Battery Best Practices

[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.

[Ernst]

Originally Posted by Ether

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

We just used a shop light that we had lying around.

[Ether]

Originally Posted by ZehP

We just used a shop light that we had lying around.

Was the DC to AC inverter lying around too? Or did you have to purchase that for this use?

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.

[Al Skierkiewicz]

Nick,
Can't wait to see it.

[Ether]

Originally Posted by 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

The Genesis NP18-12R battery (2012 FRC KoP) datasheet¹ indicates that it is rated up to 150 amps, so in theory you could measure it with a 100amp load tester, but:

1. The datasheet does not list any manufacturer specs at that high discharge rate, so any assessment based on testing done at that rate could only be relative to other batteries tested the same way.
   
   
2. In the wrong hands, testing at 100amps could damage the battery or be a real safety hazard.

Use something else.

¹ http://www.batteryplex.com/sheets/NP18-12R.pdf

[Captaindan]

Originally Posted by 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

yes ours is still going strong after 2 years and an anderson connector soldered to it