MK Battery Problems

[Jeff Rodriguez]

Two of our batteries have issues similar to this.
We put the battery in the robot, switched it on, and nothing happened. The robot didn't go on at all. We disconnected the Anderson connector and connected a different battery without actually moving the first one, switched it on and it was fine.
I think it was the battery, but after reading the thread I now suspect the Anderson connector as well. It has happened to us only a few times and each time, we haven't done a thorough investigation of the problem.
I believe we have a mix of new and old Anderson connectors on the batteries (we taken them off old, dead ones).

[Al Skierkiewicz]

Mitch,
The spec is 11mOhm nominal so I wouldn't be too worried even up to 15 or 20 mOhm. However 5 ohms is way too high. I know the construction of this battery does make it possible to damage the terminal inside the red/black coating at each terminal. Picking up by the wire is a guaranteed failure.

[Brandon Holley]

Just to reiterate, team 125 had 2 bad batteries go down on us at the boston regional.

One was from 2007 KOP the other from 2008 KOP. Other than that I dont have the exact details from them, however when put under load (with a load tester) we got a reading around 9 V for both of them.

[ebarker]

Originally Posted by squirrel

Just to keep things interesting, I'll mention that we discovered that the Andersen connectors this year are made differently from past years, and that we could get the power to the robot to go on and off by merely wiggling the Andersen connector with the new batteries, but it would stay working with the old batteries (which have the old connectors).

What was different about the connector ? Were the pins inserted into the shell correctly ? I'd like to see this thing ? Going to Atlanta ?

[fatjoe3833]

This battery issue seems to be pretty common. Maybe FIRST received a bad batch for the KOP? Has anyone informed FIRST?

[MrForbes]

Originally Posted by ebarker

What was different about the connector ? Were the pins inserted into the shell correctly ? I'd like to see this thing ? Going to Atlanta ?

We're not going to Atlanta, but when you get a chance, look at the contacts in the connectors, see for yourself. As far as I know they were all pre-terminated connectors. I don't have access to the batteries and chargers and robots right now, or I'd take some pictures.

I think Al S. is looking into this. I doubt it's the cause of all the battery problems, but we did notice a definite difference between the performance of the older and newer connectors when we were wiggling wires around at the AZ regional (when we also had another serious wiring problem).

[Mr.G]

We have 8 of the new style battery's. This year 2 of them went bad with the same symptoms as everyone else has, the voltage drops to nothing when a load is applied. We have 2 other that are down about 20% when load tested and we won't use them unless we absolutely have to. We are using the Excide chargers from prior years. The new charger is still sitting in the box.

[BT987]

i remember in Vegas team 4 asked me if i could check out there batts. for the sam reason they had a full charge but the battery would not work for more than a minute maybe that could have been why.....

[Colin]

We have not had any voltage problems with the new batteries, but have lost 6 batteries due to swelling this season. We believe that the swelling problem is due to our bank charger which we have now discontinued use with, prior to the swelling we had noticed that it was charging hot.

We did have a voltage problem in 2006. The battery in question read 13.5+ volts off the charger where it had been for an hour. But once the match started it failed to even move the robot and read something like 7 volts.

[Al Skierkiewicz]

Originally Posted by Colin

We have not had any voltage problems with the new batteries, but have lost 6 batteries due to swelling this season. We believe that the swelling problem is due to our bank charger which we have now discontinued use with, prior to the swelling we had noticed that it was charging hot.

We did have a voltage problem in 2006. The battery in question read 13.5+ volts off the charger where it had been for an hour. But once the match started it failed to even move the robot and read something like 7 volts.

Colin,
Can you give me manufacturer and model number or a link to the charger? Yes I am still working toget a handle on these issues and I need hard data on battery, charger used, approximate life span (#of matches).

For all, remember that these batteries have a specified life span of about 400 charge/discharge cycles. When high current in charge or discharge is used, then that life is severely decreased. Repeated 80% discharge can lower this to almost 200 cycles. This is also affected by charging a warm/hot battery.

[MrForbes]

How is battery life affected by sitting for a long period, discharged? I know this kills car batteries....

[ebarker]

Originally Posted by squirrel

How is battery life affected by sitting for a long period, discharged? I know this kills car batteries....

Kill these batteries too. They need charging periodically. I think it is at least every three months.

Everyone,
Please remember to recycle these dead batteries !!

[Cory]

Originally Posted by Al Skierkiewicz

Colin,
Can you give me manufacturer and model number or a link to the charger? Yes I am still working toget a handle on these issues and I need hard data on battery, charger used, approximate life span (#of matches).

The charger is an AutoMeter Professional BusPro-600S. 6 station, 5 amp per station smart charger.

The 6 in question probably had 40 or so charge cycles, tops, on them.

The charger had one station in question which had been charging slightly warm since Atlanta 07. About a month and a half ago we noticed that it was charging extremely hot, saw one very swelled battery, and 5 more that had minor swelling.

We immediately discontinued use of the banked charger and went back to the vintage kit chargers (Xenotronix HPX-60) and have not noticed anymore issues.

[adman]

Leaving Lead Acids discharged leads to a process called
Sulfation effectively messing up the Batteries ability to charge
fully the next time.

We have been wondering about our performance lateley also.
Haven't had any burn up or lose a cell yet.

[Al Skierkiewicz]

The battery brochure for this battery can be found here...http://www.mkbattery.com/images/ss.pdf
It implies that float charging can keep these batteries going for a while. With IRI we end up charging batteries during the summer for practice. Then we don't really start using them for several months and do not leave them on float. Over the years, we have not noticed any serious deterioration. We use a CBA-II from West Mountain Radio to track batteries and compare them from one year to another. We have generally been getting usable service life for practice of three years or more.