Retrofit large battery

schrader7032 · Post by **schrader7032** » Fri Jan 02, 2009 10:08 pm

Good question...I can find the part numbers for the /6-on bikes but for any /5, including SWB and LWB, they list a left half and a right half. You would think that it could be used since the frame was stretched... Hopefully someone else who owns a LWB can help out.

Sorry...Kurt in S.A.

grouch · Post by **grouch** » Sat Jan 03, 2009 12:21 am

Thank you Kurt, Yes hopefully, I suppose I can just take the dimensions of the battery,add a little and measure it. I think Snowbum mentioned something about it but evertime I start reading the Tech Tips I fall asleep. Heh,Heh. No doubt the stator will have to change as well,else it would never fully charge. Thanks again, Tom

schrader7032 · Post by **schrader7032** » Sat Jan 03, 2009 6:51 am

Tom -

Ha, ha...I know what you mean about Snowbum. There are kernels of good wisdom in there, you just have to pay attention...or hang in there long enough.

You shouldn't have to change anything else about the charging system if you just wanted to upgrade to the larger battery...I thought you were just wondering about the battery tray. The older alternator system will still charge it, just it will take longer...and you still can't run with any farkles to speak of since most of the alternator output is needed to run the ignition system and lights.

Here's some info I saved from Matt Parkhouse, who is a tech editor for the BMWMOA. He owns several /5s. Someone asked about upgrade to the 280 watt alternator:

"On the same topic, can the 280W alternator from the later airheads be bolted
into a /5, along with the diode board and regulator? I have a complete setup
lying around and it would be an easy way to up the output.

If you can locate a 280 watt stator and rotor from a 1974 or early 1975
Slash Six bike, they will bolt up to your /5..... You also need to upgrade the
diode board to one with a "Y" connector (or stick in a Thunderchild or Omega
rectifier). I've done this to several Slash Fives. Rick Jones at Motorrad
Elektric sells such a "kit" for $200."

I'm sure a larger battery will fit...not sure about the tray. My /7 tray is held down at the bottom by 2 or 3 rubber mounted fasteners. There are bolts at the sides near the top that hold it to the frame. On each side of the tray is a welded on threaded rod which extends past the top of the battery. Then there's a hold-down bar that slips over the threaded rod and a couple of plastic nuts.

Kurt in S.A.

schrader7032 · Post by **schrader7032** » Sat Jan 03, 2009 9:02 am

Tom -

I found some info on the Airhead archives where someone wanted to do the same thing...put a larger battery in his LWB /5. As I mentioned previously, my /7 battery has three vibration-style mounts at the bottom. It appears that there is a tab or bracket that is welded to the frame that accepts these mounts at the bottom of the tray. Your /5 won't have that bracketry. So, you'll have to find a way to put in that support. You'll also need to get the rubber isolators. I suspect you can get it at the dealer or your favority supplie. McMaster-Carr sells them...rubber vibration mounts. Here's another source:

http://www.sdp-si.com/estore/CoverPg/Vibration.htm

Kurt in S.A.

VBMWMO · Post by **VBMWMO** » Mon Feb 15, 2010 2:52 pm

Hello, I'm want to add a large battery to a 73' R75/5 LWB (mfg. 01/73). Will the holder used on a /6 and apparently every other machine till 84' easily adapt to my machine? Thanks, Tom