Voltage Issues

[Middy2000]

Rode into work today and went to bike to come home.....flat.


It's been faultless all summer and the issue is clearly to do with the lights being used now it's getting dark at commuting times.


So I'm after advice.


What should the voltage of the battery be:-


1.  When bike is off
1a.  When bike is off (lights on)
2.  When engine ticking over (lights off)
3.  When revved (lights off)
4.  When engine ticking over (lights on)
5.  When revved (lights on)


Once I've an idea of the values I'll go round disconnecting each light to see if it's a bulb pulling too much current. 
I used to leave the light switch to on when I turned the ignition off and this was never an issue.  If I do it now the bike is dead within hours so it's still drawing a current. 


Battery is the original as far as i know. 13k miles.


Or if anybody has any other ideas.

[darrsi]

Batteries are not designed to last 20 odd years at all, so my immediate thought would be you've had your moneys worth, get a new one.


A battery in good nick should be at least 12.6v when everything is off. It's not about the mileage, it's more about the 2 decades. 
With engine on and ticking over it could be anywhere between 13.8v and mid 14v, and upper 14v when being revved.
Headlights do make the volts drop quite a bit but once the bike is moving more charge will pass through the battery.

[Middy2000]

I have thought about just biting the bullet and getting a new battery but wanted to make sure I wasn't barking up the wrong tree with either a bad earth or voltage leak that was causing the issue.

It's odd that without the lights all through the summer it's been fine. The one journey with them on and it drains completely.

I'm no expert on how the life of a battery works and can fully see that 20 years is a good innings.

I just wanted to rule out other issues by making sure my voltage readings matched others.

Any recommendations on batteries?

[darrsi]

It's how you look after them as well if the bike is left for long periods.
We have sudden cooler weather now too.
If used daily all year round they will generally look after themselves.
Loads of brands out there Yuasa is always good, I think mine is a MotoBatt. Prices will vary, look for higher cranking power, and avoid going very cheap.

[darrsi]

This is a reasonable price for a decent battery. 11ah as well, whereas most others are 10ah. Not a huge difference but the more the merrier.
Always check the measurements are okay before ordering.


Dimensions: L 150mm x W 70mm x H 130mm

https://yambits.co.uk/fzs600-fazer-battery-motobatt-sealed-p-107891.html


This is good too, and 12ah.


https://www.tayna.co.uk/motorcycle-batteries/varta/512-901-019/

[BBROWN1664]

Are you telling us that you dont ride with your lights on normally?

[Middy2000]

I have some additional lights mounted to the sides of the radiator given that the boxeye lights are the equivalent of a tealight candle.

[darrsi]

I have some additional lights mounted to the sides of the radiator given that the boxeye lights are the equivalent of a tealight candle.

Same as, got spotlights that I leave on all year round on the sides of my radiator. Headlights only get used in winter but the spotlights outshine them.

[Middy2000]

Battery ordered.

If anyone can do some voltage tests as per my original post I'd be obliged.

[darrsi]

Battery ordered.

If anyone can do some voltage tests as per my original post I'd be obliged.

If the weather is okay tomorrow I'll do a check for you.

[Middy2000]

Cheers pal

[darrsi]

My bike actually has the Varta 12ah battery on it, and I'm a bit shocked it's 6yrs old, I thought it was more recent than that!


Bike is used at least 5 days a week all year round. I don't trickle charge it, but will give it a manual charge once or twice a year normally when the temperature really drops.


I also have 10w spotlights & heated grips


Battery readings:


Ignition off - 12.77v
Ignition on - H/L on - 12.56v
Ignition on - H/L and S/L on - 12.50v
Ignition on - H/L, S/L & H/G on - 12.30v


Engine on tickover - everything off - 14.37v
Engine revved - everything off - 14.38v
Engine on tickover - H/L on - 12.40v
Engine on tickover - H/L & S/L on - 12.35v
Engine on tickover - H/L, S/L & H/G on - 12.24v
Engine on tickover - H/G on - 14.26v


Engine revved - H/L on - 14.08v
Engine revved - HL & S/L on 14.07v
Engine revved - H/L, S/L & H/G on - 14.01v
Engine revved - H/G on - 14.31v


Obviously this is my bike, my battery, etc, but the readings are a good guideline if you suspect any battery issues.

[darrsi]

As you can see the headlights are what pulls the most power by far.
I was surprised at how little volts the heated grips use up too.


The spotlights I leave on all the time and use very little power, yet are brighter than the headlights.
By just using the spotlights as daylight running lights you get the full whack of charging to your battery when the bike is running, so it's a good way of keeping the battery topped up.
The spotlights are a great addition to the bike because you can be clearly seen from a long way off.

[Middy2000]

That's top banana.
Really comprehensive.

I agree with the daylight running lights. So much better visibility with them.
I might wire the tail light to an ignition live so that's permanently on without using the headlights.

[Grahamm]

Your best option would be to buy yourself a Drop Tester (about £20-£25 from eBay) which will check the CCA or Cold Cranking Amps.

Batteries can still read good volts even when they've lost a cell.

Also check the output from your Alternator and Regulator/ Rectifier when the bike's running. If they're out of spec, that can kill a battery.

Personally, as I keep my bike in the shed and it doesn't get ridden regularly, I have an Optimate Tender which keeps it topped up and checks everything is ok.

[darrsi]

Your best option would be to buy yourself a Drop Tester (about £20-£25 from eBay) which will check the CCA or Cold Cranking Amps.

Batteries can still read good volts even when they've lost a cell.

Also check the output from your Alternator and Regulator/ Rectifier when the bike's running. If they're out of spec, that can kill a battery.

Personally, as I keep my bike in the shed and it doesn't get ridden regularly, I have an Optimate Tender which keeps it topped up and checks everything is ok.

He has a 20 year old battery. His bike deserves a present. 

[Grahamm]

He has a 20 year old battery. His bike deserves a present. 

That battery deserves a pension!!

[Middy2000]

I've fitted the new battery and it's on charge. Once charged I'll run the tests to see how they compare to the old battery and to Darsi's test.

I would say the old battery is not the original. Not that I know what an original looks like but the one I've removed is a generic brand job.

[darrsi]

I've fitted the new battery and it's on charge. Once charged I'll run the tests to see how they compare to the old battery and to Darsi's test.

I would say the old battery is not the original. Not that I know what an original looks like but the one I've removed is a generic brand job.

Is the old battery dead or have any charge left in it at all?

[Middy2000]

The old battery had charge in it but then it'd been left on charge in between rides.


So I've fitted the new battery.  Did some old tests on the old and new and i get mixed results dependant on how warm the engine is and also bizarrely if it's in gear or not.




Anyway with the new battery:-


Ignition Off = 13.21


Ignition On = 12.94
Ig + Headlight = 12.32
Ig + HL + Spotlight = 12.28
Ig + HL + SL + Heated Grip = 12.22


Idle = 13.01
HL = 12.36
HL + SL = 12.33
HL + SL + HG = 12.28


Rev = 14.8
HL = 13.32
HL + SL = 13.16
HL + SL + HG = 12.9


The results seemed to bounce around a little.  For example at one point when the engine was warm is seemed to be idle at around 14.3V


I guess the real test will be in the coming weeks.  I'll use the headlights constantly.  If after a week of riding I suffer a flat battery I'll know there's a charging issue.  If not and I have a few weeks of nothingness I'll happily say it was the battery.

[darrsi]

If it is hitting 14.8v when revving then you have no charging issues.
The old battery had just called it a day.

[fazersharp]

My OEM battery is almost 25 years old  98 plate
I have had the bike for 22 years and since 2012 have had the battery on an optimate type charger when not riding which can be 6-7 weeks at a time. It fires up really strong and I might make numerous stops whilst out but still seems strong.However I fully expect one day to pull the bike out and find that the charger has failed and the battery is flat from which it would not recover.I brought the charger in 2012 when the bike would not start - was old plugs and I flattened the battery trying, I got a Yam branded Ctek charger and it revived the battery after (cant remember but something like24 hours )Always ride with the light mod - left and right on but do not have any other possible electric drains.
There you go that is my experience.   

[Middy2000]

Apols, thought I'd put an update.

New battery fitted and not had an issue since.  I guess the old battery had just had its day.

[unfazed]

After 20 years you could hardly complain.     I have gone through 3 in 19 years, plus one that died after 6 months and the shop where I bought it replaced it free since it was still under warranty.
The Sealey Current tester is a great little gadget for testing leakage when ignition is switched off. Have one for years and have used it for tracing faults on numerous bikes and cars. See pic,. remove the fuse of the circuit you want to check and put it in the tester. Plug in the tester to the fuse position and switch it on. Has its own little battery.