Date: 30-05-20  Time: 09:56 AM

Author Topic: Battery Voltage  (Read 1169 times)

JD-LincsUK

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Battery Voltage
« on: 10 May 2017, 06:59:29 PM »
Having had some issues with finding my battery not able to start the bike after just 7-10 days not being ridden, I decided to do some tests.

I took it off the bike and charged it up with a decent trickle charger. After charging (in the evening) the voltage was 12.47 - in the morning it was 12.31V

I charged it through the day each day for 3 days and every day the voltages were pretty much the same in the evening after unplugging the charger, and in the morning.

I then left it for 3 days and measured the voltage each morning. The voltages were 12.31 then 12.28 and finally 12.26 this morning.

When I put it on the bike, it started without hesitation. I switched it off and restarted several times and each time no problem. I then went for a 20 mile ride, at speed, and measured the voltage - 12.42V

From a voltage point of view, is this okay?

Of course, I will monitor the voltage over the next days to see how much it drops with the bike not being ridden, but if it is not enough (it does seem a little low to me) already, then I might as well just get a new one. This battery is a Motobatt and is 2 years old.

Thanks for any help.

ste131

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Re: Battery Voltage
« Reply #1 on: 10 May 2017, 09:02:47 PM »
Check the charging voltage while its running. Batteries can go bad at any age. What charger are you using?

old son

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Re: Battery Voltage
« Reply #2 on: 11 May 2017, 07:37:02 AM »
That is too low, it sounds like your battery is on its last legs. It should be showing 12.7 plus

ogri48

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Re: Battery Voltage
« Reply #3 on: 13 May 2017, 04:18:55 PM »
Mate, I have found time and time again that it just isn't worth the grief once a battery lets you down, it's just so much easier to get a new one. Even if the problem persists you've only spent fifty quid or so, it's taken summit else out of the problem equation, and for the cost of two or three tankful so of fuel you aint gotta worry about your battery again for a couple years at least ;-)

PaulSmith

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Re: Battery Voltage
« Reply #4 on: 15 May 2017, 01:09:23 PM »
There are three different problems you could be having, 1) something is draining it, 2) it is focced, or 3) it is not being properly charged. 

12.31 is a little low but not too serious, dropping to 12.26 after three days is not too bad but was the battery connected to the bike during that time? If not, try hooking it up and monitoring the drop over three days as you may have something that is draining it such as a faulty alarm or a short in the wiring.

A damaged battery can still be putting out the correct voltage but if it can't supply the current, it wont start your bike. With your battery connected, put your voltmeter across the terminals. Record the voltage. Now turn the ignition on and record it again. It should be lower but still be over 12v, preferably closer 12.5. Now press the starter and watch the voltage. If it drops below 9v you probably have internal damage and should think about replacing it. Below 10v and it might just need reconditioning.

Once the engine starts and has warmed up, measure the voltage again. If it is less then 12.75 at idle or less then 13.5 at 4k rpm then you have a problem with your charging circuit.

You should do all three tests as you may well have more than one problem.

Hedgetrimmer

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Re: Battery Voltage
« Reply #5 on: 15 May 2017, 01:25:09 PM »
Mate, I have found time and time again that it just isn't worth the grief once a battery lets you down, it's just so much easier to get a new one. Even if the problem persists you've only spent fifty quid or so, it's taken summit else out of the problem equation, and for the cost of two or three tankful so of fuel you aint gotta worry about your battery again for a couple years at least ;-)


Agree. My bike wasn't used for a couple of months over the winter. Came out to start it, battery didn't even have enough power to light the dash lights. Charged it, went up to about 12.9v, so went out for a couple of rides. Left it for a week, and found not enough to start the bike again. Charged it, fine again. For my last couple of rides, I've boosted it overnight beforehand and it has been ok, but have just bought a new one, as I don't fancy having problems when I'm away on tour.

slimwilly

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Re: Battery Voltage
« Reply #6 on: 15 May 2017, 07:34:53 PM »
Batteries are odd, I can leave my Fazer Fz1 for months and press the button and away it goes,,four year old Motobatt.
An ageing test pilot for home grown widgets that may fail at anytime.

JD-LincsUK

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Re: Battery Voltage
« Reply #7 on: 22 May 2017, 06:48:49 PM »
Thanks for the replies and advice. The voltages were all with the battery off the bike.

I put it on the bike again, and of course, it fired up immediately.  I went for a long ride.

After 10 days not riding, again, it started instantly - just in the garage, didn't ride it (bloody rain again!). Then 4 days later I tried again and it tried to turn over and started clicking. Same at each attempt.
Terminals and connections were all tight. At this point I decided it was time to get a new one.

The problem is, this is my second battery in the 3 years I've had the bike. OK, so the first one was in the bike when I bought it - and it had been quite difficult to start from the off, but I rode the bike through winter, too. I reckon the battery it came with was not up to the job. I just got rid of it about a month ago - shame, as I hadn't checked the spec before chucking it. My concern is that the next battery will go the same way.

I blame my wife for wanting to get a car, and then, despite promises to the contrary, refusing to get on it after we got the car :(

Actually, I blame the idiot bimbo who knocked us off it and knocked Mrs JD's confidence with it to make her want 4 wheels.

PaulSmith

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Re: Battery Voltage
« Reply #8 on: 24 May 2017, 12:34:26 PM »
Thanks for the replies and advice. The voltages were all with the battery off the bike.

I put it on the bike again, and of course, it fired up immediately.  I went for a long ride.

After 10 days not riding, again, it started instantly - just in the garage, didn't ride it (bloody rain again!). Then 4 days later I tried again and it tried to turn over and started clicking. Same at each attempt.
Terminals and connections were all tight. At this point I decided it was time to get a new one.

The problem is, this is my second battery in the 3 years I've had the bike. OK, so the first one was in the bike when I bought it - and it had been quite difficult to start from the off, but I rode the bike through winter, too. I reckon the battery it came with was not up to the job. I just got rid of it about a month ago - shame, as I hadn't checked the spec before chucking it. My concern is that the next battery will go the same way.

I blame my wife for wanting to get a car, and then, despite promises to the contrary, refusing to get on it after we got the car :(

Actually, I blame the idiot bimbo who knocked us off it and knocked Mrs JD's confidence with it to make her want 4 wheels.
You still don't know if the battery was at fault or not. With the battery connected, measure the voltage across the terminals every few days. If it goes down measurably, you have a wiring issue that changing the battery will not fix.