BMW R1200R R1150R/T F800 K1200R R1100R/T R1250R RnineT Message Board

I posted last week that my battery seemed to have failed. I went down to 6V and wasn't charging to a normal voltage or holding a charge.

I tried disconnecting my (brand new) Blue Sea fuse block. The only thing connected to the fuse block is an IMC MIT-100 communicator which does not yet have anything connected to it. I had this setup connected for about 4 weeks before seeing any problems.

Now, after charging for 2 days, the battery charge was 12.88V and has been able to hold a charge of 12.7V sitting for 2 days. Yesterday I rode it for about 50 miles and kept the rpm to at least 4K most of the time and didn't see any change -- still 12.7V at the end of the ride, which it still has this morning. When I start the bike, the battery light on the instrument panel takes 6 seconds to turn off.

I don't want to exchange the battery if there isn't really a problem with it and the issue is the fuse block. My dealer is 220 miles away, so it is no small undertaking to make the exchange so I want to be as sure as possible that the battery is defective before I do this. Is this enough information for anyone to advise me?

Thanks.

I believe the standard failure on the batteries is for them to go open under load. In short it looks fine till you hit the starter.
It sure looks like you have a problem with that fuse block.
6 seconds for the battery light to go off is about normal.
It seems you have a volt meter, so it would be a good idea to put it on the battery with the bike running at about 3K RPM and check that the voltage goes at least to the high 13s. That would prove your charging is OK.

It looks like you understand basic electronics, and most likely have figured out it's the fuse block so I'll let some one else drag this out if they wish

I agree with the suggestion to have the battery load checked. Any good battery place should be able to test it for you quickly.

I would also suggest checking your battery leads for corrosion. I had some on the ground lead at the battery I noted when mine died, and got the Dremel tool out and cleaned it ip too. In my case the battery was really the problem and warranty covered it with one month to go.

I'll second the suggestion of a load-test. Most large auto-parts chain stores have a station setup to do just that. Trick is finding the guy who knows how to load-test a smaller battery like a motorcycle battery.

...and since you have a voltmeter, it probably also includes an ammeter function. So re-connect your fuse block, this time through the ammeter, and measure the current into the fuse block with no other loads connected. If it's anything more than zero, your fuse block is defective.

Thanks to all who replied. I will try to find a place to load test it.

NeilS wrote:...and since you have a voltmeter, it probably also includes an ammeter function. So re-connect your fuse block, this time through the ammeter, and measure the current into the fuse block with no other loads connected. If it's anything more than zero, your fuse block is defective.

Neil: Thank you, I have been wondering how to test the fuse block. I think you are saying to re-connect the fuse block to the battery, but where do I place the test leads from the meter? (Pardon my ignorance on this one) Also, would a continuity test between the positive and negative battery connections on the fuse block, without the fuse block connected to the battery tell me anything?
Thanks.

Bob,

The continuity test you propose might be useful, but your ohmmeter probably doesn't do the test at the fuse block's normal working voltage (12-15 volts). That's why I prefer a leakage current test with an ammeter.

To do the leakage test, connect your battery's negative terminal to the fuse block's negative terminal. This doesn't have to be a permanent connection, a "clip lead" should be fine. Then set your meter to measure current. Connect the meter's positive lead to the positive terminal of the battery, and connect the meter's negative lead to the positive terminal on the fuse block. The meter will read any current that is going from the battery into the fuse block. It should be very close to zero.

If the reading is not zero, it will give you a rough indication of how long the leakage will take to discharge your bike's battery. For example, say the leakage current is 10 milliamps (1/100 of an amp). If the battery's capacity is 14 amp-hours, it will take 1400 hours (about 2 months) for the current to discharge a fully-charged battery. That's probably acceptable. But if the current is, say, 200 mA, the battery will be discharged in less than 3 days, and that would indicate a defective fuse block.

HTH,

Bob,
Without getting into basic electronics 101, it might be easier to wire a small 12v lamp (parking lanp) into the wire from the battery to the fuse block. If the lamp comes on or glows - then you have current flow (a drain). Keep disconnecting things until lamp goes out. Reading current flow with an multimeter can be trickey when measuring very small current flows. The light should work for you without all the tech stuff.

Thanks for the info Neil. I will try these fuse block tests out -- actually, the meter test sounds easier to me (my meter can report down to 0.2mA, so it shouldn't be a problem). I have tried checking the voltage with the bike running and from idle on up it shows about 14.2 volts. Last night coming home from work I saw (for the first time) something I hate seeing, though: The headlight dimmed when I was off throttle and brightened when on throttle

Tomorrow I will try to get a battery load test and the fuse block tests done and I'll report back.

Thanks again for the help.

The battery still holds a charge of 12.7V. I measured the fuse block current draw at 5.5mA. Any thoughts?

At that level of drain, it would be weeks, if not months, before your battery was so discharged that it couldn't start the bike. I'd still want to know where that 5.5 mA was going. Do you still have the communicator connected? If so, you might want to disconnect it and see if the current goes to zero.

While you have the ammeter out, it would be useful to measure the current going from the battery to the bike with the ignition off. (Same procedure: Remove the positive battery cable; connect the ammeter from the battery terminal to the cable.) This, of course, adds to the 5.5 mA in determining the rate of battery discharge. I don't know the amount to expect, but it should be greater than zero. Even though the key is off, there is current used for various electronic functions that are always functional (CANbus control, clock, ECU memory, etc.).