Welcome to Netrider ... Connecting Riders!

Interested in talking motorbikes with a terrific community of riders?
Signup (it's quick and free) to join the discussions and access the full suite of tools and information that Netrider has to offer.

Battery not holding charge

Discussion in 'Technical and Troubleshooting Torque' started by Trauts, Jul 30, 2008.

  1. hi all,
    i was hoping for some input to a problem im having with my 2001 Viffer.
    I started to have trouble with the battery about 2 months ago, so i thought that after 4 years might be a good time to change the battery. This solved the problem, i thought. But after about 2 weeks i found again that i had a flat battery. So i put it on charger then back into the bike. Seemed to fix the problem. however this has been a recurring pattern since then. So either the battery is not getting enough charge during riding time. about 2 hours each day. or its just slowly being drained which i guess would indicate an alternator problem? but if the battery was not getting any charge i would have thought it would run down faster than it currently is.

    Would appreciate any sensible input if this rings any bells for anyone.

  2. Mate its not the battery. Its the charging system.
    Run a multi meter across the treminals when the bike is running (3k) and it should be showing about 14v I bet it's not.
  3. Hi Chris, thanks for the quick reply and the figures. i havent had a chance to do that yet. i need to get a multi meter.
    Im guessing that t means a trip to the shop if its low. Id say im reasonably mechanically minded, but no mechanic. And it being my daily commute i cant afford to cock something up and have it off the road for more than a day if its not something that i could handle.
    Thanks again for your input.
  4. Hey Stu .. does your headlamp seem to glow brighter when the engine is revved, as opposed to it idling? If not, it may very well be the charging system as Chris has stated.
  5. Hey Vinnie,
    on about day 3 after charging, i do notice that the light is a little dimmer and revving does increase the brightness slightly. But up until now i had never really payed much attention to that to know if that is the norm.
    It would appear that i might have a problem with the charging system as suggested.
    Looks like its off to the shop i go. Ive just had a look at the service manual, and i dont think its something i should tackle given my expertise and time restrictions.
    Thanks for the input again however!
  6. regulator/rectifier is the achilles heal of viffers.
  7. I'd probably check out a VFR owner's website first, but many Honda's -especially VFRs - have problems with regulator/rectifier failure (I know mine did!)
  8. Fixed for you.

    Regards, Andrew.
  9. mmm. ok. Thanks for the link. i was hoping for something not quite that expensive...
  10. Read your post and it could have been mine at 36,000K. My '98 had the same symptoms and as stated it is a common, no universal, VFR problem.

    Basically the reg/rec is mounted in a place where it gets insufficient cooling air to balance the heat of operation. Earlier VFR's had the situation compounded by having no cooling fins on the reg/rec at all, current ones have solved the prob by placing it up front near the head tube.

    Despite what you will find on some forums, there is no inherent problem with the unit itself and units off other bikes (eg Yamaha R1's) are no better and fail eventually for the same reason. So to avoid wiring issues it is just as easy to replace it with an OEM unit and attach a computer cooling fan (lots of web references) wired in to the tail light circuit so it runs whenever the ignition is on. I replaced mine at 36,000K approx. 6 years ago and it is still going strong (touch wood) at 175,000K.

    When you replace it (easy and straightforward) it is worth using a contact cleaner on the terminals of the wiring plug followed by a corrosion protection spray (get from electrical supplier, dont use WD 40) as the plug can get hot and allow the contacts to oxidise, inreasing the resistance and exacerbating the issue.
  11. haha :)
    Thanks RedBruce, funnily enough mine has just clocked 40k, so in about the same ballpark kms as well. Still tossing up what to do, obviously i need to get it fixed. But im gonna struggle to be without bike for a couple of days.
    Anyway, thats my problem.
    Thanks again for the input. At least i now know my problem probably is. Just need to sort out a solution pretty soon before the battery gets fried..
  12. Hi,

    a good charge is: 13,7v - 14,4v DC
    On some bikes, charging voltage can go up to 14,8 but is not so good for the battery.

    You have to check this in different stages:

    1. bike idle
    2. ~5000rpm (normal driving)
    3. > 7000rpm (when the fun starts)

    Is not a good idea to charge a battery while is still connected to bike! (some rectifiers won't like this). Just disconnect positive and apply the alligators from charger.

    Also check the battery terminals for oxidation marks and tie them up properly. If the wires are not properly connected, resistence will be there and will heat up. Might prevent a fire. (not joking)

    If you want to check the regulator rectifier, you can check the alternator (3 yellow wires, AC voltage!!!, can have 100volts easly at hi rev on each wire)

    And don't forget this: all the automotive batteries are loosing 1% of their capacity / day. So: aprox in 3-4 months is dead!
  13. cool. thanks