Battery issues

I have 12 V5 kits. In the first week I had 2 batteries just stop working–no lights at all. I do have the new firmware. I rec’d 2 replacement batteries. Now I have 2 more that are dead the same as the first. We are using them just to learn basic programming. We use them 40 minutes a day. What is the recommended charge protocol? I want to be sure we are doing everything we can to prolong the life.

@LBrobotics Have you tried resetting the battery? I dont know exactly where the reset button is at but you’ll need a paper clip to reach it. That should help.

LifePo4 batteries are funny. To get maximum performance out of LifePo4 batteries, you need to cycle these batteries about 20 times before they can perform their optimal.

These LifePo4 batteries do not like to be over charged and or under charged. I would recommend don’t let the battery go under 15%. If you see battery life is 15% or less, go ahead and charge it immediately. With version 1.02, I think the over charging of VEX Battery has been fixed. I would remove the battery from charge once it is fully charged.

LifePo4 battery can have life 2000+ charge cycle. That means if you use the battery and charge it once every day, the battery should last 5+ years.

Ok, a few comments here.

Please stop reseting the batteries as a “fix all” solution. The only time to ever reset a battery is if it fails to light one or more leds when pressing the level button or plugging into the charger.

With the latest firmware, there are no concerns about leaving the battery on charge once it has finished.

The battery will shutdown the V5 brain when it reaches both low capacity and low voltage, usually capacity is about 5%, it’s ok to run it this low but don’t keep turning on the brain if the battery led is red and capacity low. I would agree, it’s best to put the battery on charge before it reaches this point if practical.

It’s also ok to keep topping off the battery, there are no memory effects for this type of chemistry.

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Hi, can you please tell us what all the various LED signals mean (besides the obvious green bar)? Sometimes our battery blinks red (really fast) when button pressed. We assume this means dangerously discharged, but sometimes it does that when charging, one time we had both the red blinking and the green lights after pressing the button, etc. (firmware 1.0.2). Most of the time while charging the usual green LEDs blink, but at one time all 4 green blinked once a second. Would like to be able to interpret all these signals.

Also (forgive/disregard if too off topic) what does it mean when a V5 red motor LED blinks rapidly?

Thank you.

I’ll post some information on the current battery led later, however, it’s going to change again in the next couple of weeks to allow the different errors to be identified a little better.

That usually indicates you have enabled dashboard on the brain for that motor, it’s a quick way to identify which motor is on a particular port.

What are the negative impacts of this, knowing that for many high school students, pushing the reset button is probably going to come before asking for help when something goes wrong?

The battery does some quality of life stuff like keep track of how many charges it has done and what it’s true capacity is. My understanding is reset loses all that information.

This can be harmful if the battery is trying to compute “am I so dead I should turn off”.

That makes sense. Anything else? Specifically, anything that may act as a diagnostic to indicate that the battery has been inappropriately reset too many times? Losing data like that is certainly a concern and reason enough not to make that the first line of defense. Just preparing for what will happen when it is done a lot.

One of our team’s batteries died. It possibly could have been from overcharging but we asked our coach to try resetting it and it seemed to not even click or push in and the reset button was ineffective. We tried charging it and the battery did nothing. We saved it just in case and tried emailing vex about it, but they never got back to us on that.

The impact will be that the most recent history for the battery management system will be lost. This may only be a few minutes, but could be longer. The result will usually be an incorrect display of battery capacity until the next full charge/discharge cycle has occurred, but it will also impact things like charge cycle counting. The reset switch was hidden for a reason, it’s a last resort solution. I understand that with the original battery firmware its use was needed far too often, however, after the October update we would hope that battery “crashing” (for want of a better term) is a thing of the past assuming the battery is still in good condition.

In general green is good and red not so much.

The green leds will show the capacity, if the red led displays when you push the button less than 10% remains.

A fast red flashing led can indicate one of two things. If the battery is connected to the robot and is discharging, it means critical low voltage, the battery should be charged. If the battery is being charged it means there has been a charging error, this can happen if one of the cells has become damaged or if one of the cells achieves full charge before the others. We are improving the handling of this condition in the next release, if after a few discharge/charge cycles the flashing red led does not go away when charging, the battery may have been damaged.

A slow flashing red led is extremely rare, it is another type of charging fault that would usually mean we have been charging for too long but can also be trigger by other conditions. Charging will have been terminated if this happens.

A solid red led that illuminates when powering the V5 brain when no other buttons are being pushed means that shutdown due to low voltage/capacity is imminent, usually you would have less than 10 seconds before the V5 will turn off.

All this relates to firmware in vexes 1.0.2.

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Is it still a bad idea to charge the V5 battery while it’s plugged in to the brain? (or was that just bad if the brain was turned on?)