Electrical Stuff

Discussion in 'Road Warriors' started by GS-Jake, Apr 12, 2012.

  1. GS-Jake

    GS-Jake All about the Bike

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    I know that those wires are filled with smoke cause when I short them smoke comes out. Which brings me to my question. My friend has a 2008 F800ST with a battery that goes flat after standing. She does not ride enough and after a couple of weeks the battery is flat. Of course I said that its time for a battery change but the nice guys from the auto club said (without any testing at all) that the battery is fine just needs a charge. So she went out and bought a charger then asked me what she should do. I said that it was time for a new battery, four year old bike that had about 1200km, battery probably stuffed.

    So because she has a new charger we will try to charge the battery (then we will buy a new one). So, if you were going to charge the battery on a BMW F800ST would you disconnect the positive terminal and if you did what would this do the electronics, this bike has the full kit on it.

    Thanks for you input, I am looking forward to your comments.

    Kind regards and safe riding,


    Jake
    #1
  2. NONo443

    NONo443 Been here awhile

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    If you're worried that much, just remove the whole battery from the motorcycle and charge it somewhere else. As far as the electronics, label the negative and positive side to any that are not already labeled; that is if you think you'll mix them up and they're coming right off the battery.

    I personally use a battery tender on my SV, with everything connected, and have not had any problems/meltdowns because of it. I can't speak directly for the BMW with the Can-bus system, but I can't see a big deal with doing it either way with a charger.

    Pick whatever you feel is safer.

    What charger did you get?
    #2
  3. ragtoplvr

    ragtoplvr Long timer

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    Please list brand and model of charger. This will determine if it is able to be connected to the bike and not ruin the battery. A very small battery can easily be overcharged. The fears of CAN buss are completely blown out of proportion.

    The correct charger will include a small fused pigtail that can be connected directly to the battery. Lot of us use that type, and they work well.

    Any modern starting battery that has been too discharged to start the bike more than 2 or 3 times is probably damaged and needs replaced. When fully charged it needs load tested.

    Rod
    #3
  4. Grainbelt

    Grainbelt marginal adventurer Super Moderator

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    Good advice thus far - I leave a fused SAE plug wired to my battery all the time, and either use it with the tender to charge, or can wire up a phone charger or air compressor. Never removed the battery to charge.

    Any halfassed bike shop or auto parts store will load test the battery if you bring it in. And yes, make sure you purchased a battery charger that is both gentle enough and smart enough not to fry the battery on the bike.
    #4
  5. L.B.S.

    L.B.S. Long timer

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    I have an '09 F800ST

    I would replace the battery with a new one. Many of these bikes had a somewhat infamous "Sudden Battery Death Syndrome" affliction due to the internal plates failing in a lot of the OEM batteries. They showed a full charge, but wouldn't hold the charge, and they wouldn't have the ability to crank the bike over. They would show nice voltage on a tester, but it's a load test that really needs to be done to confirm.

    I wouldn't unplug the battery to charge it, simply hook up the tried and true Battery Tender type SAE pigtail, hang it out where you can access it easily, and charge away when needed.

    If you unplug the battery for too long, or the battery goes completely dead, then you will most likely have to go to the dealer to reset the stupid *Service Due* warning and possibly an annoying yellow warning light on the dash. The internal clock date is set to show service due warnings at yearly/"X" thousand mile intervals, and if the date is defaulted back to original from being unpowered for too long, then it will think you are over due for a service.


    You can't reset this date yourself unless you have a special tool like a GS911 device. Unless you are lucky and have a good dealer, they will charge you for this bike date service reset, and also probably use this opportunity to try and sell you their "special" BMW charger for $$$ and scare you into thinking you have to use it or you will somehow make your bike spontaneously explode in a fiery mushroom cloud and kill you.

    You do not need to spend (waste) $$$ money on any special BMW charger that hooks up through the power socket on the right hand side of the bike. Many people have reported a big hassle and bikes that don't charge properly, or are confused and baffled by the bizarre complicated ritual to get the Can-Bus power socket battery charger to actually work. All the people who do the old "usual" method with SAE pigtail and a plain old motorcycle charger, have reported zero problems after all these years.

    Of course common sense is still required. Choose the proper motorcycle battery charger that will not create the aforementioned fiery mushroom cloud, LOL. A Battery Tender, Battery Tender Jr. (what I use) is just fine. It cost me less than $25.00 dollars.

    Edit: Oh, and what Mr. Grainbelt and others have said, a fused SAE pigtail of course, make sure of that. :)
    #5
  6. GS-Jake

    GS-Jake All about the Bike

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    Thanks for your advice, much appreciated
    #6
  7. skysailor

    skysailor Rat Rider

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    If you can't fix it with a hammer, it's probably electrical....
    Lyle
    #7