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Old 03-16-2007, 02:10 PM   #31
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"I stand corrected. My point was the cells used in the incidents I described are not cheap Chinese products. It was not my intention to slight your company.

And I should point out that the person I was talking about is a proponent of LiPo technology. (For those of you in Rio Linda, that means he thinks we should use them) He just wants to make sure people are careful with them. And I don't want something to happen that ruins the hobby for everyone.

Would it be a bad idea for all RC tracks to have a fire extinguisher handy?" -JimiI

No infact I believe they should and I think in most states it would be illegal not to?

I Understand and if I seemed harsh I appoligize I just want to make sure the whole truth comes to the surface as sometimes having the partial story is very damaging even if the intent was not there. I understand you meant no desrespect I am applaud you being a volunteer for our hobby I think often people in your position are under appreciated.
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Old 03-16-2007, 03:10 PM   #32
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Oy, can't we do this on one thread?
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Old 03-16-2007, 03:26 PM   #33
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i honsetly never knew of any problems with LiPo, or even NiMH... hell, i abuse my NiMh's to the highest level (4.8v car [bought for 10] running at 12v, anyone?) and even though they were 1 each (from lidl[value supermarket for those retail challenged]) i have never had any probelms. when i get around to finding a solution to centering the steering on my 1/14th i might try LiPos though.

every time i write that acronym i think of some guy in a mask sucking fat out of a fat woman with a tube.... uhg
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Old 03-16-2007, 03:29 PM   #34
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Quote:
Originally Posted by jiml
Oy, can't we do this on one thread?
I agree 100%
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Old 03-16-2007, 05:40 PM   #35
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I've been running Lipo for a while now. I get mine from MaxAmps (great service BTW). I have had zero problems. I would not go back to ni-mh unless I was forced. Lipo is just so much easier. They are very easy to maintain. You just have to remember to balance them when you charge and to set the LVC on the ESC and you're set. Then of course don't store them in high humidity, hot places, and other common sense scenarios. Then of course use a good Li-po charger and not your old ni-cad charger. I've also put mine though some abuse in my trucks. I've had hard landings big crashes at 50mph and have had nothing go wrong with the batteries.
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Old 03-17-2007, 05:53 AM   #36
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Ok I'm thinking of getting Lipo batteries for practice and bashing. Can someone explain the C rating and charging C please. And whats a good charger, pros and cons.

Thank you
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Old 03-17-2007, 08:06 AM   #37
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C rating is capacity. When it says it's rated at "20C", that means it can safely discharge at 20 x capacity. If your running a 3200mah battery rated at 20C, then it will support 3200 x 20 = 6400mah or 64amps. So that battery will support 64amps. When you charge at 1C, you are charging at 1 x capacity. That same 3200mah battery then needs to be charged at 3200mah or 3.2 amps.
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Old 03-17-2007, 11:01 AM   #38
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I'm currently using a Duratrax ICE to charge my lipo's. It is very nice and it loaded with features. But the Super Brain 989 is very good as well and it comes with a power supply. Both of those are excellent chargers.
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Old 03-17-2007, 01:48 PM   #39
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Quote:
Originally Posted by seth556
I'm currently using a Duratrax ICE to charge my lipo's. It is very nice and it loaded with features. But the Super Brain 989 is very good as well and it comes with a power supply. Both of those are excellent chargers.
Do you need to have a balancer or is it not needed with the ice? Dan
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Old 03-17-2007, 04:05 PM   #40
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The ICE does not have a built in balancer.
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Old 03-17-2007, 04:48 PM   #41
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Quote:
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The ICE does not have a built in balancer.
Ok so what happens to the lipo's after charging without a balancer for extended periods of time? Dan.
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Old 03-17-2007, 05:04 PM   #42
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When you charge an unbalanced lipo one cell gets a little over charged and one a little under charged. When you discharge them one gets worked a little harder than the other. So the performance drops.

If you continue to use it unbalanced it gets more unbalanced. If it gets way out of wack it could cause on of the cells to get dangerously over charged or discharged.

My experience with ThunderPower packs is this is more likely to occur if you charge at more than 1C or if you discharge them at near or over there C rating or if you over discharge them. If you push the packs hard and charge at 2 or 3 C then you should definatly use a balancer while charging. If you baby them then you don't need to do it very often.

If you don't have a balancer then you can just measure the voltage through the balance tap and if it needs to be balanced you can charge each cell individually at a less than 1C and it will usually fix it.

The thunder power 10Amp charger and balacer is one of the best I've seen and I've heard good things about the FMA chargers. With these you can safely charge quality cells at 2 or 3C.

BUT I've noticed that when charged at over 1C they tend to lose there voltage quicker at the begining of the dischage curve. So the initial punch will fade quicker. They also lose that initial punch faster the higher C they are discharged.

So if weight and all other things are equal a 6000 pack charged at 1c will have an advantage over a 3200 pack charged at 2C.

btw: I have no charts or hard evidence for this. It's just what I've noticed with my planes and helis using a watts up meter.

Last edited by IlikeRCstuff; 03-17-2007 at 07:51 PM.
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Old 03-17-2007, 05:04 PM   #43
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Not much.

After 50-100 cycles, the relative voltages between the two cells can be off by a little bit and it makes the charger thing that the pack is full when it really isn't. A balancer just charges them individually, rather than as one pack.
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Old 03-17-2007, 10:17 PM   #44
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Quote:
Originally Posted by sportpak
C rating is capacity. When it says it's rated at "20C", that means it can safely discharge at 20 x capacity. If your running a 3200mah battery rated at 20C, then it will support 3200 x 20 = 6400mah or 64amps. So that battery will support 64amps. When you charge at 1C, you are charging at 1 x capacity. That same 3200mah battery then needs to be charged at 3200mah or 3.2 amps.
Thanks,you answered one of my questions about the C rating.As I was reading the rest of your post you gave an example of a 6400 mah or 64 amps.Is that correct or did you mean 6.4 amps ? Thanks.
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Old 03-17-2007, 10:54 PM   #45
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"then it will support 3200 x 20 = 6400mah or 64amps"

I think he meant 3200 x 20 = 64000mah or 64amps
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