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Battery Problem

Discussion in 'Technical and Troubleshooting Torque' at netrider.net.au started by Casey, Mar 25, 2007.

  1. I had a problem with my bike the other day ('99 CBR600f). I was an idiot and left the lights when I parked it in the morning, so when I was leaving work in the afternoon, the battery was as dead as.
    I tried to clutch start it, which worked for a while but it was misfiring all over the place and after a minute or so, it completely gave up the ghost. Took it to the bike shop who diagnosed the problem to the battery being stuffed.
    They put a new one in and now it goes as good as new. I was told by the mechanic however, that generally, if the battery is run completely flat, it generally means that you’ll be up for a new one as this apparently stuffs up the plates permanently.
    This surprised me because with car batteries, you can still jump start a battery that has been run completely flat (done it many times), with usually no side effects (just means you need to take it on a long run to get the alternator to bring back up the charge again).
    Is a bike battery different by design (i.e. sealed unit) to a car battery that make this happen or is the mechanic telling me porky pies to boost future sales. He reckons that this will happen to a new battery as well and not just old ones.
    Also, I was surprised to notice the batteries ranged in price from about $60 to $240. Does anyone know what the huge discrepancy is due to (does the $240 battery actually last 4 times longer than the $60 Supercheap Auto one?).

  2. The mechanic is correct. For deep-cycle batteries (car, bikes, boats, etc.) it's due to process called "sulfation". Car batteries have more 'cells' than bike batteries, so the sulfation affect can also take longer on a car battery.

    Car batteries are usually overpowered for lights and accessories, and have lots of crank power to start the engine. If you completely drain a car battery of power, you will diminish is crank ability, but generally still have enough to start the engine.

    With a bike, the batteries are usually 'paired' a lot closer so that the battery has just enough crankpower to start the engine. Lighting and accessories are a lot lower than a car so overpowered batteries aren't needed. Plus a bike will generally want a smaller and lighter battery for space and weight distribution reasons. Drain a bike battery flat and diminish it's crank power and you often aren;t then left with enough to start the bike engine reliably, if at all.
  3. OK Mouth that all makes sense, the other question that I would also like an answer to is what is the difference between the cheaper and dearer batteries? I need to get a new one I think, I have had to jump start my bike for the last few months and it is a royal pain in the arse.

    Oh an I like your avator, I just got a Palm Treo on NextG and it rocks! :p :grin:
  4. Mouth is basically correct. However there are six "cells" in a 12Volt battery irrespective of whether it is a bike or car (lead acid) battery. What differs is the size, construction and amount of lead for each cells. Smaller loads will be met with smaller thinner plates etc.

    One consequence of this is that bike batteries dont recover from dead flat as well as car batteries, especially if jump started and exposed to the full power from a bike alternator. Tends to cause plate failure hence the commonly reported catastrophic battery collapse.

    Cheaper batteries tend to be constructed with less lead, less durable separators, casing etc. However its all about matching the battery to the job. If you regularly ride then a mid priced battery will generally do (ie I have had the same life from the original Yuasa battery in my VFR as the made in Phillipines by Yuasa when used daily - $190 Vs $110). If you leave the bike sitting around unused for long periods you will never get your monies worth from an expensive battery as it will sulfate up at only a marginally slower rate than a cheapy - just chemistry at work. If you regularly ride in cold conditions and use accessories like additional lights, heated grips etc then a high quality battery would be better.

    Given that why are bike batteries so much dearer than car batteries - well thats another story.
  5. You certainly get what you pay for in batteries, but if you keep it well maintained by leaving it plugged into a charger such as below over non-riding periods, the battery will be in tip top shape, especially over the harsher colder months.


    I can't recommend the Jaycar one enough, only tops up the battery when it needs to (not a potentially damaging trickle charger), and comes with a harness to bolt specifically onto bike batteries so you can just plug it in when needed.
  6. I buy my batteries from a car battery place and don't pay much for them. so far they have lasted longer then the ones I get at bike shops. though the comparison is not fair, as the one I've bought from bike shops have been "wet" types and I always buy "sealed" these days.

    If you believe money buys you quality (and I don't in this case) then you should be using the dearer battery for a bike that sits around a lot. The reason being that batteries don't like slow discharge.

    Is your bike FI? If so this may also explain why a highly drained battery had trouble coming bake from the dead.