Battery for PVS-2

I recently acquired a PVS-2 Starlight Scope to fit my L1A1. It came with a harness taking four AA torch batteries that fits into the scope's battery housing. I attach a photo.

This appears to work reasonably well but is naturally only 6 volts whereas the original PVS-2 battery was nearer 7 volts.

To my way of thinking it would not be difficult to manufacture a suitably sized shell the size of the original battery containing three 3 volt lithium camera batteries giving 9 volts. This voltage could be reduced by internal diodes to just under 7 volts.

has anybody views on such a set-up? Would this give even better results than
I am presently getting?

I think the original batteries were rated at 6.5v. Mil-specs are on-line that were found using info printed on an original A/N PVS-1 battery. If you want the specs I'll see if I can round up the battery. The 6v set-up seems to work OK, though. (not what I'm using currently) Not sure if it affects tube life!

So far as I remember, the original batteries were in fact made up of 5 round flat batteries piled up so as to make one 7.5v battery OR 5 AA's in a circle around a central core that did the same job.

These batteries are still available in the commercial world. If you're really stuffed, let me know

Yup, I've the stacked versions (amongst some solid shell variants which I think are just fancy covered stacked). Now I'm not sure of the voltage! Probably needs five AAA rather than AA due to space limitations (?).

Thanks, Chaps. Your input is much appreciated. Unfortunately, where I live there is little chance that suitable commercial batteries would be available. A substitute will have to do.

I attach photos of progress to date. I also have a suitable pill box for the AAA option. However, the camera battery option is simpler, more robust and easier to reload.

I'd be very grateful if one of you could give me the final voltage specs, since that will determine whether I incorporate two or three diodes into the final assembly.

My only immediately accessable military battery is marked 6.5v. The blue shrink-wrap stacked battery assmblies aren't marked- at least the ones I have aren't. If I get some more info it will probably Friday or so before I can get back to you.

ETA Something tells me that Mr. Laidler's 7.5v specification is correct, I just can't put finger to it yet!

All the info on these batteries is available in the IIW user handbook available from BDL in SC. Cheap too as I understand it. But in short, battery cap was was 7.5v but the IIW drew 6.5 or so...............

Many thanks for the info. Looks as if the 3 diode option giving about 6.9 volts is my path. I trust that this is not too high? I'll buy the diodes next week when I'm in town and report back when the project is complete. In the meantime any further tips would be much appreciated.

The best bet is 2 ea. 1CR2 Lithium batteries stacked parallel in a fake battery body made from Delrin rod.

Its 2.1" long X 1.375 in dia. with a .605 dia. hole.

I have a PVS-1, PVS-2 and a British L1A7 sight that I use these in with no problem. The up side is that this set up has about 10 times more life than the original Mercury cells.

The Batt spec voltage is 7.5 but they draw down to about 6 volts right away. The great thing about the Lipo batteries it there is not a big voltage drop like Carbon or Mercury batteries, they run at about 6V almost until they die.

Now there's the question of what the roaring h*** my 6.5v battery was made for! It works, but--- Gotta find that milspec gleaned from the oscillator pulled from a PVS-1 that I printed out a while back.

Did a bit more digging in the IWS handbook No. 60684 (1986), the Spec on the issue battery
is 6.75v and 2.7Ah.

But when you draw these type of batteries down they drop to about 6v.

Just for reference- the battery in question that came w/ the AN/PVS night vision "thinggy"- I don't remember which one any more:

(+)
6.5 volt
BATTERY DRY
BA1100/U
LYNTRONICS INC.
*569 ACORN ST., UNIT *
DEER PARK NY *1**9
@&$#^#%$ $*#$&&^#

(Asterisks and symbols denote altogether unreadable info-sorry about that)
Bottom line looks like it may have been a NATO stock number, but I'm not sure!

Since the last post I have had a most interesting time experimenting with homemade batteries and comparing the results with the original 4 XAA assembly that came with my PVS-2.

Firstly, I tried three lithium camera batteries in series (9 volts) reduced to 6.7 volts by means of seven diodes against the 6 volts of the AA Harness. In both instances the through-sight drop was found to be in the region of half a volt as mentioned in several of the postings. This resulted in just over 6.1 volts with my creation and 5.5 volts using the AA assembly. One would have thought that my effort would have had an edge over the original set-up. All I can say is that it worked! Was not nearly as good as with the lower voltage supplied by the four AAs. Obviously the ampere rating of the lithium batteries is too low.

The next test involved what I call my "Pill Box Special" whidh consisted of five AAA batteries connected in series (7.6 volts) reduced to 6.72 volts by means of three diodes. The through-sight voltage drop was again in the region of half a volt to 6.18 volts. Well, the results on looking through the sight at objects about 25 metres away are somewhat better than with the original AA assembly, but not greatly so. As yet I have not had an opportunity to test the sight at longer ranges, but will do so. However, as things stand at present. and in the absence of an opportunity to test the sight and rifle out on some crop-raiding bush pigs, I'll save myself the trouble and stick with the original 4 X AA harness. Its less bother to replace the batteries!

Now two final questions in which I request input from those who are a lot more familiar with the internal workings of the PVS-2 than I:

Firstly, there appear to be a few specs of dust on the internal lenses. Please, some tips on how to clean them. With my lack of experience I am reluctant to pull the sight to pieces and hope for the best.

Secondly, the T-shaped "cross-hair" is not quite vertical by perhaps 7 degrees. How is that adjusted?

If Mr laidler or other good folks haven't given you a virtual tour of the innards of your PVS-2 in a few days, I know a fellow (WBS2111) who has been into and repaired one or two(!) AN/PVS sights. Perhaps I can cajole him into posting.

I'm not familiar with the innards of the PVS's except for a few that were floating around in the Falklands, captured from the Argentinians. I had one once but the tube was finished. I'm more famliar with the RP Controls SS20 IIW's (the L1 A 1 to 7 types) but even then, I know them better that I can fix 'em.

Incidentally, I've just been informed that a UK company named MAPLINS do a 4x AA battery holder that wil fit and fire-up the 7.5v UK IIW although we've touched on this subject in this thread. But good to keep these old ladies on the road as I keep telling my wife............

For dismounting the tube:
1. Remove battery

2. Remove oscillator or ABC plug (red plug adaptor with ABC or oscillator and cap) under front screw on cap

3. Remove the knurled ring at the rear of the scope body (rh threads)

4. Remover the rear lens assembly by pulling to the rear, it has an "O" ring and might be snug.

5. The tube will now drop out of the scope body.

The most likely culprit for the rotated reticule is the locating pin on the front of the tube. The tube has a ring at the front that is threaded into the tube body. This ring has a hole in it for the locating pin. The tube is held in place with silicone plastic that is pored/molded around the tube with the ring on. Someone takes the ring off and tries to put it back on and the silicone gets in the way. Hence the locating pin is no longer in the proper position rotating your reticule that is etched on the tube end. If you remove the pin (it should just pull out) rotate the ring (sometimes necessary to remove it and clean out the threads) you should see a hole for the pin to go back into.

Hope that was not to convoluted to understand. I can send some pics if so.
Regards,
Burrell

That's pretty damn comprehensive WBS. What about one of those written and photo wotsits to walk us amateurs through the system. It SOUNDS very much like the old SS20 British IIW where the innards all come out through the rear