My auto-darkening welding helmet has failed in the dark position i.e.
the clear state is no longer evident, only the darkened state which is
still adjustable through the shades DIN 9 to 13 via the pot on the
helmet. The solar cells still charge the 2 lithium ion batteries
which are showing the requisite 3V. Nevertheless, if the solar panel
is covered up, the filter goes totally black.

I'd be grateful for any ideas. I can't find a circuit diagram on
the Internet, and am figuring that I'll have to get a new helmet.
Nevertheless, if a repair is feasible, I'd like to have a crack if
only to better understand how it works.

Thanks

Martin

On Mon, 29 Jun 2009 14:14:43 -0700 (PDT), Martin
wrote:

My auto-darkening welding helmet has failed in the dark position i.e.
the clear state is no longer evident, only the darkened state which is
still adjustable through the shades DIN 9 to 13 via the pot on the
helmet. The solar cells still charge the 2 lithium ion batteries
which are showing the requisite 3V. Nevertheless, if the solar panel
is covered up, the filter goes totally black.

I'd be grateful for any ideas. I can't find a circuit diagram on
the Internet, and am figuring that I'll have to get a new helmet.
Nevertheless, if a repair is feasible, I'd like to have a crack if
only to better understand how it works.

Thanks

Martin


Well a brand and model would be helfpful. If the battery is replacable
I'd suggest replkacing it anyway.

On Mon, 29 Jun 2009 14:14:43 -0700 (PDT), Martin
wrote:

My auto-darkening welding helmet has failed in the dark position i.e.
the clear state is no longer evident, only the darkened state which is
still adjustable through the shades DIN 9 to 13 via the pot on the
helmet. The solar cells still charge the 2 lithium ion batteries
which are showing the requisite 3V. Nevertheless, if the solar panel
is covered up, the filter goes totally black.

I'd be grateful for any ideas. I can't find a circuit diagram on
the Internet, and am figuring that I'll have to get a new helmet.
Nevertheless, if a repair is feasible, I'd like to have a crack if
only to better understand how it works.

If they really are Lithium-Ion batteries, 3V is end-of-discharge and if there is
any protection circuit to prevent under-voltage it will most likely have kicked
in.

On Jun 29, 8:25*pm, rebel wrote:
On Mon, 29 Jun 2009 14:14:43 -0700 (PDT), Martin
wrote:

My auto-darkening welding helmet has failed in the dark position i.e.
the clear state is no longer evident, only the darkened state which is
still adjustable through the shades DIN 9 to 13 via the pot on the
helmet. * * *The solar cells still charge the 2 lithium ion batteries
which are showing the requisite 3V. * Nevertheless, if the solar panel
is covered up, the filter goes totally black.

I'd be grateful for any ideas. * * I can't find a circuit diagram on
the Internet, and am figuring that I'll have to get a new helmet.
Nevertheless, if a repair is feasible, I'd like to have a crack if
only to better understand how it works.

If they really are Lithium-Ion batteries, 3V is end-of-discharge and if there is
any protection circuit to prevent under-voltage it will most likely have kicked
in.

Do you have the ability to charge the batteries from an external
source other than solar cells, like a battery charger with an accurate
voltmeter?

On Mon, 29 Jun 2009 19:51:05 -0700 (PDT), "hr(bob) "
wrote:

On Jun 29, 8:25*pm, rebel wrote:
On Mon, 29 Jun 2009 14:14:43 -0700 (PDT), Martin
wrote:

My auto-darkening welding helmet has failed in the dark position i.e.
the clear state is no longer evident, only the darkened state which is
still adjustable through the shades DIN 9 to 13 via the pot on the
helmet. * * *The solar cells still charge the 2 lithium ion batteries
which are showing the requisite 3V. * Nevertheless, if the solar panel
is covered up, the filter goes totally black.

I'd be grateful for any ideas. * * I can't find a circuit diagram on
the Internet, and am figuring that I'll have to get a new helmet.
Nevertheless, if a repair is feasible, I'd like to have a crack if
only to better understand how it works.

If they really are Lithium-Ion batteries, 3V is end-of-discharge and if there is
any protection circuit to prevent under-voltage it will most likely have kicked
in.

Do you have the ability to charge the batteries from an external
source other than solar cells, like a battery charger with an accurate
voltmeter?

I have, but I can't speak for the O/P.

On Jun 30, 2:25*am, rebel wrote:
On Mon, 29 Jun 2009 14:14:43 -0700 (PDT), Martin
wrote:

My auto-darkening welding helmet has failed in the dark position i.e.
the clear state is no longer evident, only the darkened state which is
still adjustable through the shades DIN 9 to 13 via the pot on the
helmet. * * *The solar cells still charge the 2 lithium ion batteries
which are showing the requisite 3V. * Nevertheless, if the solar panel
is covered up, the filter goes totally black.

I'd be grateful for any ideas. * * I can't find a circuit diagram on
the Internet, and am figuring that I'll have to get a new helmet.
Nevertheless, if a repair is feasible, I'd like to have a crack if
only to better understand how it works.

If they really are Lithium-Ion batteries, 3V is end-of-discharge and if there is
any protection circuit to prevent under-voltage it will most likely have kicked
in.

They are Panasonic Li cells with 3V stamped on the case. The
helmet is probably 10 years old so you may well be onto something.
I have been toying with disconnecting the batteries and - for test
purposes - replacing with 2xAA batteries in series. And if that
works then getting replacement batts.

Thanks for the advice and your thoughts.

Martin

On Jun 30, 3:51*am, "hr(bob) "
wrote:
On Jun 29, 8:25*pm, rebel wrote:





On Mon, 29 Jun 2009 14:14:43 -0700 (PDT), Martin
wrote:

My auto-darkening welding helmet has failed in the dark position i.e.
the clear state is no longer evident, only the darkened state which is
still adjustable through the shades DIN 9 to 13 via the pot on the
helmet. * * *The solar cells still charge the 2 lithium ion batteries
which are showing the requisite 3V. * Nevertheless, if the solar panel
is covered up, the filter goes totally black.

I'd be grateful for any ideas. * * I can't find a circuit diagram on
the Internet, and am figuring that I'll have to get a new helmet.
Nevertheless, if a repair is feasible, I'd like to have a crack if
only to better understand how it works.

If they really are Lithium-Ion batteries, 3V is end-of-discharge and if there is
any protection circuit to prevent under-voltage it will most likely have kicked
in.

Do you have the ability to charge the batteries from an external
source other than solar cells, like a battery charger with an accurate
voltmeter?

No, but I'm going to have a go at disconnecting the batts and
connecting some AA batts to generate 3V and if that fixes it then
replacing the Li cells. Your ideas have prompted me to do what was
at the back of my mind. Many thanks.

Martin

I tried using 2xAAs instead if the Lithium cells but it didn't
help. However, I had a 2032 cell and, whilst its nominal voltage
as stamped on the case is 3V, the actual voltage is 3.3V new. So,
assuming that the 2 rechargeable Panasonic BR2330s would similarly
show 3.3V when fully charged, my experiment with AAs may well prove
nothing,

I realise I was wrong to call the batteries "lithium ion". They
are rechargeable lithium coin cells, which I now realise is not the
same thing. But if Rebel's comments still hold:

"If they really are Lithium-Ion batteries, 3V is end-of-discharge and
if there is
any protection circuit to prevent under-voltage it will most likely
have kicked
in."

then my best bet is to replace the batts with new ones. Having
now disconnected the 2 batts, the clear vision state, when not
welding, has returned provided the solar panel is covered.

I hope to report back when I have the new batts.

Thanks again for the guidance.

Martin