01-01-2017, 04:11 AM
Unless bikes are designed to support the use of high-draw accessories (vests, jackets, gloves, lights, etc.), I've noticed that alternators generally have sufficient capacity to maintain the battery and operate the ECU, fuel injection and ABS, but really not much else, at least not for an extended period. On my K1200RS, which has a huge alternator, simply using an electric vest (85W) with the heated grips on their highest setting and the headlight on high beam is enough to discharge the battery in short order. The police version of BMW bikes have a second battery to support the flashing lights, strobes, sirens, radio, etc.