Who has had a leaky battery this year?

[tsaksa]

We had two batteries leak this year with no signs of mechanical damage. This was a small amount of acid appearing near the two rectangular indentations near the terminals on top of the battery. We do not think they were over charged, and we were using the standard single battery chargers sold by Andy-Mark.

I hear via rumor that at least a few other teams at our regional had at least one leaky battery this year as well. These were the first two leaky batteries our team ever had, and according to the safety folks I spoke with at regionals battery leaks have been fairly rare in the past few years. Hopefully we are not looking at a systemic problem or a bad lot of batteries, but I am curious to hear from other teams that may have had leaking batteries this year. If you did have a leak, did you notice the location or any other significant conditions?

[dez250]

Which orientation do you charge and use your batteries in (ever upside-down)?
Also have you noticed any bulging in the case or missing the top rectangular cover on either battery?
Also do you notice any movement or play in the terminal lugs on the batteries?

[ENIAC]

Our batteries are placed in the robot horizontally, but we did this in 2010 with no issues. This year, two batteries, one that was used in the robot and one that was just sitting on a table, showed up with staining beneath the tape holding on the label.

[Al Skierkiewicz]

T,
Are both batteries from this year? Had you run them in the robot during matches while on the bridge or going over the barrier? Do your students carry them by the wires? All of these can cause seal damage to the batteries.

[Steven Sigley]

Originally Posted by ENIAC

Our batteries are placed in the robot horizontally, but we did this in 2010 with no issues. This year, two batteries, one that was used in the robot and one that was just sitting on a table, showed up with staining beneath the tape holding on the label.

I believe we cracked the glass on the inside of our batteries by playing with them laying horizontally in 2008 at the San Diego regional. No idea if problems like leakage could be related though. (I've never observed any leakage myself)

[Ether]

Originally Posted by Steven Sigley

I believe we cracked the glass on the inside of our batteries

The "glass" is a fiberglass mat. Perhaps someone who has taken one apart could comment on how brittle it is and likely it would be to crack.

[tsaksa]

Originally Posted by Ether

The "glass" is a fiberglass mat. Perhaps someone who has taken one apart could comment on how brittle it is and likely it would be to crack.

I believe the glass mat is not very brittle, but perhaps I can track more information down without needing to dissemble a battery. By a strange coincidence the battery separator material is actually made in our town.

[PAR_WIG1350]

Originally Posted by Ether

The "glass" is a fiberglass mat. Perhaps someone who has taken one apart could comment on how brittle it is and likely it would be to crack.

Wikipedia has some decent images of that.

[Steven Sigley]

note: DO NOT OPEN UP YOUR BATTERIES EVER. Thanks for your time

now for the lazy:



Also these look roughly like what we use if i had to guess

[tsaksa]

An important note. Both batteries were labeled with a large paper label and tape that covered the area marked (pressurized vent system). There was also very little liquid present, and it was only noticeable because there was paper and tape trapping it in the area we now know is a vent. There is at least some possibility that the batteries did not actually leak, but that it was just that the tape trapped and helped to condense normal venting gasses.

I will carefully look over the batteries later this week and see if this may be the case. One interesting fact is that the person responding to the leak commented that baking soda did not fizz when dumped on the battery. This along with the very limited amount of liquid suggests to me there is at least some chance that this is not a classic spill.

Don't worry, I will be careful. I just want to make sure that we know what happened. I suspect that we may at least want to have whoever labels batteries in the future be more careful not to accidentally cover the vent area.

[marccenter]

We had two batteries leak in 2011 - new ones from FIRST. We checked the chargers for current, voltage, etc? and was not able to determine the nature of the cause. We had FIRST personnel at the Troy district tournament last year working with us to help figure our the issue to no avail.

Speculation on my part is that the batteries may have been dropped in shipment.

[Al Skierkiewicz]

T,
A normal by-product of the charge and discharge cycle is water vapor due to heat genrated within the cell. The vents open to release this pressure in the form of vapor. Even though the manufacturer says the battery can be charged in any orientation, I recommend that the battery only be charged in the upright position. Any liquid at the vent will be forced out when the cell pressure exceeds the vent trip. That liquid then pushes out of the vent. Following the charge cycle this water then recombines in the cell. As a battery loses water, it's peak capability is also lost. In gel cells this is more of an issue as the gel then decreases to the point were the plates are not fully covered by electrolyte. With gel cells it is/was easy to pickup a battery and actually feel the weight loss compared to a newer battery.

[tsaksa]

Originally Posted by Al Skierkiewicz

T,
A normal by-product of the charge and discharge cycle is water vapor due to heat genrated within the cell. The vents open to release this pressure in the form of vapor. Even though the manufacturer says the battery can be charged in any orientation, I recommend that the battery only be charged in the upright position. Any liquid at the vent will be forced out when the cell pressure exceeds the vent trip. That liquid then pushes out of the vent. Following the charge cycle this water then recombines in the cell. As a battery loses water, it's peak capability is also lost. In gel cells this is more of an issue as the gel then decreases to the point were the plates are not fully covered by electrolyte. With gel cells it is/was easy to pickup a battery and actually feel the weight loss compared to a newer battery.

Thanks.

I had a feeling the labeling was a tad excessive and the batteries may not have been really leaking. I will discuss this with the team and make a plan for how to proceed. Batteries remain one area where we need to exercise more diligence.

[perlgerl]

If the leak was from the terminal seals, this is a manufacturing defect and should be communicated to the manufacturer. Please post the manufacturer (ie Genesis or MK battery) and the manufacturing date code (ie YYMMDD + extra letters) which is stamped in the top of the battery case.

This year in our kit of parts, the Kinetic Knights Team 781, received a Genesis battery manufactured July 17 2010 (batch code E100717FB). We have not had any leaks. We inspected our terminal seals and saw no defects. Some pictures of a disassembled MK Battery are posted on our website (3 MB pdf).