› Tech­know: High Volt­age!

Ev­ery­thing you need to know about bat­ter­ies

RC Car Action - - CONTENTS - By Peter Vieira

As dis­cussed pre­vi­ously, stan­dard Lipo bat­ter­ies have a nom­i­nal volt­age of 3.7 volts per cell. But there is a new breed of “high-volt­age” Lipo (Lipo HV or LIHV) with a nom­i­nal volt­age of 3.8 volts per cell. That’s not a huge dif­fer­ence, but in or­ga­nized rac­ing where hun­dredths of a se­cond count, that ex­tra tenth of a volt per cell adds up. To take ad­van­tage of the LIHV tech­nol­ogy, you must use a charger de­signed to charge to the higher volt­age—an “HV” charger will stop charg­ing when each cell reaches 4.35 volts, rather than the 4.2-volt set­ting used by “reg­u­lar” Li­pos. You’ll also note rac­ers of­ten use “shorty” packs, which save weight and may al­low more op­tions for bat­tery po­si­tion on the chas­sis. For sport run­ning, there’s no ad­van­tage to a “shorty” pack.

A “shorty” pack is about 3.8 inches long, ver­sus 5.5 inches for a stan­dard-size pack.

Note that this Reedy

Zap­per is 7.6 volts in­stead of the usual 7.4—it’s a “high-volt­age” pack. And if it looks a lit­tle short, that’s be­cause it’s a “shorty.”

Rac­ers typ­i­cally use bat­ter­ies that have tubes to ac­cept bul­let plugs sol­dered di­rectly to the speed con­trol wires. Or, an adapter har­ness like this one may be used to add a plug and bal­ance con­nec­tor to a pack with tubes.

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