Night Vision PVS1531 + COTI Battery Issues (with and w/o battery pack)

[NHPiper]

Yeah, I remember my back and forth with one of the (so say) SME on this issue when he said it was fine to mount to the focus ring.

I guess what Optics 1 had to say about that, vindicates my back and forth with SME.

I sure hope he reads your post on what Optics 1 had to say.

Haha my experience putting it on the focus ring of the 1531 goggles is that the COTI needed to be at the 6pm position or a slight bump, or even without a bump, would make you lose focus.

I have heard guys say the tactical dudes run it there to quick focus, and maybe that works on other units that have stuffer focus rings, but not on my pvs1531 or pvs14. Seems like a high risk for the benefit in a high-threat situation.

 

[WhereNow&How]

I have heard guys say the tactical dudes run it there to quick focus, and maybe that works on other units that have stuffer focus rings, but not on my pvs1531 or pvs14. Seems like a high risk for the benefit in a high-threat situation.

Yeah that quick focus sounds good and all, but it is really just a backup excuse because proper installation could not be achieved.

Additionally how often does one really change their focus when out. If quick focus ability is really a priority, just put some purpose built type iris device on the other pod that does not have a COTI.

 

[NHPiper]

Here is the most recent update.

Optics1 thoroughyl tested my battery pack, cable, COTI, and PVS1531 goggles. The battery pack, cable, and COTI all work fine. Unfortunately, the PVS1531s are drawing more current than the are supposed to according to the spec sheet that L3 provided to Optics1 when Optics1 designed the battery pack/Y cable system. The system has no problem supporting either just the goggles or just the COTI, but can't support both. My guess is that the PVS31s are drawing slightly lower voltage than the PVS1531 which is why the system works with that setup.

Interestingly, the PVS1531s are designed to run off of a single AA lithium in the housing which provides 1.35v, but I get a low battery warning when running the dual system once the output from the battery pack drops below 2.7v when the COTI is jointly turned on. Optics1 can't figure out why this is happening.

The only solution they have found is that the 6 AA battery pack for the ECOTI runs both the PVS1531 and COTI for 12+ hours with no issues.

I am trying to connect with @WillHugh to confirm that his PVS1531 goggles have the same issues mine do. That way we know its likely a universal problem and not just a defect with my goggles.

 

[WhereNow&How]

Here is the most recent update.

Optics1 thoroughyl tested my battery pack, cable, COTI, and PVS1531 goggles. The battery pack, cable, and COTI all work fine. Unfortunately, the PVS1531s are drawing more current than the are supposed to according to the spec sheet that L3 provided to Optics1 when Optics1 designed the battery pack/Y cable system. The system has no problem supporting either just the goggles or just the COTI, but can't support both. My guess is that the PVS31s are drawing slightly lower voltage than the PVS1531 which is why the system works with that setup.

Interestingly, the PVS1531s are designed to run off of a single AA lithium in the housing which provides 1.35v, but I get a low battery warning when running the dual system once the output from the battery pack drops below 2.7v when the COTI is jointly turned on. Optics1 can't figure out why this is happening.

The only solution they have found is that the 6 AA battery pack for the ECOTI runs both the PVS1531 and COTI for 12+ hours with no issues.

I am trying to connect with @WillHugh to confirm that his PVS1531 goggles have the same issues mine do. That way we know its likely a universal problem and not just a defect with my goggles.

Well the best solution would be for them to put a USB fitting on the back of that cable so you can run the system with any rechargeable Power System like the Anker Candy bar which has enough umph to handle it no problem.

But if they did that simple solution they could know longer sell their "expensive battery pack"

I run my COTI's off of the below battery and it runs for about 20 hours. The Pas 29A Coti draws 0.33 amps at 3.20 Volts when it goes through the step down transformer from 5.18 Volts to 3.20 Volts.

This is with the Gain Nob set about 1/2 way which is the normal place to run it.

https://www.amazon.com/Anker-Upgraded-Candy-Bar-High-Speed-Technology/dp/B06XS9RMWS

 

[NHPiper]

Bear in mind I am not an engineer, so I am doing my best to understand the findings. So the FINAL RESULT

After more testing and research by Optics1, it turns out that the BNVD battery is not made to run both the PVS1531/PVS31 and a COTI/ECOTI, despite marketing that leads people to believe that the BNVD battery pack + Y cable is a "complete" system.

Each pair of batteries in the BNVD pack generates 1.4v for a total of 2.8v (see 1st chart in the attached pic). Optics1 found that the Low Battery Indicator (LBI) triggers in the PVS1531 at 2.7v. You can see in that chart that 4 lithium batteries provide enough power at the low drain (goggle only, no thermal) to get 45+ hours of life before falling below that threshold. With just the PVS1531, the goggle is pulling 75mA (compared to a PVS31 at 77mA).

When you plug a Y cable and COTI in, the power converter on the Y cable boosts the output to 450mA to fuel the COTI, which consequently drops tue voltage to just under 2.7v (see chart 2 on the right). Basically, the voltage drops just enough to cause the LBI to kick on and power the goggles down in a matter of minutes. Anyone out there who has this system working got lucky and has a battery pack putting out slightly more voltage or a goggle that has slightly more tolerance before the LBI triggers. It is a thin margin.

Optics1 was able to get the PVS1531 and COTI to run jointly for 12+ hours using a prototype pack they are working on that has more AA batteries. However, that hasn't hit production yet and is a few months out.

The strange thing is that a single AA battery putting out about 1.35v can power the goggles for 15-20+ hours. This indicated to us that L3 programmed the LBI to override the goggles and shut down at the 2.7v threshhold. We don't know why, but maybe it was to protect the goggles, and hopefully wasn't an arbitrary number.

It isn't the end of the world to have this setup. If you aren"t running a COTI, then you get a great battery pack for the goggles. When you want to add the overlay, it just means most of us will have to toss in a AA battery to the goggles and hook up the battery to the thermal.

 

[jwramp]

Good info, thanks for spearheading this. Interesting to see that the binos draw 75ish mA. How was that measured? Could be neat to see what different kinds of tubes draw and if there’s much variation as some have alluded to elsewhere.
Am I reading you right that the COTI pulls 450mA? Or is that the combined draw with two devices plugged into the Y cable?

 

[NHPiper]

Good info, thanks for spearheading this. Interesting to see that the binos draw 75ish mA. How was that measured? Could be neat to see what different kinds of tubes draw and if there’s much variation as some have alluded to elsewhere.
Am I reading you right that the COTI pulls 450mA? Or is that the combined draw with two devices plugged into the Y cable?

I am not sure how they measured it....and the COTI with the goggles draws 450mA.

 

[WhereNow&How]

JW: I can confirm for sure that a Pas 29A draws 330 mA at 3.2 Volts.

I have tested my units and I run them off stand alone power systems that are powered by Anker Candy Bar rechargeables. The run time is right at 20 hrs at approximately 70 degrees.

NV tubes sip power compared to thermal, but I don't know what the draw is on those.

 

[WhereNow&How]

I am not sure how they measured it....and the COTI with the goggles draws 450mA.

That sounds about right per my stand alone tests on the Pas 29A Coti.

 

[WhereNow&How]

Another thing really nice about using those Anker Candy Bar rechargeables to power the system is that you do not get the low power warning symbol in your COTI which is a big pain in the ass with its regular batteries because there is no way to turn that warning off.

 

[Smeeg]

How are you using anger battery packs? Did you make a new wire or cap? Very interested

 

[WhereNow&How]

How are you using anger battery packs? Did you make a new wire or cap? Very interested

I did not make them. They were built by others. The builder has health issues so no more have been made.

An adapter cap and wiring were made and they work very well.

 

[Smeeg]

I did not make them. They were built by others. The builder has health issues so no more have been made.

An adapter cap and wiring were made and they work very well.

dam please message me here if any more are made or put a link to the thread discussing them if there is one

 

[WhereNow&How]

dam please message me here if any more are made or put a link to the thread discussing them if there is one

Will do.

At some point I think efforts will likely resume as there is a good bit of demand for a solid external powering system for the TACS-M & Pas 29 COTIs.

Using CR123's just doesn't cut it and OEM systems are either unobtainium or seriously overpriced.

 

[red6actual]

Any updates on the issue?

 

[newguy2k3v2]

Curious if they ever came out with a proper coti/ecoti mount for the 1531?