Modern Vespa

So, bought a new Yuasha battery about 10 months ago and all seemed good until the other night when my wife couldn't start it.

The bike has no alarm to drain battery, the bike had a new rectifier last year and checking the volts when running is charging fine even with lights and high beam on.

Some journeys are just a couple of miles but rest are about 9 miles long.

Today she left for work with freshly charged battery, rode the 9 miles, parked there for about 6.5hrs, rode the 9 miles back and I checked the battery upon her return and it was only at 11.94

Assuming the rectifier doesn't have an intermittent fault and is as when tested, charging fine. What could be draining the battery when parked?

My thoughts are can't be a relay as everything works as it should and only when it should.

I'm sure it was a coincidence but this only happened since a car backed into her bike last week. But no, bike was not left sat on side and battery levels are correct.

I thought about changing to a lithium battery but the battery should not have failed after just 10 months.

Will go to the bike shop on Monday to see if they can load test it but assuming it's fine, any ideas?

Maybe you should check the battery leads for corrosion. then move onto the charging system itself. What reading are you getting off the leads while the scooter is running? It should be between 13.2 to 13.8 or there abouts. When the battery is fully charged, let it rest a while then check the voltage again. A battery that new should be 12.6 volts, maybe 12.4, but no lower.

Could be some of the wiring has worn through somewhere from rubbing against the body.
I've had the wiring to the rear lights and indicators rust and short onto the frame on three different gts's. The wiring running along the exhaust side to the rear lights gets a lot of weather on it and gets cooked by the exhaust over time.

I can't remember the exact reading but it was 13.something with engine running.

I'll check along the wires to see if I can find any crispy wiring

Currently on 12.64 but only just taken trickle charger off so need to let it settle but have removed it from bike to be sure if it's the battery or the bike.

Visual & touch inspection of wires round battery holder, above engine, under rear and although the 3 wires that go across top of engine are as expected a little harder than others, all seemed fine.

Will leave battery for a good 8hrs then check again and once checked will put back on and check it charges again when running and finally leave overnight connected but not on trickle and check again in morning.

My guess is, battery will be fine, charging will be fine, will lose power over night connected.... Just can't figure out why

Just to add, we are currently in a warm ish climate and every night it is always garaged.

Some batteries just don't last, even Yuasa's.

10 months is no good obviously, but I would wait until it is properly load-tested before you purchase a $200 Li-Fe-Ph........which might then ALSO go flat.

Hope you have it fixed soon.

Replacing a (probably) perfectly good battery with a very expensive battery, without finding the actual problem is not a good plan.

Either your battery isn't charging (although it looks like it is), or it is being discharged when parked. A faulty ignition switch could do it. Do you have a DVM? You need to shut everything off and see if current is going to ground.

Tough one.

I have a multi meter but my knowledge is limited to testing voltage

I did try to google how to do it but couldn't see anything?

So, disconnected positive wire and joined my multimeter from positive terminal to positive lead that would normally connect to positive terminal.

Read -12.5 or 12.5 depending on which way round I connect it.

So, am I right in thinking this means I have a ground leak?

If yes, I'm assuming I disconnect one item at a time until it reads zero?

No. With everything off, put the meter onto a current range rather than a voltage range. Start with a 10A range - if it reads zero (or near zero) then move to a lower current range.

You want to see a current drain of less than 5mA.

Also, for safety's sake, put the meter between the negative terminal and the frame connection, NOT on the positive side.

do I remove negative wire from battery and ignore?

Remove negative lead, and put the meter between the terminal and that lead.

Crocodile clips will help here...

Ah, got it, like in this:

My multi meter is a basic one so off to shop tomorrow to buy a better one so I can do this

You should be able to get a multimeter for less than $10 at Harbor Freight that'll do the job.

Now this is weird.... It constantly jumps between 0.3 & 0.5 then flashes for less than a second at 2.9

The time it takes to cycle to the 2.9 seems very constant at about every couple of seconds or so?

That said, I'm using a pen type multi meter and it does not allow to set 10a instead it allows me to move the decimal point so either 0.00 or 00.0 etc.

Does any of this make sense to anyone as its hurting my head

Without knowing what units you're measuring there's no way to give an opinion.

I'm assuming those are amps? 0.5A, 2.9A

I hate to say it, and I am trying to help not hinder, but multimeters flicker around on current and resistance measurements when........

the battery is going flat!
Sorry mate!

You'll get it fixed man, don't stress. The $10 meter for low current sounds like a good idea for checking things, I have one in the toolbox as well as the expensive multimeter.

Ah, good to know.

They are only £7.99 from screwfix so picking one up tomorrow.

While there the bike shop is just round the corner so going to take battery to see if they can load test it.

Charge your battery let it sit attached to the bike and see how much the voltage drops in 24 hours. Then charge it again and disconnect the negative cable from the battery and let it sit again and see how much it drops. If the drop is approximately the same then the issue is the battery itself. If there is a big difference between the two readings than there is a drain somewhere in the bike. Keep in mind some bikes have a slight parasitic drain that will draw down the battery over time but this should be so slight that the bike with a health battery should tolerate this drain for months.

Went to bike shop, they said battery is flat so are charging it before doing a stress test on it.

Weird as it has sat at 12.5 volts for over 12hrs disconnected right up to an hour before taking it to them so either they are telling porkies or they put it under load and that killed it.

Makes me think something is not right with battery. But I have to phone them tomorrow to find out.

The problem I have found with most electrical shops is that their equipment is not suitable for load testing a motorcycle battery and will flat the battery immediately. I have to determine battery fitness by a process of elimination due to this inavaibility of proper testing equipment.

It's a Yamaha dealer

That reading sounds quite high for a static bike. Maybe that is milliamperes.
You have checked to make sure the light isn't staying on in the pet carrier.

Light? Some come with a light?....

I have now bought a more traditional multi meter so can check properly but have to wait til I get the battery back tomorrow

My suspicions/hopes were right, it holds charge fine but fails under load.

Luckily it still had two days left in the warranty

I am having similar problems and am on the second brand new battery (a Motobatt). I've gotten 12.84-96 on the meter with the bike not turned on. What are you reading with the bad battery once you fire up the bike? Is it your charging system or the battery?

Thanks for going through this a week before me.

That's the thing, when running it was fine at 13.5-14.5 (can't remember exactly) and when charged and not connected it held at 12.54.

But when in use it dropped below 12

That's why I asked them to do a load test but in all fairness I guess I could have done the same test just by starting the bike then turning it straight off and testing the voltage....

Nothing worse than hard to find faults

You have my vote there!

So-you are just replacing the battery? Let me/us know how that goes. Thanks again!

Shop gave us a new one today

Hmmmm..... Might have slight drain as well battery was at 12.2 this morning

Handy chart on this link for volts percentage of power left

http://www.totalmotorcycle.com/maintenance/battery.htm

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For me-I am guessing a new strator or voltage regulator. I get 12.8 when the scooter is off and battery attached, but only 12.2 or so when I turn the scooter on and rev up to 3000 rpm's-way too low for the new battery to get charged. I guess I'll find someone with much more knowledge to figure out and fix it.

Will I do any damage if I use a battery tender to get the battery to come back up and then ride the bike to a shop for repair? About 15 miles.

Right, I did as the video instructed and removed my negative cable and put my meter in series and got this fluctuating reading:

Any idea what it means or if bad or normal?

It seems very rhythmic in its cycle.

The biggest number being 1.97 and 1.73 but lower numbers being less than 0.5
This was done with the meter dial on the 20m setting

That's perfectly fine at between 0.5mA and 2mA. You don't have any significant parasitic draw - the increase to 2mA would be when the immobiliser does its 'tick'.

Did you give the new battery a full equalising charge before first use? If not, do that now before using it any more.

Then take the scoot for a good run and see what the battery reads, with engine running and when the engine has been switched off for a few hours.

Will do.

Just noticed, looking at that video, shouldn't the red lead be plugged into the 10a splot on the bottom left?......

First time using this for amps....

Will move it over and take another reading as well.

Update:
With red probe wire in the 10a slot and dial to 10a then put in line between negative wire and terminal the reading is 0.00

With engine running the volts are:
No revs 14.07 lights off
No revs 13.93 lights on
Low revs 14.25 lights off
Low revs 14.10 lights on
Higher revs 14.27 lights off
Higher revs 14.25/14.27 lights on

To me that seems good but I'm no expert.... Far from.... Your thoughts?

Those readings show it's AOK.

Thank you for confirmation

It's now had a full charge on a smart charger and is settling.... Will leave it for the night and in theory it should be circa 12.5 or so tomorrow for its final exam

Volts this morning after being connected all night 12.9 so safe to say problem resolved

Big thank you to all for your help

This is a perfect example of why ever bit of testing for electrical or running issues on a vehicle starts with making sure the battery is good That is stressed over and over in training.