research

With a lot of help from this page and various BMW motorcycle forums, I went looking for an inexpensive battery for my 1993 BMW K75/ABS. This bike comes with a 25 amp-hour battery from the factory, which is BMW part number 61 21 1 495 650. Other choices include:

Yuasa Yumimicron Y60-N24AL-B

Exide Edge Y60-N24AL-B

Wesco 12V28AP (maintenance-free)

Panasonic LC-X1228P or LC-X1228AP (maintenance-free)

All four of those are 28 amp-hour batteries. The Yuasa, Exide, and Wesco are in the $90-100 range. The Panasonic can be bought for $62 from Digi-Key. The Wesco is reportedly made by Panasonic and is the same as the LC-X1228AP.

The LC-X1228P and LC-X1228AP differ only in the type of battery terminals. The LC-X1228P has a flat post with a hole in it, suitable for connecting to a nut and bolt. The LC-X1228AP has a threaded receptacle.

I am not sure which of those two terminals are the right ones for unmodified bikes. I’ve seen both mentioned in BMW motorcycle forums. My bike was fitted with the less expensive and lighter 20 amp-hour LC-X1220P when I bought it, and it’s possible that the wiring was modified to use the nut-and-bolt terminals. I’ve never seen the stock battery so I have no idea what kind of terminals it has.

A lot of BMW motorcycles only have room for the narrower LC-X1220P, and that appears to be a fairly common battery choice. Many K75 and K100 bikes have a 5″ wide battery pan and can take either the LC-X1220P or LC-X1228P (or AP, depending on the terminal posts). I decided it was worth the extra $14.50 and the extra ten pounds to get the larger battery.

I read that the Panasonic battery isn’t designed or rated for motorcycle use, but enough people are using them – and my bike already has one, as it turns out – that it seems like a safe choice. However, since the battery isn’t made for motorcycle use, use this information at your own risk, do your own research and make your own decisions, etc.

If you buy the Panasonic battery from Digi-Key, you can get free shipping if you print out their order form (pdf) and send them a check.

The Panasonic batteries appear on this page (pdf) of the Digi-Key catalog. The data sheet is here (pdf).

If you’re reading this page much later than October, 2006, those links will probably not work. Search their home page for LC-X1228P (or whichever battery you want) instead, and view the printed catalog’s table of contents to find the order form.

UPDATE: More good information available here.

UPDATE 2: PLEASE TAKE NOTE. I received the LC-X1228P, and found that it is too tall for my 1993 BMW K75. In my research I found several sources that said either the LC-X1220P or the LC-X1228P would fit, as long as the battery tray was wide enough to accomodate the wider LC-X1228P. This is incorrect. On this motorcycle, the bracket which holds the battery down is also responsible for securing the coolant overflow tank. If the battery is too tall, the bracket does not touch the coolant overflow tank. In addition, the battery tray has a recessed space about three inches wide, allowing the narrower LC-X1220P to sit about 1/4″ lower than the wider LC-X1228P. With the LC-X1228P installed, the long bolts which secure the hold-down bracket don’t even reach the battery tray. I am returning the LC-X1228P and will purchase the LC-X1220P instead.

UPDATE 3: You may need to pay sales tax on your order from Digi-Key. I called their accounting department to find out what rate they wanted for my order (8.25% for Austin, Texas). If you don’t include sales tax, they’ll call you to make sure you approve the extra charge before they ship the battery.