MK 12 volt battery question
 

Re: MK 12 volt battery question
 

The batteries are slightly different from those last year. I'm not sure of exact specs. You are not aloud to use batteries from last year as this would create an unfair advantage to those teams who dont have those batteries from last year

Re: MK 12 volt battery question
 

It is not the voltage of the battery that is different. It is the model number. If you would go look at your batteries from previous years you would notice the are exide ES-xxx* model number. EX-xxx* != MK 12

-John

*I do not know the exact model number off hand.

Re: MK 12 volt battery question
 

Specs for the 2007 battery are here.

Specs for the 2006 battery are here.

The new one appears to have about 10% less stated capacity at 1C discharge rate. So if you could use the older battery you might get an advantage over a team using the new one -- which is almost certainly the reason why the older ones are not allowed this year. For more, see this post.

Re: MK 12 volt battery question
 

And it is definetly fair to all of a sudden make the batteries from previous years extinct in order to make the teams who collected their batteries from previous years and who can't afford to buy 10 extra batteries like other teams go through all the trouble of possibly losing qaulifiers due to the fact that the batteries don't charge fast enough.

Sadly there's nothing we can do about that. Might as well learn to deal with it. Big disappointment but oh well.

Re: MK 12 volt battery question
 

Not every team is going to be in a match at the same time. We do know how to share.:D

Re: MK 12 volt battery question
 

Everyone's in the same boat. Everyone has only 2 batteries and no collected batteries from previous years. That is, in fact, MORE fair than everyone but rookies having a collection of batteries from prior years. You can still use old batteries for testing and practice day. You have more chargers than the rookies. With even a little bit of effort on your part to solving the problem you could make 2 batteries work just fine for a regional. If you buy just one extra battery you should be more than covered. They can be had for around $50.

I speak from experience by the way. 57 takes just 3 batteries anywhere we travel and we don't have any problems.

Re: MK 12 volt battery question
 

One of the bullets in <R46> says:

I interperet that to say that we can only use the 2 batteries provided in the kit. Opinions?

Re: MK 12 volt battery question
 

If that is FIRST's intention, I don't think it could be enforced. (How would FIRST know if a team brought more than two batteries to the regional?)

That said, I wonder if that is a mistake in the manual.

Re: MK 12 volt battery question
 

That rule was the same last year as well. You will be able to buy more of the same battery and use them, as long as they are the same as the ones in the KOP.

Expect a clarification in the Q&A or a Team Update.

Re: MK 12 volt battery question
 

No. I would interpret that to mean we can't use a battery in the kit, and another battery not in the kit at the same time on the robot.

Re: MK 12 volt battery question
 

I would interpret this:
To mean that we can purchase additional batteries, and therefore, use them in competition, as long as they are MK ES17-12s.

-Nate

Re: MK 12 volt battery question
 

Agreed. R46 covers what you can use ON the robot at any time. No using 2 batteries at once, no using a different battery on the robot. Doesn't cover what you can have at the comp. So I would expect some Q&As but no updates on that.

Re: MK 12 volt battery question
 

Don't know if anyone has noticed this, but the new batteries seem a bit heavier as well. We pulled out the scale today and clocked them at about 13.5lbs, which is about 1.5 lbs more than the old batteries (someone correct me if I'm wrong that the old ones weighed 12lbs)

Re: MK 12 volt battery question
 

Richard,

There are some major differences between the two sections of spec sheets you posted.

That's a huge difference. The Exide battery from 2006 had a 230A max discharge. Can anyone confirm which of these is right? Am I missing something here? If the max discharge has dropped all the way to 90A, we'll definitely be reconsidering our motor usage.

Re: MK 12 volt battery question
 

Based on the spec sheets linked by Richard, the new batteries are only about .4 lbs heavier

The old exides list approx 13.44 lbs while the new MKs list 13.82 lbs

I'm more concerned about the max current draw - like Karthik said, if the draw is that much different than it will definitely have an impact on robot performance and capabilities

Re: MK 12 volt battery question
 

I'd guess that the 90A figure in the top section is an error. The lower section shows 360A maximum discharge current for 30 seconds. Also, the discharge time vs. discharge current curves shown near the bottom indicate several minutes capability at 3C (54A) discharge current; this is similar to the 3C capability of the older battery. It appears the new and old batteries are similarly constructed, and that the new one is designed for slightly (~10%) lower capacity. This may be a design trade-off to allow higher short-duration discharge currents. (A little more lead, a little less acid.):]

Re: MK 12 volt battery question
 

Karthik,
The specifications on the MK site are very close to the specifications for the old battery. The differences are slight enough to merely be differences in testing methods or the influence of the marketing departments. A close inspection of the discharge curves show that they are at slightly different currents from the batteries we have used in the past. A quick interpolation of the data would show them to be almost identical. Let's face it, a battery of the same physical size and chemistry with the same amp hour rating is going to be pretty close in performance. You can only pack so much lead and acid into that package. I hate to have to buy new batteries this year but if those are the rules then so be it.

Re: MK 12 volt battery question
 

As I am reading this chart it seems the new battery has a HIGHER discharge rate. 5 seconds @ 720A this years battery and last years battery is 5 seconds @ 230A. Therefore it would better seem the new battery is BETTER for burst and a quick pushing match...

-Mike

Re: MK 12 volt battery question
 

Mike,
Although that specification looks different, last year's battery was capable of the same high current for short periods and when new and fully charged. "Your mileage will vary." In fact most teams will not be able to draw this kind of current simply because there are other limiting factors like the combined resistance of the wiring, breakers, speed controllers and connectors.
Remember that the real test will be how much you can draw over a two+ minute match and remain above 8 volts, the critical cutout for the RC.

Re: MK 12 volt battery question
 

Reading the label on the battery, this years battery is 18AH instead of last years 17AH.

The R46 rule says the use of batteries different from or in addition to the ones provided, nothing about more then one on a robot.

This can be read as the ones given in the KOP are the only ones to be used on the field.

Re: MK 12 volt battery question
 

First of all, last year's battery was an Exide ES 18-12 (or the EX 18-12, in some cases), which is the same battery that we have used for many years, and it is indeed an 18AH battery. Many people have linked to the datasheet for this, so you can confirm there.

Also, as stated before, <R53> clearly states that we CAN purchase additional MK batteries for use during the competition. <R46> states that you can not use more than one battery on the robot during a match.

-Nate

Re: MK 12 volt battery question
 

You are right but it does not matter because it dose not factor into the weight of the robot.

Re: MK 12 volt battery question
 

Thanks for listing the specs for the 2007 battery

Re: MK 12 volt battery question
 

Thank you, there are many conflects in the rules.

Re: MK 12 volt battery question
 

It appears that the new batteries should not have a great effect on teams. MOE only uses the new batteries in competitions any way, and the old ones are perfectly legal for practice. As always, we're always willing to share with other teams, just let us know you need them:)

Re: MK 12 volt battery question
 

The 10% difference sited on old vs new battery may or may not exist. The old battery specs its 9Ah at 0C/32F. The new battery specs its 8.1Ah at 25C. Specmanship in play as the temperature of the measurement is important.

The old battery lists 9AH with a 18A (1C) draw at 0C/32F temperature.
It also has a curve for 20C/68F which shows roughly something like ~7.5Ah-8Ah (hard to get exact with the log graph shown but looks like 24+/-2 minutes until 100% depth of discharge (DoD) is reached).

The new battery lists 8.1Ah with 18A (1C) draw at 25C, about 27 minutes to 100% DoD. The actual discharge graph only shows a 17A discharge curve, but it too looks to be in the 28 minute range to 100% DoD.

http://www.rpci-inc.com/pdf/ES17-12.pdf

I overlaid the discharge curves between old/new. The 17A/18A are green/red curves. What is more interesting are the 36A (old) vs 34A (new) curves. The 36A (old) curve shows 100% DoD at about 16-18 minutes vs 34A (new) curve shows 100% DoD at about 9-10 minutes. The voltage drop under load favors the new battery which maintains a much higher voltage output under similar load. This was confirmed by a quickie test using a 50A dummy load on last year's ES18-12 vs this year's ES17-12. The ES17 had a ~.2-.3v higher voltage while under load. Load was held for 20-30 seconds.

The batteries are close, but are different and diverge at larger discharge rates. The biggest difference seems to be the maximum spec'd discharge; 230A (old) vs 720A (new). Greater safety margin?

Bud

Re: MK 12 volt battery question
 

this is the right battery right?

http://store.aiconsol.com/es17-12-mk-battery.html

Re: MK 12 volt battery question
 

As an Israeli team we dont have a local seller of hose batteries..
What are we supposed to doif we want more of them?

Re: MK 12 volt battery question
 

I'd explore <R25>:

Re: MK 12 volt battery question
 

I think these people will ship to Israel.

http://www.economybatteries.com

http://www.economybatteries.com/qsea...eld.y=0&bhcp=1

Order the ES17-12, not the ES17-12AP

Ed

Re: MK 12 volt battery question
 

That's a really good price. I've been between $40 and $50 from most other battery sites.

Re: MK 12 volt battery question
 

From MK's website ..

http://www.mkbattery.com/images/ES17-12.pdf

Looks like the 720A discharge wins.

Re: MK 12 volt battery question
 

Thanks Bud for overlaying the graphs. It shows pretty conclusively that the differences between the batteries lies mostly in the method used to test. Let's not get hung up on the max current spec. The real difference between the batteries is the internal resistance, 11mohm for the old battery and 10mohm for the new. Hang a dead short on the output terminals (please don't do this) and Ohm's Law tells you...12/.011 vs. 12/.010=1099 vs. 1200. Throw in some safety margin so you don't cause the battery to explode and you get down to the 720 amps max discharge for a new, fully charged battery, no matter the manufacturer.

Re: MK 12 volt battery question
 

<R53> The only legal main source of electrical energy on the ROBOT during the competition is the
12VDC non-spillable lead acid battery provided in the 2007 Kit Of Parts. That 12V battery is
the MK Battery, ES17-12. Additional batteries may be purchased through a local MK
Battery supplier. Teams may use other equivalent 12V batteries during development,
testing and practice matches. However, during the qualifier and elimination matches, only
the MK Battery, ES17-12 can be used (this means NO pre-2007 batteries can be used
during qualification and elimination matches at any official 2007 FIRST competition).

The batteries from past years can be used, but not in qualifying or elimination rounds.

Re: MK 12 volt battery question
 

Forgive me if this have been mentioned already but could I make a suggestion for all you veteran teams? Find a rookie team nearby and offer them two of your old Exide batteries. I'm sure they'll all appreciate having the extra batteries for testing and practice. Go to usfirst.org to find the rookie teams nearest you!

Re: MK 12 volt battery question
 

is this the right battery :confused:



http://store.aiconsol.com/es17-12-mk-battery.html

Re: MK 12 volt battery question
 

Yes. Be careful where you buy so that you don't have to wait until May to get delivery.

Re: MK 12 volt battery question
 

Great idea! This is a cool way for a veteran team to painlessly help rookie teams out.

Re: MK 12 volt battery question
 

Re: MK 12 volt battery question
 

Re: MK 12 volt battery question
 

We ordered, and received, several extra ES17-12 batteries
from this source. To cause even more confusion on the battery
situation, the kit batteries were grey and these batteries
are black. The model number on the kit batteries is ES17-12,
with the printed (on the battery) amp hour rating being 18 ah
at the 20 hour rate. The model number on the batteries we got
from this source is also ES17-12, with the printed amp hour rating
being 17 ah at the 20 hour rate. This is consistent with the amp
hour rating in the specification chart for the ES17-12AP battery,
but the battery we ordered, and the model number printed on
the battery we received, is ES17-12.

All I care about at this point is passing inspection!

Eugene

Re: MK 12 volt battery question
 

For anyone concerned about disposing old worn out FRC batteries please read the first notice in TEAM UPDATE #1 for more information about disposal.

Ed

Re: MK 12 volt battery question
 

I didn't find your lower cost source before ordering from here: http://www.batteriesasap.com/659.html. Arrived within 2 days, shipped from Illinois.

The batteries are the same grey color included in the kit and have a date code of 060928 stamped into the top, which I would guess means they were manufactured Sept. 28th, 2006.

They arrived with terminal voltages of 12.78 and 12.76 volts and didn't take much of an equalizing charge.

Re: MK 12 volt battery question
 

Gene,
Inspectors ran into this problem last year if you remember. The various suppliers make batteries stamped with the same part # but as I remember the black ones were not allowed for competition. It would seem that First needs to address this issue NOW.

Re: MK 12 volt battery question
 

Yeah. 675 Had that problem last year, we didn't have enough of the Exide batteries and they do charge slow.

Very slow.



Here's the thing, too. Not every team will be willing to pass out their extra batteries willy-nilly because they'll need them eventually as well, and going into a match with a half charged battery on the bot and a plethora of dead ones won't do you much good.

Oh, and don't forget that if you don't keep track of them, you might not get them back. If I'm not mistaken, 675 might have accidentally taken other teams' tools without knowing it last year (and if we did, sorry, and please confront one of us, preferably me, and notify us).

Re: MK 12 volt battery question
 

One very nice thing about this year's battery is the battery is labelled with:

Not restricted for passenger or cargo aircraft. Meets air transportation requirements under title 49 CFR173.159 and special provision A67 as decreed by IATA and ICAO.


In prior years we had a tough time dealing with some airlines and shippers. They were reluctant to ship the Exide batteries because there was no documentation proving that the batteries met the vibration, differential pressure tests, etc. required under CFR179.159. This year's battery should "fly" through the season without any problems.

P.S. I found the response to FRC845's post in the Q&A Forum less than definitive:

Batteries <R46>

MK Batteries told the member from FRC845 that batteries ES17-12 12V-18AH/20HR and ES17-12 12V-17AH/20HR are the same. Does FIRST concur with this statement or not??

Re: MK 12 volt battery question
 

I asked that question on the Q&A's this morning. Let's let the GDC see if they can clarify. Basically I asked if inspectors are to go by part number or specs and if by specs how can we be sure of getting the right battery as the company seems to ship two different amp/hour but the same part number.

Watch the Q&A's for answer.

Re: MK 12 volt battery question
 

hey all.i been looking all over,but i cant find where to buy a 12v 18ah mk-battery, if any of u guys would be so kind to email me a link to a good supplier, cheap would help, i would be very appreciative, my email is fortyniner_fan056@yahoo.com

Re: MK 12 volt battery question
 

Today's Team Update #5 reads, "Batteries will be inspected by part number, not by rating or serial number."

Re: MK 12 volt battery question
 

So, assuming that ES17-12 is the MK Battery part number, both batteries are acceptable for competition per Update #5.
Agree?

Re: MK 12 volt battery question
 

That is correct. This was answered in both the Q&A section 10 and the latest update. Kudos to FIRST for quick response.

Re: MK 12 volt battery question
 

Check with one of Batteries Plus stores in your area. If not, Batteries Plus in Ann Arbor MI (7349752441) has this at $45 a piece.

Re: MK 12 volt battery question
 

As a reminder to all teams...
Make your inspectors and refs happy by NOT painting your batteries.

Re: MK 12 volt battery question
 

How are the batteries holding up?
How many batteries does it take to get through a regional?