Battery Best Practices

[Superllama12]

For testing, we have a voltmeter with the tips of the cables cut off and soldered to a battery connector. We normally bring one charger per battery, and about seven to the competition (though this is probably a bit overkill). Some major advice: if the battery drops below 10.5 volts, it will get damaged! I would advise to check the batteries pretty frequently, and make sure they don't go below 11v. Also, when they charge, their max is 14.4v, but it will drop to 13.8v (its max rest charge) afterwards, so don't freak out if they seem to charge and then drop again!

[Nate Laverdure]

The Andymark Battery Plugs provided in the KOP are an excellent way to indicate that a battery is charged.

[thefro526]

1) We generally take as many batteries to a competition that we can. In previous years this number has ranged from 4-6 'competition' batteries and 2-3 'Practice/Testing' batteries.

2) Recently, we've taken 3 Chargers to most competitions, this is usually enough at most regional events until later in eliminations when battery changes happen more frequently.

3) In previous years we never had a scientific method of testing batteries, we've usually just relied on pre-season robot testing to find out what batteries are the best.

4) After a match ends and the robot is brought back to the pits that battery is immediately put on the charger and one of the charged batteries is staged to go into the robot for the next match.

5) Sometimes you'll come across an older battery or two that won't quite make it through an entire match but will hold enough of a charge to run the robot for some period of time. We usually set these batteries aside for pre-match testing and practice field use. In years that we've used the compressor, we'll often use these batteries to initially charge the pneumatic system. If you don't have enough batteries to do this, then you can always leave the battery from your previous match in your bot up until it's time to go into que for your next match and use that battery for testing and pneumatic charging. No reason to drain a fresh battery before a match just to see if everything's working, IMO.

[nahstobor]

Team 612 takes 9 batteries and usually 4 to 5 chargers. Our logic is that with 9 batteries, that is normally the maximum amount of matches a team would play in the playoffs. 3 QF matches, 3 SF matches, 3 Finals matches. Its also nice to have extra batteries just in case an alliance partner needs one.

[Siri]

1640 brings around 9 batteries and 7 chargers to competition. This lasts us through finals if none break, and usually gives us one to loan to an alliance partner or opponent.

My number one recommendation is to clearly number all your batteries and chargers. We also test all the batteries beforehand with a CBA III and test any questionable chargers as well.

At competition, we use a comprehensive match chart which includes the match number, battery and charger numbers, and battery performance (namely actual starting and final voltage from the dashboard if they're abnormal). We also keep them all carefully sorted in the pit, using a standard sequence as well as checking the charge lights on the SC-600A (highest amperage). We've also purchased a Battery Beak, which we've been using in the shop and plan to use in the pits. We looking to build a battery cart in the off-season, as the current setup is sort of table-space intensive.

[nuggetsyl]

You want to keep up with your batteries. Buy this http://www.crosstheroadelectronics.com/Beak.html

[Bill_B]

Originally Posted by nuggetsyl

You want to keep up with your batteries. Buy this http://www.crosstheroadelectronics.com/Beak.html

I'm using one of these this year. We only have four batteries at present, so knowing the capabilities of each is critical. I have recorded measurements of all batteries at well-defined points. E.g. after each use in a testing session, after each charge session, after each idle period. I expect to use the information as evidence that we need more batteries for competition.

My only objection to the device so far is that it comes with a lanyard (around the neck) that doesn't split. Safety hazard in a mechanical environment.

[kjohnson]

Originally Posted by nuggetsyl

You want to keep up with your batteries. Buy this http://www.crosstheroadelectronics.com/Beak.html

I second this. We ordered one through AndyMark and have found it very useful to give a quick charge rate and reasonable idea of battery health.

[chi-town-biker]

We bought a battery beak this year and think it’s great. If we monitor the internal resistance of our batteries over time using the beak, is that a fair substitute for a CBA III for a team on a budget?

[chadr03]

We are a team on a bit of a tight budget looking into a load tester. Does anyone have any experience with the attached relatively cheap tester from Harbor Freight?


http://www.harborfreight.com/100-amp...ter-90636.html

[Al Skierkiewicz]

Chad,
I would recommend that no team use the linked battery checker. The minimum load is 100 amps. While FRC robots can draw that much, the battery will likely show up deficient on this tester. In the hands of an inexperienced user this tester could cause some internal damage to the battery. The CBA can run a duplicate test to the manufacturer printed test to calculate amp hour rating. The CBA tests can be stored on the host computer and compared over time with the same battery or with all batteries. The Battery Beak is a quick tester that determines battery condition at 1 amp and at 15 amp and makes calculations to determine internal impedance and battery condition. The Beak is a good quick tester while the CBA tests over a two hour period. The Beak fits in your pocket and requires no special cable, the CBA does not fit in your pocket and requires a USB connection to a computer.

[AcesJames]

1) - 7 or 8 competition batteries, 1 "pit test" battery for testing code, charging pneumatics in the pits, etc.

2) - One triple charger and two single chargers (5 batteries max charging at once).

3) - Our EE mentor spends about a week discharging and recharging batteries before competitions start. He reconditions the batteries, and then load tests them. Those which do not pass the competition load test become "pit test" batteries, and they are replaced with brand new batteries for competition use. All passing batteries are then labeled "Competition OK 2012"

4) - We label our batteries by number, and keep a running list of how often they're used during a competition, and what their individual voltages are when they're finished charging. We put 1 charged battery in the robot, take 1 extra charged battery on our cart to the field just in case, and have at least 2 charged batteries ready to replace them in the pits.

[Ernst]

We tested our batteries this year as follows:

1. Acquire battery
2. Plug battery into dc to ac converter
3. Attach volt meter to leads
4. Plug Halogen bulb into converter
5. Turn on converter
6. Turn on bulb
7. Record Battery start voltage
8. Wait for battery to drop below 10 volts
9. Record time taken
10. Label battery accordingly

It took awhile, but worked fairly well for reheating pizza.


Also,

Originally Posted by fox46

Both the teams I mentor use these: http://www.tecmate.com/u_accumate_pro5.php

What are the approximate dimensions of this battery charger? We're considering building a new battery cart (wooden box containing chargers, slots for batteries, and AndyMark battery plugs. On wheels.) and this seems almost perfect.

[Ether]

Originally Posted by ZehP

We tested our batteries this year as follows:
...
2. Plug battery into dc to ac converter
...

FWIW you can buy 300 watt 12 volt bulbs at a pool supply store. Not the safest thing to do either.

1. All of them (we only have 4)
2. 2, maybe? (we only have 1 right now)
3. We plug them into the charger to see it they're charged (no Beak yet)
4. Nope
5. Charge them always. They run out of juice super fast.