Steripen Adveturer "Gotcha"

[Remix]

I am on my second unit, the first having failed completely and unresponsive even with fresh batteries. EMS took it back no questions asked.

I replaced the unit over the summer and put in the fresh batteries. I never did use it because I was ceramic filtering until it got cold. When I went on hike over Thanksgiving, the unit would not work. Subsequent testing at home showed the fresh batteries had drained even though the unit was not used.

I would not have expected this since the only power that needs to be consumed is to sense a button press, but indeed the manufacturer recommends rechargeable batteries and is vague about shelf life of fresh CR123 cells installed inside the unit.

So if you have one of these unit, put fresh batteries in when you pack, and leave the batteries out when it is in storage.

 

[David Metsky]

Standard NiMH rechargeables lose power very quickly when not being used. Even after 2-3 weeks of sitting unused they will be mostly drained with no load on them. Taking them out of the Steripen will have no effect, they'll still be dead.

For an application like this you want long lasting NiMH like Enloops or similar brands. They have different formulation and will hold their charge for months.

 

[DougPaul]

CR123 cells are generally lithium primary or Lion rechargable, not NiMH. Lithium primary cells have a ~10yr shelf life, Lion has some self-discharge but not as fast as NiMH.

A lot of modern electronics are never truly off (ie they always draw some current) unless you remove the batteries. Don't know about the Steripen, but this could be a factor.


BTW, there are two kinds of NiMH cells. The older variety loses charge (5-10% first day, then .5-1% per day after at room temp according to one source*, but the rate depends on the brand, the temp, the age of the cell, and the individual cell). The low self-discharge cells have a somewhat smaller capacity but retain 70-85% of their charge after a year* (depends on the temp, etc).

* http://en.wikipedia.org/wiki/Nickel-metal_hydride_battery

Doug

 

[Remix]

The engineer in me has to speak up and state there should be no reason for a device which is triggered by a button press to kill 2 CR123 cells in a few months (while it has been sitting in its pouch)

We can sense button closures with microamps, using capacitors to keep the button contacts electrically clean, or use bifurcated button contacts. The button press can start the controller up, so it does not have to be using energy until necessary.

 

[DougPaul]

The engineer in me has to speak up and state there should be no reason for a device which is triggered by a button press to kill 2 CR123 cells in a few months (while it has been sitting in its pouch)

The engineer in me also wishes it were so.

The problem is to convince the designers and marketers of such products...

We can sense button closures with microamps, using capacitors to keep the button contacts electrically clean, or use bifurcated button contacts. The button press can start the controller up, so it does not have to be using energy until necessary.

I have some FRS radios with measured drains of ~1mA when off which will kill the batteries in ~1 month. I considered buying a different battery-powered electronic device, but reports of the off drain caused me to reject it. Look also at the "off" drain of a number of our 120V AC devices...

The power may be used for more than just detecting a button press. For instance, saving state info (as in my FRS radios) or doing something (such as running the timer in a VCR).


IMO, many designers have little incentive to care about the power consumption of devices (on or off). In fact, the device may be cheaper to manufacture if they consume more power. Until they are given incentive*, such devices are likely to continue to be sold (and, of course, this misfeature will not be documented).

* The Energy Star program does provide incentive to reduce both the on and off power consumption of some devices.

Doug

 

[Lawn Sale]

I am on my second unit, the first having failed completely and unresponsive even with fresh batteries. EMS took it back no questions asked.

I replaced the unit over the summer and put in the fresh batteries. I never did use it because I was ceramic filtering until it got cold. When I went on hike over Thanksgiving, the unit would not work. Subsequent testing at home showed the fresh batteries had drained even though the unit was not used.

I would not have expected this since the only power that needs to be consumed is to sense a button press, but indeed the manufacturer recommends rechargeable batteries and is vague about shelf life of fresh CR123 cells installed inside the unit.

So if you have one of these unit, put fresh batteries in when you pack, and leave the batteries out when it is in storage.

Did you run through the "things to check" section of the manual? It states in there what to do if it's been sitting awhile. Most notably is shaking the mercury to the end of the bulb, otherwise it can't vaporize and create the UV light.

As to the batteries, they will discharge over time (as others have mentioned), at least the rechargeable ones will. The manufacturer recommends them because the unit was developed with them in mind so you wouldn't have to use non-rechargeable batteries, which are much more expensive over time.

I know the guys at Hydro-Photon as I've been there a few times with questions and I am very impressed (I treat water for a career and wasn't exactly easy on them). They are reputable people and are more than willing to help out with any problems you might have. They stand by their product, which is why it carries a lifetime guarantee, how many electrical products have that? I returned one because it was defective (1st gen) and they made it right and then some, apologizing all the time. I have the Classic and Adventurer, and am thinking of a Journey because it fits the smaller bottles.

 

[Remix]

Thanks Lawn sale for your additional thoughts. I shook the unit around to get water away from the contacts that detect water after it failed again and again.

The unit came with non-rechargeable batteries, and these were consumed over 2-3 months. Certainly the device used the battery energy, because the shelf life of lithium batteries are in the years.

I was just googling around and found other gear review sites report the battery drain. Might be nice of them to put a storage pouch on the neoprene cover to hold batteries when the unit is placed in storage.

Like all products its has its limitations, and I just wanted to prevent some one from running into the problems that I had. Hopefully the next iteration of the product will not have this characteristic.

 

[Paradox]

I have an idea for a simple tester for rechargable batteries that I want to bounce off this thread. Set a standard AA powered quartz wall clock to 12:00 with a questionable battery in it and wire an incandesent flashlight bulb across the leads. The clock will stop when the bulb has consumed the charge on the battery. Then just write the running time on the battery, and compare it to others.

What, if any, are the shortcomings of this system?

 

[DougPaul]

I have an idea for a simple tester for rechargable batteries that I want to bounce off this thread. Set a standard AA powered quartz wall clock to 12:00 with a questionable battery in it and wire an incandesent flashlight bulb across the leads. The clock will stop when the bulb has consumed the charge on the battery. Then just write the running time on the battery, and compare it to others.

What, if any, are the shortcomings of this system?

1. It is a bit OT for this thread...
2. Better be a mechanical clock--an LCD display won't remember the time at cut-out.
3. A clock is a poor device for detecting voltage dropping below a threshold.
- how do you set the threshold to a desired voltage?
4. A bulb is a poor load--the resistance depends on the temp.
5. A good tester will remove the load when the voltage gets below a threshold to minimize damage to the battery.

You might take a look at the BC-900 charger. It has a built-in facility for measuring the capacity of an NiMH battery and will give you a meaningful number. http://www.thomas-distributing.com/la_crosse_bc-900_battery_charger.php

There are also several meaningful load types: constant resistance, constant current, constant power. (A bulb does none of these.)

Pros would use a computer controlled testing device with a controllable load and a voltage measuring A/D converter.

BTW, the value for the capacity of the battery depends on the test conditions. Lower discharge rates give higher numbers.

Doug