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Old 11-29-2008, 01:18 AM   #1396
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Actually the 5000 pack I have with me has about the same IR and voltage as the 24C pack but the capacity is 12 seconds less so the test would provide similar results/numbers.
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Old 11-29-2008, 05:01 AM   #1397
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Non Heated with a pack temp of 72 degrees: 529 - 7.38 - 6.1
Heated to 103 degrees: 533 - 7.45 - 4.2
Heated to 150 degrees: 538 - 7.50 - 3.4
Would a pre-heated pack had a higer temperature when the discharging be finished, which is too hot and might be dangerous?

Btw, Danny would you take a photo of latest batch of 5000 pack? I'm kind lost on all the re-version/color-change...
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Old 11-29-2008, 08:23 AM   #1398
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I think all testing should be done with a 1c charge rate. Isn't that what almost all packs on the market are rated for?
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Old 11-29-2008, 09:00 AM   #1399
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I totally agree !!!
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Old 11-29-2008, 11:44 AM   #1400
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I think all testing should be done with a 1c charge rate. Isn't that what almost all packs on the market are rated for?

Can you tell me the difference between a 1C charge rate and 2C charge rate on the packs numbers ? I can tell you it doesn't change them plus when doing tests it saves half the time. Actually our packs can handle up to 3C for charge rates but we reccomend 2C.
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Old 11-29-2008, 11:47 AM   #1401
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Originally Posted by ttso View Post
Would a pre-heated pack had a higer temperature when the discharging be finished, which is too hot and might be dangerous?

Btw, Danny would you take a photo of latest batch of 5000 pack? I'm kind lost on all the re-version/color-change...
Yes it will be a bit warmer at the end of discharge using a constant 35 amps but in your car you won't be pulling as much amps plus there is airflow in your car.

All the latest 5000/28C packs have the same color as the single cell pack I posted pictures of in the 4000/single cell thread and the wires come out the top. We sent packs for pictures to be posted on our website.
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Old 11-29-2008, 01:16 PM   #1402
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Today I did some testing on cycle numbers on a heated pack versus a pack that isn't heated.
-snip-
Non Heated with a pack temp of 72 degrees: 529 - 7.38 - 6.1

Heated to 103 degrees: 533 - 7.45 - 4.2

Heated to 150 degrees: 538 - 7.50 - 3.4
You went from charge to discharge pretty quickly I'm assuming, but how long does the heated pack hold it's advantage if you have to wait a bit before you race?

The pack finishes charging and you take it out of the heater, say, at the start of the race right before yours. Go through tech, grid and then go. I'd say a 5 to 7 minute gap. Would the advantages of heating disappear by that point?
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Old 11-29-2008, 01:31 PM   #1403
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If you look at the numbers you can see the difference between 72 and 103 and 150 so if you warm up your pack and lets say you race in 10 minutes from when the pack is pulled from your heat pad it should still be warmer than if it wasn't heated.

I also think track owners/race directors shouldn't allow heating as it's one step that everybody will think they have to do and if everyone does it there will be no advantage so it's one more thing to worry about. Since tracks should be testing for over charging it would be simple to tech for heating.
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Old 11-29-2008, 01:47 PM   #1404
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I've seen the 5000's swell slightly at temps under 150. I'd be pretty scared to try and get them up there.
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Old 11-29-2008, 01:51 PM   #1405
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Danny,

Are you saying there's no difference in performance between a 1C charge and a 2C or 3C charge? And that the ONLY difference is that the packs charge up faster? Also, do you feel 2C or 3C will have much impact on cycle life of your packs?

I know of a lot of guys that are charging are very high rates because they think it's making them faster. All it really seems to do create an unnecessary risk for those of us pitting near them.
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Old 11-29-2008, 02:15 PM   #1406
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I've seen the 5000's swell slightly at temps under 150. I'd be pretty scared to try and get them up there.

I don't reccomend heating of Lipos as it's just one more thing racers have to worry about. So it shouldn't be allowed.

I have heard of some packs swelling when heating them but I think that could be caused by charging them while there being heated or maybe the heating pad is creating more heat as it's touching the case. All my heating tests were don on an oven. I have went as high as 180 with no issues but once again this was only for testing and I don't reccomend it. The goal with my post is to show that Lipo numbers can easily be changed so we need to take this into account when looking at and trying to compare numbers.
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Old 11-29-2008, 02:21 PM   #1407
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Danny,

Are you saying there's no difference in performance between a 1C charge and a 2C or 3C charge? And that the ONLY difference is that the packs charge up faster? Also, do you feel 2C or 3C will have much impact on cycle life of your packs?

I know of a lot of guys that are charging are very high rates because they think it's making them faster. All it really seems to do create an unnecessary risk for those of us pitting near them.
I tested the 2 different packs with 1C and 2C and the numbers were the same. I can't test 3C as my GFX only goes up to 12 amps. From what our supplier tells us 2C will not have much of an impact on cycle life but 3C may shorten it some.

As far as creating risks at the track I don't think there is any more risks using a higher charge rate. If you want to cut the risks at your track get the track to enforce a Lipo sack rule. I don't think charging at 2C is a risk. In fact when playing around with overcharging we found that overcharging at higher amp rate actually worked better than a lower charge rate. At the lower charge rate we did see some swelling. Once again overcharging should never bee accepted but I'm just pointing some of my findings.
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Old 11-29-2008, 03:42 PM   #1408
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Swelling from the lower charge rate ?
Is that a typo?
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Old 11-30-2008, 02:32 AM   #1409
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No it's not a typo. If you read my post correctly you will see that I'm referring to the charge rate when overcharging a pack. This is what we noticed. Feel free to don your own tests.
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Old 11-30-2008, 02:32 AM   #1410
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Quote:
Originally Posted by Adam? View Post



I know of a lot of guys that are charging are very high rates because they think it's making them faster. All it really seems to do create an unnecessary risk for those of us pitting near them.
Adam, First of all hope all is well in Colorado. Secondly I have never heard of Lipo's exploding like the good old NiMH. They just puff smoke and catch fire, right?
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