How does your team charge & test batteries?

[Ether]

Al,

The unit draws only 125 amps, not 200. The CCA setting on the tester doesn't change the load on the battery, it just affects the computation that the tester displays.

I would use this tester in combination with an inexpensive digital voltmeter to get a reading with more resolution.

Asking an FRC battery to supply 125 amps for 5 seconds is no different from what these batteries often see in competition.

[Japper]

Originally Posted by Ether

Al,

The unit draws only 125 amps, not 200. The CCA setting on the tester doesn't change the load on the battery, it just affects the computation that the tester displays.

I would use this tester in combination with an inexpensive digital voltmeter to get a reading with more resolution.

Asking an FRC battery to supply 125 amps for 5 seconds is no different from what these batteries often see in competition.

That is good to know that this tester may not harm the batteries, as I certainly
wouldn't want to put any additional drain on the battery in the process...

I'm not sure but I am under the impression that when this tester is plugged into a 12 v
battery that it is measuring the voltage under a load (unlike a DMM/ Voltmeter might do)
and the
CCA start test is an additional load test that is selected by adjusting the
CCA voltage on the tester before performing the CCA start test.

Is this correct or is the tester only reading the voltage without a load (like a DMM/ Voltmeter
might do) when the CCA start test button is not pressed?

I wanted to do more than just measure the voltage as I experienced the same situation once
where we had a battery that measured 13 V and it died too soon during a competition...
Once is enough for me thanks...

Thanks for the suggestions and feedback!

[Japper]

OK, I just found out that the battery is not under load until you press
the start test button which applies a load based upon the CCA
(cold cranking amps) that is selected to match what the battery is rated
at but what would be a safe value of this to test the batteries against?

[M.O'Reilly]

Aside from a charging station/battery beak, we cut up red and green pool noodles in 1 inch slices (the kind with the hollow center). When a battery comes off the robot after a match, we pop a red noodle around the wire. When the battery is fully charged (and checked with the beak), we put a green noodle on it. This way, we always have a stock of recognizable and fresh batteries for the quick turnaround matches on Saturday afternoons.

[Ether]

Originally Posted by Japper

OK, I just found out that the battery is not under load until you press the start test button which applies a load based upon the CCA (cold cranking amps) that is selected to match what the battery is rated at

This tester is clearly marketed as a 125 amp tester. I doubt that the selection of the CCA rating affects the load that the tester actually supplies -- only the way the tester interprets the data and displays it on the 3 LEDs. But to be on the safe side, set the CCA to the lowest value anyway (200).

I recommend that you ignore the LED readout, and use the actual voltage under load, and compare it to the value for a known good battery, and keep a time history of each battery's results to see trends.

[Tom Line]

Originally Posted by coalhot

This. I accidentally put a battery just like this in our robot in 2009, went from 13 to 7 volts after the match started (the battery had been killed by trying to test a motor that was shorted, and happened to find a way into the rotation of good ones).

You can ask Akash, we were allied with 11 in that match. There's nothing worse than losing a match because of an error.

Edit: I wish I had a battery beak, it would have prevented the mistake from ever happening. Reason being that the battery beak puts a load on the battery, so if it's actually dead, the beak will show it. Best. Tool. Ever. Wish they existed in '09

The battery beak is an awesome product for a quick check, but it absolutely will not identify poorly performing batteries.

For that, I strongly recommend what Al has suggested a number of times. A West Mountain Radio battery tester.

Even this year, we found several batteries that would test fine on the battery beak, run fine at a 1 or 2 amp draw, then suddenly dump down so that their final amp hour rating was 13 or 12 Ah, rather than around 18.

[Mr V]

The Wel-built load tester like most inexpensive load testers intended for testing automotive starting batteries just load the battery at 125 or 100 amps so you can measure the voltage and infer the CCA based on the voltage under that load.

They do not put excessive strain on the batteries if occasionally used per their instructions and they are a good way to see how the battery will perform when asked to supply the kids of loads that one might see in a match.

The Battery Beak is good for seeing the internal resistance of the battery, which does give you some insight as too its health, and it's SOC.

A volt meter will only give you and indication of the SOC but no info on the health of the battery.

[Ether]

Originally Posted by Mr V

The Wel-built load tester like most inexpensive load testers intended for testing automotive starting batteries just load the battery at 125 or 100 amps so you can measure the voltage and infer the CCA based on the voltage under that load.

...which is why I said in my previous post that changing the CCA setting on that tester doesn't change the load, it just changes the way the tester computes and reports the battery's health: Presumably if you've told the tester that the battery under test is 500 CCA it expects to see a somewhat higher voltage under load than for a 200 CCA battery.

[Mr V]

Originally Posted by Ether

...which is why I said in my previous post that changing the CCA setting on that tester doesn't change the load, it just changes the way the tester computes and reports the battery's health: Presumably if you've told the tester that the battery under test is 500 CCA it expects to see a somewhat higher voltage under load than for a 200 CCA battery.

You are correct.

[Al Skierkiewicz]

Never drain these batteries all the way down. This is a technique that was used on old chemistry NiCad batteries, never for lead acid.
Ether, the instruction sheet is very misleading by specifying 200-1000 amps and then specifying 125 amps. A team once showed me a tester they were using to make tests and when they connected it to the battery a resistor glowed inside. Since that day, I have been leary of any automotive type tester.

[Mr V]

Originally Posted by Al Skierkiewicz

Never drain these batteries all the way down. This is a technique that was used on old chemistry NiCad batteries, never for lead acid.
Ether, the instruction sheet is very misleading by specifying 200-1000 amps and then specifying 125 amps. A team once showed me a tester they were using to make tests and when they connected it to the battery a resistor glowed inside. Since that day, I have been leary of any automotive type tester.

I've never seen a load tester intended for automotive starting batteries that loaded the battery except when the momentary switch was activated. When that is done yes you can see a resistor glow in some of them IF you leave in in the "load on" position long enough.

As mentioned above all of this style (inexpensive) load tester I've ever seen applies a fixed load of 100 or 125 amps and is only intended to do so for 5 or 10 seconds. Now there are testers out there that are adjustable and can put a higher load on the battery but I've never seen one that didn't cost hundreds, if not thousands, of dollars.

Really there is no reason to be leery of this style of tester. For it to be able to drain a healthy, fully charged, FRC legal battery down to a 0 SOC you better have some serious gloves on because it will become too hot to touch, or you'd have to run the test over and over and over again w/o charging the battery. The key is using it as intended with no more than a 5 or 10 sec load on the battery.

[Ether]

Originally Posted by Al Skierkiewicz

Ether, the instruction sheet is very misleading by specifying 200-1000 amps and then specifying 125 amps.

It's written in Chinglish, Al. Ya gotta read between the lines.

[mman1506]

We use a Dual PRO RS3 and it works great. We used to use a raw car battery charge with 9 batteries in parallel but it only charged the battery to 12.6 volts and slowly.

We put a boat battery on are cart with a Turnigy accucell 6 wired up for internal charging, Last minute queue charging and secret overnight charging. What's nice about it is that it has a display to show the voltage and it runs of a 12v supply (it will charge above 12v). It's also dirt cheap

[hobbes20xxx]

One of our mentors built us a battery tester back around 2009 that puts a 30 amp load on the battery with voltage feedback, leave it on for about ~15 seconds and hope your around 11.5V...

[Calvin Hartley]

My team has a battery cart with a 3-way charger like this one. We use a Battery Beak for testing. I highly suggest the Battery Beak. Hope this helps.