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Old 03-24-2008, 11:19 AM   #76
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I think SMC is on the right track by providing numbers other than some meaningless C rating. Unfortunately, as Team Tekin pointed out, it doesn't seem like a linear 35A discharge really tells the whole story.

Identifying a way to bench test batteries to give some indication of how they'll perform in stock & mod is the first step. The second would be to get everybody on the same page with that style of testing. Though if they don't, I imagine you'll see private individuals start doing it. This has already happened in the R/C flight world.
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Old 03-24-2008, 11:52 AM   #77
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A linear 35 amp discharge may not tell the whole story, but it IS a way to quantify performance that translates into "real world" applications. Packs that check out better on the GFX usually run better on the track. We can bench race all day, but on-track performance is what counts. Like I've said, we have nothing to hide. I'm surprised more manufacturers have not followed our lead.

billjacobs- who are you calling out in your last paragraph?
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Old 03-24-2008, 12:00 PM   #78
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Originally Posted by Jack Rimer View Post
A linear 35 amp discharge may not tell the whole story, but it IS a way to quantify performance that translates into "real world" applications. Packs that check out better on the GFX usually run better on the track. We can bench race all day, but on-track performance is what counts. Like I've said, we have nothing to hide. I'm surprised more manufacturers have not followed our lead.
Jack,

Even Danny has stated that while the 35A numbers look great on LiPo, they don't hold so true for stock racing since LiPo holds its voltage better at high amp draw than NiMH, but may have lower voltage at low amp draw, like we see in stock racing.

I agree, the track is where it's at. If IIC allows LiPo, I'm going to take a chance against NiMH and see how things work out. I'll probably even go with SMC. I'm gonna take the sticker off, though! j/k :-)
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Old 03-24-2008, 12:09 PM   #79
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Actually numbers on the GFX don't tell the entire story when testing Lipos but when the voltage increases and the IR decreases on the GFX the results will be a faster pack on the track.

To prove my point you can take your Lipo and charge it up at 5 amps and run it as soon as it's ready. The next time you use your Lipo charge it up at 10 amps and run it as soon as it's ready. You will notice that it's faster when charged at 10 amps. Now take a GFX and cycle your pack by charging it at 5 amps. The do another cycle by charging it at 10 amps. The GFX will have better looking numbers when charging at 10 amps and you should of felt the performance increase on the track using 10 amps.

In my testing I have come to the conclusion that charging at a higher amp rate is not the reason why the pack is faster but it's because it gets the pack warmer so I reccomend heating up the pack prior to using it. Once again a heated up pack will run faster on the track and yield better numbers on the GFX.
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Old 03-24-2008, 12:16 PM   #80
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Originally Posted by Fred_B View Post
Yes, for a given mAh pack, the C rating can give a good direction for performance but if you start comparing packs of different mAh ratings the C rating is not likely the best way to compare the packs. 28C at 3200 may not be as good as 20C at 5000.

You're the first company to actually cycle the packs that you sell and provide useful numbers that the RC car guys can easily identify. For me, that's much more important than some crummy C rating. All we need to do is standardize what we do (more standardized than NiMh)

When it comes to Lipos the size of the cells normally makes them better so your correct that a 20C/5000 maybe better than 3200/28C pack. If you take our 28C/4000 and 28C/5000 the 5000 will have better voltage throughout the discharge curve and has lower IR by 1 milliohm but a 28C/5000 will be better than a 20C/5000.

We decided to introduce cycled packs with numbers to show the racers what the packs look like as we feel we have very high performance Lipos. It also allows us to find any packs that are below the performance we expect them to be at.
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Old 03-24-2008, 01:23 PM   #81
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Jack, this is not a playground, so I wasn't calling anyone out. Just making an observation.
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Old 04-01-2008, 11:12 AM   #82
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Balancing lipos. How much of an issue is it? Do people mind the hassle of needing to balance the cells often.

How valuable is it to not have to worry about it?

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Old 04-01-2008, 01:59 PM   #83
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Thumbs up Balancing...

I know some racers that do not like having the balancing wires hanging out.

I like having a battery that I can balance. My charger has a built in balancer and all you have to do is connect one extra connection.

I also have a little box that connects to the balancing plug of the Lipo and tell me the voltage of each cell and the total voltage of the battery. I can see how balanced the pack is and just how much of it I have used. I could not use this without the balancing plug.


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Balancing lipos. How much of an issue is it? Do people mind the hassle of needing to balance the cells often.

How valuable is it to not have to worry about it?

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Old 04-01-2008, 05:01 PM   #84
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Should you have to balance them? During our testing batteries that tended to go out of balance with use also tended to loose up to 30% capacity quickly with mod BL motors especially if you use the 100% DODů. Even if we balanced them fairly regularly, some every cycle. Sorta reduces the easy handling, drop and go usability that makes them popular.

Is it worth more if you do not have to balance them? Do you think it is also a measure of expected battery life and quality?
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Old 04-14-2008, 10:25 AM   #85
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Still trying to figure out the right product to offer for form, fit and function. You know, actually engineer something with thought and investment.

How important is it if the batteries do not need to be balanced? Is the center tap an acceptable balance method instead of a dangling plug?

We struggle with the packs that have the wires coming out sidways. They do not fit in the tray of offroad cars and hang out in our TC's. Is straight up wire exits still the best for overall fit?

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Old 04-14-2008, 11:14 AM   #86
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Originally Posted by TeamTekin View Post
We struggle with the packs that have the wires coming out sidways. They do not fit in the tray of offroad cars and hang out in our TC's. Is straight up wire exits still the best for overall fit?
It seems to depend on the car. In some cases, it interferes with the top deck.

I don't suppose it's reasonable to create top exit plugs (orion style) on the short sides of the pack, and then include another plug at the opposite long end? If you duplicated, say, the positive plug, it would give you a lot of options for cars where the top deck is an issue, 'cause you could just plug into the other end of the "long" side of the pack that's toward the outside of the chassis. As for balancing, the internal plugs are really nice. Having that unruly thing hang out is a hassle. Orion's system seems decent enough. I saw one company that made an internal balancing plug where all the leads were in one plug, but it was easy to have a screw or something get in there, short across the pins, and destroy the pack. I think it was CSRC that did it this way.

Here's what I mean on the pack:

-----+
+-----
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Old 04-14-2008, 11:26 AM   #87
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Originally Posted by TeamTekin View Post
Should you have to balance them? During our testing batteries that tended to go out of balance with use also tended to loose up to 30% capacity quickly with mod BL motors especially if you use the 100% DODů. Even if we balanced them fairly regularly, some every cycle. Sorta reduces the easy handling, drop and go usability that makes them popular.

Is it worth more if you do not have to balance them? Do you think it is also a measure of expected battery life and quality?
Balancing seems relatively easy. Most are either built into the charger or put between the charger and pack. Not really anything you need to do additionaly besides maybe plug in 1 extra plug.
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Old 04-14-2008, 12:19 PM   #88
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Quote:
Originally Posted by TeamTekin View Post
Still trying to figure out the right product to offer for form, fit and function. You know, actually engineer something with thought and investment.

How important is it if the batteries do not need to be balanced? Is the center tap an acceptable balance method instead of a dangling plug?

We struggle with the packs that have the wires coming out sidways. They do not fit in the tray of offroad cars and hang out in our TC's. Is straight up wire exits still the best for overall fit?

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I personally hate the dangling plug. Besides being ugly, the main reason is because there are about 10 different plug types out there. It's confusing as heck. I really wish someone standarized the plugs.
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