Over discharge protection circuit for r123?

[PEU]

I searched thru the forum but found nothing, is there any simple circuit to protect unprotected li-ions from over discharge?

I want to try a direct drive mod, but dont want to degrade the r123s...

Thanks


Pablo

 

[luminaria]

I have been looking around also an somewhere I found a link to this IC that is able to protect one r123. I have requested some free samples /ubbthreads/images/graemlins/naughty.gif to test.

 

[Amorphous]

PEU,

Check this out.

http://www.batteryspace.com/index.asp?PageAction=VIEWCATS&Category=711

 

[PEU]

I though that the solution was going to be simpler, I mean, a couple of transistors or fets and voila!

Now that I saw that the solution is a bit complicated, I will use protected r123.

This is not related to my projects, I wanted to do a simple direct drive light consisting of only the star, the reflector and the battery, thus making the smallest 123 light.

Well, I'm going direct drive baby!!! will find a nice piece of copper for the best possible heatsinking and begin turning it next week, I miss using the lathe with all the neoca bl frenzy /ubbthreads/images/graemlins/smile.gif


Pablo

 

[SilverFox]

Hello Pablo,

/ubbthreads/images/graemlins/evilgrin07.gif Don't forget to install your BatMax device on your protected R-123... /ubbthreads/images/graemlins/evilgrin07.gif

Tom

 

[Ctechlite]

Hello, I bought some r123's from Battery Station and I've observed that at <2.8V they go open circuit and at around 100F they go open circuit.

I assume that it has over discharge protection and some kind over heating protection. The overheating happens in a light I put together, but I do not know yet if the heat is from the 3 Lux III's or from the hi current I am drawing from the battery. I beleive it is from the hi current draw, which is a little under 1A at max light output.

<edit> I used a heatgun/hair dryer to heat up a cell, it did not go open circuit, so there is no internal heat switch. I got the temp up to around 108F before I stopped heating it. So I can only assume it is the hi current draw causing the r123 to have an open circuit condition.

As soon as I put it back in the charger for 1 second it goes back to normal and works again.

 

[wptski]

[ QUOTE ]
Amorphous said:
PEU,

Check this out.

http://www.batteryspace.com/index.asp?PageAction=VIEWCATS&Category=711

[/ QUOTE ]
Look at this thread that I started: Battery Space PCB

I've let to receive a answer either from email or via their forum! /ubbthreads/images/graemlins/mad.gif

 

[wptski]

[ QUOTE ]
Ctechlite said:
Hello, I bought some r123's from Battery Station and I've observed that at <2.8V they go open circuit and at around 100F they go open circuit.

I assume that it has over discharge protection and some kind over heating protection. The overheating happens in a light I put together, but I do not know yet if the heat is from the 3 Lux III's or from the hi current I am drawing from the battery. I beleive it is from the hi current draw, which is a little under 1A at max light output.

<edit> I used a heatgun/hair dryer to heat up a cell, it did not go open circuit, so there is no internal heat switch. I got the temp up to around 108F before I stopped heating it. So I can only assume it is the hi current draw causing the r123 to have an open circuit condition.

As soon as I put it back in the charger for 1 second it goes back to normal and works again.

[/ QUOTE ]
Nothing wrong with that! A Li-Ion can be damaged above 95 deg. Your better chargers that monitor heat will tell you to set them at 90 deg. shutoff. A LVC of 2.8V is better than a Pila that goes to 2.3V/2.4V. Look at the URL I posted above.