargeable technology LiIon, has a volate of about 3.7V.

Thanks for the explanation on the 1.2s. Seems like the answer then would be to make all appliances operate on a lower voltage

[feeling_better]

Thanks for the explanation on the 1.2s. Seems like the answer then would be to make all appliances operate on a lower voltage

Yes, that is the direction of the new devices. Also there is a technology (a chip) becoming available rather cheap, that would take a range input voltage say 4 to 6 and deliver a fixed output voltage say, 5v, with efficiency >95%. Use of such devices will also increase battery life. I would expect in next 15 years, many portable devices use these.

[Nodzy]

Update:
The NiMH N-cell batteries and N-cell charger are providing great service for the Nonin 3100 WristOx Oximeter. The only drawback is getting only two (2) nights of monitoring per charge instead of three (3) nights on-average with the N-cell Alkaline batteries. At nearing 90-days of use I have found no problems with functionality, despite the 1.2v of the N-cells being lower than the Alkaline rating.

I would say it's a success in saving on battery costs, even over Alkalines bought in-bulk online. Now it's a matter of recouping the costs of the NiMH charger and batteries by not having to purchase Alkaline N-cells every few months.

DISCLAIMER: While I have not experienced any problems with data validity or the operation of Nonin 3100 by using NiMH batteries, there is no guarantee that a problem will not occur at some point in the future. You use this information and NiMH rechargeable batteries at your own risk. Follow all safety warnings and precautions, and battery disposal guidelines and regulations for the area in which you reside.

Nodzy

[feeling_better]

Update:
The NiMH N-cell batteries and N-cell charger are providing great service for the Nonin 3100 WristOx Oximeter. The only drawback is getting only two (2) nights of monitoring per charge instead of three (3) nights on-average with the N-cell Alkaline batteries. At nearing 90-days of use I have found no problems with functionality, despite the 1.2v of the N-cells being lower than the Alkaline rating.

Nodzy, Does the spec say the battery voltage range required? I just got the new CMS-60D handheld oximeter two days ago. Its spec does specify input as 2.2~3.6, which means two NiMh will be good for it even towards the end of discharge. You can even use one LiIo battery, but there is no battery form of LiIo that will fit in the space of two AA

I would say it's a success in saving on battery costs, even over Alkalines bought in-bulk online. Now it's a matter of recouping the costs of the NiMH charger and batteries by not having to purchase Alkaline N-cells every few months.

The way to go is to convert all your battery use everywhere else to NiMh and then make use of the charger you already have. 6 years ago we had converted to all NiMh from Alkaline in our household, except for very long shelf life, very low current applications such as fire alarms, sprinkler settings backup, TV remotes, where an alkaline will last for over a year, and NiMh will have to recharged a lot more often because of their inherent self discharge. We have a set of AA, AAA and 9v and we seldom buy batteries now.

It is more than cost saving, rechargeables are environment friendly too; the latter was the initial reason we had switched. I had also put in a 500w rooftop solar panel 10 years ago, and we use a hybrid car too

[Nodzy]

Yep, Feeling Better...
All of my rechargeable batteries are NiMH. And like you, I use only Alkalines in CO-detectors, smoke alarms and remotes etc.

The Nonin literature calls for 1.5v... without a range. Obviously, it is tolerant of the NiMH batteries thus far. Thanks for the input.

Nodzy