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Old 11-07-2005, 10:57 AM   #61
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Lithium Polymer batteries are the future of r/c ladies and gentlemen. They have been used in the r/c planes now for a couple of years and are getting better all the time.
~~I personally recommend Thunder Power, Apogee, or Astroflight chargers for the LiPo packs. The Astroflight, while being the most expensive, is the best charger on the commercially available market. I am sure many companies are now starting to explore this pathway and will have new chargers out within the year.
~~The biggest problem with the LiPo packs is the ability to handle certain amounts of ampdraw for extended periods of time and how far they are run down. The current nicad and nimh batteries can be run down past their voltage levels but LiPo's CANNOT! They must be run to a certain cutoff voltage or they will detonate or deteriorate depending on the ampdraw at the time. If the pack is overdrawn for any extended period of time the motor will lag and you will notice a slowdown. This can be shown on an ammeter or watt meter. These devices will help show how much load is being put on the battery while being run. If the amp draw exceeds the pack recommended limits it will not perform as it was advertised too. This will be a very expensive mistake by the user if not checked consistently.
~~I have seen many LiPo packs come in shredded to pieces because they exploded, literally exploded in people's airplanes because the were overdrawn or overcharged.
~~Please be careful with new technology and follow the battery manufacturers recommended charging and discharging rates.
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Old 11-08-2005, 12:06 AM   #62
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This is what I've found about the astroflight charger:
http://www.rcuniverse.com/forum/m_3327993/tm.htm
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Old 11-08-2005, 12:17 AM   #63
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Quote:
Originally Posted by scoobydo
Whats the news for 1/12th size packs?
Well forget an equivalent to 4cell 12th, the Lipos are 3.7V per cell, so it's either 3.7V or 7.4V for 12th and I would HATE to see a 12th go with only 3.7V!

So stock would be close to as fast as todays mod with 7.4V Lipos and mod 12th will be stupidly fast with around the same weight but with 7.4V, 7 & 8turn 7.4V 12th anyone?
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Old 11-08-2005, 12:34 AM   #64
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Quote:
Originally Posted by fathead
Well forget an equivalent to 4cell 12th, the Lipos are 3.2V per cell, so it's either 3.2V or 7.4V for 12th and I would HATE to see a 12th go with only 3.2V!

So stock would be close to as fast as todays mod with 7.4V Lipos and mod 12th will be stupidly fast with around the same weight but with 7.4V, 7 & 8turn 7.4V 12th anyone?
Acutally 4 cell 1/12th is pretty boring. 1/12th mod is the only class that is sort of fun. Stock and 19t 4cell are dog slow.

When I started out all pan cars were 6 cell

1/12th will eventually go 7.4v LiPo but I bet there will Kv limits on the BL motors used to control the speed.
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Old 11-08-2005, 12:38 AM   #65
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lol yeah otherwise they would be stupid fast, when I started racing 12th a few years ago we ran 6cell mod, and even with a 13x3 they were insane, couldn't imagine them with a 7turn!
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Old 11-08-2005, 04:28 AM   #66
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Quote:
Originally Posted by fathead
Well forget an equivalent to 4cell 12th, the Lipos are 3.2V per cell, so it's either 3.2V or 7.4V for 12th and I would HATE to see a 12th go with only 3.2V!

So stock would be close to as fast as todays mod with 7.4V Lipos and mod 12th will be stupidly fast with around the same weight but with 7.4V, 7 & 8turn 7.4V 12th anyone?
If math is not subjective ...
1 Lipo cell is 3.7 V - 2S Lipo is 7.4V

So 3.7V ... vs your wrong 3.2 quote.

e_lm_70

P.S: LiPo is the future no question, but if price is not comparable with NiMh the future could be quite far.

As well without ROAR/IFMAR approval, LiPo will be just for bashing.

Conrad did released alread 2 years ago a cheap LiPo 5600mAh for just 60$ ! Ready for be used in a RC car ! In a similar plastic package like the Orion LiPo.

Due to the technology on that time, the Conrad LiPo was just good for being used in a soft motor ... for long run time (max 15/20Amp continius discharge was suggested)

e_lm_70

P.S: Price have to be in the right range ... over 100$ there is no sense to use LiPO in a car .... and no sense for ROAR for try to approve it ... since they do have the rule that a motor should not cost more then xx$ ... same should be for batteries !!!
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Old 11-08-2005, 05:07 AM   #67
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Quote:
Originally Posted by fathead
Must have been having a blonde day with the numbers today, still 12th with 3.7V would be ****
If you allow less weight ... 1S Lipo can pump many amps without mayor voltage drop ... so a Kokam 3200 1S can still deliver over 200 peak watts power ... (ok 4 SubC can deliver over 300 watts)

I think a 1S Lipo in a 1:12 should be ok ... but we are on the edge of the servo and RX voltage limit.

Still a 2S Lipo is lighter then 4 SubC NiMH ...

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Old 11-08-2005, 05:12 AM   #68
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Quote:
Originally Posted by e_lm_70
If math is not subjective ...
1 Lipo cell is 3.7 V - 2S Lipo is 7.4V

So 3.7V ... vs your wrong 3.2 quote.

e_lm_70

Must have been having a blonde day with the numbers today, still 12th with 3.7V would be ****
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Old 11-08-2005, 05:45 AM   #69
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They also finish charging at 4.2v which they maintain for a while so it would be 8.4v to start with!!!
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Old 11-08-2005, 05:49 AM   #70
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Are these Li-Po batts compatible with any ESC? Wiil it charge with any of today's chargers?

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Old 11-08-2005, 06:07 AM   #71
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Yes; no.
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Old 11-08-2005, 06:57 AM   #72
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Quote:
Originally Posted by Nicadrauspro4
Are these Li-Po batts compatible with any ESC? Wiil it charge with any of today's chargers?

Yes & No. And since orion don't provide further details ... who knows !

BTW, I did ballon my Kokam 3200 2s (80$ pack) in one run with my F201, a 17T motor, and a GM SX6 ESC ... I guess it has been for two reason : It was a quite hot day ... and the reverse charge in the ESC under brake did push too many times, too many high amps spikes of back current ... that did cause the cells to get damage.

Under brake, with reverse charging (most of ESC do have this feature) zou can easily push back spike of 10/20 Amp ... and on the initial stage you can see voltage over 8.4V that is the max that a 2S Lipo cell should see !

e_lm_70

PS: So far there are only two LiIon technologies that are safe for overdisharge and at some level over charge, with high amps charging and discharging ...these are made around saphion technology, that has also a nominal voltage below 3.5V .... so Orion is not using the latest technology ... so the risk on damage these expensive cells is very high if just you do wrong one little thing !
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Old 11-08-2005, 07:16 AM   #73
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Saphion is just one company making cells. Thier technology is not industry standard and thier performance is not on par with other current cells.
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Old 11-08-2005, 08:22 AM   #74
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Quote:
Originally Posted by AdrianM
Saphion is just one company making cells. Thier technology is not industry standard and thier performance is not on par with other current cells.
Here you can get some info about the latest LiIon technology:
http://www.a123systems.com/html/technology.html (charge in 5 minutes !)

Sorry saphion is just a company name ... they use a Lithium Phosphate technology that allow discharge down to 2V (from a nominal 3.2v, and fully charge 4.2v) ... about perfomances, thay deliver 15C/25C discharge ... that is inline with standards.

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Old 11-08-2005, 08:52 AM   #75
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Quote:
Originally Posted by Nicadrauspro4
Are these Li-Po batts compatible with any ESC? Wiil it charge with any of today's chargers?

Any esc will work btu you have to watch how far you discharge if the esc doesn't have a cutoff. Some of the currently used chargers will work, namely the Duratrax Ice, Triton, and a few others.
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