Maximum current capacity

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tome36

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Hello folks, I am upgrading to hid lighting and was curious what is the maximum safe amps you can draw on a 2001 V-Max fused off the battery of course for feeding relays before you risk damage to the alternator or components ( stator, rectifier, regulator).
 
The early model Vmax is a 25 amp system. I run two 55 watt hid projectors concurrently and my old style R/R does fine.


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If your stator is putting out well, and your regulator is working properly, there should be no problem with HID lights. Remembering that a stator can only put out maximum amps and volts dependent on RPM, there is no way to throttle a stators output except by lowering RPM. running a (to a point) heavier load is actually EASIER on the components, as they don't have to shunt so much excess power to ground, causing heat and eventual damage. Both the original shunt and the newer MOSFET units shunt to ground. Latest SERIES units actually shut off or open the stator phases. Nothing gets shunted to ground. Things stay a lot cooler, which is what you want. I have a SERIES regulator on my Roadstar, living under the seat. At Thunder, after a 50 mile ride, a few of the guys were there when I took the seat off to replace a fuse, while at Days Inn. I told them about the regulator, and a couple guys laid their hand on the unit, and were amazed that it was still cool. A shunt unit would have burnt them.
 
As Mark noted, I see 25W @ 14V listed as the alternator output. This is in the 1992 OEM supplemental manual. Not sure if that spec was increased in later years or not.

As far as how much can you draw, that exact amount would be different on every bike pending any accessories you add, the type of turn signals and brake light you run, and the condition of your existing electrical system. If you have resistance in the wiring due to poor connections you will be using a higher amount of amperage to get the same work done.

If you want to know the exact amount, take some measurements on your machine. Disconnect the headlight since it won't be factored int. Get it warmed up so the fan comes on, put on the turn signal, hit the brakes so the brake light comes on an rev to 6K so the vboost opens. That should be about as much power as the bike is going to use at any given time. You can use a DVM with peak recording capabilities. Subtract the peak measurement from the listed alternator output and that will give you the max available amperage. Subtract 5-8% from that for a safety cushion. Use ohms law to convert to watt. Use 14 VDC for the voltage input on the equation an then you have a real number.

Or, just post what the wattage is of the lights you plan to use and ask if anyone has run something similar. Probably a lot easier that way. :biglaugh:
 
Thanks to all so far. I have installed the dual cybermax projector light system with 55 watt hid lamps and ballasts that pull 16 amps starting up and 8 amps running. All turn signals have been converted to led. I can calculate total amp draw, that's the easy part. My biggest concern is not blowing fuses on all the separated circuits, it is damaging components as when the bike is warm and on a restart with the fan on, hid's in startup mode, tail, brake, it is close to if not over the 22.5 amp spec in the shop manual for 1990-on models. Earlier models were rated at 25@.
 
The headlight circuit has a separate fuse to protect. Also, main fuse protects the rest including the stator. Make sure stator and r/r connections are soldered and clean.


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