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New 5C charge rate LiPo

A few initial thoughts....

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New Li-Pos...

New Li-Pos...

...with a 5C charge rate have arrived! - 8/5/09

Tim Mackey08/05/2009 08:08:43
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I doubt I will be trying them until the price drops a bit .
I also wonder just how much effect on overall lifespan of the cells charging at 5C is going to have, and whether there is a weight penalty. Remember also that to charge them at 5C your''e going to need a meaty charger and suitable PSU, the 3200 4s packs would need a charger capable of almost 300 Watt output !
( Check your charger output...and I bet its nearer 50 ! ) 
 

Edited By Timbo - Moderator on 08/05/2009 08:10:44

David Ashby - Moderator08/05/2009 08:38:13
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Good point Tim, I still charge everything at 1C - is anyone regularly doing 2C or more I wonder?
YakMad08/05/2009 09:23:21
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Robotbirds have been selling 5c charge Hyperion cells for a few weeks now, I bought 3 2100mah 3s packs but have'nt tried them yet (weather!!) but I am more interested in the claimed 4 times cycle lifespan compared to previous cells than the charge rate also they are only a few pounds more expensive than their 1c charge cells. 
Dave Towell08/05/2009 10:29:42
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Cost is the issue here, like Timbo said you are going to need a REALLY meaty charger, the packs are a bit on the pricey side, and the life/cycle issue needs verifying. I think i'll wait a while to see peoples feed back first.
Tom Foreman08/05/2009 10:33:43
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I'm more interested in life cycle, voltage under load and actual real life capacity rather than charge rate, but I do have a 300W capable charger . As Timbo says driving it in the field is the problem without large heavy lead acid batteries - we need more model fields with mains electric like in the States
Tom Foreman08/05/2009 10:40:16
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As an aside I only buy 30C discharge batteries at the moment, they give better voltage under load and stay cooler for longer, you can even downsize to save weight and still have amps to spare. In the states they have 40C Thunder Powers for their big EDF jets which are now on par with Turbines with 200 mph flying speeds!  BVM Jets 
 
The future of electric flight is looking bright!
Nick Rigg08/05/2009 10:56:59
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I blew up my last PSU charging 2 4S 5000s one after the other at 1C
 
I'm more careful now....
Keith Lewzey08/05/2009 13:00:21
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What is the obsession with faster & faster charge times? It's a bit like faster & faster computers, broadband or car manufactures claiming they have increased the interior space in an updated model of a car when all they have really done is lengthened the car. It doesn't really fool anyone with half or more of a brain!! I agree with Timbo that there must be some penalty in terms of cycles possible & deffinately a penalty in terms of the wallet just because they are top price because they are "NEW". Sorry it doesn't fool me. Higher discharge rates I can see the point of paying for but not faster charge rates. I say lets show a little patience & spend that hour charging at 1C using another pack or two (cos you can afford them cos they are half the price, never mind the charger/PSU issue) or chatting with the chaps at the patch.
 
Rant over
David Ashby - Moderator08/05/2009 13:02:08
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Don't stop Keith I was enjoying that
YakMad08/05/2009 15:52:21
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The advantage of higher charge rates for me is not the charge rate at all I would still only charge at 1c, but the manufacturers have to take more care matching and using higher quality cells to produce these packs which has to produce a higher quality pack which should perform better for longer.
Keith Lewzey11/05/2009 13:15:36
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Good point YakMad but how many flyers would use that intelligent informed point of view & how many would just blast as much charge into the packs as fast as possible. My son Jonathan & I always charge everything at or below 1C.
Phil Winks11/05/2009 17:20:25
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I think every things been said already so all I can say is I agree with you all.
Ps a cautionary note on disposal of damaged packs a few weeks ago I lost and aircraft to structural failure and the bty was so badly squashed I decide on the safest route and following BMFA guidelines I discharged the pack or so I thought with a resistor type dis-charger     the sort used to cycle nihm's there was the mistake I reckon these devices switch of at 1 v any way holding the lipo in a welding gloved hand I proceeded to pierce the pack prior to marinading in salt water as per instructions the pack immediately started to fizz so I promptly threw it on the lawn where upon it issued a huge cloud of white smoke and obviously got very hot. (the blackend grass still hasn't grown back) I guess a bulb will be used to discharge the next damaged pack.

Edited By Phil Winks on 11/05/2009 17:24:48

Eric Bray11/05/2009 22:07:11
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I guess a bulb will be used
Tulip or daffodil?
Tom Foreman19/05/2009 14:25:02
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Interesting test data on the other forum. This is the Hyperion G3 35C and the Thunder Power 40C, looking bad for A123's
 
Tom
 
 
Bert19/05/2009 14:50:03
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'I guess a bulb will be used
Tulip or daffodil? '
 
No Eric - it will have to be a Lithium-Onion!
 
Bert
260 Flyer20/05/2009 07:44:57
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5C charge rate, one question do you need to let them cool before charging?

Or can you Land-Charge-Fly as you can with A123's?

If you need to charge them at ambient temp it will take more than the 1C charge time to cool down! 

Tom Foreman20/05/2009 09:13:46
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Depends how hard you run your packs and whether you balance charge or not. If you run your packs hard so that they are hot and you don't balance charge then you would probably be wise to wait for them to cool. But if your packs are cool to the touch or you balance charge then Land-Charge-Fly.
 
Of course you still need a hefty charger and PSU to get the fast re-charge rate, my charger will only do a maximum of 10A, but then again I have so many Lipo's and a couple of A123 packs that I'm never waiting for packs to charge.
 
Tom
Nick Rigg20/05/2009 17:29:25
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That's the idea Tom, get loads of batteries and then charge 'em at leisure later.
I presume you're a Rt. Hon Member of Parliament and you bought all the lipos on expenses....
Tom Foreman21/05/2009 08:37:54
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Yeah, or is it that I got rid of my car many years ago and have spare cash to spend on my hobby!  Who knows Riggy
Chris Channon22/05/2009 17:48:47
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Rob,
" Land -refuel-fly" Sounds like you need to convert to glow, we have been doing this for years !!!!!!
Regards
Chris.

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