Jump to content
cglaeser

Wireless PIR battery calculations

Recommended Posts

Some Optex outdoor PIRs are available in both wired and wireless models. The wireless models are powered by a 9V battery and I get between 9 and 12 months per battery. The wired models are rated at 28mA and 35mA depending on whether the relay is set to NC or NO. Given that 9V batteries have a typical capacity in the range of 500 to 800 mAh, how is it possible to power the wireless models for up to a year on one 9V battery? 800 mAh divided by 28 mA is less than 30 hours. Is my math wrong, or does the wireless model use considerably less power than the wired model?

 

Best,

Christopher

Share this post


Link to post
Share on other sites

Math looks good to me

 

There's no way the wireless model uses nearly the same as the wired model. If you have a multimeter capable of reading current, hook it up between the motion and the battery. Set it to milliamps (mA) and see how much the wireless model draws. I would expect it to draw less than 0.2mAh, because 800mAh / (12mo. * 3wks. * 7d. * 24hrs.) = 0.13 mAh.

 

I'm sure the design for the wireless model is a lot different than the wired model. The wireless models probably use transistors to replace power hungry relays. This may cost more, but enabled battery to last longer. Wired is probably cheaper, and consequently less efficient.

 

The only motions I've worked with were for alarm systems. The IR sensor uses practically no power at all. The little test-light LED uses like 5mAh, but only stays on for test mode.

Edited by Guest

Share this post


Link to post
Share on other sites
Math looks good to me

 

There's no way the wireless model uses nearly the same as the wired model. If you have a multimeter capable of reading current, hook it up between the motion and the battery. Set it to milliamps (mA) and see how much the wireless model draws. I would expect it to draw less than 0.2mAh, because 800mAh / (12mo. * 3wks. * 7d. * 24hrs.) = 0.13 mAh.

 

I'm sure the design for the wireless model is a lot different than the wired model. The wireless models probably use transistors to replace power hungry relays. This may cost more, but enabled battery to last longer. Wired is probably cheaper, and consequently less efficient.

 

Wireless portion of sensor is "sleeping"

and transmit only when receive trigger from motion or sending sync pulse to base

but whole another story

Share this post


Link to post
Share on other sites

Thanks for responding. The Optex outdoor PIRs work fine, but they are big, bulky, and pricey. I'm working on a project that needs a several dozen outdoor wireless PIRs. I'm tempted to try and seal a few indoor PIRs and test the performance in the elements.

 

Best,

Christopher

Share this post


Link to post
Share on other sites
Wireless portion of sensor is "sleeping"

and transmit only when receive trigger from motion or sending sync pulse to base

but whole another story

 

Many indoor PIRs use one battery (or a pair of batteries) for both the IR sensor and the wireless transmitter. This particular Optex outdoor wireless PIR uses a 9V for the IR sensor, and has a NO/NC relay that you can connect to anything. Typically, the relay is connected to wireless alarm transmitter, which has a completely separate battery (commonly CR123). In this instance, the wireless transmissions have no impact on the PIR power consumption. I get about 9 to 12 months from the 9V sensor battery, but I expect to get several years from the CR123 transmitter battery, depending on the number of transmissions.

 

Best,

Christopher

Share this post


Link to post
Share on other sites
Wait, there is actually a relay in that thing?? Must be magic...

 

The specs call it a relay. It's likely solid state.

 

Best,

Christopher

Share this post


Link to post
Share on other sites
Thanks for responding. The Optex outdoor PIRs work fine, but they are big, bulky, and pricey. I'm working on a project that needs a several dozen outdoor wireless PIRs. I'm tempted to try and seal a few indoor PIRs and test the performance in the elements.

 

Best,

Christopher

 

On retail side I sell lots of Optex 1000 and 2000

the same 9 Volt inside

easily last 7-8-10 month ( that what my customers saying)

Share this post


Link to post
Share on other sites
Thanks for responding. The Optex outdoor PIRs work fine, but they are big, bulky, and pricey. I'm working on a project that needs a several dozen outdoor wireless PIRs. I'm tempted to try and seal a few indoor PIRs and test the performance in the elements.

 

Best,

Christopher

 

On retail side I sell lots of Optex 1000 and 2000

the same 9 Volt inside

easily last 7-8-10 month ( that what my customers saying)

The cold up there probably kills the battery faster in the winter...

Share this post


Link to post
Share on other sites

I had a customer with about 12 TD-20U PIR and receiver pairs calling PTZ presets, they ran about two years between battery changes with Lithium 9 volt batteries.

 

I'd stick with outdoor rated PIR's, if at all possible, for temperature and false alarm considerations.

 

***Edit****

Where I'm at, we can't store perishable food outdoors year round

Share this post


Link to post
Share on other sites
I had a customer with about 12 TD-20U PIR and receiver pairs calling PTZ presets, they ran about two years between battery changes with Lithium 9 volt batteries.

 

Is there room inside for third-party wireless transmitters?

 

Best,

Christopher

Share this post


Link to post
Share on other sites

No, not in that one.

(Well, maybe a really small one, but none of the circuitry is normally accessible, and I think the PIR and wireless are all on one board, it would require some hacking, at best...).

Share this post


Link to post
Share on other sites
No, not in that one.

(Well, maybe a really small one, but none of the circuitry is normally accessible, and I think the PIR and wireless are all on one board, it would require some hacking, at best...).

 

Yeah, guessed so. My latest project is writing some software for an Inovonics Network Mesh that includes outdoor PIRs. The Inovonics PIRs are indoor. The Inovonics transmitters will easily fit in an Optex 402. I have a couple Optex 402 units mated with Ademco transmitters and they perform well, 9V battery lasts 9 to 12 months, but they are a bit large and I was hoping to find something in a smaller form factor, and, with only one battery type.

 

Best,

Christopher

Share this post


Link to post
Share on other sites
... and, with only one battery type.

 

I called Optex technical support regarding the Inovonics i series of Optex wireless products. They have combined the two products in a way that only uses one CR123 battery. Nice. The size is still the original 402 brick, but at least they have addressed the multiple battery type issue.

 

Best,

Christopher

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×