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E-maxx EVX2 and 18,8 volt A123 possible??

E-maxx EVX2 and 18,8 volt A123 possible??

Old 03-18-2009, 12:52 PM
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Default E-maxx EVX2 and 18,8 volt A123 possible??

My Nephews bought an new E-maxx 3905 after they drove with mine... Now we can have fun togehter bashing around.

I drive with 6s2p A123 cells and MMM 2200 KV setup. They like the A123 cells and would like to drive the standerd E-maxx with it.

I was thinking about a 3s4p setup (two triangular 3s1p packages in parallel on each side) so they can be put in serie by the EVX2. Then it would be 18,8 Volt and 4600 Mah, am i right?

But, how big a risk would it be to put 18,8 Volts on the standard EVX2 ESC?

Would appreciate advice.

Thanks!

Rob
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Old 03-18-2009, 03:03 PM
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so, max stock is 16.8? it should be ok, you can usually overrun by a few volts.
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Old 03-18-2009, 06:25 PM
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Yes you can, fully charged 7 cell NiMH pacs will go 9.1- 9.4v or as seen by the esc 18.2 - 18.4v. But, the newer esc, EVX-2 has a rep for not tolerating that extra voltage. Plenty have learned not to rush their NiMhs off the charger onto the new Emaxx cause it won't arm - strg works, it just won't move. Over on TRX, standard advice is to work strg back and forth long enough to bleed some voltage off and then it will go. My old EVX on the 3906 doesn't do this.

The batt setup you're outlining would be 10.8v (3x3S - a123s are 3.6v max voltage/cell), the 4P means you'd have extra capacity, not volts - 4 x 2300 = 9200mah on tap. The 1st number is the cells in series, the 2nd figure is the cells/pacs in parallel. Series adds voltage, but doesn't increase capacity, parallel doesn't increase voltage, but adds capacity.

Your 6S2P is 21.6v (6 x 3.6v/c) and 4600mah (2x 2300). 5S would be 18.0v - I've seen twin tubes of 4 cells with a 5cell on top inbetween the two if that makes sense. Pr of these on each side - you'd find out how well the EVX2 could take the extra v. 4S (14.4v) wouldn't have the zip....
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