Be aware of battery and charger inconsistencies!

[BigJ]

You can argue however much you want about how it isn't really a rule, but when the LRI tells you that it's not allowed to be used on your robot batteries, you aren't going to win.

[Chris_Ely]

Originally Posted by sanelss

that's only a recommendation and the safety guidelines aren't really competition rules, they are just that, guidelines. We may not win a safety award but this doesn't seem illegal. Esp considering the chargers state automatic charge current setting with no specification for capacity rating so we believe we are working well within the design constraints of both the battery and charger. Worst case we use a 6A charger for bulk charge then these for top off and consistency guarantee.

Except that the Safety Manual is not just guidelines.

Originally Posted by Safety Manual

This manual applies to anyone involved with the FIRST Robotics Competition including all student team members, Mentors, and support personnel.

The spec sheet for the battery that I linked to in my post above states that the maximum charging rate for these batteries is 5.4A. You will damage you batteries if charge them above this rate.

[sanelss]

Originally Posted by Steve W

I am sorry to disagree with those that state there is no rule about chargers. It is found in the safety manual and as LRI's we have been told to enforce it. The highlight is mine but a direct quote. From the safety manual:

"Charging and Handling
 Keep the battery-charging area clean and orderly.
 Place your battery charger in an area where cooling air can freely circulate around
the charger. Battery chargers can fail without proper ventilation.
 Do not short out the battery terminals. If metal tools/parts contact the terminals
simultaneously, it will create a direct short circuit. This may cause high heat to
develop in the battery terminal/part/tool area and the battery could explode.
 If a quick disconnect is not available and you must use tools to disconnect the
battery, make sure metal tools don’t contact both terminals at the same time.
 Do not charge battery at greater than the manufacturer’s maximum recommended
rate."

We consider the safety manual as guidelines not competition rules. If everything stated in that manual were enforced then every single team would be disqualified for one reason or another. Also the chargers state they automatically set he charge current. Even if they do deliver more than 7A it's not for a very long time either. Worst case is we do bulk charge on old 6A chargers then top off with these. That way they never do get charged higher than 6A but this is just playing around a technicality and more or less on a guideline rather than a competition rule anyway. Either way it won't really be an issue if that's all we have to adhere to.

[sanelss]

Originally Posted by BigJ

You can argue however much you want about how it isn't really a rule, but when the LRI tells you that it's not allowed to be used on your robot batteries, you aren't going to win.

then we'll just play around it. do bulk charge on old 6A and top off with these, win-win?

[Chris_Ely]

Originally Posted by sanelss

We consider the safety manual as guidelines not competition rules. If everything stated in that manual were enforced then every single team would be disqualified for one reason or another. Also the chargers state they automatically set he charge current. Even if they do deliver more than 7A it's not for a very long time either. Worst case is we do bulk charge on old 6A chargers then top off with these. That way they never do get charged higher than 6A but this is just playing around a technicality and more or less on a guideline rather than a competition rule anyway. Either way it won't really be an issue if that's all we have to adhere to.

The charger you linked to is meant for car batteries, not FRC batteries. The charger does not know that the battery connected to it is not what it is designed for.
The safety rules are rules, and you will be told to follow them.

[sanelss]

Originally Posted by luckof13

Except that the Safety Manual is not just guidelines.

The spec sheet for the battery that I linked to in my post above states that the maximum charging rate for these batteries is 5.4A. You will damage you batteries if charge them above this rate.

It's not that we set the charge rate to 15A, the charger states: "automatically selects charge rate from 0 to 15 AMPS to maximize battery life, charge speed and maintenance" it also makes no claims as to a rating of battery it can/can't charge. From other online documentation I found there is no danger at charging up to 1C other than shortening the battery life, which you may consider damage I suppose though. Honestly i'm no worried since we can work around it by bulk charging on 6A then cycling to these for top off

[GearsOfFury]

Originally Posted by sanelss

then we'll just play around it. do bulk charge on old 6A and top off with these, win-win?

At the week 1 event I inspected at, our LRI (Al) specifically asked us to look for chargers that operate above 6A, and instructed that they WOULD NOT be allowed, regardless of how you told us you would "program" or use them. OP there is no way for us to enforce that you are following what you are suggesting. I would highly recommend you bring other (i.e. legal) chargers to your event and consider leaving these at home.

[efoote868]

Originally Posted by sanelss

From other online documentation I found there is no danger at charging up to 1C other than shortening the battery life, which you may consider damage I suppose though. Honestly i'm no worried since we can work around it by bulk charging on 6A then cycling to these for top off

1C for a 40AH car battery is different and bigger than 1C for a 17AH FRC battery.

[sanelss]

Originally Posted by luckof13

The charger you linked to is meant for car batteries, not FRC batteries. The charger does not know that the battery connected to it is not what it is designed for.
The safety rules are rules, and you will be told to follow them.

actually it makes no claim as to what types of batteries it can and can't/shouldn't charge. The only indicator is: "automatically selects charge rate from 0 to 15 AMPS to maximize battery life, charge speed and maintenance"

From some online documentation it shows that batteries can be charged faster than manufacturer's recommended rate but it shortens their lifespan, which is fine.

Also from numerous places people are charging all kinds of batteries with these, including FRC batteries. It's a general purpose 12V lead acid battery charger, we are using fairly generic 12V lead acid batteries.

Even so we can easily adhere to the rules by bulk charging on old 6A then cycling to these for the top off

[sanelss]

Originally Posted by GearsOfFury

At the week 1 event I inspected at, our LRI (Al) specifically asked us to look for chargers that operate above 6A, and instructed that they WOULD NOT be allowed, regardless of how you told us you would "program" or use them. OP there is no way for us to enforce that you are following what you are suggesting. I would highly recommend you bring other (i.e. legal) chargers to your event and consider leaving these at home.

there are a lot of things that you can't enforce what a team says they will do other than to take their word for it. As stated we can work within every single rule and planned on it anyway, that doesn't mean that just because something CAN be used in a way that violates the rules that it WILL and that doesn't mean it SHOULDN'T be used just because it might if not used properly. Kind of like the usage of a dremel.

[tim-tim]

Originally Posted by sanelss

Even so we can easily adhere to the rules by bulk charging on old 6A then cycling to these for the top off

How is "cycling to these for the top off" adhering to the rules? If you can't use them, you can't use them.

Adhering to the rules would mean to use (and only use) LEGAL chargers at ALL times, while at the event. This would mean that the batteries never see the charger you are suggesting.

Save yourself the headache and space by leaving the charger at home when you compete.

[sanelss]

Originally Posted by efoote868

1C for a 40AH car battery is different and bigger than 1C for a 17AH FRC battery.

indeed it is, but battery ratings are in C which is relative to capacity and is more or less identical for each type of battery chemistry unless it was specifically designed a bit differently for some purpose. These are general purpose lead acid batteries, so as far as C ratings go the documentation talking about C ratings for generic lead acid batteries still applies. That's why the documentation does it this way, because it applies to all batteries of that chemistry regardless of capacity.

[Ether]

Originally Posted by sanelss

It's not that we limit it, it's that they simply aren't sufficiently usable. We have batteries going back a few years and 2012's and back simply don't perform as required

How do you store your batteries during the off season?

[sanelss]

Originally Posted by tim-tim

How is "cycling to these for the top off" adhering to the rules? If you can't use them, you can't use them.

Adhering to the rules would mean to use (and only use) LEGAL chargers at ALL times, while at the event. This would mean that the batteries never see the charger you are suggesting.

Save yourself the headache and space by leaving the charger at home when you compete.

because there is no distinction to what is and isn't a legal or illegal charger. the rule states "Do not charge battery at greater than the manufacturer’s maximum recommended rate." which we can adhere to by doing bulk charge on 6A chargers then top them off with these where we know for a fact it won't draw even 2A. Just because something can be used it one way doesn't mean it will and so long as we adhere to the rule the usage of such a device is permitted.

Also leaving them at home is not an option. Our older chargers are not acceptable for robot performance. Each one charges the battery differently which is a major problem for us. I'll post on the QA and look for an official response but regardless I believe we can easily adhere to the rules to there shouldn't be any problems.

[Chris_Ely]

Originally Posted by sanelss

actually it makes no claim as to what types of batteries it can and can't/shouldn't charge. The only indicator is: "automatically selects charge rate from 0 to 15 AMPS to maximize battery life, charge speed and maintenance"

What "automatically selects charge rate" most likely means is that it does what most other "automatic" chargers do: cycles through a factory-set charging algorithm which changes the current and voltage supplied to the battery.
http://batterytender.com/resources/battery-basics.htm/