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  #46   Spotlight this post!  
Unread 06-03-2014, 16:22
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Re: Be aware of battery and charger inconsistencies!

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Originally Posted by sanelss View Post
we are aware it will decrease the battery life but we don't care.
You should. Batteries are expensive, and you do plan on competing in FIRST for multiple years, right?
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  #47   Spotlight this post!  
Unread 06-03-2014, 16:23
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Re: Be aware of battery and charger inconsistencies!

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Originally Posted by luckof13 View Post
How do you know that the charging rate will not be above 6A?
The 15A charger will supply 15A to the battery at some point in it's charging cycle--it's part of it's charging algorithm to charge car batteries. It doesn't matter how long the battery is connected. This means that you will violate the rules if you use that charger.
Also, 6A is pushing it for these batteries. You should charge your batteries at the lowest charging rate you can get away with to maximize the lifespan of the batteries. The only thing charging at a higher rate gives you is less time to charge.
it will to a dead battery but we never plan on putting a dead battery on these chargers. only batteries that are indicated as fully charged by our old chargers. essentially we are just taking a charged battery, and moving i to another charger to maintain trickle. So no, no rules will be violated since it will never get into that state where it can possibly output that much current. No commercial charger is "dumb" enough to output anywhere near that much current to a battery that's indicated as already fully charged. We can argue this until the cows come home but from our observations this state is never achieved so we do fall within the rules.
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Unread 06-03-2014, 16:25
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Re: Be aware of battery and charger inconsistencies!

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Originally Posted by Ether View Post
My tentative working hypothesis, based on the presently insufficient information available, is that the Stanley BC1509 is overcharging the FRC battery (for which it was not designed).



Some "smart" battery chargers are not smart enough. If you interrupt them in the middle of a charge cycle and then try to continue, they may mis-read the state of the battery and fail to complete the charge cycle. I know my Schumacher SC-1200A sometimes does this.


according to the information here: http://www.powerstream.com/SLA-fast-charge.htm with the max charge voltage this thing outputs it can't go into an overcharge state. it can be a higher than 0.3C rating yes but no overcharge.
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Unread 06-03-2014, 16:27
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Re: Be aware of battery and charger inconsistencies!

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Originally Posted by cgmv123 View Post
You should. Batteries are expensive, and you do plan on competing in FIRST for multiple years, right?
we already have and will continue to. We get about 4 batteries every year and the ones from the previous year are still good so we can manage with those. We care more about battery performance during a game than longevity.
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Unread 06-03-2014, 16:30
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Re: Be aware of battery and charger inconsistencies!

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Originally Posted by sanelss View Post
according to the information here: http://www.powerstream.com/SLA-fast-charge.htm with the max charge voltage this thing outputs
I don't see a max output voltage spec for the Stanley BC1509 anywhere on the page you linked.


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Unread 06-03-2014, 16:30
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Re: Be aware of battery and charger inconsistencies!

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Originally Posted by sanelss View Post
The max charge current is actually irrelevant to us, what matters is the state the batteries are in when they get taken off the chargers.
Until you find that the state of a battery includes bulging sides & won't fit in your robot, or until it's smoking. Then the manufacture's max current spec may become more important to you.

And before you ask: no, I haven't seen either of these personally. However, I do trust Big Al, who has seen them & told his inspectors at Central IL (one of which was me) about it when he told us to look for >6A chargers.

I'll repeat what someone else said earlier: if it comes down to a disagreement on this -- regardless of the evidence you present -- between your team and the LRI, you're not going to win. Unless you have a Q&A answer that states your chargers are legal. When you craft your question, you should be specific about the charger you would like to use.
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Unread 06-03-2014, 16:33
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Re: Be aware of battery and charger inconsistencies!

Thought I might ask here,

We are currently using the Schumacher SSC-1000a 2/6/10amp charger.
It does support motorcycle/tractor/jetski batteries, which the FRC battery seems to resemble.

The amount of charge has to be selected after the battery is attached. We only use the 6a mode during competition and the 2a mode for overnight trickle charge / maintenance.

We are going to order a few more to bring to our regional competition. Is this charger NOT going to be allowed?

Here is a link to the charger information.

http://www.amazon.com/Schumacher-SSC-1000A-SpeedCharge-Battery-Maintainer/dp/B0009IBJE4/ref=sr_1_3?s=automotive&ie=UTF8&qid=1394141261&sr= 1-3&keywords=schumacher+sc1000a

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  #53   Spotlight this post!  
Unread 06-03-2014, 16:36
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Re: Be aware of battery and charger inconsistencies!

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Originally Posted by sanelss View Post
...we will move over to the stanly, there is actually a current readout of the charge rate so yes we did measure it and once it reaches a certain point it goes into float charge which documentation states is not more than a few amps.
Of course the float charge will be very small.

What I was asking was how long does it take to get to that certain point, and what is the current while it is getting to that certain point.


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Unread 06-03-2014, 16:39
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Re: Be aware of battery and charger inconsistencies!

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Originally Posted by sanelss View Post
...the old chargers can't put out more than 6 so they will charge them as much as they can until hey reach a fully charged status(which isn't really fully charged it seems like)
Are you actually measuring the state of charge with some test equipment?


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Unread 06-03-2014, 16:40
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Re: Be aware of battery and charger inconsistencies!

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Originally Posted by Ether View Post
I don't see a max output voltage spec for the Stanley BC1509 anywhere on the page you linked.


oh sorry it just tells you this when it's charging, when we do put dead batteries on it's 14.x i don't remember the last digit. I can grab a multimeter if need be bu from what i've seen it never goes above 15V which according to that info can't cause an overcharge state
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Unread 06-03-2014, 16:41
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Re: Be aware of battery and charger inconsistencies!

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Originally Posted by luckof13 View Post
How do you know that the charging rate will not be above 6A?
The 15A charger will supply 15A to the battery at some point in it's charging cycle
That is not necessarily true. It depends on design of the charger and the health and state-of-charge of the battery when the cycle is started.


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Unread 06-03-2014, 16:43
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Re: Be aware of battery and charger inconsistencies!

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Originally Posted by sanelss View Post
From the information I found online here "http://www.powerstream.com/SLA-fast-charge.htm" there is absolutely no danger what so ever in using this charger with these batteries. Possibly through missuse or abuse but under normal conditions nothing dangerous should happen.
You're probably right. But that still doesn't make it legal. Have you posted to Q&A yet?


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Unread 06-03-2014, 16:45
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Re: Be aware of battery and charger inconsistencies!

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Originally Posted by Ether View Post
Of course the float charge will be very small.

What I was asking was how long does it take to get to that certain point, and what is the current while it is getting to that certain point.


I can't tell you exact numbers at this moment but i can get them and can use them as proof that we are within the rule. However it's not even really needed all we want to use these Stanley for is trickle. as stated we will be putting fully charged batteries(as indicated by our old chargers) on these stanly so they should only ever be in a trickle mode. even if they arnt' i wouldn't imagine it be more than a few amps anyway but can verify this and will when I get around to it.
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Unread 06-03-2014, 16:48
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Re: Be aware of battery and charger inconsistencies!

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Originally Posted by Ether View Post
You're probably right. But that still doesn't make it legal. Have you posted to Q&A yet?


no not yet, but again the rules state nothing about chargers, only charge rate. I can prove that we fall within the rules with the method mentioned in several other replies of only putting fully charged batteries from old chargers on the Stanley simply to trickle charge. that's what really matters to us is the quality of the trickle charge, not the brunt current capability.
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Unread 06-03-2014, 16:51
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Re: Be aware of battery and charger inconsistencies!

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Originally Posted by GearsOfFury View Post
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.
I don't agree with inspectors not taking a team's word for it. As mentioned previously, the rule states that we shouldn't charge more than the manufacturer's spec charge rate, which is set at 5.4 Amps. If that's the case, why are you allowing chargers that go up to 6 Amps? If we're adhering strictly to the rules (and FIRST has a tendancy to do that), we shouldn't be charging at 6 Amps either. Most chargers have a selectable charge rate from 2 A, 4 A and 6 A. To satisfy the rule, we would have to charge at 4 Amps. But right there, you're taking the team's word for it that we're going to charge at 4 Amps. The rule doesn't say that chargers that are capable of charging more than that are against the rules. The rule states that teams shouldn't charge more than the recommended maximum charge rate. It's a subtle, yet important difference. If we ruled out all chargers that are capable of charging at greater than 5.4 Amps, then most every team in FRC will need to get new chargers. Take the team's word for it and be done with it.
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