Red LEDs on battery board after several hours of charging
Buck Rogers
Posts: 2,185
Hello!
I own this fellow http://www.parallax.com/product/28989 and the documentation states that blinking blue LEDs insist that the unit is charged. However steady red ones are supposed to indicate a fault. Irregardless of how old it is, (its not a new unit) what caused that condition and why?
Last night whilst working my way through developing an application that would be displayed on a small LCD screen with data delivered from the Prop Backpack, the system started again to show signs of low voltage. I then stopped and set it up to charge itself.
According to the document its supposed to take from 1 to 6 hours to come to a full charge as stated here:
"Charging Time: 1 6 hrs or more, depending upon the discharge level and capacity of the cells" from the actual document, page one under key specifications.
And then it says here:
"Cell B Red Status: This LED indicates a fault condition in Cell B.
Solid = There is/was a fault in the cell, or there was a glitch during the charging process.
Remove and then re-apply power to the board, to see if the condition persists.
Blinking = The temperature of the cell is outside the safe charging zone. The safe charging
zone is typically set for between 32 and 113 °F (0 to 45 °C).
Off = There is no fault condition detected with Cell B, or there is no cell in the holder.
Cell B Blue Status: This LED indicates the charging status of Cell B.
Solid = The cell is charging.
Blinking = The cell is fully charged.
Off = The cell was already fully charged and no charging was needed, there is no cell in the
holder, or the cell is not fully-seated into the holder."
And of course:
"Cell A Red Status: This LED indicates a fault condition in Cell A.
Solid = There is/was a fault in the cell, or there was a glitch during the charging process.
Remove and then re-apply power to the board, to see if the condition persists.
Blinking = The temperature of the cell is outside the safe charging zone. The safe charging
zone is typically set for between 32 and 113 °F (0 to 45 °C).
Off = There is no fault condition detected with Cell A, or there is no cell in the holder.
Copyright © Parallax Inc. 28986 Li-ion Power-Pack/Charger 2 Cell v1.0 6/21/2011 Page 6 of 7
Cell A Blue Status: This LED indicates the charging status of Cell A.
Solid = The cell is charging.
Blinking = The cell is fully charged.
Off = The cell was already fully charged and no charging was needed, there is no cell in the
holder, or the cell is not fully-seated into the holder."
From pages 5 and 6.
Now those Red LED on both surfaced after about three hours of attempted charging.
What do I do to clear it? That is so I can charge them when necessary, and of course use this board to power the BOE its attached to. Replacing the cells is possible, but given that the document claims that removing them is difficult because of how they fit into the holders. Also please note that the board was obtained used......
I own this fellow http://www.parallax.com/product/28989 and the documentation states that blinking blue LEDs insist that the unit is charged. However steady red ones are supposed to indicate a fault. Irregardless of how old it is, (its not a new unit) what caused that condition and why?
Last night whilst working my way through developing an application that would be displayed on a small LCD screen with data delivered from the Prop Backpack, the system started again to show signs of low voltage. I then stopped and set it up to charge itself.
According to the document its supposed to take from 1 to 6 hours to come to a full charge as stated here:
"Charging Time: 1 6 hrs or more, depending upon the discharge level and capacity of the cells" from the actual document, page one under key specifications.
And then it says here:
"Cell B Red Status: This LED indicates a fault condition in Cell B.
Solid = There is/was a fault in the cell, or there was a glitch during the charging process.
Remove and then re-apply power to the board, to see if the condition persists.
Blinking = The temperature of the cell is outside the safe charging zone. The safe charging
zone is typically set for between 32 and 113 °F (0 to 45 °C).
Off = There is no fault condition detected with Cell B, or there is no cell in the holder.
Cell B Blue Status: This LED indicates the charging status of Cell B.
Solid = The cell is charging.
Blinking = The cell is fully charged.
Off = The cell was already fully charged and no charging was needed, there is no cell in the
holder, or the cell is not fully-seated into the holder."
And of course:
"Cell A Red Status: This LED indicates a fault condition in Cell A.
Solid = There is/was a fault in the cell, or there was a glitch during the charging process.
Remove and then re-apply power to the board, to see if the condition persists.
Blinking = The temperature of the cell is outside the safe charging zone. The safe charging
zone is typically set for between 32 and 113 °F (0 to 45 °C).
Off = There is no fault condition detected with Cell A, or there is no cell in the holder.
Copyright © Parallax Inc. 28986 Li-ion Power-Pack/Charger 2 Cell v1.0 6/21/2011 Page 6 of 7
Cell A Blue Status: This LED indicates the charging status of Cell A.
Solid = The cell is charging.
Blinking = The cell is fully charged.
Off = The cell was already fully charged and no charging was needed, there is no cell in the
holder, or the cell is not fully-seated into the holder."
From pages 5 and 6.
Now those Red LED on both surfaced after about three hours of attempted charging.
What do I do to clear it? That is so I can charge them when necessary, and of course use this board to power the BOE its attached to. Replacing the cells is possible, but given that the document claims that removing them is difficult because of how they fit into the holders. Also please note that the board was obtained used......
Comments
Do you have a voltmeter you can check each cell with?
It could be one of the following:
A. You used the cells in a project that did not monitor the discharge and went below the safe limit. (The Parallax board is suppose to prevent this with an orderly shutdown.)
B. You didn't top off the Lithium cells when first used and that somehow caused them to go below their safe limit. (maybe they were actually below 3.3 V when you started to use them.)
C. The cells were simply no good from the start.
D. Heavy loading of the lithium cells (like a direct short or stalled motor) pulled the cells below their safe limit.
If the cells are rated at 3.7VDC, the conservative safe discharge limit is 3.3VDC. I have killed brand new cells by letting kids play with a robot until the cell goes below the limit in just one use. You just don't get second chances.
Resting the cells and trying again is worth doing. With a full charge, a 3.7VDC cell might read as high as 4.2VDC on a meter.
Li-Ion cell voltage should be round 3.7xx volts (nominal) Try to keep the cell from going below 3.1xx volts, a charged cell should be around 3.9xx volts. Clean or burnish the contact points of the cell, for good electrical contact. I also found that removing power to reset the Fault LEDs also resets the maximum time a cell should be charged (this needs to be confirmed, my observation only). Finally new cells need to be discharged & recharged several times before they reliably recharge correctly. Read & study t he spec sheets, I still have not figured out everything there is to know about Li-Ion cells. Just my ideas, and I am sure others have different thoughts on Li-Ion cells.
This particular product has many safety checks in it, and everything needs to be just right for it to work out.
Do you have a power supply or smaller transformer you could use?
Ken Gracey
Hello!
I believe so. I'll need to keep looking for the wall wart collection I do have. That one was a second grab. I also have a 5v one that was originally used for powering certain examples of early media players, which was a first.
In fact my printer just suggested its hanging around in the bins its using as a stand.
So all of you are suggesting that it might be too much power despite what the documentation says concerning the power margins.
and
and
All of you have given good advice. Ken's is first for many reasons. And yes fellow gadgeteer I do have a meter. And PG2 these aren't new guys in old holders.
I shall be looking for the supply I need RSN. Thanks all. I owe you all something special soon. Oh right Loopy, I can't really offer anything because you're in the perfect location for it......
And Ken I'm fighting with a green eyed monster because of that photo.
Update: Found one, set it for 7,5v and plugged it in. Right now its busy charging. I'll know more in another half hour.
Update2: Now using the second one. The first one was shedding heat improperly, which told me that it was delivering too much current which was a while ago. Right now its still charging and the thing is only warm to the touch, not hot which was the case of the other one.
And no flashing red lights?
Hello!
Indeed. No blinking red lights, and not even any rude sirens. I started charging with this one about 9:15 EDT, so far they are still solid blue,so I'm going to let it keep doing so for at least another fifteen minutes. If they stay solid, then for an hour.
My mistake. B Cell shows solid red. A Cell shows solid blue. Document says to remove and re-apply power. What happens if these fault conditions persist?
I'd start by putting the A cell into the B slot, and see if it continues to be solid blue or blinking blue in the B's former position. If so, then perhaps the A cell has gone bad and should be replaced.
Hello!
Okay. More information, I've realized that both of my wall warts are the wrong size. They are both under the 1AMP rating for the one that the board/box needs. And naturally as the unit starts drawing more power the units heat up, it gets transferred to the unit causing these issues. Fortunately I found a ready candidate...... But I'll keep your idea as a valid one. In the end I might end up replacing both cells.
I have learned to always start new lithium cells by attempting to fully charge. That should avoid going too low on a discharge.
And now with the arrival of the appropriate wall wart, it managed to fully charge both of them. The first one was fully charged it seemed, and the process of doing so must have stressed and badly the original one. Now both are indeed fully charged. It only took about 90 minutes.