Primary Arms Advanced Micro Dot- MD-ADS

[boykinlp]

I am looking at putting one of these on my AAC MPW 300 Blackout. I am in no hurry to buy one and I know that Primary Arms has sales. Anybody bought one of these on sale? If so, how much was the sale price?

 

[Checkmate]

That's not a bad idea McE. However, I've done some testing with batteries and your suggestion really is a wag. PA probably didn't even do that. They probably calculated the current draw based on the circuit design and matched that up with the mAh of the battery.

The issue with battery drain extrapolation is that batteries don't dissipate in a linear fashion. Also, each type of battery has a different dissipation curve. In any kind of measurement, extrapolation is never a good idea. The further away from an actual measurement point you get, the worse the prediction becomes.

Most regular alkaline batteries will maintain a decent voltage right up until about 20% before failure. Then they will drop off dramatically.

Meh, nothing like a real world test. I compressed a spring for a year to prove that springs really do compress. This is no big deal. I have the optic. I'm going to leave it on. We'll see how it is as time goes by. If I remember, I'll post a blurb every month or so.

The new battery is in. It's an Energizer. Time will tell. If it lasts a year, I'll call it a success.

Since it was August when you posted that, have you had to replace the battery at all yet? I'm really interested in the 50k+ hour assertion as well.

 

[Heyman]

Since it was August when you posted that, have you had to replace the battery at all yet? I'm really interested in the 50k+ hour assertion as well.

Mine was shipped to me April 17th of 2015. I don't know when I actually received it, but when I did, I turned it on a setting that was bright enough to see with a weapons lights activated. So it's on a higher setting. I've left the sight on since I bought it, and as of last night, it's still on. (Battery that came with the sight)

 

[McE]

Coincidence that this thread got revived.
I've been playing around with designs for the circuitry to make a red dot.
Even with a 1mA draw LED, a big CR123 battery with 1500mAh is looking very simplistically at a max of 1500 hours run time.
3000 hours with very low draw 0.5mA.
The Primary Arms 50,000hr thing is working with a CR2032 hovering around only 200mAh
Crudely, that's a 0.004mA draw. I don't know of LEDs that work with that, for constant on, anyway.

Then you get into methods of stretching runtime like not actually having the LED constantly be on, but actually pulsing it at a frequency above the threshold of human perception. For example, a light flashing at even just 60hz can appear to always be on, but in terms of stretching runtime, maybe you can double it by flashing it so it is imperceptibly actually off half of the time that you think it's on.

There are some simple circuitry tricks to eke out juice from batteries, but at its core, red dots are extremely simple. I've yet to figure out the kind of LED they're using, what they draw, and if they are using the pulsing trick and additional joule thief type circuitry to get more out of the battery. I will probably sacrifice a few red dots to see all of the components myself.

 

[Checkmate]

Anyone interested in donating an MD-ADS to me, I'll put it on my oscilloscope to see if it's pulsing that LED output

 

[McE]

Anyone interested in donating an MD-ADS to me, I'll put it on my oscilloscope to see if it's pulsing that LED output

Oscilloscope? Sounds fancy. I'd probably just tie it to a rope and swing it around in the dark

 

[Checkmate]

Nope, not too fancy. Very low low tech. In fact, it's older than I am. My dad built it in the 1960s from a Heathkit.

Swinging it would almost work, if it was bright enough to see at swinging distance and not tumbling all over.

 

[Rastoff]

Since it was August when you posted that, have you had to replace the battery at all yet? I'm really interested in the 50k+ hour assertion as well.

I check it every few days. I don't have it mounted right now and it's just sitting on my desk. It's still on.

Anyone interested in donating an MD-ADS to me, I'll put it on my oscilloscope to see if it's pulsing that LED output

Funny you should mention that. I'm an electronic technician (not my actual title, but no one knows what a Metrologist is) for the Air Force. I just got a new o-scope at work. This one:

This is a Tektronix MDO 4,000 series oscilloscope. It is mixed domain which means it has a spectrum analyzer built in. Anyone who knows how to use a scope would love this thing and I'm really excited to have it.

However, there is a problem with your potential test; it requires destruction of the optic. The PA Advanced Microdot is a sealed optic. In fact, I don't know any that aren't. So, to test the circuitry, you'll have to break it open. Even if you wanted to do it, it's likely the circuit would be destroyed in the process.

As far as how they achieve the long life, who cares how they do it? Yes, even switching as slow as 30Hz would appear to be solid on to the human eye. So what? I only care that it works.

Several of the good optics claim super long life. Aimpoint and Trijicon both have optics with battery life of more than 2 years. This is essential for any optic that will be used for self-defense.

 

[McE]

I have some old oscilloscope stored away somewhere from when I dabbled in circuitry back in grade school, might have to get the parents to dig it out and ship it to me.

I'm no metrologist, but I know that every battery powered product, sights included, have their circuitry accessible at the battery, naturally. Would the use of pulse width modulation be detectable at that point in the circuitry?

When he first mentioned oscilloscope, I imagined an optical variety.

 

[Checkmate]

Very nice! I am interested in hearing what the result is with the new battery. I'm inclined to change out a battery every year or so, not to wait the full 5+y for it to die. As long as I can rely on it beyond a year, then that would qualify it for serious purposes.

 

[Rastoff]

I completely agree. If it lasts a year, that's enough for me. I have no problem changing the battery every year.

Access to the electronics is not necessarily available at the battery compartment. If it's sealed, like this one is, the only thing accessible is the two contacts for the battery. That won't allow any probing of the internal circuitry.

 

[McE]

A little off topic, but how does one end up as metrologist? And what does a usual day look like?
I enjoy measuring things, reverse engineering things, etc. Every time I see a "certified by dept of weights and measures" on a gas pump, I think that I'd like to work at that dept. I'm fascinated by how they still don't have a theoretical definition of a kilogram and the sample zero, so to speak, is changing due to decay.

 

[Gaucho59]

Just sighted my new SportII and PA red dot today. Nice, tight groups at 50yrds, perfect co-witness and everything is working great. Very pleased with it.

 

[Rastoff]

OK, this is my last update to this thread.

About a month ago my PA Advanced Micro Dot battery was still going strong. However, that's where the good parts ends.

We mounted it on my son's rifle to use at a class. Went to the range to zero it. The POI was about 4" to the right at 50 yards. The windage adjustment was not moving the POI at all.

Call PA and they say send it in. A week later I get a new one in the mail. No muss, no fuss. Even though it was past its one year warranty, they sent me a new one. Can't argue with that.

Why did it fail? I don't know. It's possible to turn the adjustment too far, but you should feel some resistance before that happens and I didn't. I don't know what the deal was, but it did fail.

The new one is working fine and if you use a fresh battery to start, it should last plenty long.

 

[ChattanoogaPhil]

Rastoff's story is a great example of why it's a good idea to do business with Primary Arms. Their customer service is second to none.

As far as the optic failure.... it's a recreational optic. Whether it's a $50 red dot or a $200 red dot... still recreational. Redfield... Vortex... Primary Arms... et al., it don't matter.

 

[Glockguy949]

Would 4 inches off at 50 yards be 2 inches at 25 yards? Just thinking that even then it is accurate enough for home defense where distances are going to be much closer. Yes/No?

 

[Rastoff]

Yes, 4" at 50 yards would be about 2" at 25 yards and less off the closer you got. That is not the issue however. The issue was that it could not be adjusted at all.

They stood behind their product and replaced it even thought they didn't have to. This makes them a good company to me.

 

[Rastoff]

Yes, this is an old thread. However, I'm intentionally bringing it up for an update.

The battery in my Primary Arms Advanced Microdot was new in March of 2016. The optic has been on continuously since then and the dot is still bright and clear as of this post.

Some may not care, but this confirms that their optic will last at least 17,623 hours of continuous use. That's 2 years and 3.5 months. I consider that long enough to be useful for defensive purposes. Replacing the battery every two years is reasonable and how I will use it if used for defensive purposes.

 

[Kadonny]

Yes, this is an old thread. However, I'm intentionally bringing it up for an update.

The battery in my Primary Arms Advanced Microdot was new in March of 2016. The optic has been on continuously since then and the dot is still bright and clear as of this post.

Some may not care, but this confirms that their optic will last at least 17,623 hours of continuous use. That's 2 years and 3.5 months. I consider that long enough to be useful for defensive purposes. Replacing the battery every two years is reasonable and how I will use it if used for defensive purposes.

When you say "on", you really mean on, correct? How bright is your setting? That's really good for one battery. Great update, I have one of these too but it sits in my safe on my Sport since I hardly use it anymore.

 

[Rastoff]

Yes, on means on as in illuminated. In fact, I've never turned it off. The specs say the battery will last up to 50K hours at the middle brightness setting. I've not quite reached half that, but I'm satisfied.

Yes, it's on the middle setting. I can see it in daylight, but I would bump it up one or two if I were using it in bright daylight. Where is is now is perfect for me from daytime shade to night.