On-Board Battery Checker
Price: $16.00
reviewed in Jet International, February/March 2001, p.53. Reprinted with permission.

A range of on-board battery voltage monitors has been introduced. The monitors are supplied with a selection of plug-in resistors marked 4.8v, 6.0v, 7.2v, 8.4v, and 9.6v to enable the monitor to be used with NiCad batteries with 4 to 8 cells. In operation the unit is installed in a visible place on the model with double-sided adhesive tape or two screws through the rubber grommets. The display has three red, four yellow and three green LEDs.

If any green LED is lit the battery voltage is regarded as safe. If a yellow LED is lit the battery is low enough to serve as a warning that not much battery capacity remains. If a red LED is lit the battery voltage is dangerously low.