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Old Dec 29, 2004, 11:54 PM
Registered User
Sydney, Australia
Joined Dec 2004
261 Posts
What Lipo should I be looking for?

Hi all,

Not really sure about these Lipos. I keep reading stories of how good they are (weight saving) but then read stories of nasty accidents with them.

Currently got an E-glider that I am changing the power system which will be pulling about 40Amps. Brushed system with a gearbox (no i dont want brushless).

My charger is Lipo ready, my new ESC on its way from Aircraft World is also Lipo friendly. I am currently using 8.4V NiCad packs (1700).

So what should I be looking for in Li-po's??????

A little explanation in how they are categorised (terminology) would be helpful.

Cheers
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Old Dec 30, 2004, 07:16 AM
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Joined Jan 2002
6,586 Posts
One of the problems with conversions from nickel-based cells to lithium is the voltage-per-cell increment difference. Nickel are about 1.2V per cell or so nominal, whereas LiPos are 3.7.

So, your 8.4 volt requirement calls for 2 1/2 LiPos, and there ain't no such animal. If your system will work OK on either 7.4 volts or 11.1, you're in business.

Let us know.

- RD
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Old Dec 30, 2004, 07:57 AM
Southern Pride
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Haralson County GA. USA
Joined Oct 2004
34,369 Posts
He will also need a Lipo friendly LVC speed controller or a device such as the Li-Saver
http://www.rcgroups.com/forums/showthread.php?t=291387
.
I have flow one of my 2 meter AF Geared Cobalt 05 on 2 cell Lipos inplace of the 7-8 Sub C SCR Nicads which I have used in it for th past 15 years.
I had to limit throttle to max of 80% to keep amps below 30 and ,limit motor runs to 30 seconds to prevent over heating the Lipos. Weight reduction was major and climb out was still good. Not like with Nicads but witout any effort I managed 5 climbouts and a 20 minute flight in dead air.My guess would be that a 7 cell Nicas would have been a 8 minute flight under same conditions.
I am not a pro. glider pilot however I do have many flights over 30 minutes and a few over an hour.

Charles
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Old Dec 30, 2004, 09:07 AM
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Best Lipo U can Buy

Tanic 2220 Mah packs, new slim size with 10 mm wide TABs, the best LIPO U can buy
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Old Dec 30, 2004, 11:15 AM
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Ft Myers, Fl
Joined Feb 2003
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hall woo,

Is that a single tanic pack delivering 40a or two paralleled packs?

Jim
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Old Dec 30, 2004, 03:02 PM
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Jim

Call Brian at 800 728 6976

He can customize a 2220 3S2P pack for 40 amp service with no problems
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