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Thread: My First Post: Battery Reco for 1971 R75/5

  1. #1
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    My First Post: Battery Reco for 1971 R75/5

    I am new to this forum but not to motorcycling: I currently own three, including a 1985 Honda NightHawk, a 1971 Triumph Tiger and I just bought a near duplicate of a 1971 BMW R75/5 that I owned a decade ago except this one is not running and needs work. The current dead battery is a BMW Branded one that is approx. 7 1/4" L, 3 1/8" W and 6 3/4" H. I have AGM batteries in most of my vehicles and would like to replace this dead battery with an AGM or similar. I have searched this forum but did not find a thread about batteries for my bike and searching the 'net is difficult since most motorcycle batteries are not listed by size. Those of you who are R75/5 owners know that the original battery is a very snug fit and therefore any battery that is even a 1/8" larger than the original will not fit. I have a smaller AGM battery in my '71 Triumph Tiger but, of course, that battery is not needed to be as powerful as what the original BMW battery is since the Tiger is not electric start. I want to maximize the size/power of a new battery without exceeding the size of the dead one.
    Any battery, brand and source recommendations?
    Thanks,
    Jim
    Kirkwood, MO

  2. #2
    Registered User ebeeby's Avatar
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    I can't recall if it matters, but your '71 would -from the factory- be a short wheel base v. my '73 long wheel base. Others will have to confirm whether or not that matters but I recommend the Odyssey PC-680-P

    https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1
    Last edited by ebeeby; 09-16-2020 at 11:15 PM.
    1973 R75/5

  3. #3
    Registered User m_stock10506's Avatar
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    Panasonic AGM battery, LC-X1220P. Just watch out for the vendors that sell the “replacement” Panasonic batteries at reduced prices. The Panasonic is a quality product, the off brand choices are your best guess.
    Michael Stock, Trinity, NC
    R1100RT, R100, R60/6

  4. #4
    Registered User barryg's Avatar
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    I can't recall if it matters, but your '71 would -from the factory- be a short wheel base v. my '73 long wheel base. Others will have to confirm whether or not that matters

    Both short and long wheel base /5’s used the same smaller battery. Many years ago a buddy of mine acquired a ‘73 long wheel base model. In fact he had owned the bike many years before that. He had a large collection of bikes to choose from to ride. I had installed a lot of battery tenders to keep those bikes charged up and ready to ride. I was concerned about the bike’s small battery acid capacity to dry up. Doing a little checking using my ‘74 R90/6 as a model, I decided I could make the large battery fit. Had a friend fab in a large battery box for the /5. Worked like a champ. I also know how to make a short and sweet story long and boring. My specialty.

  5. #5
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    Thanks

    I am the OP and I appreciate the responses so far. Yes, my R75/5 is the shorter wheel base model. It's good to know that the battery size isn't different between my shorty and the longer wheel base model. I keep a C-Tek battery maintainer on most of my vehicles since some are very sensitive to voltage. I have them wired to each battery so I can connect them when not in use.

  6. #6
    Liaison 20774's Avatar
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    Snowbum has a statement on this page towards the bottom which says that the larger AH batteries (28AH) won't fit the /5 as well as the R65, GS. or ST. RealOEM indicates that the stock /5 battery was 15-20AH.

    https://bmwmotorcycletech.info/newbattery.htm
    Kurt -- Forum Liaison ---> Resources and Links Thread <---
    '78 R100/7 & '69 R69S & '52 R25/2
    mine-ineye-deatheah-pielayah-jooa-kalayus. oolah-minane-hay-meeriah-kal-oyus-algay-a-thaykin', buddy!

  7. #7
    Registered User m_stock10506's Avatar
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    Quote Originally Posted by jimmiejag View Post
    I am the OP and I appreciate the responses so far. Yes, my R75/5 is the shorter wheel base model. It's good to know that the battery size isn't different between my shorty and the longer wheel base model. I keep a C-Tek battery maintainer on most of my vehicles since some are very sensitive to voltage. I have them wired to each battery so I can connect them when not in use.
    The /5 standard setup takes the smaller battery, typically around 17-20 Ah. The later bikes have the larger battery box and take a 28 Ah battery. Kurt points out that there are a few exceptions.
    Michael Stock, Trinity, NC
    R1100RT, R100, R60/6

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