› Techknow: High Voltage!
Everything you need to know about batteries
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.