Battery question..

CJhaughey

Its nothing to do with extra starting power, its a measure of battery capacity.
It won't start any faster but a bigger battery should allow more turns of the starter which may be the difference between getting started and sitting by the side of the road or in your shed.
One thing all motorcycles apart from BMW's have in common is that their batteries are all too small for the work that they do, big twins and singles especially.

Kevin McCloud

I know what amp hour is charlie, you are incorrect in saying for definite that a bigger amh hour will not start a bike quicker than a smaller amh hour one.

CJhaughey

Kevin McCloud wrote: »

I know what amp hour is charlie, you are incorrect in saying for definite that a bigger amh hour will not start a bike quicker than a smaller amh hour one.

Hows that Kev? Assuming the discharge rate is the same due to it being the same current draw from the starting system as its the same bike, two different batteries with the same discharge rate will only give you more cranking time.
If you have two different classes of battery, for example an AGM and a Gel which have different discharge rates then the calculation is different.
Peukerts law is probably a better calculation of battery capacity.
Given the same bike and same type of battery with higher and lower Ah ratings the higher Ah battery will crank the bike for longer before it drops below usable voltage.

Skill Magill

CJhaughey wrote: »

One thing all motorcycles apart from BMW's have in common is that their batteries are all too small for the work that they do, big twins and singles especially.

I drove an f 650 and am pretty sure it used a standard battery, not 100% sure though, whats your reasoning cj?

Kevin McCloud

Cj what is your view/opinion on battery cca?

CJhaughey

Kevin McCloud wrote: »

Cj what is your view/opinion on battery cca?

I don't use it.
Never seen it on any bike battery I ever bought.

CJhaughey

Skill Magill wrote: »

I drove an f 650 and am pretty sure it used a standard battery, not 100% sure though, whats your reasoning cj?

I was thinking of the old R80 style BMW's they had massive 30Ah batteries.

Kevin McCloud

CJhaughey wrote: »

I don't use it.
Never seen it on any bike battery I ever bought.

It is something you should research, carbon pile battery testing too. Choosing a battery on amp hour alone is naive.

Zascar

Interesting stuff. I got a new battery anyway, one of the Dynavolt Gel ones from Battery world. All grand now. Only €50 and the guy in Battery world was very helpful.

A mate has this fancy battery charger which can actually repair problems so we've stuck it on and I'll see how it goes, no harm in having a spare just in case!

CJhaughey

Kevin McCloud wrote: »

It is something you should research, carbon pile battery testing too. Choosing a battery on amp hour alone is naive.

Really, Tell me which motorcycle batteries here have CCA marked on them?
I have only ever bought Yuasa, Motobatt and Oddyssey batteries
None of them have CCA on the battery.
I have seen car batteries with it marked but never bike batteries.
So tell me how buying a battery on capacity is naiive?
I don't start many bikes at -18°C so as a rating its pretty meaningless to me.
I also don't see any accreditation next to the CCA on car batteries so I don't really think its a valid rating, a manufacturer can print anything they want on a battery and if its not backed up by decent testing by an independent lab its worthless.

Anyway Kev, tell me how I am incorrect in stating that a larger Ah won't start any faster than a lower Ah battery?
I would love to hear how you can make that claim.

Kevin McCloud

CJhaughey wrote: »

Really, Tell me which motorcycle batteries here have CCA marked on them?

Your battery supplier should have the specs on the batteries he sells.

So tell me how buying a battery on capacity is naiive?

You are buying batteries solely on amp hour value. The cranking amp of a battery does not increase accordingly with amp hour.

I don't start many bikes at -18°C so as a rating its pretty meaningless to me.
I also don't see any accreditation next to the CCA on car batteries so I don't really think its a valid rating, a manufacturer can print anything they want on a battery and if its not backed up by decent testing by an independent lab its worthless.

If you are of the opinion that battery cca and carbon pile battery testing is worthless it explains your logic in the way you think batteries perform etc. They do carbon pile testing in realistic temperature.

Anyway Kev, tell me how I am incorrect in stating that a larger Ah won't start any faster than a lower Ah battery?

If you have more cranking amps available in your battery you have more power, I saw a jeep last week a friend bought with a twin battery set up. It had only one battery fitted by its last owner, starting ok as the european version of these vehicles only have one battery anyway. Since he was going putting a winch on the jeep he fitted a second battery and its swinging away quicker thus starting quicker.

CJhaughey

Kevin McCloud wrote: »

Your battery supplier should have the specs on the batteries he sells.
You are buying batteries solely on amp hour value. The cranking amp of a battery does not increase accordingly with amp hour.

I am aware of this, I am also aware that the type of battery also alters the way the power is delivered, if you read my post I referred to discharge rate which is the amount of current that the battery can deliver in a given time.
Which goes back to Peukerts law.
AGM and Gel batteries have faster discharge rates than flooded lead acid batteries.
Thats why Oddyssey and Motobatt batteries outperform an equivalent VRFLA type battery.
And also the reason I would always opt for an AGM over a standard VRFLA battery.

Kevin McCloud wrote: »

If you are of the opinion that battery cca and carbon pile battery testing is worthless it explains your logic in the way you think batteries perform etc. They do carbon pile testing in realistic temperature.

If the CCA has a proper accreditation then it may be of value, Like I said if it doesn't refer to a standard then its meaningless.

Kevin McCloud wrote: »

If you have more cranking amps available in your battery you have more power, I saw a jeep last week a friend bought with a twin battery set up. It had only one battery fitted by its last owner, starting ok as the european version of these vehicles only have one battery anyway. Since he was going putting a winch on the jeep he fitted a second battery and its swinging away quicker thus starting quicker.

This example is of no value, the initial battery may have been old or otherwise impaired.
For that example to be of value both batteries would have to be the same type and age, one new and one old battery is a meaningless test.

Kevin McCloud

CJhaughey wrote: »

I am aware of this, I am also aware that the type of battery also alters the way the power is delivered, if you read my post I referred to discharge rate which is the amount of current that the battery can deliver in a given time.
Which goes back to Peukerts law.

Peukerts law is what it is, is testing a low load from a battery over several hours something that you want from a battery. Maybe if you are a fan of leaving parking lights on. What makes one battery better than the next one is the cranking power. And as i have said previously this does not increase in proportion to amp hour.

If the CCA has a proper accreditation then it may be of value, Like I said if it doesn't refer to a standard then its meaningless.

What is your opinion on carbon pile testing? The BCI (Battery Council International) sets out the protocol on how that should be done. It is more accurate than Peukerts law. Has Peukerts law an accreditation?

This example is of no value, the initial battery may have been old or otherwise impaired.
For that example to be of value both batteries would have to be the same type and age, one new and one old battery is a meaningless test.

As it happens the second battery was the exact same as with any twin battery set up you have to keep them the same.