Battery output requirements

[Half Ton]

Being a wee tad scared of electrickery, Is there a way of calculating the power requirements of a battery   i.e. the one on my Matchless is a YB14L-A2    12N14-3A    14Ah ..as it has electric start,And is large to say the least.. I was wondering if I fitted an led H/light bulb 20 watts (60/55 equivalent) and an led rear light and indicators could I safely reduce the size of my battery.....please be gentle with me ....cos oi is a bit of a muppet sometimes
      Ta very muchly Steve P.

[CrazyFrog]

It's the current drawn by the starter motor which governs the size of the battery you need really - unless you have a modern bike where the lights are permanently on, the currrent draw of the bulbs is insignificant.

On my similar MZ SilverStar I have used a MotoBat glass mat battery which though the same size as the original gives considerably more 'oomph' for starting (technical term, cos I've forgotten the exact specs of the battery!). They are more expensive, but a good investment IMHO...

[Half Ton]

Thanks for the info Mr Frog  So am I right in thinking the glass matt batteries can be fitted on their side, which might give me a bit more space to play with for the air filter.

Looking at the Yuasa lead acid Battery info it quotes   128 cca but a lithium ion battery quotes 290 cca, is it the cold cranking amps that you referred to when you said "current drawn by the starter motor" on the battery (I did warn that I know nowt about electrics) or is it just the 14 amps in the battery spec 

[timbo]

I am also interested in this subject. I have recently purchased an MT500, but converted to electric start. However, the conversion to accept the larger battery, as fitted to the MT350, has not been done. I take it, with modern technology, that I can now get a small battery, which is high output?

[Half Ton]

Hello Tim, "nail on head" That is what I'm after,I have been looking at Lithium ion batteries ,So far I have concluded 1 ..  expensive, about £100-150 for the "correct"one    2 .. you seem to need a certain type of charger for Li Po batteries  again £50+ and  3 .. I have read a couple of bits that say you must have a modern reg/rectifier possibly the Mosfet type ?(I might be wrong here)....I think Rex's speed shop do the reg /rec.
    I was hoping to be able to go for a Li Po battery around 1/2 the size with similar or better CCA's to the recommended lead acid version  ..but it would be a smaller amps output i.e. 9amps instead of 14:-[

[johnr]

you can also get lithium batteries that can be fitted on their sides too, they have more cranking power than a standard battery but have the major advantage of being incredibly light compared to pretty much anything else. downside is that they are very expensive, although they have a very long lifespan so it may be the last battery you buy for yars and years. iirc they also need a specific battery charger to recharge them if you let them go flat or use a battery tender like an optimate, but they do seem to be the futur of automotive batterys.

[Half Ton]

Hello John,My brother has had a lithium ion battery on his Hinckley Bonneville for nearly 3 years now and loves it,I remember when he got it he gave me the battery still in its box to hold and I thought he had taken the Battery out as it was so light and yep they can be fitted in any way you like apparently..I suppose I might have to just bite the bullet and get a smaller one and see how I go....at least I have a kickstart as well (just in case)

[CrazyFrog]

Yes, I think I've read about problems with charging systems on older bikes and the new lithium batteries. Make sure you get it right cos I think there's a fire risk if you don't. I would recommend  consulting an expert, maybe Goffy or somebody like that....