Another important battery question (18650's this time)

[D-Dog]

One of my 18650's unprotected DLG brand 1 year old 2200mah is doing something interesting on my multimeter. The meter updates maybe once every .1 sec and when I connect the battery I ramps up to 4.22 volts over maybe .5 sec and then it drop to 4.06 volts the next refresh. I know it's not the meter as it works fine for every other battery where the meter ramps up the voltage until it settles.

The cell looks fine, is not warm, etc. I was charging it and I figure it should be 4.2 volts by now by estimation... not 4.06, however, that is where the meter sits until I remove the battery...

I stopped charging because I don't want it much above 4.2... and the charger may thin kthe voltage is 4.06 too and I don't want a thermal runaway in a dorm room... that wouldn't be a good momentfro flashaholics...

What should I do?

 

[VidPro]

the charger is Pulsing to top it off, from what your indicating.
its not doing that when oFF the charger is it?

there are many ways to do the slower topping off , one is by pulsing, one is by just being a slower charger (there is no actual slow down needed), and one is by reducing the total current when finishing the top off.

as long as it it not going over spec for the battery, it will eventually be fully charged.
OR
you can pull it off now, at the lower voltage, and it will work ok too.

 

[D-Dog]

the charger is Pulsing to top it off, from what your indicating.
its not doing that when oFF the charger is it?

No, I took it off the charger (Ultrafire WF-139 I think) and that is when it does it... now it is going from 4.21 to 4.04 so at least I am not as worried about overcharging it...

I will post a video on youtube of what is happening so you can see... but the update cycle of my multimeter goes like this

0
1.23
3.48
4.21
4.06
4.05
4.05
...


wheras any other battery I try (even another 18650) goes up linearly and stays there... the kicker is that the batter SHOULD be 4.2, not 4.06 which is where it settles...

 

[VidPro]

so its bouncing when off the charger?
that doesnt sound good, i have only one li-ion that does that.
it sounds like plate seperation, or some such thing that i dont know enough about.

the one i had doing that was getting a buildup of gas internally (it was a bagged cell so i could see it) and a special pulse charging method i have reduces the internal gas buildup, and "fixed" it.

has this battery been taken below specs?

also the slight posibility that the PCT (power disconnect ) or the anode disconnect (gas buildup disconnect) are doing that

you could sorta guess at which it is, by putting a load on and seeing if it can output some amps still, and smell the top , which is stupid because they are dangerous toxins, to see if its leaking anything.

 

[D-Dog]

http://hosted.filefront.com/dgross0818/

I put up a video showing the problem...it's the only one there on my page

 

[VidPro]

http://hosted.filefront.com/dgross0818/

I put up a video showing the problem...it's the only one there on my page

that doesnt look like your connection (to the meter) is stable enough?
but i assume you checked with another battery . and that looks bad.
(i mention the connection, because them stupid bannana plugs are giving me trouble often.)

in the video i wouldnt even call that a Reading unless your psycic :devil: with those changes, you need a SCOPE to read it.

what does it do under load?

its Dead Jim.

 

[D-Dog]

that doesnt look like your connection (to the meter) is stable enough?
but i assume you checked with another battery . and that looks bad.
(i mention the connection, because them stupid bannana plugs are giving me trouble often.)

in the video i wouldnt even call that a Reading unless your psycic :devil: with those changes, you need a SCOPE to read it.

what does it do under load?

its Dead Jim.

Yea, the meter scales automatically which is why the numbers bounce around more than they should perhaps.

The bananas, though I too don't like them are in really good shape as the leads are almost brand new.

I don't really have a way to measure under load with the multimeter ummm... what would you suggest?

 

[VidPro]

Yea, the meter scales automatically which is why the numbers bounce around more than they should perhaps.

The bananas, though I too don't like them are in really good shape as the leads are almost brand new.

I don't really have a way to measure under load with the multimeter ummm... what would you suggest?

oh well take it off of auto, some button around there somwhere will take it off AUTORANGE? and then it will quit swtiching to the different scales.
(helps if your IN the range/scale you want, then put it in manuel, then it will stay in that range)

you already have a thread on measuring under load

MYSELF i use a led or a set of leds usually, because thats the load i am going to have .
but ANY forms of resistance put in the curcuit will put a "load" of some sort on, so the battery is under a load.

so a high powered led and say 1-4Ohms of a resister
or
a 10ohm power resister
or
a small bulb that can take at least that voltage, like a PR bulb from a lantern, even a 12v small bulb will work .

then your connection is to parellel the "resistance" to the battery, and read the battery voltage

|+{=====]-|
|...{~~}....|


Note: dont flash amp stuff with the AMPS reading, its just not good for the batteries or the meter, and really tells you little about the ability for the battery to KEEP doing that over time. its fun to see, but its still a SHORT and not so good. (flash amps is putting JUST the meter on its 10amp mode across the battery)

 

[D-Dog]

oh well take it off of manuel, some button around there somwhere will take it off AUTORANGE? and then it will quit swtiching to the different scales.

you already have a thread on measuring under load

MYSELF i use a led or a set of leds usually, because thats the load i am going to have .
but ANY forms of resistance put in the curcuit will put a "load" of some sort on, so the battery is under a load.

so a high powered led and say 1-4Ohms of a resister
or
a 10ohm power resister
or
a small bulb that can take at least that voltage, like a PR bulb from a lantern .

then you connection is to parellel the "resistance" to the battery, and read the battery voltage

|+{=====]-|
|...{~~}....|


Note: dont flash amp stuff with the AMPS reading, its just not good for the batteries or the meter, and really tells you little about the ability for the battery to KEEP doing that over time. its fun to see, but its still a SHORT and not so good. (flash amps is putting JUST the meter on its 10amp mode across the battery)

Oh yup, I remember that thread although that is a 2 cell light I have (Stinger XT with 2 18650' and a wa 1274) and I don't want to really put the battery in with another one I Know is 4.2 volts.

If I take it off of auto it will update to 4.05 and stay there... no spike.... so I am figuring maybe it is just the meter adjusting?

Oh well, at least I feel better about the cell now

 

[VidPro]

If I take it off of auto it will update to 4.05 and stay there... no spike.... so I am figuring maybe it is just the meter adjusting?

yup mabey, some of them switch around 3-4v , which can drive you up the wall depending on what your trying to read.
also doesnt hurt to have another meter, like an Old crusty cheap analog thing (old school), with the physical needle going up and down, its a cheap addition to a cheap setup (me being a cheapskate) , and then you can do both a AMPS AND volt reading at the same time.

 

[D-Dog]

Yup, this guys switches at 4 so that was probably what was causing the problem... still don't know why it was only happening to one cell, however, looks like it kinda sorted itself out.

 

[VidPro]

Yup, this guys switches at 4 so that was probably what was causing the problem... still don't know why it was only happening to one cell, however, looks like it kinda sorted itself out.

no YOU sorted it out the machines are still stupid

i would still want to check it under a load.

 

[D-Dog]

Not relevant any more

 

[D-Dog]

Alright same minute update... I tried another 18650 not used in the test yet and it too spikes so I guess my multimeter is just adjusting the scale and it overshoots for a sec... Maybe I just never noticed it before? I don't know, however, I feel a lot better knowing 2 batteries have the same issue...

I guess we can call this solved... blame the multimeter?

The voltage seemed to increase because I was dumb and mixed up the cells which look exactly the same

Edit: tried an RCR2 and had the same issue... dumb multimeter I guess... overshoots when it rescales