Re: Battery Chargers
 

We typically cycle them after every match. Around 8 total.

Re: Battery Chargers
 

We have around 9. We also cycle them every match.

Keep in mind every rookie will get 2 batteries, and every veteran will get 1.

Re: Battery Chargers
 

Going on precedent, but without the 2013 KoP list we don't actually know for sure...

Re: Battery Chargers
 

Re: Battery Chargers
 

Do not try to charge batteries in parallel please. I asked this question of MK and The Battery Association of America (I think that was the name) and both responded that the only way that was acceptable was if the batteries were all purchased at the same time, had been charged the same and had the same loads applied over their lifetime. And then it may work or it may damage all of the batteries. In other words if the batteries were assembled into a larger array and only used that way could other methods of charge and discharge be used. These batteries are not like the large arrays used on electric subs or in large UPSs where the acid is checked regularly and specific gravity is monitored cell by cell.
The best way to test batteries is to use an analyzer like the CBA III from West Mountain Radio. when they can no longer supply more than 15 amp hour, I would move them into the practice pile. When they fall to 10-12 amp hour, then it is time to recycle. If one cell dies before the others, recycle immediately, that cell is likely damaged internally. The Battery Beak from Cross the Road Electronics should also indicate when to remove the battery from competition.

Thanks! Missed that.

Re: Battery Chargers
 

I aim to please. :cool: :rolleyes:

Re: Battery Chargers
 

We bring 8. Enough for testing, matches and loaning.

Wetzel

Re: Battery Chargers
 

Typo on my behalf, I was referring to the NP18-12. Sorry!

We won't be getting the BatteryMINDER, but if we had my intent had been to run it at 4A, not 8A. I understand and see the reasoning behind your perspective that 6A is a purely nominal maximum setting, but I still can't help but be mildly uncomfortable charging batteries rated for max charge currents of 5.1A and 4.3A at "6A" (let alone 8A!)

I thought as much - I was rather skeptical of the method when I noticed it, because I just couldn't see charging them in parallel as a safe method, given that batteries often tend to differ from unit to unit. Thanks for confirming.

We buy a new batch of batteries every year, since most of our robots tend to err towards ridiculous power consumption. Our competition batteries tend to consist of mostly ones we buy that year, supplemented by ones from the previous two years that have good max charge records (we made a simple battery tester in-house that displays the battery voltage measured across a small load on an LCD screen; a "good" max charge record, with reference to our usage, tends to mean that it consistently charges up to 12.5V or higher).

We bring 8 with us. During qualification matches, we'll often have as many as 3 at full charge (the rest are either charging, in the robot for practice/testing/matches, or being used for auxiliary 120VAC through an inverter), but we make sure every battery is fully charged (or as many as possible) going into elims, because of the rapid turnaround time between matches.

Thanks to everyone for the outpour of feedback :)

I'm still curious if anyone has found success with alternatives to the Schumacher and Dual Pro. Speaking of which, it seems that Dual Pro makes an IS3 along the RS3, but I can't seem to identify a difference between the two... :confused:

Re: Battery Chargers
 

Our batteries last 2 or 3 seasons generally, sometimes more. It is critically important to keep them fully charged, even over the summer, since A) they are damaged by sitting even a little discharged and B) they have a self-discharge that requires charging every 60 days or so.

We have 10 to 12 batteries we bring to competition.

Re: Battery Chargers
 

My team usually ends up buying 2-4 batteries each year. We use the best ones at competitions and relegate the older ones for practice or shop testing.

After a team accumulates a lot of batteries, keeping track of their age and condition is a chore. I have ours labelled and we keep a log at competitions. We are careful to use them in sequence, so that the last one used gets to charge and rest while all the others are used. Every battery is labelled with a number and we follow that sequence.

We test every battery once at the beginning of the season on a West Mountain CBA-III. It's a wonderful device which gives a real picture of the battery's condition, but it is time-consuming, often more than an hour per battery.

This year, we are considering buying fresh batteries for competition and calling everything from previous years either practice batteries, or recycling. You can get through most regionals with 6 batteries as long as they are good ones. Use a fresh battery for every match - never more than one match. You have enough time to charge the battery from your first match well before you reach a seventh match.

Put one person on your pit crew in charge of batteries so that they always know what is going on with them. Have them keep a log on a clipboard to track what time the battery went on the charger and when it came off. Analyzing these logs later can identify both weak batteries and defective chargers.

We have a battery manual for the team and review it with the entire team once a season. It covers everything from theory to handling to use and charging to spill procedures and recycling. A copy is kept in the pits for reference.

Re: Battery Chargers
 

Does any one have a solution to running the robot from A/C power? A A/C to 12V converter that's safe for the circuitry.
I seem to recall seeing one on AndyMark, but I can't find it now. This would be handy for programming and imaging.

Thanks

Re: Battery Chargers
 

How much of the robot do you want to run?

A simple 12 volt power supply at a few amps will handle the control system and sensors. You can do a lot of software development that way. It's probably best to use a linear supply, as a fancier "switching" power supply is likely to balk at the boost regulators in the Power Distribution Board.

Motors are another thing entirely. If you want to be able to supply the same kinds of current you can get from a robot battery, you'll end up with something huge, heavy, and expensive.

Re: Battery Chargers
 

We started using these chargers last year after suffering with poor performance from past and present kit chargers, we were loosing them 1 by one.



http://smartercharger.com/products/b...-multi-us-4-3/

Our new battery cart with 6 of those things with all their LED's glowing on the front sure generated a lot of attention at the AZ regional last year.

It's the only charger I will use on small backup generators, and battery backups now too.



We also load tested and purged all of our old and failed batteries and got fresh ones so now we roll with 12 good batteries and 6 good chargers.

Re: Battery Chargers
 

Batteries or chargers? The charger shown appears to be a nice alternative.