Products > Test Equipment

Test Equipment Anonymous (TEA) group therapy thread

<< < (22396/25096) > >>

Robert763:

--- Quote from: Vince on January 23, 2022, 01:10:47 pm ---VARTA Battery :

I am sad to say that the poor battery did not survive the night.

IIRC I started discharging it at 2AM last night. I just woke up, 12H45, so about 10+ hours, immediately checked on the battery.... only to find voltage was down to.... 7 V ? No... well below that.... which is still a massive understatement.... voltage was down to....  0.8V !!  :scared:

Rob I am so sorry, I failed to protect this battery from under voltage.... I am a failure....

That said... even at 0.8V believe it or not, it was still spitting out a sizable current, 1mA !!  :o

After 5 minutes or so, battery recovered a bit and unloaded voltage went up to 2.5V.... which from memory was also the voltage it read after its 30 years of storage when I dug it out the other day !
So I guess this battery "likes" this particular voltage...  :-//

So what to do now...

First I would like to not over dramatize the fact that I let it go flat.... because it had already been flat for 30 years, so I probably didn't do any more damage than had already been done, eh ?

Also, the fact it was still putting out 1mA at only 0.8V means, to me at least, that it's a warrior, it wants to live...

So I think I will charge it again, using Wilson. Slow C/10 again.

Then will do another discharge cycle, but this time I will conduct the experiment during the day, so that I can keep an eye on it regularly, from beginning to end, and will take note of precise start time, and time stamp for every voltage and current check I do.

Would be easier if I could do it automagically with a GPIB setup and some clever S/W on a computer... but alas the lab is nowhere near as sophisticated for now ! It's my plan for it be, though...

Also, since I have plenty of real estate on the bread board, I could add a comparator chip and a little miniature relay to automatically disconnect the battery when it reaches a certain voltage threshold. That would be neat.

The saga continues....

--- End quote ---

Best you can do is recharge at C/10 nd see what happens.
Unfortunatly discharging it to flat is not the same as it self-discharging it to flat. Self dischrg  happens to each cell independently. A discharge through an external circuit causes the first cell(s) to reach 0 V to be charged in reverse by the discharg current from the other cells flowing through them.  Thi can damge the cells.

TERRA Operative:
Well, a Croatian friend here in Japan talks about driving from there to here, with the only real sea crossing being from Korea that can be done by boat, oh and the Adriatic Sea when you are heading out of Italy, but just bring a canoe.
Apparently the Asian Highway 1 connects to the European route E80, so you can drive from over your way all the way to Tokyo.

I'll meet you at Tokyo Station, call me when you are near. Good luck! Haha  :-DD

Vince:
Wow your friend is well motivated !  :o

As for me, my right foo and knee and leg hurt very badly after 45 minutes of driving or so... so... going to Japan is not possible  !  ;D
Plus, petrol is so expensive, not to mention the cost of maintenance with all those kilometers that... it's 100% certain that even a business class flight would be much less expensive !  :scared:

Luckily internet and TEA exist to keep people in touch from all over the world for next to nothing ! :D

Vince:

--- Quote from: Robert763 on January 23, 2022, 03:19:35 pm ---Best you can do is recharge at C/10 nd see what happens.
Unfortunatly discharging it to flat is not the same as it self-discharging it to flat. Self dischrg  happens to each cell independently. A discharge through an external circuit causes the first cell(s) to reach 0 V to be charged in reverse by the discharg current from the other cells flowing through them.  Thi can damge the cells.

--- End quote ---

Ah well... not too worried given the price of a new battery if I ever need to use one. I am just having a bit of fun here of course, it's for educational purposes mostly...  :-[

So let's recharge it slowly and see how it goes... nothing to lose eh... it's 30 years old, I had zero expectations about it from the get go anyway !  :-//

Stay tuned...

TERRA Operative:

--- Quote from: Vince on January 23, 2022, 03:30:11 pm ---Wow your friend is well motivated !  :o

As for me, my right foo and knee and leg hurt very badly after 45 minutes of driving or so... so... going to Japan is not possible  !  ;D
Plus, petrol is so expensive, not to mention the cost of maintenance with all those kilometers that... it's 100% certain that even a business class flight would be much less expensive !  :scared:

Luckily internet and TEA exist to keep people in touch from all over the world for next to nothing ! :D



--- End quote ---

What's a quick 53,000km trip anyway? :D Barely a trip down to the shops! Hahahaha

Navigation

[0] Message Index

[#] Next page

[*] Previous page

There was an error while thanking
Thanking...
Go to full version