Bonneville America Forums Forums Technical Forums Accessories More light bar (or alternator) woes . . .

Prologue: A couple weeks ago, I drained my battery by leaving the key in the ignition (with the headlights on) while at a movie. I got the bike restarted using a booster pack from the garrage I was in, but fried the battery in the attempt (the booster was running at 20 or 40 amps, I think). In any case, the bike died a couple days later and the battery will no longer take a charge.

Lesson learned. With a new batter, I still seem to be having problems. Last week, the bike sat for three days in my garage. Started up fine Saturday. Started up fine Sunday. Started up fine Monday night when I took it out to the 'burbs and ran fine for almost 60 miles (on the highway, so none of that local battery-depleting driving). Parked it Monday night in the garage. Removed the key from the ignition. All electrical systems appeared to be off. No obvious reason why it would drain. Came down to start it Tuesday morning, and while the headlight appeared strong, I got the click-click-click from the starter that you get when you don't have enough juice to turn the engine over. Put the battery back on a trickle charger, and it charged fine.

Now, on a fully charged battery, my voltmeter shows about 12.6-12.7 volts across the terminals on the bike. Off, but with the ignition in the on position, that drops to around 12.3. Idling, it is closer 13, and a RPM, it goes up to 14. That seems to me to indicate that my alternator is working, and that I didn't fry it along with the initial battery. Interestingly, if I switch my factory light bar on, I get a drop in voltage below 12.6 while at idle, though at any additional RPM, it gets back to 13-14.

Any thoughts? Could the factory alternator not supply enough juice to run the factory light bar? Could it be the high intensity bulbs I put in drawing more juice than the stock ones? Another possiblity is a short drain in the light bar switch (which I've had problems with since installation; 6 fuses later, though -- and as I posted here before -- I thought I solved that problem with a new Radio Shack switch). Could there yet be a problem with the electrical pack after my ill-fated jumpstarting attempt?

Check to be sure the battery contacts are indeed nice and snug. Be sure to put some dielectric grease on them too.

If it's running up to 14V the alternator's fine. 12.6V is a little low for a "fully charged" battery, I'd be looking for closer to 13.2V. If this is recurrent (ie it ALWAYS discharges when the bike's off) and you've checked your battery connections as Pat suggested, you either have a partial short someplace or a dodgy battery that'll accept a charge but won't hold it. If your volt meter's actually a multimeter (or if you have an ammeter handy) set it up to measure current leaving the battery when the bike's ignition is off. It should be nil current unless you have a clock or alarm (disconnect them and measure again). If you find a current, start unplugging things (start with the light bar) till it stops.

Anders, I installed the Optronics driving light which work great EXCEPT they drained my battery. As soon as I get a chance to trouble shoot this I'll let you know what I've found.
My GUESS is my battery is not up to snuff.

I took it to the dealer this morning and we came to the same conclusion: The high output lights in the light bar are burning more than the bike generates at idle, running the battery down. Its too bad, because they really light up the night! Any thoughts on boosting the charging output? Anyone else have this trouble?

What wattage are the bulbs? The stock Triumph bulbs are 35 watts each I believe.

I run 55 watt auxiliary lights on a 2 year old battery with no dead battery issues. I'm wondering if low 12s are normal for idle. As the others posted, it's a great idea to thoroughly clean the battery terminals and connections. That's ususally the first place to start.

As you probably know, batteries don't store well. If the one you bought has been on the shelf for a while, it may be weak.

From Consumer Reports:
http://shopping.yahoo.com/premium/consumerreports/silver.html?id=95700426