Battery probs.

[Rocketjock]

My 80 GS750 had a totally dead battery a year ago when I acquired it. Bought a new one and didn't have it running much in that year due to some surgery I had to go thru. When I finally was able to get back at it several months ago I found the battery dead again. Purchased another new one and, sure enough, after the bike sat for a couple of weeks, the battery was run down enough so that the bike wouldn't start. Am I just having a run of bad batteries or could there be something else here? Where do I start and what do I look for? I have a new Clymer manual so perhaps it can help me out but first I thought I would query yous guys. The battery may still be under warrenty so I can probably get one for free but what if it's the alternator or regulator?

[adamgagne]

Does the battery go dead if you are riding it daily?

[Rocketjock]

Negatory. Battery hasn't gone dead. just not holding charge.

[qslim]

If you don't have one already, head over to sears and buy a digital multi-meter. You can get an decent one for about 30 or 40 bucks. Simple tests like parasitic draw and a voltage reading while the bike is running will point you to the problem area.

[Planecrazy]

Excellent advice on the multitester. You might discover that there's a minor short circuit somewhere that's draining the battery. You might find that the charging circuit is not putting out enough voltage. The wiring harness could have cracks that prevent enough amperage from flowing back to the battery, etc. etc.

All these things can be tested for with a good multitester. GS's have notoriously problematic charging systems, and the multitester will help you determine if yours is one of them. Having said that, there are plenty of people here who've never had a charging problem (myself among them)...

One suggestion ... if you find that everything checks out and you can't find an obvious problem, you might want to consider adding a master power switch to the battery (which cuts it off from the entire electrical system). Then when you park the bike you'll know for certain that there aren't any slow drains happening while it sits...

Good Luck,

[Rocketjock]

Thanks for the advice, guys.
I do have a multitester but am not sure where to look. Perhaps the Clymer book will tell me. I do know that with head and taillights alwas running, there's a lot of juice being used up even before it gets to the battery.

[arveejay]

Not to insult your inteligence but, are you turning the key off to the right or to the left? If your turning the key to the right and removing the key, the tail light will be on. Sidenote, when it's running do you keep the tach at 4000 rpm or more as much as possible? Putting around at 2000-3500 rpm will not recharge the battery as fast as the lights are draining them. I find myself guilty of that one every now and then, but am getting better. Just keep it in a gear that will keep the rpm's up. When you get your multi-meter, set to ohms and remove the battery wires and test between them for shorts, if reading goes up you've got problems, possible shorted stator. Keep us informed.

[UncleMike]

Not to insult your inteligence but, are you turning the key off to the right or to the left? If your turning the key to the right and removing the key, the tail light will be on. Sidenote, when it's running do you keep the tach at 4000 rpm or more as much as possible? Putting around at 2000-3500 rpm will not recharge the battery as fast as the lights are draining them. I find myself guilty of that one every now and then, but am getting better. Just keep it in a gear that will keep the rpm's up. When you get your multi-meter, set to ohms and remove the battery wires and test between them for shorts, if reading goes up you've got problems, possible shorted stator. Keep us informed.

Can you be more specific? Which setting on ohms and what should I be looking for? Should I just put the red connector to the red battery wire and the black to the black?

[arveejay]

My meter only has 1 setting, I would set it at lowest scale, you should get no reading. Yes black to black and red to red. You can fully charge the battery with no cables hooked up, check the volts let it set overnight and check it again in the morn. With no cables hooked up the reading shouldn't change.

[UncleMike]

I got no reading across the board for any of the ohm settings on the battery cables. Battery is reading as fully charged at 13.27v. I'll see what it's at tonight.

[tfb]

Three faulty batteries in a row would not be impossible, but the odds are so small that I'd be looking for a much more plausible explanation. Here goes...

A faulty reg./rect. unit will allow your battery to slowly drain of power while the bike is parked up.

To find out if it is the reg./rect. that is causing the battery drain, simply disconnect the reg./rect. from the battery when you park the bike.

Then see if it holds its charge. If so, the reg./rect. is your problem. If not, then you have some other cause of the battery drain, eg. a short in the wiring somewhere else.

But check out the reg./rect. first.

Mike.

[UncleMike]

I got no reading across the board for any of the ohm settings on the battery cables. Battery is reading as fully charged at 13.27v. I'll see what it's at tonight.

Battery not connected all day, and now reading at 12.85v. Still no reading on the ohms at the battery cables. Seems as though the battery is just dead. Would it be better to ground the OEM R/R, or install the Honda CX500 R/R?

More than twelve hours later and the battery is down to 12.80v.

[DaveDanger]

UncleMike,
Go a tiny bit further with the voltmeter check if you would. To start with, consider that a battery will have its highest possible voltage reading as soon as you disconnect the charger. It WILL drop some to a nominal voltage after it's been disconnected for several hours. I'd personally take the first reading at least 4 hours after you've disconnected the charger, then again 8 hours after that to see if it is losing voltage. The possibility exists that the battery has been ruined (Its capacitance, or ability to hold a charge) by the constant draw on it, if that is indeed the problem.

Next step, check for a voltage drain in the wiring. With the battery fully charged and the key switch OFF, disconnect one cable from the battery, preferably the ground. Set your meter to DC voltage, at a higher range than 15 volts. Connect one meter probe from the disconnected cable end, and the other cable to the battery terminal post. The polarity is not important for this test, but if it makes you feel better, connect the black test lead to the battery post and the red lead to the disconnected cable end. If you see ANY voltage reading on your meter, there is a drain in your wiring. You should not see ANY voltage in the electrical system wiring with the key switch turned off. The meter should read as if you were testing voltage in a popsicle stick.

If you read voltage in this test, begin looking for your drain by pulling your fuses one by one until the voltage drop goes away. That will point you in the direction to continue searching.

Post back with results.

[J_C]

Thanks Dave!!

I am having a similar issue documented here: http://www.thegsresources.com/_forum...ad.php?t=90406

I thought I was just having a charging issue until I went out today and tested the battery.... 2 days ago it was 12.5 and today it was 9.5 I immediately disconnected the battery before it got below 9 (that kills it right?)

Anyway now I know I have a charging issue AND some sort of parasitic draw. I opened the fuse box and saw that my signals fuse had blown out and been bypassed with some foil, but that wouldn't cause a draw, right? I'll go out tomorrow and start the test you described above.

I love these threads.... extremely helpful

[Big N daft]

Can I just add something to this debate, regardless of whether there is a draw on the battery or not, if you leave the bike untouched for a couple of months then there is always a risk of deterioration over time. For the cost of a battery you can get a decent charger, like an optimate, that will not only keep your battery charged and serviceable whilst not in use, but it can also bring back to life some batteries that have been given up for dead.

Basically if your going to leave the bike for more than a couple of weeks then put the battery on the optimate, they come with a moulded connector that you can wire into the fuse box to give you a simple quick and easy connection point. The electronics in the charger ensure that the voltage is monitored and as soon as it drops below what the unit considers safe, it begins a controlled trickle charger.

http://www.accumate.co.uk/it010003.html

Is their web site, I'm sure you can get them, or an equivalent, in the states.