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Old 12-02-2005, 08:33 PM   #1
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Default 30 amps vs. 35

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Last edited by Khan48; 07-21-2014 at 01:44 PM.
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Old 12-02-2005, 08:53 PM   #2
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35 amp discharge just helps weed out the weaker cells a bit better than 30 amp. With the increase in cell capacity and the newer range of brushed motors, I feel the 35 amp discharge rate for matching will become a lot more popular.
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Old 12-03-2005, 01:48 AM   #3
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It also helps the matchers get through the cells faster. A minute or so per cell. When your doing 5000 cells a week, like SMC, that can add up.

But it does show how strong the newer cells really are. When you have 1.200 at 35 amps, versus 1.185 at 30. I think I'll be taking the 1.2 ANY DAY!!

Even 1.2 at 35 versus 1.2 at 30 amps is significant.
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Old 12-03-2005, 01:52 AM   #4
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weed out bad cells? if a cell is good at 30amps its going to be good at 35amps. jmo.
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Old 12-03-2005, 01:56 AM   #5
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Quote:
Originally Posted by qwerty
weed out bad cells? if a cell is good at 30amps its going to be good at 35amps. jmo.
Nope

35A cells will have more seconds & slightly higher volts @ 30A
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Old 12-03-2005, 02:12 AM   #6
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Quote:
Originally Posted by asw7576
Nope

35A cells will have more seconds & slightly higher volts @ 30A
You need to explain your answer. The use of 35 amp discharge gives lower numbers all round. That is understandable. It is a higher discharge rate.

I have cycled 1000's of cells and have found no huge difference in weeding out weak cells.
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Old 12-03-2005, 02:58 AM   #7
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Quote:
Originally Posted by asw7576
Nope

35A cells will have more seconds & slightly higher volts @ 30A

He's saying a cell that has 410sec and 1.200 at 35 amps will have something like 460sec 1.23 at 30 amps. (for example)
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Old 12-03-2005, 03:03 AM   #8
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This is from the br00d site........


"When comparing a 30amp discharge rate verse a 35amp discharge rate typically you will need to add about 60-70 seconds of runtime and .015 voltage.

Example a 1.190 with 390 runtime pack will be 1.205 455 at 30 amps.


How to convert 35amp runtime to 30amp runtime ?
Multiply runtime by 35 then divide by 30 .. 360s at 35amp = 420s at 30amp

How to convert 35amp IR ?
Subtract 0.1 from 35 IR.. 2.4IR at 35amp = 2.3 IR at 30amp

How to convert 35amp AVG to 30 amp ?
Add .015v to 35amp AVG 1.1905 at 35amp = 1.205v at 30amp"
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Old 12-03-2005, 03:44 AM   #9
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Yes, but the reply was regarding good and bad cells at 30 and 35 amp discharging. The reply made no sense in relation to the previous comment.
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Old 12-03-2005, 07:33 AM   #10
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a 35 amp discharge is harder on the cell, thus putting more pressure on the cell and the weaker ones fail, while a weak cell being matched at 30 amps might make it through the matching process.

Man I remember back in the day they matched cells at 10 amps
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Old 12-03-2005, 08:49 AM   #11
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Our philosophy at SMC is to provide the customer with the best match possible. We feel that in order to do that you must come as close as possible to simulating an actual run on a pack. Right now, 35 amps is as close as you can come to simulating racing conditions using standard equipment. For the most part, good 30 amp batteries are good 35 amp batteries, however we believe the MATCH is better using 35 amps. After all, our job is to match the cells to the best of our abilities. It may be splitting hairs to debate this issue, but we have had very good race results using 35 amps. Everyone has their own philosophy on batteries so my advice would be to run them both then decide. BTW, we did not switch to 35 amps to decrease cycle time. Our goal is to put out the fastest batteries, not be the fastest to put out batteries.
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Old 12-03-2005, 10:28 AM   #12
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jack knows his stuff, quality products from smc, i have tried many and theyseems to be the constant. i know this isn't the thread but kkep up the quality jack.
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Old 12-03-2005, 10:32 AM   #13
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Last edited by Khan48; 07-21-2014 at 01:44 PM.
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Old 12-03-2005, 10:47 AM   #14
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Quote:
Originally Posted by Khan48
what battery matchers match at 35 amps?
SMC, Team Brood, and maybe DC battery ( not sure on the last one ).

Safe bets SMC IB3800 or Team Brood IB3800
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Old 12-03-2005, 10:59 AM   #15
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There are more important factors that define a battery performance than constant amp draw...or voltage...

Each matcher has their own theories and techniques...

However, we do know that a battery NEVER performs under constant current in our application. For example,most stock motors operate at around 34 to 20 amps... going constantly up and down within that range...averaging this is not the same...

The BEST way to weed out batteries and find the BEST cells is to find the ones that will respond to changes in current at the fastest speed. We call that current transient response. So if you test a battery at variable currents at fast changig times (duty cycles) you can always find te BEST cells.

35 AMPs has its merrits....so does 30, ans 25, and 10...

TurboMatchers are very limited with the information they provide...
Is matching batteries finding batteries that have the same discharge times or finding batteries that respond to changes in current demand at an equal manner. I am sure that with time people (racers) will start seeing the differences. Yes time (capacity) is important and it is part of the matching process... and we use it too...but we report it as amphours...which can be converted to seconds very easily...BUT???????

SMC matches so many batteries that no matter what and how they test cells just by statistics alone they will always have GREAT batteries...and YES, they are providing the r/c market with GREAT batteries.

Don't think just voltages and run time to select batteries...there are many more important factors that define a good battery....

Also, if the test equipment would be accurate enough you should not have to make adjustments for IR... IR is a constant and it should (theoreticaly) not change as current changes... That is why testing for transient current response is the best way to select cells. Yes, it does take very specialized equipment to do this, but the quality of the cells can be seen in an instant.

Look at it as an EKG of a battery. In a heart you want to see how well it pumps blood as the heart expands and contracts, blood supply...with batteries we need to see how FAST the battery can supply the everchanging current that the motor is demanding from the battery at the fastest possible time. We can see that real time with each battery we test, and thus we can find the best cells...and BTW, this test is done from 1 to X amps... way above the 35 AMP level.... and the battery has less chances of being damaged by excessive heat build up...

Batteries get excessively hot at a constant 35 amp discharge and there is always that slight possibility of cell damage...or reduced performance aftter the matching process....

Last edited by BATT_MAN; 12-04-2005 at 12:23 AM.
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