6-Volt Batteries for Slash-2 BMW Motorcycles
And What About 12-Volt Conversons?
by Jeff Dean

Batteries Plus stores sell an inexpensive AGM sealed 6-volt, 14 ampere-hour battery that I use on all my slash-2 BMW motorcycles. I have found that they hold their charges better than any lead-acid battery I have ever used. The two-pin “S” connector that comes stock on the battery allows you to disconnect the battery in seconds for service or for attachment to a battery charger. These batteries also have an in-line fuse, an invaluable addition to your otherwise fuseless slash-2.

The Werker is an older version of the battery, shown on the left, below. Currently, Batteries Plus lists the identical Ray-O-Vac battery on its website. It does not matter which is in stock because they are the same battery. (Personally, I like the name Werker better because it seems more Germanic. And you can say, "Verker".

The dimensions of the battery are 5 inches (146 mm) high, 2 inches (70 mm) deep, and 4⅛ inches (105 mm) wide. Because the Werker type battery is a little shorter than the stock battery, depending on the length and antiquity of your battery strap an additional pad under it may be necessary.

To attach the battery to your motorcycle, you need to replace the stock leads with a short “S” connector wire, which is available at any Radio Shack or electronics store.

   

The photos below show the Werker battery mounted in an R60/2. The photo on the right shows the connector wire needed to complete the installation. Cut the connector wire in half and then connect the half with the exposed pin to the motorcycle's positive lead on its harness (the covered pin from the battery is the plus wire).

  

The last time I bought one of these batteries from Batteries Plus it cost $38.

To charge them I used Battery Tender's 6 volt battery charger. In my last purchase they cost $42 from Amazon with no shipping and no sales tax.

Click here for Batteries Plus' 6 volt battery

There are other batteries on the market pretty much the same as the Werker battery above. Three of them — Power Patrol, Power Sonic, and Powertron — are shown below. Use Google to find sources for them. The $30 Power Patrol battery is available from Amazon.

What about maintenance-free 6-volt batteries for the R51/3, R67/3, or R68? Bench Mark Works now has the solution. Its part number is 61 21 8 042 025S — for the Noris AGM original style hard case battery with square lid. Dimensions are 6 716 x 358 x 3316 inches, or 92x82x166 millimeters.


What about 12-volt coversions?

I have done three Bench Mark Works 12-volt conversions to R60/2s. Of course, this mean changing the batteries to 12 volts as the batteries above no longer work. I have tried two solution. First, I used a regular 12-volt battery as you would use in an R75/5 or even an R1200RT. They work fine, but are so large you have to flatten the battery tray and fitting the battery into a /2 is not easy.

Second, I used a Shorai LFX14A2-BS12 lithium battery, which is so tiny it surprised me (see photos below). While it costs about twice as much as the regular battery, it is much smaller than the 6-volt batteries I discussed above. At 14 A/Hr, is also as powerful as the standard 12-volt battery.