Battery

[darkember]

Had some issues with starting the other day & would like to know some voltage answers. All earth bondings have been cleaned & scrubbed.

What are the potential voltages I should be seeing form my battery to tell me it is good/bad?

At present my battery left for several days without any intervention, ie: optimate or other charging is sitting at 12.13 - 12.20 VDC. This I believe to be ok however, what reading should I get when I load it when the starter is applied. Presently I cannot do it as I do not have any croc clips or an apprentice to assist. All I'm after is how far can the battery drop before it is deemed to be tired at the point of full load?

[VTRDark]

12.1 and 12.2 is a bit low. When at a stand still and ignition off it should be above 12.3v but ideally between 12.6 and 12.9 for a good healthy battery. This could be why you having the odd starting problems. Don't forget that motorcycle batteries will loose some charge over time especially if you have things running like an alarm or something while the bike is sitting around. So all motorcycle batteries will need a top up charge with an optimate or something from time to time.

As for the load test while cranking over, I'm not sure of the exact voltages before one starts to encounter problems but I think it also depends on the kind of battery. I seem to recall 9.6v being a number that it should never drop below after cranking for 10 secs or something. Less than this then you going to encounter problems.

(:-})

[darkember]

Thanks for that Cyber. I do believe its time for a new one as it is over 3 years old already & I have no idea how long its been in the bike before I got it. Any advice on a decent replacement would be welcome

[VTRDark]

I have always been a fan of yuasa batteries but I think when mine needs replacing I may go for one of the Yellow MotoBatt ones as you get an extra couple of terminals which could be handy for accessories. You can even go for one with slightly higher amperage but they start to become a bit of a tight fit in the battery tray/box so a strap around them is handy to help lift them out.

(:-})

[darkember]

Would this be up to the job??

http://www.amazon.co.uk/s/ref=nb_sb_nos ... +firestorm

[VTRDark]

That's the jobbie. Not got one myself yet but many peole on here use them.

(:-})

[darkember]

Ok before I go & splash-out on a new battery here are some readings I took this evening.

Bike cold having not touched or charged the battery for several days. Reading: 12.56 VDC

Bike started & allowed to warm to 76 degrees at tickover 1100 rpm lights off. Reading 14.79 VDC
tickover 1100 rpm lights on. Reading 12.84 VDC
4000 rpm lights off. Reading 14.14 VDC
4000 rpm lights on. Reading 13.36 VDC

How do these compare all comments welcome.

[Tweety]

Ok before I go & splash-out on a new battery here are some readings I took this evening.

Bike cold having not touched or charged the battery for several days. Reading: 12.56 VDC

Bike started & allowed to warm to 76 degrees at tickover 1100 rpm lights off. Reading 14.79 VDC
tickover 1100 rpm lights on. Reading 12.84 VDC
4000 rpm lights off. Reading 14.14 VDC
4000 rpm lights on. Reading 13.36 VDC

How do these compare all comments welcome.

Well they tell you bugger all about the battery, just about the charging system... Once the engine is running, you are are measuring the charging system, not the battery...

12.56 V open circuit, ie what you measured to start with seems low for a SLA battery... It should be around 12.8-13 V fully charged, and left alone for a day or two...

Then, if you want to know anything about your battery, not your charging circuit, clip the leads on the battery, and look very intently on the meter as you hit the starter... If it drops signficantly below 12V, say 10V or so, the battery might need replacing...

Edited to add: The numbers do however tell me that you have a Tyristor based R/R, ie stock or stock replacement, not a Mosfet type...

[darkember]

Ok before I go & splash-out on a new battery here are some readings I took this evening.

Bike cold having not touched or charged the battery for several days. Reading: 12.56 VDC

Bike started & allowed to warm to 76 degrees at tickover 1100 rpm lights off. Reading 14.79 VDC
tickover 1100 rpm lights on. Reading 12.84 VDC
4000 rpm lights off. Reading 14.14 VDC
4000 rpm lights on. Reading 13.36 VDC

How do these compare all comments welcome.

Well they tell you bugger all about the battery, just about the charging system... Once the engine is running, you are are measuring the charging system, not the battery...

12.56 V open circuit, ie what you measured to start with seems low for a SLA battery... It should be around 12.8-13 V fully charged, and left alone for a day or two...

Then, if you want to know anything about your battery, not your charging circuit, clip the leads on the battery, and look very intently on the meter as you hit the starter... If it drops signficantly below 12V, say 10V or so, the battery might need replacing...

Agreed on that one, forgetting the battery, how does the charging system compare then??

[Tweety]

Ok before I go & splash-out on a new battery here are some readings I took this evening.

Bike cold having not touched or charged the battery for several days. Reading: 12.56 VDC

Bike started & allowed to warm to 76 degrees at tickover 1100 rpm lights off. Reading 14.79 VDC
tickover 1100 rpm lights on. Reading 12.84 VDC
4000 rpm lights off. Reading 14.14 VDC
4000 rpm lights on. Reading 13.36 VDC

How do these compare all comments welcome.

Well they tell you bugger all about the battery, just about the charging system... Once the engine is running, you are are measuring the charging system, not the battery...

12.56 V open circuit, ie what you measured to start with seems low for a SLA battery... It should be around 12.8-13 V fully charged, and left alone for a day or two...

Then, if you want to know anything about your battery, not your charging circuit, clip the leads on the battery, and look very intently on the meter as you hit the starter... If it drops signficantly below 12V, say 10V or so, the battery might need replacing...

Agreed on that one, forgetting the battery, how does the charging system compare then??

It's a tyristor based R/R... Ie stock or stock replacement... It's charging from low RPM's which is good, but it's unable to sustain voltage for charging with the lights on at idle, which is bad... Ie, you are drianing the battery sitting at idle with lights on...

Also the voltages swing to much for my liking... Should stay at 13.5-14.5V at all times, even at idle with lights on... Then you have a fully dependable bike... But you will at best get that from around 1500 rpm with a stock R/R... I'd say a Mosfet R/R is worth while...