Advil

iTrader: (19)

Sigh....

The lower internal resistance of the new batteries allow our motors to utilize current at a higher rate than was possible with the older design batteries. This coupled with our "racing" motors' inherent inefficiencies promote a quicker degradation in performace than was possible before. A new way of tuning our motors is needed to allow them to handle the new batteries' ability to allow current to flow in the circuit.

How about....The batteries have more POWER so we have to RE-TUNE our motors so they don't burn up so fast. It is not 100% accurate but it gets the point across without the "slide rule" explanations.

Then next thing you know we will be taking into account the gravitaional constant as well as the Earth's rotation in account when doing our laptime calculations......

cr250

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TryHard

iTrader: (4)

Like this?

http://www.batteryuniversity.com/index.htm

Danny/SMC

iTrader: (2)

cr250: When we started using IB cells in stock oval with the same rollout and motor setup as we did with GP cells our motors were 30 degrees hotter measured directly on the comm at the end of the run. By removing some amp draw and tuning the rollout the temp dropped back down to were it should be and our lap times were faster throughout the run with no fading effect. So if you detune your motor some and can go faster wouldn't it be safe to say that the cells provide more power ?

I can't talk like an engineer as i'm not one but I like to base my comments from actual track testing and what our drivers/customers have to say.

cr250

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cr250

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Danny/SMC

iTrader: (2)

Maybe in onroad racing the motors don't heat up as much but in oval we got a difference. Same car, motor , setup the only difference was switching from GP to IBs.

Average voltage is part of what makes a cell fast but the way it's manufactured and the materials used is what makes a cell better than an other. In September Intellect made a change to one of the materials in the IB3800 and the voltage and IR stayed pretty much the same but the cell ran a bit faster on the track with this new material. The mod guys noticed this update the most.

cr250

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fjm9898

iTrader: (11)

but ib cells still have som of the best IR out there, which still makes them great cells on top of run time and AV

cr250

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Advil

iTrader: (19)

Why not? All things being equal, if the only change is the IB cell, and we agree that it has a lower IR than our other batteries, why can't the circuit's overall lower resistance account for more current to the motor? Wouldn't more current on demand at the motor increase its power output and heat? Even in just two minutes?

BATT_MAN

Danny -- Indeed IB made changes to the cell. The main MATERIALS that you are talking about are the alloys used for the electrodes. IB is using a much cleaner and efficient alloy at the electrodes (the positive and negative side of the cell).
A cell performs a chemical reaction, thus generating ENERGY. This is an endothermic and exothermic process. IB has managed to achieve the best balance attainable between the endo and exo reactions, thus efficiency increases. THEREFORE THE HIGHER VOLTAGES THAT WE SEE

The voltage of a NiMh battery is defined by the chemical reaction listed here, nothing else can alter or increase the voltage:

Location ........Reactions................................... Voltage
Anode .........MH + OH- —> M + H2O + e- ...............0.83
Cathode .....NiOOH + H2O + e- —> Ni(OH)2 + OH- ....0.52
Overall .......NiOOH + MH —> Ni(OH)2 + M ...............1.35 TOTAL

As you can see the reaction generates 1.35V. Anyone that tests NiMh batteries on an ongoing basis knows that this the intitial discharge voltage for an IB (which is GREAT!!!) . It will start droping to 1.27v(+/-) within a few milliamps(seconds) after a load is applied.

The anodes used in these cells are complex alloys containing many metals. such as an alloy of V, Ti, Zr, Ni, Cr, Co, and Fe. The underlying chemistry of these alloys and the reasons for superior performance are not clearly understood. Only through continous testing can we find the best empirical combinations
A very interesting fact about these alloys is that some metals absorb heat when absorbiong hydrogen, and some give off heat when absorbing hydrogen. Both of these are bad for a battery, since it is better for the hydregen to move easily in and out without any energy transfer. The successful alloys are all mixtures of exothermic and endothermic metals to achieve this. It is obvious that the chemists at IB have found the right metal alloys to build the BEST possible electrodes up to date.
NOTE: Hydrogen is a byproduct of the chemical reaction

This is one of the reasons why motors are getting hot. BETTER EFFICIENCY AND CELL PERFORMANCE. I am not going to go into detail, but the answer lies herein.

Those who understand how motors operate can achieve the best possible balance (tuning a motor) between current, power, temp, and speed. You just can not tune a motor based on no load current, because as many have said, the IB's seem to deliver more current than other batteries when the motors demand it. IT IS NOT POWER it's the current handling capabilities of the IB.
Motors are not timed right, gearing is not done right, brush selection may not be right... etc... All people need to do is experiment untill they get the right combination. By understanding how motors operate the process is much easier.

The current that Danny is talking about is oversaturating the magnetic field, thus causing a higher IR (at the motor), this increases the temperature and becomes an infinite loop.

In all honesty, EVERYONE in here has a true point about the motor overheating problem.

Some of you may laugh at engineers, our calculations, and everything else, but WE can figure out why this is happening and figure out REAL solutions to the problem. NO BS

I have been testing IBs since late April so we (Axxis Racing) know what is happening and we have found some solutions to these problems.

BTW, AXXIS RACING will start testing the IB4200s the first week of Jan. It will take us some time to figure out the best way to enhance and get the most energy out of them. Once we figure how we can increase the performance through the HES process we will release it for sale. In the meantime, we will be doing lab and track tests on the IB4200.
The results will be posted at our website.

I am going to this extent to explain what happens inside the battery so that most of you will have a better knowledge of batteries. The more you know, better decisions you will make, and maybe you will be the one with the "WINNER" sign in the front cover of the magazines

I hope this will help.

Isaac

Johnboy Walton

iTrader: (3)

First off Isaac, from a fellow engineer, I truly appreciate the information you presented in this post. I hadn't even considered some of these effects, so when these questions start to come up at the track, it will be nice to have a fact-based response to comment from.

Since you've so graciously brought up the concept of cell chemistry, I would be ecstatic if you could enlighten me on a subject that has bothered me since I first heard of it - cell "zapping."

It's not that I don't believe that it has an effect. Given that it seems accepted practice, I'll assume that it does something benficial. That said, what exactly is it doing that's so beneficial? Is it altering the alloy of the plates, does it enhance the electrolyte, or is it something truly obscure or 5th-order-effect-type-thing?

If this is beyond the scope of this thread, then my apolgies to all.

Either way, GREAT DISCUSSION, all! Thank you for taking the time to share this information with us!!

Mike

BATT_MAN

Mike -- Thanks for the kind words.
Regarding the zapping question I will be glad to talk with you about it, but not in this platform.
The forum is NOT the place.

Feel free to email or contact me at my office.

Thanks

Isaac

cr250

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