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Old Jan 23, 2003, 05:08 AM
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Indpls.,In.
Joined Oct 2000
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Li-poly battery to replace 10 cell RC 2400 ?

Is this possible? What would be the weight and cost ? Can a
li-poly tolerate 36 amps ?
Thanks
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Old Jan 23, 2003, 05:24 AM
Hellenic Flyer
Athens, Hellas
Joined Nov 2001
42 Posts
LiPoCalc

Although I am not an expert i could suggest this link

http://www.fmadirect.com/site/lipocalc.htm

I hope that you'll find it useful

Regards,
Christos
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Old Jan 23, 2003, 07:26 AM
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Yes, it's possible. A properly configured LiPoly pack will weigh slightly less than the CP2400, and it will be outrageously expensive. By themselves, even the largest available LiPoly (3270mAh) can't handle more than about 9 Amps continuous, though. You have to combine multiple LiPoly packs in parallel to get the current capacity. This has the added benefit of outrageous duration. The only downside is that the Lipoly pack will take forever to recharge with the chargers we have available.

There have been several discussions on this exact subject. Search for "Kokam Lipoly E3D". Betcha the 10xRC2400 you want to replace with Lipoly is for an E3D. Am I right?

Now, when you go to use Lipocalc, make sure you pay attention to the discharge "C" rate. Use 3C if you're flying full-throttle all the time, and 4C or 5C if you only have short bursts of full throttle. Currently-available LiPoly cells do not deal well with being discharged continuously at rates higher than 3C (3 times their capacity in mAh), but can handle those levels for a few seconds at a time.
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Old Jan 23, 2003, 07:51 AM
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The lith poly pack I'm flying in an E3D (replacing 10-cell sub-C pack) is 16 ounces versus 23 ounces for the sub-C 10-cell pack (the 2600's are just a few grams heavier per cell than your 2400's). so,.. 7 ounces lighter,.... almost 1/2 lb! It's a 3S4P pack of 1950mah cells. These are not kokam cells, and can withstand fairly high currents (like the "new" kokam cells being talked about). Pack is rated at 11.1V and 7800mah. Peak current is 40 amps (just over 5C) but my flight times (32~34 minutes) indicate average 2C. Another pack of these same cells is being testing in a Venus, it's 5S4P (same as mine, 7800mah capacity, but 5 cells series instead of 3). It's being ran at a peak current of 56 amps (7C) and average 3 to 4 C (they've flown some 40 minute flights, and also pushed it really hard for 15 to 20 minute flights). That plane normally flies on 16 sub-C's, so it's just over 1/2 lb lighter with the lithiums.
When these cells become available, and the "new" kokams that are being talked about, I think we'll start seeing a revolution in e-flight. Also, with multiple companies competing, maybe the price will become affordable (I can always hope can't I ).
I should be recieving a couple more of the 3S4P packs so I can combine 3 of them for the Funtana (currently 30 cell Sub-C, 66 amps peak current, 22~24 average current). I'm told that 8C peak won't be a problem in bursts, even higher would be OK. At 4C continuous, I know these cells deliver 90+ percent of capacity. In the thread about "high current" kokams, it sounds like their next generation cells will be close to this same performance level. It's truly an exciting time to be flying electric!
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Old Jan 23, 2003, 09:29 AM
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Gary,

What? No pricing or availablity information?

It sounds much like your motor information.
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Old Jan 23, 2003, 07:37 PM
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Low blow. I guess from now on, if I'm testing something new for someone I'll keep my mouth shut and not let anyone know what's coming down the pipe in the future.

Quote:
Originally posted by Greg Covey
Gary,

What? No pricing or availablity information?

It sounds much like your motor information.
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Old Jan 23, 2003, 08:08 PM
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Ahh... Gary, don't get upset, thet are just green with envy that you get to test all the good toys!

Brad
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Old Jan 24, 2003, 07:03 AM
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" ...I guess from now on, if I'm testing something new for someone I'll keep my mouth shut and not let anyone know what's coming down the pipe in the future." - GW

Hey, GW Keep testing and reporting.

I want your info - the personal stuff is discounted up front.

- Jube
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Old Jan 24, 2003, 08:29 AM
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Gary,

Your reaction is interesting. What you consider to be a restriction is the industry standard for most manufacturers.

I meant no disrespect but please consider that many vendors have products available today and to supply detailed information for other readers to access it is a true benefit of the E-Zone.

Regards.
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Old Jan 24, 2003, 09:18 AM
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Quote:
Originally posted by GWRIGHT
The lith poly pack I'm flying in an E3D (replacing 10-cell sub-C pack) is 16 ounces versus 23 ounces for the sub-C 10-cell pack (the 2600's are just a few grams heavier per cell than your 2400's). so,.. 7 ounces lighter,.... almost 1/2 lb! It's a 3S4P pack of 1950mah cells. These are not kokam cells, and can withstand fairly high currents (like the "new" kokam cells being talked about). Pack is rated at 11.1V and 7800mah. Peak current is 40 amps (just over 5C) but my flight times (32~34 minutes) indicate average 2C. Another pack of these same cells is being testing in a Venus, it's 5S4P (same as mine, 7800mah capacity, but 5 cells series instead of 3). It's being ran at a peak current of 56 amps (7C) and average 3 to 4 C (they've flown some 40 minute flights, and also pushed it really hard for 15 to 20 minute flights). That plane normally flies on 16 sub-C's, so it's just over 1/2 lb lighter with the lithiums.
When these cells become available, and the "new" kokams that are being talked about, I think we'll start seeing a revolution in e-flight. Also, with multiple companies competing, maybe the price will become affordable (I can always hope can't I ).
I should be recieving a couple more of the 3S4P packs so I can combine 3 of them for the Funtana (currently 30 cell Sub-C, 66 amps peak current, 22~24 average current). I'm told that 8C peak won't be a problem in bursts, even higher would be OK. At 4C continuous, I know these cells deliver 90+ percent of capacity. In the thread about "high current" kokams, it sounds like their next generation cells will be close to this same performance level. It's truly an exciting time to be flying electric!
Gary,
The 15 to 20 minutes flight was charged to 70% only(20V), the last test of the same flight style was 25 minutes.
Charlie
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Old Jan 24, 2003, 09:27 AM
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Yes, talked to him this morning so I understand that now. He's trying to cycle them at least a couple or three times a day (flying) to determine cycle life. Unfortunately, due to my full-time job, I don't have that luxury . I have realized how to get them up quicker (at the field) using pb mode on my chargers, just have to monitor it closely, changing current manually when voltage reaches 4.2/cell, but now I can get more than one flight on them per day. I got a triton, but it doesn't charge them fully, seems to be set to reduce current starting at 11.1V instead of 12.6. pb mode with manual reduction of current as voltage approaches 12.6 seems to work fine, just have to monitor them closely.

Quote:
Originally posted by Charlie Wang
Gary,
The 15 to 20 minutes flight was charged to 70% only(20V), the last test of the same flight style was 25 minutes.
Charlie
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Old Jan 24, 2003, 09:46 AM
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Quote:
Originally posted by Greg Covey
Gary,

Your reaction is interesting. What you consider to be a restriction is the industry standard for most manufacturers.

I meant no disrespect but please consider that many vendors have products available today and to supply detailed information for other readers to access it is a true benefit of the E-Zone.

Regards.
Gentleman,
Gary and some other world class pilots were asked to help me perfect our batteries, they are not involved in marketing and so not given any information on pricing and availability.

Usually, it took 3 to 6 months for field testing to perfect a product. I will annouce pricing in about 3 weeks. We also have batteries for park flyer,
sports/aerobatic, giant scale plane and micro helicopters, 50/60 size E-helicopters. + Li-polymer chargers.

Regards
Charlie
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Old Jan 24, 2003, 10:29 AM
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"I got a triton, but it doesn't charge (Charlie's LiPolys) fully, seems to be set to reduce current starting at 11.1V instead of 12.6..." - GW

GW, Have you happened to charge any single LiPoly cell, or cells in parallel only, on the Triton?

Reason I ask - I've tested the Triton on several sizes of single LiPolys. Charge voltage went to 4.2V (measured with a DVM) on the larger cells (Kokam 1020s and 3270s) and appeared to fully charge them.

Perhaps I should go back and retest three in series?

Also, when did you get your Triton? I have a relatively new one - shipped from Tower in late December - there has been discussion of Tritons re-programmability, and I wonder if Great Planes might be tweaking their current Triton production up to a more complete charginging level.

- Jube
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Old Jan 24, 2003, 11:01 AM
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Quote:
Originally posted by Jube T Cornpone
"I got a triton, but it doesn't charge (Charlie's LiPolys) fully, seems to be set to reduce current starting at 11.1V instead of 12.6..." - GW

GW, Have you happened to charge any single LiPoly cell, or cells in parallel only, on the Triton?

Reason I ask - I've tested the Triton on several sizes of single LiPolys. Charge voltage went to 4.2V

- Jube
Jube,
I have tested 4 Lithium chargers.
1)Orbit Pro...... seriously over charge battery by 20%, I tested two units !!!!
2)Orbit 6.....Charge to about 4.23V/cell,I like it, because you can fly a full 4.2V/cell pack the next day with close to no penallty for cycle life,(still have problem sellecting wrong cell count !!!)

3)Ginzel....Same comment as Orbit 6, but with higher current.

4)Trinton....the charge voltage at 11.1V Gary meantioned is the starting voltage to charge a fully deputed 3cells pack for all chargers. but Trinton use a longer detecting process and gradually increase the current to the preset current.(so voltage increase very slowly in the first few minutes)
this charger charge to 4.2V or slightly lower. good value,I have not yet test what if we sellect the wrong cell count.
Charlie
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Old Jan 24, 2003, 11:05 AM
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Thanks, Charlie!

- Jube
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