Chief Delphi - FRC batteries wont charge

Chief Delphi (http://www.chiefdelphi.com/forums/index.php)

- Electrical (http://www.chiefdelphi.com/forums/forumdisplay.php?f=53)

- - FRC batteries wont charge (http://www.chiefdelphi.com/forums/showthread.php?t=111056)

FRC batteries wont charge

Our FRC batteries from 2010,2011,and 2012 all are not charging. We have used two different chargers and both are giving the same thing, no charge.

Anyone else have this same issue? What's the solution?

Re: FRC batteries wont charge

When was the last time you charged them?

Re: FRC batteries wont charge

well, last summer really, but that was only one of them. (This is, of course, besides their individual uses in each years competition.)

Re: FRC batteries wont charge

These batteries must be recharged on a regular basis. If not they will die a premature death. This has to do with the construction and material of the battery. We typically top them off every month. If they've are stored in the cold they eill also discharge quicker.

Re: FRC batteries wont charge

Also, avoid vibration when they are discharged. Try to keep the ones that are on the robot topped off as well as possible. This is due to the chemical reactions inside the battery, as Lead Sulfate forms a powdery residue on the surface of the lead plate which can be shaken off and eventually degrade the entire terminal. This is also how deep-discharged batteries fail.

Re: FRC batteries wont charge

So the bad news is, those batteries have failed. You need to replace them. Sorry.

Keeping them charged all the time is important, as you now have learned.

Re: FRC batteries wont charge

Quote:

Originally Posted by Coffeeism (Post 1213714)

If they've are stored in the cold they eill also discharge quicker.

"Self-discharge is a chemical reaction, just as closed-circuit discharge is, and tends to occur more quickly at higher temperatures. Storing batteries at lower temperatures thus reduces the rate of self-discharge and preserves the initial energy stored in the battery."

http://en.wikipedia.org/wiki/Self-discharge

Re: FRC batteries wont charge

Ether is correct. The cold weather myth regarding lead acid batteries comes from the fact that a car's engine requires more energy to start in cold weather than in warm weather, because of the difference in lubrication viscosity and in the combustibility of fuel at low temperatures.

Since you need more energy at low temperatures, a slightly weak battery won't have enough energy to start the engine. This makes people believe the cold weather is bad for batteries, whereas hot weather is worse for battery life.

Re: FRC batteries wont charge

Quote:

Originally Posted by DonRotolo (Post 1214068)

Think about it twice... you're both right. I recall this statement being told to me by the guy who sold me my motorcycle...

Re: FRC batteries wont charge

If you've let them discharge to far then some chargers won't charge them as they don't see the extremely low voltage as a valid battery and won't turn on. If you can find an old school charger you may be able to get them to charge. If you don't have access to a old school charger you can hook the battery up in parallel and charge them both for a short time. That should trick the charger to turning on and get them to a high enough voltage to make them accept a charge. However you have comprimised the batteries capacity and it may not have the power and length of use you desire. They may be suitable for another year as a practice only battery though.

Re: FRC batteries wont charge

Quote:

Originally Posted by Mr V (Post 1214176)

...they don't see the extremely low voltage as a valid battery and won't turn on... If you don't have access to a old school charger you can hook the battery up in parallel

Did you mean "series" ?

Re: FRC batteries wont charge

No, I think he meant parallel. The myth is that good battery fools the charger into supplying energy, applying charge to the bad battery.

The sad reality is that permanent damage has already occurred, and no snake oil is going to change the chemical facts. Yes, you can get some charge into it, but hardly worth it, as even fully charged they will be woefully inadequate.

Re: FRC batteries wont charge

Quote:

Originally Posted by DonRotolo (Post 1214264)

No, I think he meant parallel. The myth is that good battery fools the charger into supplying energy, applying charge to the bad battery.

Yes, that's a possible interpretation. But since he never mentioned a good battery, what he appeared to be saying is that two of the bad batteries -- in series -- would present enough voltage to the charger to fool it into thinking there was one partially discharged battery.

But if the two bad batteries are so bad that it takes two of them in series to mimic a partially-discharged good battery -- and they've been stored that way for some time -- then the following is almost certainly true:

Quote:

The sad reality is that permanent damage has already occurred, and no snake oil is going to change the chemical facts. Yes, you can get some charge into it, but hardly worth it, as even fully charged they will be woefully inadequate.

Re: FRC batteries wont charge

Quote:

Originally Posted by Ether (Post 1214248)

Did you mean "series" ?

Quote:

Originally Posted by DonRotolo (Post 1214264)

Sorry I wasn't clear last night, I was tired after getting up at 5am to judge a FTC event and then not getting home until late.

Yes I meant hook it up in parallel with a charged battery. That will fool the charger into turning on and charging the battery. That is no myth, that is what is recommended by manufacturer of the best known automotive application AGM batteries, Optima.

From the FAQ on their website.

Quote:

If an OPTIMA battery is deeply discharged (below 10.5 volts), most basic chargers will not supply a charge. Also keep in mind that an OPTIMA battery will not recharge properly if treated as a regular flooded or gel battery. To charge the battery, you can wire a second fully charged automotive battery (12+volts) to the discharged AGM in parallel (+ to + and – to –). Then hook up the charger to the deeply discharged battery, setting the charger at 10 amps. Leave for two hours, monitoring frequently. During this process, if the discharged battery gets very hot or if it is venting (hissing sound from vents), then stop this process immediately. When the discharged battery reaches 10.5 volts or more, remove the standard battery and continue charging the AGM until fully charged.

For normal charging, a relatively low current, such as one or two amps, can work well, but when the battery has been deeply discharged, some sulfation of the battery plates may have occurred. If you charge at 10 amps, the higher current will help to break up this sulfation.

If you have an automatic charger, let it run until the charger indicates charging is complete. If you have a manual charger, you can get a rough estimate of the charging time in hours of a completely discharged battery (11.2 volts) by multiplying the capacity (amp hours or Ah) of the battery by 1.2. If your battery is not completely discharged, the time would be less.

In most cases these steps will recover an AGM battery. It’s OK for the AGM battery to get slightly warm during the charging process. If it’s hot to the touch, it means there’s a short and the process should be discontinued.

Note the 2hour/10 amp recommendation is for an automotive sized (44AH and larger) battery not a FRC sized battery. Do not exceed the 4A recommended rate for the FRC battery and I would not charge it for more than 30 minutes at a time, before trying to get it to charge by itself. Pay special attention to the parts I've italicized in red above, with everyone in the area wearing safety glasses.

Even if they do come back to life, I would not consider the batteries to be competition worthy.

Re: FRC batteries wont charge

In most cases, leaving AGM batteries for several months without charging does not cause death. As to the cold myths, very cold temps (i.e. less than 30 F) will simply slow the chemical reaction. The colder the battery temp the less chemical activity hence lower charge is available. As pointed out above, the engine conditions simply worsen this already compromised battery. An old trick is to turn the headlights on for 30 seconds to get the juices flowing and warm the battery. Don't know if that is enough but on really cold days in Chicago I have been able to start the car. ( I have never had a garage.)

Many smart chargers sense low battery voltage as a dead battery and they will not attempt to charge it. So the bigger question here, have you measured the terminal voltage on the batteries? Are they zero volts, 4 volts or something odd like 6.8? If the batteries measure one of the low voltages you can try the parallel trick or you can use a variable voltage power supply. Monitoring of the output current is essential so a supply with meters helps a lot. Adjust the output of the supply to 12 volts then turn the power off. Connect the output of the power supply to the battery, positive to positive please. Turn on the power supply and begin slowly increasing the voltage while monitoring current. The current should start out low and increase as you increase the output voltage. Do not raise the output voltage above 14-14.5 volts or stop operation if the current suddenly spikes. In this range, charge current should remain in the 1-3 amp range. Monitor for heating of the battery and wait about 15 minutes. Remove the battery from the supply and measure the terminal voltage. If it has gone back up to 12 volts, then connect to the battery charger and see if it will charge normally. If not, try repeating this procedure for another 15 minutes. If after this charging period the battery terminal voltage does not change, or if the battery is at zero volts, it may be time to recycle.
The biggest problem team face is storing dead batteries. Self discharge for these batteries is measured in months from full charge. A discharged battery left in storage can only get much worse over the months.

Re: FRC batteries wont charge

Also check your cable polarities! Apparently some APP battery connectors were wired with reverse colors this year. Your charger may be smartly preventing charging

Re: FRC batteries wont charge

Step 1: See if the batteries can be recovered to some level of usefulness. Similar to suggestions above, I would try an old-fashioned current charger (not a "smart charger", as sometimes they are too smart to work). The old charger may bring the batteries up to a level where the smart charger can work properly and finish the job.

Step 2: TEST the batteries to see if they are good enough for competition, or just practice, or should be recycled. Our team uses a Battery Beak. If the battery is good enough to keep, label it so everyone knows whether to use it in competition or not.

Step 3: Track of all of your batteries, retest periodically, record results. Retest means they need to be charged from time to time, whether they've been used or not. Re-evaluate batteries after testing, and disposition them accordingly. It's miserable to perform poorly in a match because the battery isn't as good as you assumed it was (we learned the hard way:( ).

Re: FRC batteries wont charge

Modern chargers look for a back EMF to ensure the charging clips are not meandering about energized. More of a safety issue really. Safety note: when paralleling cells with significant terminal voltage differences, a LARGE amount of current will flow for a short time, and sparks will issue when the last connection is made. If you should pursue this action, make the last connection on the good battery. Batteries evolve hydrogen when discharged, some residual gasses may be present. (do this outside, with a face shield) Hope this helps.