I have seen a few teams with some elaborate battery stations but I am looking for an inexpensive way to ensure that our batteries are fully charged before each match.
Recently I bought a Wel-Bilt 125 Amp battery load tester from Northern Tool but not sure how well this will fit the bill.
Anyone with experience with this tester or with helpful suggestions is appreciated.
Thanks and Best wishes to your teams at the competitions…
As a preseason project, we made a batter charging station. it is on wheels and painted our team’s colours. It can charge 12 batteries at once and is nicely organized.
We just use the load tester you bought to test batteries preseason. During competition we a Fluke voltmeter to check how charged the battery is. As for a system of charging batteries, we label each battery a letter. Starting with A we use them sequentially for each match. This seems to work for us because the battery we use next is the one that has been charging the longest and theoretically should have the best charge. I hope this helps!
Buy a Battery Beak!!! Such a great product! I sound like an infomercial but after using one of these things I will never need anything else for batteries.
We use the battery beak during competition. Full charge is 115% or above. In the off season we perform a capacity check on the batteries to ensure they are still useable.
We also built a 9-battery charging station using the tripple battery chargers from Andymark. They are much better than the charger FIRST supplies with the KOP.
Our battery charging station uses 2 4-bank battery chargers (http://tinyurl.com/a95lyts) to charge our batteries. It can probably hold 12 batteries, but we only have 8 good ones which is why we bought two 4-bank chargers. The chargers have led lights that are supposed to represent the charging state of each battery, and they seem pretty reliable, but we just use a standard multimeter to test batteries. That Wel-bilt tester seems like it would work fine, but it doesn’t seem to do anything that a multimeter couldn’t. Anyways hope this helped!
The only thing a multimeter will tell you is voltage. You can charge a battery that is shot to 13V, but it could drop out on you 15s into the match. A multimeter won’t catch that.
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
Using a multimeter to check the voltage of a battery is only accurate to know the charge status of a battery, not whether it is “healthy” or not. Some batteries may appear to be fine after checking the voltage but will not be able to provide high current draw without significant voltage drops.
Load testers will give a more accurate assessment of the health of a battery.
Japper,
I would recommend against the use of the device you list. It is intended for batteries with a much higher capacity/peak current. Continued use of this device is likely to shorten your battery life.
The use of the West Mountain Radio CBA III or the Battery Beak is a much better choice for FRC batteries. The CBA will allow you to test the battery the same way method as used by the manufacturer and the Battery Beak is a simple, pocket tool to give a good indication of battery health.
As pointed out above, a voltmeter tells you nothing other than a cell is shorted of the battery is open.
*The Wel-Bilt 125amp tester doesn’t look like it’s intended to be used like the CBA (i.e. hooked up to the battery and left for a period of time discharging the battery).
It’s more like the Battery Beak, only with a much higher load.
Is a 125 amp load applied to the battery for 5 seconds once or twice a year going to harm the battery?
*** @ Japper: can you post a pic of the user instructions for this product? I couldn’t find them online.**
Do you use it to test Cold cranking amps (CCA) and a start test or do you just connect it to
a battery to measure the voltage under a load?
If you are testing CCA what are you setting the CCA value to?
Not a bad tester for $24 (on sale)…but I had to upgrade mine with a pair of anderson connectors
beween the unit and the clamps…
thanks
I scanned the instruction manual in and attached it to this post…
thanks
wel-bilt 125 battery tester.pdf (244 KB)
wel-bilt 125 battery tester.pdf (244 KB)
Ether,
The sheet is hard to interpret but the specs state CCA of 200-1000 CCA. Each test lasts 5 seconds. If the tester is in the 200 amp setting it might be OK for our batteries but we rarely will draw current for that length of time. My general rule of thumb is always to submit the battery to the least amount of shock. This type of tester will ultimately lead to decreased life in my opinion.
I don’t know all the specifics but 955 built a 4 battery cart with a custom board that drains batteries all the way before charging them again to ensure maximum charge. Probably too much to do before competition as it took them 3 years
*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!
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?
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.
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.