Battery for PVS-2

[Terrylee]

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?

Information

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[jmoore]

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!

[Peter Laidler]

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

[jmoore]

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 (?).

[Terrylee]

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.

[jmoore]

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!

[Peter Laidler]

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...............

[Terrylee]

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.

[m4carbine]

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.

[jmoore]

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.