Charging the battery
 

Hi Guys, I have done a search honest.

My bike, a K3 won't quite turn over, (it has been stood in the garage since October) I would like to charge the battery with an good old fashioned 12V charger.

1. Can I charge it while it's still connected and leave it on the bike or do I need to disconnect it and charge away from the bike?

2. Is it possible to jump start it from a car battery with jump leads?

My MOT's tomorrow and it's too far to push it.

Thanks,
Paul

Re: Charging the battery
 

1. I think it's normally recommended you remove the battery

2. Yes, just ensure that the car is NOT running while the two are connected


If the battery has gone very flat you may be able to jump it but it may not hold a charge any more, in that case a new battery is the only option

Get an Optimate, connect it when you're not using the bike and it'll take care of the battery 24/7

Re: Charging the battery
 

thanks TLW,

Can anyone point me towards any good deals on optimate or similar, time to crawl in to the 21st century I think.

Thanks,
Paul

Re: Charging the battery
 

Couple of weeks ago www.intobikes.co.uk was the cheapest place - £39.99

For someone like me who may not get to use the bike all week it's nice to know the battery isn't gettin' busy dyin' in the garage...

Re: Charging the battery
 

Just out of interest why can't a 'normal' (car) trickle charger be used on a bike battery?

Re: Charging the battery
 

AFAIK it can

12V is 12V, so long as the charging rate (in amps) isn't higher than the battery can handle you should be fine


What you shouldn't do is start a flat bike battery from a running car battery, the charging system on a car is much stronger and when it sees the bike's 12V system it will attempt to charge it, possibly damaging components on the bike or exceeding the charging rate the m/c battery can take

Re: Charging the battery
 

Tech 7 make an altered for legal reasons but otherwise carbon copy of the oxford oximizer but for a 3rd of the price.

Re: Charging the battery
 

I think the term "old fashioned" carries the answer.

Yes you can use them to charge a bike battery, but you need to exercise some care. They didn't use any sort of clever charge rate control so it was easy to overcharge, and any spikeyness had a habit of popping diodes in rectifiers etc. With an old type charger by far the safest option is to remove/disconnect the battery from the bike electrics before connecting the charger and then switching it on.

As a rule of thumb a lead acid battery likes to be charged at around 1/10th of it's nominal Amp-hour capacity, so a typical bike battery of 10Ah use around 1Amp (ish). Older chargers usually had an ammeter on them so you could check it wasn't overcharging, which is fine if everyone knows what max current to allow and watches over it while on charge. It's essential not to leave it on charge for too long, and on a bike battery something like 2Amps is probably getting a bit high for a bench charge rate, in which case turn it off and wait an hour or so then restart the charger and see what it does.

Optimates etc will look after all this and don't spike the voltage, so won't fry electronics and don't need an ammeter.

Re: Charging the battery
 

If possible I would avoid a jump start - its not proven but I suspect theres a risk that when u disconnect the car battery after starting (independant of whether the cars running or not) the heavy and long charging of the flat SV battery can fry its sensitive (see the posts!) reg/rectifier.

Re: Charging the battery
 

Tech 7 optimate at Busters.
http://www.busters-accessories.co.uk...tech+7+charger
£19.99 works for me after nackin a battery with a cheap Argos charger