Help needed: what does this video tell you about my battery?

Tim Cullis

Tim Cullis

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I'm having some problems with a new battery on my F650GS twin. Three different symptoms:

1. Often (but not always) when I start the bike, the battery has difficulty cranking the
engine. But when I test the voltage it is normally reasonable (12.6v or higher).

2. I've had the battery on an Acumen optimiser half a dozen times in the three weeks since
I fitted it and most times (but not always) it fails to turn the light green and when I test the
voltage--even after 22 hours on charge-- it's less than 13.2v.

3. The battery seems to lose its charge fairly quickly even though I've been running in lower
gears with everything but the headlight switched off.

Although it's short, the video below shows several things
a) voltage one hour after a longish run is around 11.8v (not good)
b) dials go through the self-test sweep as I switch the ignition on
c) voltage drops to 6.1v as engine cranks
d) voltage rises to 13.3v on tickover
e) dials go through self-test sweep again (due to the low voltage during cranking)

It's not a great example as the engine was warm so it caught very quickly, but sometimes it cranks very slowly for two or three seconds with the voltage below 7v. I think I may know what is wrong but am no technical expert so I would welcome views from fellow GSers.

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Voltage is not a reliable indicator of battery condition. It should be checked under load with a proper tester.

Going by the symptoms, I'd agree with Tim. Battery fecked.
 
How odd. My bike (F650GS twin 08 plate) has just started to hesitate when i try to start it. Dont have a charger so cant do much about it. I wanted to know if it should bump start ok if all else fails.

Any ideas???
 
don't have a charger
Click to expand...

When there's no battery power the fuel pump doesn't work, so bump starting is iffy at best.
cheapest of eBay buy-it-now
cheapest of eBay auctions but 9 days to run

________________________________________________________________________________

Not wishing to sound ungrateful for the responses so far, but I need to go back to the company I bought it from and I was hoping for something a bit more technical than "it's fooked". :)

As I wrote above, I think I might know what is wrong but I don't want to put words into anyone's mouth.

.
 
Tim Cullis said:
________________________________________________________________________________

Not wishing to sound ungrateful for the responses so far, but I need to go back to the company I bought it from and I was hoping for something a bit more technical than "it's fooked". :)

As I wrote above, I think I might know what is wrong but I don't want to put words into anyone's mouth.

.
Click to expand...

Oh, it's a quiz:blast
 
Tim Cullis said:
When there's no battery power the fuel pump doesn't work, so bump starting is iffy at best.
cheapest of eBay buy-it-now
cheapest of eBay auctions but 9 days to run

________________________________________________________________________________

Not wishing to sound ungrateful for the responses so far, but I need to go back to the company I bought it from and I was hoping for something a bit more technical than "it's fooked". :)

As I wrote above, I think I might know what is wrong but I don't want to put words into anyone's mouth.

.
Click to expand...

Not sure what a better explanation will achieve - the battery is no more, kaput, and ex battery etc
Your measurement tells us two things, 1,the charging system seems healthy and 2,as having a multimeter you can measure any current drain when the bike is off.

Top and bottom, you will need a new battery, whether you can get some consideration from the seller of the bike/battery is really up to you, dealer transaction will give you the reasonable expectation of fit for purpose for a reasonable time, try that avenue

Edit
Forget a trickle charger, they will pretty much only maintain a batery, get one of the intelligent chargers, will modify its function to recover charge, condition and maintain your battery

Lidl ones are brilliant value for money at £13 when they have them in stock - if you like ebay there are two listed under Ultimate speed charger (crap name I know), one is auction other is a chancer hoping to double his cost price at £25!
Lidl one operates in similar way to Ctek which are very good if just four times the price
 
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Not that i'm in any way knowledgeable* / but i had exactly the same problem recently - but on a K100.
Apparently my problem was ampage.
I suspect your battery never came up to full charge from the start and now despite hours on charge now wont come up to full charge.
Technically; fooked. :blast
However - please re-read my first line. :pullface
~~
* ask Jaythro for a reference :hide i'm driving him nuts with questions. :augie
 
Tim, take the battery off,drop it a couple of times from approx 1ft onto something hard like wood so not to chip the battery.Then try it on a charger .
 
Thanks John, I understand where you are coming from, will try and lever out the filler plastics and check. If it's a faulty cell it should also gas off when under cranking load as well.

_______________________________________________


Well the battery has only been in the bike for three weeks and I contacted the company who supplied it within a week of fitting it to let them know there were problems. It's a battery they recommend for the F650GS twin.

But they are suggesting I get some form of "independent testing" done. The advice I've had locally is that it looks like one of the cells is flaky. Some quotes from battery web sites,

"The battery should be able to maintain at least 10 volts for up to 20 seconds of cranking the starter with a cold engine."

"Disable the ignition or injection to prevent the engine from starting. Now crank for 15 seconds; the battery voltage should remain 9.6 volts or above (General Motors' specs for a battery at 70 F)"
 
You need to check the votage across the battery when cranking with an oscilloscope. Your multimeter does not give a proper indication of voltage when cranking. See if you can get an electrician to put his scopemeter across the battery when you crank the starter.
 
Tim Cullis said:
Thanks John, I understand where you are coming from, will try and lever out the filler plastics and check. If it's a faulty cell it should also gas off when under cranking load as well.
Click to expand...

You might be able to see the gassing off if it's got clear sides, or possibly hear it.

With the charging route it's a bit more controlled, ie you can remove the battery from the bike and if there's any acid getting blown around ..... and you're not hammering the stater as much. And if you're taking it back to the supplier it's easier to show them. But you knew that already :blast
 
doyle said:
Tim, take the battery off,drop it a couple of times from approx 1ft onto something hard like wood so not to chip the battery.Then try it on a charger .
Click to expand...
Bloody hell!!! Does this really work, err and if it does , HOW????? Normally dropping things is only a recipe for disaster, Unless its a bomb and they are designed to be dropped....,lol
 
Nippy Normans supply Touratech, Wunderlich, Desert Fox and many other makes of accessories.
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