Battery / Electrics

[stu]

Right, I need to do a few things on my '99 model Mk2 so I've been using the Mk1 recently.
When I came to start the Mk 2, I found the battery completely flat, and wouldn't take a charge from a trickle charger, so I jumped it off the car. It ran fine until I disconnected the jump-leads, at which point it would barely tickover, and both nedles were flicking to fsd. Electrically incompetent as I am, I figure the ECU must need some residual charge in the battery to function properly. Is this correct?

I wanna ride the bike to the mechanic to get the exhaust sorted and the battery replaced, but looks like I'll have to do the battery myself just to get it there
Any suggestions for a short-term fix?
Thanks.

[King OFF the Road]

When a battery goes very flat, it can be very difficult (if not imposable) to bring it back to life. You should first check that there is enough electrolyte in the dead battery (the tops of the plates covered).
As you have found normal trickle charges are often not up to the job when a battery is very dead.
You can sometimes get away with using another fully charged battery to bump it up enough for the charger to start working. So in this case after checking the levels I would try connecting it up as for a jump start but leave the two batteries connected for half an hour or so, then having disconnected the good battery try the charger again.
Some of the more expensive chargers claim to be able to recover badly discharged batteries but I am yet to be convinced.

[spin]

firstly
I hope you didnt have the car runing to jump start the bike
this can damage the ECU.
if its completly flat
1 battery shagged
2 you left the park light on the bat will recharge if you leave
it connected to the car[not runing]have the bike runing but
it will take about 15 mins before you can disconnect the jump
leads if it then ticks over blip throttle if it revs it should be alright
if not give bike another 10 mins under its own steam if no better
bat shagged
3 reg/rect fault the rectifire will discharge a bat over night if faulty
get this checked anyway to be safe
most bikes wont run below 3000 revs with faulty rect
if you have to ride it wire another bat in line even a car one will do

[Guest]

<!--quoteo(post=23044:date=Mon 27th Nov 2006, 01:07 PM:name=Andy K)-->QUOTE(Andy K @ Mon 27th Nov 2006, 01:07 PM) <{POST_SNAPBACK}><!--quotec-->When a battery goes very flat, it can be very difficult (if not imposable) to bring it back to life. You should first check that there is enough electrolyte in the dead battery (the tops of the plates covered).<!--QuoteEnd--><!--QuoteEEnd-->

DO NOT OPEN the Battery = MKII's use a sealed battery.

<!--quoteo(post=23044:date=Mon 27th Nov 2006, 01:07 PM:name=Andy K)-->QUOTE(Andy K @ Mon 27th Nov 2006, 01:07 PM) <{POST_SNAPBACK}><!--quotec-->As you have found normal trickle charges are often not up to the job when a battery is very dead.
You can sometimes get away with using another fully charged battery to bump it up enough for the charger to start working. So in this case after checking the levels I would try connecting it up as for a jump start but leave the two batteries connected for half an hour or so, then having disconnected the good battery try the charger again.
Some of the more expensive chargers claim to be able to recover badly discharged batteries but I am yet to be convinced.<!--QuoteEnd--><!--QuoteEEnd-->

Yes - Buy an Optimate battery charger (approx £40) - it probably won't save this battery, but your next battery should be charged once a month if you are not using it, or left on charge permanantly with the Optimate, if you have an alarm of similiar which has a constant draw on the battery.

Once Lead Acid batteries are completely flat they are hard to recover, plus if left is a discharged state, the acid eats away at the lead plates, resulting in battery sulfation.

An Optimate is a good investment.

Don't use a normal charger, as the battery needs a constat current charge, and normal (cheap & car chargers) do not provide this. This will also shag you battery

This post was last modified: 27-11-2006, 07:47 PM by GuyGraham.

[ROB1]

In my experiance dont buy a cheap trickle charger,waste of money.Buy the best you can get & it will reward you with years of fault free service.Same advice for the battery thats going to be fitted.

[Peter Ertl]

<!--quoteo(post=23051:date=Mon 27th Nov 2006, 04:51 PM:name=SPIN)-->QUOTE(SPIN @ Mon 27th Nov 2006, 04:51 PM) <{POST_SNAPBACK}><!--quotec-->if you have to ride it wire another bat <!--coloro:red--><!--/coloro--> in line <!--colorc-->
<!--/colorc--> even a car one will do<!--QuoteEnd--><!--QuoteEEnd-->
I think this could be mis-interpreted. I'm sure you mean 'in parallel' - in line implies 'in series' to me. Or did you mean remove the old battery and patch another one 'in line' temporarily?

[Jez]

<!--quoteo(post=23042:date=Mon 27th Nov 2006, 02:42 PM:name=stu)-->QUOTE(stu @ Mon 27th Nov 2006, 02:42 PM) <{POST_SNAPBACK}><!--quotec--><!--coloro:#FF0000--><!--/coloro-->the ECU must need some residual charge in the battery to function properly. Is this correct?<!--colorc-->
<!--/colorc-->

I wanna ride the bike to the mechanic to get the exhaust sorted and the battery replaced, but looks like I'll have to do the battery myself just to get it there
Any suggestions for a short-term fix?
Thanks.<!--QuoteEnd--><!--QuoteEEnd-->

Don't know about this but new bikes are not like old'uns which would run without a battery, nowadays they just won't.

If the bike has been standing and the battery is old then just replace it. Do not worry too much about other things at this point as I am not aware of any known serious battery drain issues (except alarms of course).

If yer new'un goes flat then that's different

<!--quoteo(post=23071:date=Mon 27th Nov 2006, 09:31 PM:name=GuyGraham)-->QUOTE(GuyGraham @ Mon 27th Nov 2006, 09:31 PM) <{POST_SNAPBACK}><!--quotec-->Yes - Buy an Optimate battery charger<!--QuoteEnd--><!--QuoteEEnd-->

Brilliant peice of kit . If you have a 'spare' bike that doesn't get used much you could leave it plugged in permanently, although I just plug it in every few weeks - more often if the weather is frosty. Do not waste money on a cheap charger and do not use you car charger for the bike - it will charge too quickly..


<!--quoteo(post=23051:date=Mon 27th Nov 2006, 04:51 PM:name=SPIN)-->QUOTE(SPIN @ Mon 27th Nov 2006, 04:51 PM) <{POST_SNAPBACK}><!--quotec-->if you have to ride it wire another bat in line even a car one will do<!--QuoteEnd--><!--QuoteEEnd-->

How do you attach a car battery to a bike ? Especially as a 'piggy back'.

[spin]

in line in parralel piggy back all same to me
all you need is two lengths of heavy gauge wire negative to earth positive to bat
side of solenoid strap bat to back seat it will get him to garage