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Load testing your battery

9K views 22 replies 14 participants last post by  oink 
#1 ·
I've seen some posts about electrical problems and this should help fault find some problems.

You should use a good multimeter (MM) and put the leads on your batteries posts and then move them onto the cables, if the voltages you get are different the problem is your connections.

This should be corrected, undo, clean the poles and cables, replace the cables and test again.

Each test should be done on both the poles and the cables at the same time EG; get the start voltage on the post then move to the cables and record the voltages.

A battery is full at 12.7 volts, anything above this is surface charge in will burn off very quickly on a small bike battery.

Take note of your standing voltage, if it is much below 12.7v you already have a problem, after noting the standing voltage you need to turn your ignition on (DON'T START THE BIKE) this will bring in the fuel pump and turn the headlight on (low beam), your voltage will quickly drop to about 12v and slowly fall from there, leave the ignition on for 60 seconds, the voltage will be around 11.5v, now turn the ignition off, if the battery is good the voltage will start to climb and after about 5 minutes it should be back to about 12.65v.

If the battery does not climb back up while standing it is stuffed or very close to it.

If the ignition on test shows less than 11v the battery is stuffed or very close to it.

Most often a bad battery will fall to about 10.5v this is because a it has a dead cell, you are taking a risk with your electrical system if you ride a bike with a dead cell, your battery is like a power sponge and with a dead cell the capacity is greatly reduced.

You may get different voltages to the ones in this post but if your battery does not climb back (while standing) close to what your started with your battery is failing.

If your bike had been standing for a few days and your starting voltage is less than 12.5v your battery is failing.

Hope this helps.
 
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#10 ·
Great info, and timely. Went out to ride my 2012 Wee Sunday after 2-3 weeks parked and the battery was dead. After 20 hours on a Battery Tender Jr it was still dead, so I took it down to Batteries Plus nearby. They said it had one or more bad cells so I replaced it.

The wife and I have two of these bikes, raising the question of how dependable hers is at this point. You've given me a great way to track it, but can anyone advise me on the typical life of an OEM battery? A friend tells me his Yamaha OEM batteries lasted only 1-2 years. Might make sense to just replace the other one pro actively?


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#5 ·
A battery is full at 12.7 volts, anything above this is surface charge in will burn off very quickly on a small bike battery.

Take note of your standing voltage, if it is much below 12.7v you already have a problem,

Hope this helps.
It is best to start with a standing battery in the bike and look for it to recover some by itself, then start the bike and see it recover the rest.

If you have charged it by a charger you won't get the full story as to how the bike is working but the load test will still tell the batteries story.
 
#8 ·
"That presumes a healthy charging system, and a fully-charged battery to start with."

Actually that is the purpose of the test. To see if the battery is up to snuffy.
The test is not for the charging system, only battery health.
Two thumbs up for an informative bit which will be lost on those who can't manipulate a multimeter.:thumbup:
 
#14 ·
Another Tip

This is not science it's something I have found over the years, it works better on cars but can help with bikes too.

Your battery is a big sponge for your electrical system and as the battery gets older or the fluid level gets low the battery will show signs it is starting to fail.

If you have low fluid or a failing battery as you rev the motor the brightness of your lights will go up and down with the revs, of course this happens anyway but it is much more visible as the sponge/battery begins to fail.

So take a mental note now as to how much change you get when you rev your motor then pay attention in the future, you may just catch a bad battery before it lets you down.

If you suspect your battery is on it's way out use jumper leads onto a known good battery and see if your lights stabilize.
 
#16 ·
I picked up my Vee back in late 2010, and the OEM battery died the next summer. I picked up a new Yuasa battery and it had been great since then. The PO had neglected the bike and hadn't ridden it regularly for some time. It only had 20k on it after 5 years. Since buying the bike, I ride every weekday, around 40 miles each day, year round, and I've put almost another 20k on the bike since replacing the battery.

Over the last month or so, occasionally I will have trouble getting the bike to start, usually when running errands during my lunch hour. My commute is about 20 miles one way, so the battery should be charging effectively. I generally ride with my brights on, but have since gone back to riding with my low beams when I began getting issues starting the Vee.

I checked the battery today, not having ridden it since yesterday, and it reads 12.7v. Turning the ignition ON, it drops down to about 11.9v, then rises quickly again when turning the ignition OFF back to 12.7v. When starting, the volts drop to 7-8v, then settle around 14.8v when idling or holding at 5k RPMs.

My worry is the drop to 7-8v when starting, is that excessive? Or could the charging system simply not be recharging the battery quickly when going out on short rides (1-3 miles)? Any help is appreciated. I'd rather troubleshoot it than go out and buy a new battery, just to find out that the alternator or something else is the problem.

I need to convince my wife that I need a spare motorbike! :mrgreen:
 
#18 ·
If your battery is at 12.7 it is full so your charging system is working (14.8 also tells me you charging system is working).

But is it always at 12.7 ? is it at 12.7 for every start ? your short rides could cause problems.

Turn your ignition on for say 3 minutes, note the voltage at the exact time you turn the ignition off and leave the multi meter in place, you should see a very quick recovery and then a slower one.

The quick one is the load of your lights being turned off, the slower recovery is your battery, providing the battery shows some recovery the battery is OK, if the battery dose not recover some volts it is stuffed.

The fact your battery is at 12.7 after only sitting for one day could be of some concern, if it was a realy good battery there should be more surface charge than that but many bikes wil work just fine on very a average battery.

7-8 volts could be a little low but I have never tested mine, I would clean all the cables and conections at the battery and the starter, a high resistance will affect the starter and hold up the charging system.
 
#17 · (Edited)
Everyone should educate themselves about batteries, because there's a lot of "stories" out there. I think most misunderstand what maintenance they should do to prevent them from going below half charge. Those who only get a couple of years out of one are either letting it discharge too often or living in a very hot climate where heat helps kill them. A battery will deteriorate (slowly over time) if allowed to discharge below half charge too many times. Sulphation occurs, which in most cases cannot be successfully reversed (a desulphation mode charger will help, but.....).

What most don't understand is a battery is half discharged around 12.3-12.4 volts, fully discharged at 11.9-12.0. Surprising since full charge is 12.7-12.8. IF it's going to sit, and your bike has a parasitic drain (keeping the clock going and saving the trip odometers), it will be at half charge in a short time. My advice, if you know the bike is going to sit a week, put it on a Battery Tender or such charger.

I had an excellent website to visit, but I've lost it.... you can try this one, there may be a little bias or inaccuracy here or there, but you'll get the general idea. Yuasa used to have a good tutorial on their site, but no more.

Motorcycle Batteries, ATV, Car, Marine, and Solar Battery Products | BatteryStuff.com
Try the tutorials, battery articles and the FAQ. I'm no expert, but I just wanted to help educate with some basics for those that don't know.

Actually I am an exspurt.... an 'ex' is a has-been, and a spurt is a drip under pressure.

Cheers.

Edit - Good starting test process by Rolex. But, battery places or a dealer will sometimes do a free load test for you if you take it in fully charged.
 
#20 · (Edited)
A load test as defined by the Battery Council International is the current a lead acid Battery can produce for 30 seconds at 80 degrees F with out dropping below 1.6 volts per cell.

This is cranking amps. A battery can hold proper voltage and still not produce a proper load.

Cold cranking amps is the SE test but at 32 degrees F.

If you battery if dropping below 9.6 volts during engine cranking and it's not below freezing then either the battery is not producing proper spec load amps or the starter is drawing to many amps. Or you have a dirty conection in the circuit either at the battery posts, starter or ground bond.


The commonly recognized CCA or cold cranking amps for a general 12BS sealed motorcycle battery (dl650) is 180cca the 14BS (dl1k) is 200.




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#23 ·
On my Dr650 I had a warranty dispute over my battery which totally died with the bike at the shop. It wasn't their battery so they weren't involved in the dispute. They gave me an old battery they had taken out of someone elses bike that they had tested as bad (bad cell I think they said). I've been using it ever since. 2+ years. I think it's a little weak on reserves but works every time. I need to replace it someday but I haven't taken the bike out too far in the boonies.
 
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