DOH!!!! flat battery

[True Blue]

So I wake up and the sun is shinning. At last! Leathers on and off I go. Open garage door....tits, I've left the parking light on. Hold on everything lights up ok. Tried to start it but the battery is indeed flat.



To make matters worse, my GF has taken my car to work. Double tits! So I phone a taxi to go to the nearest bike shop ( about 6 miles away) to get a charger.

"what chargers do you have mate?"
"just the Optimate III"
"Well I guess I'll have the Optimate III then."
"45 quid please"
" "

So any way I asked the guy would how long it would take to charge a totally discharged battery and he said about 6 hours. I was wanting to know if I could charge it just enough to start the bike and would it be ok once the bike was going?

He said that if the battery wasn't fully charged, it would cause misfiring. Does that sound right or is it BS?

Cheers

Ritchie
____________________
Past >>>> Honda NSR 125 >>>> Suzuki GSXR 600 K1 >>>> Suzuki GSXR 600 K4 >>>>Kawasaki Z1000 DAF >>>>Suzuki RMZ 250 >>>> Current >>>> KTM Superduke R 1290 >>>>

[Danny]

I reckon you only need enough charge to get the engine started, then the alternator will charge it.

[hush]

Surely he's talking rubbish - after all, if that were the case, you shouldn't be able to jump start from a car without misfiring (that doesn't charge you battery)... Once the engine is running, it should run off the alternator whilst recharging the battery. After all, the battery is only turning the starter motor... Providing you have enough power to turn the starter motor to ignite, it should be fine.

I'm not a bike mechanic, so I wouldn't swear that I was right, but that's the way it works on a car...

[True Blue]

[True Blue]

[hush]

So many 'specialists' who hire sales assistants, and then neglect to train them properly because it costs too much

I'm lucky, I have a motor shop just down the road which is staffed by four guys who are real motor maniacs, but it's all too easy to open a store and say 'specialist' without knowing jack about what you sell, and the different products people may already have...

[T.C]

It is possible that a knackered battery will cause a misfire, particularly if it has totally discharged and then been re-charged.

I had a customer a few years ago who did exactly the same as you, jump started it and took it for a 20 + mile ride hoping that it would put sufficient current into the battery, but by the time he had finished the ride it was coughing and spluttering so badly he thought he had a major internal engine problem.

Turned out that the current wasn't going into the battery quick enough against the drain that was being used, and because it was knackered although 12.5 volts was going in, the battery was only running at about 8 volts.

It appears that when a battery drops its voltage (and don't quote me on this as I am no electrical expert) below 8 volts even on a full charge it is very difficult to get the full power of the battery back up and this in turn causes problems for the generator as well as the regulator.

Anyway, we fitted a new battery and the bike immediately chimed onto all 4 pots and away he went as happy as larry.

So as I say, it is possible that the knackered battery will be the cause of a misfire.
____________________
It is better to arrive 30 seconds late in this world, than 30 years early in the next

[True Blue]

Was he riding around with his lights on? I was thinking that if the battery is discharged then the alternator should charge it very quickly, it sounds as though your mates battery was actually knackered. What caused it to discharge in the first place?

Although I am in theory "an electrical expert" . I don't know too much about batteries.
____________________
Past >>>> Honda NSR 125 >>>> Suzuki GSXR 600 K1 >>>> Suzuki GSXR 600 K4 >>>>Kawasaki Z1000 DAF >>>>Suzuki RMZ 250 >>>> Current >>>> KTM Superduke R 1290 >>>>

[needa400]

If you are using any form of electrical drain then this could cause problems. Also, if your alternator is not working correctly then the drain is too much and this could cause misfiring.

However, seeing as ur alternator should be ok, then it should be fine to start it and leave it running to gain a charge, or ride it even, but it's best to use the lights as little as possible!

Needa
____________________
I was here, now I'm not, coz I covering the missus in me special man snot!

[ZaphodBeeble]

The misfiring problem will only arise if the battery is knackered, not only if it is discharged. A good battery will take a charge quite easily whereas a knackered one will absorb too much of the charge so that the coil has no power to ignite the fuel mixture.

So, if the battery is flat but in good condition you can bump start it or jump start it, but if the battery will not hold a charge it will probably cause you problems.
____________________
Current bike: VTR1000F Firestorm. Previous: Firestorm (written off) - XJ600 Divvy - NSR125 - DT125 and a load of offroaders.

[Sparks!]

True Blue, if you've bought the optimate, it's a good idea to wire in the permanent lead they include onto your battery, and plug the charger in over night until it's fully charge, then stick it on over night again once a week or so.

I had a problem with my battery where it died on me, it's mostly down to the alarm and the fact I left the ignition on while we pulled over, it turned out we were waiting a little longer then I imagined and forgot about it.

I bought an oxford optimizer as it was only £30 and came with a wall bracket etc, which the optimate doesn't as far as I know. The sales man in the shop told me they are practically the same item, just been re-badged. Not sure how true that is but it does the job anyway, not had a problem since (altho it's only been a week and a bit)

My battery was 100% flat, but once we bump started it with an electric thing, I rode off with no problems, no mis firing and it charged back up fine since then. Was lucky I guess as it never killed the battery beyond repair!

Good choice on the optimate though, it's worth it in the long run.
____________________
Current Toys: 06 Yamaha WR250F | Nissan 350Z GT | Tech 4 Homes

[True Blue]

[Sparks!]

To be honest, when your riding, it doesn't matter about the lights! You can have them all on with no problems at all. It'll still charge as normal and won't affect the battery.

But it's always advisable never to start your bike with the lights on (provided you have a on/off switch!) as this can cause problems apparantly.
____________________
Current Toys: 06 Yamaha WR250F | Nissan 350Z GT | Tech 4 Homes

[Danny]

True Blue, there is a guide to bump starting bikes somewhere on BCF I think. I'm just too lazy to find it.

[Sparks!]

I first heard about it from my mate, (hes about 55 and been riding forever, he's an engineer and knows his stuff) he was saying how it /could/ do damage etc.

BUT

A lot of new bikes are now having always on lights, if it done damage then they wouldn't be able to be always on etc.

I don't know 100% to be honest, but I always turn my lights off anyway when starting, it's un-neccsesary drain on the battery before the bike is started anyway.

So basically, not 100% sure of it's wrong or not, but it doesn't matter to me to turn my lights off as it's second nature now.
____________________
Current Toys: 06 Yamaha WR250F | Nissan 350Z GT | Tech 4 Homes

[hush]

If you start with an electric starter, the battery is supplying the lights as well as the ignition system before starting. If you have a semi flat battery and attempt to start with your lights on, it'll turn over slowly, turn them off and it turns over a bit quicker. I'm not sure of the repercussions, but it certainly puts more drain on the battery starting with the lights on.

[True Blue]

Found that post Danny, cheers
____________________
Past >>>> Honda NSR 125 >>>> Suzuki GSXR 600 K1 >>>> Suzuki GSXR 600 K4 >>>>Kawasaki Z1000 DAF >>>>Suzuki RMZ 250 >>>> Current >>>> KTM Superduke R 1290 >>>>

[Kickstart]

Hi

A flat battery can cause a misfire, especially at low revs. Some bikes can be prone to a misfire, steadily getting worse, if you leave them idling for too long. A few people on the FZ750 board have suffered this.

A fuel injected bike will draw a hell of a lot more current, and it is also unlikely to manage to pressurise the system if you try and bump start it.

I would say that as long as you have a reasonable amount of charge in the battery then it will be fine. However I would not be too surprised if it has problems if you just get it started and then go and sit in slow moving traffic for ages, with the radiator fans drawing loads of current.

All the best

Keith
____________________
Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing