Rapid Battery Drain

[Bunzena]

Hi. Have fitted a brand new battery as bike wouldn't start.

Voltage showing on dash as 11.9 - and this corresponded to a multimeter reading too. Was original battery - 5 years old. Always been on a tender - but ho hum.

New battery [which has been fully charged] shows initial voltage [with ignition on] as 12.6 - and bike starts. However after 5-10 minutes voltage has dropped to around 12.0 volts and bike won't turn over.

There's no apparent heavy or even parasitic drain other than the LED lights. But can't see how these would have an impact in such a short time.

My suspicion is that the Regulator/Rectifier may be kapput?

Bike is a 5 year old NC750X - low mileage.

Any thoughts on what could be happening?

[Rob W]

What does the multimeter say when the bike is running?
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'90 TS50 > '04 Senda 125 > '91 ZXR400 > '90 CB-1 > '04 GSX-R1000 > '96 Bandit 600 > '89 ZXR750 H1 > '96 GSX-R750 SRAD > '98 RR-W Fireblade > '98 T595 Daytona > '03 Hornet 900 > '04 Fireblade > '16 GSX-S1000F (x2) > '23 XSR900

[Bunzena]

Thanks for response/question.

Registers around 14.4v steady.

So seems to be charging.

Haven't pulled the Reg/Rec out of the bike yet [it's in an awkward location] - so haven't tested it.

But suspicion is that the diode may have failed?

[A100man]

could be a duff new battery - does it charge off the bike?
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Now: A100, SRX250, XJ598, FZ750, SL1000

Then: Fizz, RS200, KL250, XJ550, Laverda Alpina, XJ600, FZS600, Skorpion, GT 250

[Bunzena]

I did think it might be the new battery - but the retailer [who was very pro-active] sent a new one I fitted this morning [after charging].

Had exactly the same issue.

When newly fitted and charged - showed a static 12.6v

After 30 minutes had fallen to 12.3v - now [6 hours later] at 12.1v

So there's a significant drain. I have heated grips and fog lights [using factory harness] - but they've been onboard for a while. The bike is garaged and has no corrosion. Earths look good.

So - and I'm guessing - the Reg/Rec may be playing up. Dodgy diode.

The Reg/Rec an absolute pig to get at. Petrol tank has to come out, rear mudguard, brake light, and multiple body panels off. Previous nakeds have always had the Reg/Rec in the airstream.

[Easy-X]

Do you have a multimeter with a current setting? A decent one can handle 10amps but with ignition off I'd only expect 10 to 100mA. Be interesting to see what the drain is just sitting there. Also try disconnecting the reg/rec and see if it affects things.
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Royal Enfield Continental GT 535, Husqvarna Vitpilen 401, Yamaha XSR700, Honda Rebel, Yamaha DT175, Suzuki SV650 (loan) Fazer 600, Keeway Superlight 125, 50cc turd scooter

[Bunzena]

Thanks Easy-X

My multimeter does have a current setting. But I'm not sure it's working.

With the ignition off it's not registering any drain at all.

I guess that's possible?

Getting to the Reg/Rec is a shocker - been at it an hour or so - and still not able to get access to it.

[A100man]

[Bunzena]

Good thinking A100man.

I have a more modern multimeter on the way that might reveal more.

In the morning - I shall start pulling fuses...

[jeffyjeff]

Don't forget to check the fuses in your multimeter. Bridging the leads in parallel to a live circuit with the meter set to measure Amperes will blow the meter fuse instantly. As far as I know, most multimeters will not indicate a blown fuse on the meter display, and a blown fuse will prevent the meter from measuring current.
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History shows again and again how nature points out the folly of men - BOC

[Bunzena]

[doggone]

If you pull the fuses in a rather dark place you will see a small spark most likely especially with a serious draw like that.
There aren't many things live with ignition off as a rule.

[A100man]

[Bunzena]

[Bunzena]

Problem seems to be solved.

It appears that I was sold a dud battery – and then it’s warranty replacement was little better.

Both batteries charged-up – the first quickly lost voltage and I mistakenly put that down to a drain from the bike.

The second, replacement held voltage at around 12.87 to 12.6 volts over a ten day period. But really didn’t want to crack the engine after a couple of days.

My own fault – but should have run a deeper diagnostic on the batteries. An analogue “load-type” tester showed both batteries as “weak and needing replacement”. The first more than the second.

A more sophisticated test using a friends iCarsoft rig – suggested both batteries had very low SOH and high internal resistance.

The online retailer [who I have used many times before] looked at those readings and immediately offered a full refund.

So what to do next?

Order a third one [same Yuasa brand] from the same retailer? [I have asked them to check it’s okay before despatch.]

Order another brand?

Switch to an equivalent LiPO battery?

My real issue with LiPO is that there’s no definitive answer as to whether I can jump start that with a Lithium jump pack if I get stranded. Any thoughts?

Finally thanks to all those who contributed.

[jaffa90]

Just googled ( what is a motor cycle lipo battery ) and was shocked.

My biking days are over but would not consider these.

[A100man]

[Kawasaki Jimbo]

[jeffyjeff]

I have had very good experiences with Yuasa batteries. If a new battery fails to crank the motor after a few days idle, but the charging system and battery no-load specs are otherwise OK, I would consider a problem in the starting circuit. Check voltage drop between the battery and starter during cranking. Check the starter current draw. Problem could be in the starter relay or wiring. If you have another bike available, try swapping batteries to see if the problem follows the battery. You might be overlooking the cause of your problem.
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History shows again and again how nature points out the folly of men - BOC

[WD Forte]

My Battery analyser has been a very useful tool for checking car/van/bike batteries
especially this time of year when temps drop and battery weakness can manifest itself.
A year or two ago it help prove a mates new battery didn't have anything near the cranking amps
it should have had, so a replacement was given (and immediately tested of course)
It's also useful to check if those spare batteries are worth the space they occupy and just been checking some of mine.
I keep a few old bike batteries for bench test/experimends and stuff and this one still exceeds the stated CCA so it stays

https://i.postimg.cc/YqqK9Sd0/topdon1.jpg
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bikers smell of wee

[sickpup]