Electrathon America Forum

We are running red tops. We have not done any specific testing, but I feel that the red tops can be fully drained in an hour and the yellow top will have more trouble fully draining them in the allotted time. If the races were 4 hours long, I would likely run them.

If you are looking to try differant things, one 75/25 and one 78 series battery would have a lot more output than any two 75/25 series batteries. Be carefull with the weight, you will need to weigh them in the store and find the lighter ones.

The published weights are only an approximation, they can be off a lot.  If you are using "approved" batteries listed in the rulebook, you do not have to weigh in your batteries.  If you are using other batteries, they must pass the scale test.

Nathan McCaw is using the yellow tops and I believe is in 3rd overall.

Let's try to answer one question about Yellow Top batteries.

Do the Yellow Top batteries provide the 8% energy increase for this application as per Interstate Battery engineers?

bd64 wrote:

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Let's try to answer one question about Yellow Top batteries.

Do the Yellow Top batteries provide the 8% energy increase for this application as per Interstate Battery engineers?

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I think the energy is in there, just not able to get it all out in an hour.

Shannon, if Dave has data it would be great if you would post it.

I ran Yellow tops all season long in my car along with several of my students. I found that I had to drive the yellow tops a little different. When you start out they get down to a combined 22.? volts a lot sooner than the red tops did but they stay there for a very long time. If you keep pushing them they will drop down below 22.0 and then lower around 45-50 minutes and you will start to slow down. But I think I found a way to keep them going and get more out them then the red tops. Since I don't use any fancy monitoring equipment (simple Harbor Freight volt and amp meters) I watched by volt meter closely. When it got down to about 22.2 volts I would 'take a lap off' and coast more and be sure not to push the amps up at all. After that lap I was up to 23.? something again under power pulling normal amps. I would then race hard for a while until the voltage dropped again to about 22.2 and do it again. With this method I think I might have actually gotten more out of my yellow tops than the red tops last year. When driving them hard I could push a little more than I could with the red tops. The last two race I raced this year I went farther than I did the year before. Again without any specific monitoring systems this is just a guess but I will see how I do this summer and fall in our last races. I usually had to take my first lap off at about 30-40 minutes and again around 40-50 and maybe a partial lap off at around 50-55 if the track had a lot of slow traffic our a very tight corner.

I will be honest--If I can get about the same distance out of these batteries as the red tops and they last me for several race seasons I will consider it a win. The red tops seemed to only last us in top form for about 17-20 races before they started to not last the full hour. In the NW we have about 15 days of racing a year so we got one good season out of them before we had to replace them. Those on my team that tried to use last year's batteries found out that part way through this race season their batteries that made 10-15 races last year started to die before the full hour. With 20 cars a year and 2 batteries per car I can not afford to buy 40 batteries each year at over $5000. I also think that is not what Electrathon is about--not a very green system to replace that many batteries.

Mike

Thanks, Will you be at KC this year?

New York Electrathon has some interesting data posted at

http://www.nyelectrathon.com/index.php?option=com_ccboard&view=topiclist&forum=14&Itemid=99

-- Edited by bd64 on Wednesday 16th of June 2010 12:10:20 PM

Testing results at a 50 amp rate:

reds: 42+ amp hours
Yellows:35 amp hours

What does this data mean? Could you please elaborate?

Optima says 44 for red, 48 for yellows at C20.
Data sheet HERE




-- Edited by churd on Saturday 18th of September 2010 01:56:19 AM

Below is a post I made after doing some testing on yellovs red tops.  The full discussion, including full downloads of all data and testing procedures can be found here:

http://www.nyelectrathon.com/index.php?option=com_ccboard&view=postlist&forum=14&topic=30&Itemid=99

From carefully analyzing the data in the previous post (and summarized above) we have drawn the following conclusions:

1. All batteries are NOT created equal. From the factory, the batteries can have a C1 rating that can vary by up to 3-4 Ahrs from battery to battery.  Choose wisely; if you have a choice.

2. Both Reds & Yellows are green directly from the factory; They do NOT hold an optimal charge, and get better over time. (see data in the previous post)

3. Both Reds & Yellows improve with age; to a point. What is that point? We don't know, as we haven't reached it yet. It could be as many as 10 to 15 charge/discharge cycles for the yellow tops. (Thanks Dave!)

4. How you charge the batteries does have an effect on the final Ahr rating, but when charged similarly, the yellows and the reds overall differ by less than 1Ahr at a C1 rating.

5. The discharge curves for the two diferent batteries have almost exactly the same profiles.  See the attached files as well as the graph below.

In the chart above, the red & green lines represent the factory yellow tops, and the black & blue the factory red tops. As you can see the curves are exactly the same with the C1 Ahr rating averages differ by less than 1 Ahr.

6. Contrary to popular belief, the Red's and Yellow's C1 rating differ, on average, by LESS THAN 1Ahr. See chart above. (Have I stressed this enough?)

Popular thinking was that because the batteries had a C20 rating difference of 4 Ahrs (see specs here), it was assumed that electrathon racers would be able to go either much further, or much faster in the given hour. This would be a huge safety concern to me as a teacher, as my top priority is safety for my students. This was proven not to be true as shown by the data.

Since we use the batteries in one hour, you cannot apply the C20 rating.

We have tested old, not so old, and brand new batteries, and have come to the above conclusions. Please see the posts previous to this for the Testing Procedure we used, as well as the test set up.

This data does not take into account any different driving "styles", just the cold hard facts about the two batteries: Optima Red & Yellow Tops.

In closing: because the Yellow tops will have a much greater life span than the Red Tops, and do NOT give a significant difference in Ahr rating for one hour, I strongly recommend moving to the Yellows for cost savings and recycleability alone. They may cost a bit more but will last 5x's (at least; I'm being conservative, as we have not tested this) as many charge/discharge cycles.

Special Thanks to Dave at Optima Batteries in Syracuse, NY for his expertise and the loaning of the brand new batteries!

We would love to hear your comments!

Churd, 

-- Edited by Zaine Stapleton on Friday 21st of January 2011 06:33:30 PM

"because the Yellow tops will have a much greater life span than the Red Tops" ---  I would not bet on it.  Continued cycling can be used as an indicator but only that.  If they follow the 22NF lead they will sulfate with time and become worthless.

mhodgertt wrote:

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That is why I pushed the yellow tops through. I used to have to buy about 40 red top batteries EVERY YEAR for our 20 cars. I could not afford to keep replacing them after 12 to 18 races depending on care and abuse.

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I couldn't agree more, I am just glad that after the testing was done, it proved that there was not an 8-15% increase in Ahr rating. This way we keep the safety factor, save money, and it is better for the environment!

 

I sure hope Chris is right and I am wrong about how long the yellows last but the number of cycles does not tell the whole story. Batteries need to last through period of inactivity and even some neglect to truely save money on batteries. The Red tops can and should be repurposed rather than recycled, the old SLIs and currently Red tops are still starting cars, trucks, tractors and other gas powered equipment before they are returned for core charges. What will you use the Yellow tops for?? The sales people missed on the 8% increase in output will their prediction on longivity be any better? Time will tell.

I will admit that I would be very surprised if the batteries last 4 to 6 years of racing as the number of cycles would indicate. But if they even just last 2 seasons instead of one they are half price!!!!!! and half as many batteries to find homes for. I am fairly confident that they will last 2 seasons and I am hoping they still will well work for a full three years of races which for us would be about 45 to 55 cycles or races.

+1 with what Chris said about the safety factor. These yellows are pulling the same numbers as reds, no increase in speeds, plus according to an applications engineer at Optima "in our lab testing, if you discharge 100% you'll get approx. 300 cycles, if you discharge 50% you'll get about 1000 cycles." This information is for the yellows.

ha, only to not do it. 

no data though.


-- Edited by bgilmore on Sunday 23rd of January 2011 06:04:12 PM

Mike, I am considering putting in a Harbor Freight battery disconnect near the battery out of the way so that won't happen.  I'll probably use the same type of kill switch I'm using in my electrathon car, usually $5.  I just haven't had time to do it since I'm only at home for a couple days.

-- Edited by Zaine Stapleton on Monday 24th of January 2011 04:45:21 AM

my battery requires a frequent recharge & doesn't last nearly as long as it used to, maybe that's because I'm 72, (I'm only good for about 4 miles a day).