How long should a battery last without charging? - Page 2

Brother Thadeus · #21 24th June 2010, 01:09 PM

It might be worth a mention that it is a Kyoyo battery and not a Yuasa. I went for the cheaper option
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Fr_Jack · #22 24th June 2010, 01:32 PM

check the charging voltage, the manual will tell you how to. Just to give you an idea, on the Hornet it's between 13 -15.5v at 5000 rpm, no idea what it should be on the Deauville.
Reg/rec is a common Honda weakness, if it's that and you get a new battery you'll have the same issue in a month.

Brother Thadeus · #23 24th June 2010, 03:47 PM

OK lads - thanks for all the info.
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I'll be taking the bike off the road over the weekend and I'll report back next week how the testing goes - might be useful to someone else that stumbles across this thread

FZRMutt · #24 24th June 2010, 08:43 PM

Batteries self discharge about 10% each month.
If a battery is left discharged or flat over a long period of time, the sulphur in the battery attaches itself chemically to the lead plates. The result being that the electrolyte fluid becomes weaker and your battery does not hold a charge any more.
There are however little black boxes out there which give a high energy pulse at a certain frequency to knock the sulphur out of the plates and back into the electrolyte (Look up De-Sulphaters in google or ebay).
If you do use a de-sulphater remember it can take a month to fully recondition the battery!
If you have a battery which initially wont take a charge try tapping the positive terminal of the battery charger on the positive terminal on the battery about twenty times. This technique is somthing similar to using a de-sulphater and can help if a battery is not too badly sulphated.
If like me you left the ignition key in, and the bike turned on over a day or two, your battery can go completely flat. Left discharged, even a week might affect the performance of your battery.
To test the electrolyte in a battery, you can use an hydrometer but these are bulky, fragile (because they are made of glass), and are usually designed for cars and lorries. You also have to suck nearly all the electrolyte out of the battery to get a reading, not suitable for a motorbike battery!
An alternative is a small robust and quite compact device called a refractometer. I bought one recently off ebay for about 20 €. They are really accurate and you only need to use one or two drops of electrolyte to get a reading, about the same amount you would spill from an hydrometer.
If you do leave a battery run flat charge it slowly because charging it to quickly can buckle plates and even break bits of the lead plates which deposit at the bottom of the battery and can short the plates out next time you knee slide around a corner.

So I guess the short answer to a battery gone flat which wont hold charge is really - get a new one!
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Unless its an electrical fault
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Hope this helps but then again I have been accused of going on a bit
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superbadonkey · #25 24th June 2010, 11:22 PM

if you have an alarm and immobilizer they can drain the battery as well, i wouldn't think it would go that quickly,used to happen to my old bike but i never left it for more then a day so it didn't bother me so i never bothered to get it sorted

Brother Thadeus · #26 25th June 2010, 11:48 AM

FZRMutt - thanks for all that, but the battery is a sealed\maintenance free type. Also, it's less then a year old and I've been running the bike during the winter.

Superbadonkey - Yep, I have an alarm and hotgrips and they've both been physically disconnected for well over a month now.

Brother Thadeus · #27 25th June 2010, 12:49 PM

Right lads - here's some more info after the testing\charging done last night. Started going through this when I got in so the battery should have been fully charged.

1. Voltage with engine running started at 14.8v and then steadily rose to 15.08v after 5 mins. This seems a bit higher then what was suggested above but not sure if it could damage the battery.

2. Disconnected the + terminal with the engine running. The regulator voltage dropped suddenly to 5v and the engine revs dropped right down and she struggled to turn over. This was strange to me - I figured that the bike could run without the battery.
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3. Stopped the engine and put the multimeter (in A mode) between + terminal of batt and + cable. Didn't notice any current flowing.

I've fully recharged the battery with my Optimate and its going to sit there for a few days before I test it again - it's the only way for me to be sure.

Thanks for the info lads - learning a lot here. If anyone can decipher the points above it's be a big help!!
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armadillo · #28 25th June 2010, 01:29 PM

I reckon if you drop over to cotters, they will replace it for you. Only ten minutes from leixlip to ballymount drive.

jimgoose · #29 25th June 2010, 02:24 PM

Originally Posted by Brother Thadeus

Right lads - here's some more info after the testing\charging done last night. Started going through this when I got in so the battery should have been fully charged.

1. Voltage with engine running started at 14.8v and then steadily rose to 15.08v after 5 mins. This seems a bit higher then what was suggested above but not sure if it could damage the battery.

Looks like a reasonably sane voltage for a bike on fast idle and charging well. What RPM was the bike doing while this was going on, and how accurate is that meter? Note that much over 15v charging voltage is too much for a 12v battery - you could be looking at a faulty regulator on the bike.

Originally Posted by Brother Thadeus

2. Disconnected the + terminal with the engine running. The regulator voltage dropped suddenly to 5v and the engine revs dropped right down and she struggled to turn over. This was strange to me - I figured that the bike could run without the battery.
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Some bikes run fine with the battery disconnected, some don't. Something to do with the Roswell Incident (
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).

Originally Posted by Brother Thadeus

3. Stopped the engine and put the multimeter (in A mode) between + terminal of batt and + cable. Didn't notice any current flowing.

Are you sure? If you used something like the 20A scale a bothersome current draw mightn't show. Assuming not, OK - that means you're probably OK for shorts. That's good to know.

Originally Posted by Brother Thadeus

I've fully recharged the battery with my Optimate and its going to sit there for a few days before I test it again - it's the only way for me to be sure.

Right. You can put the voltmeter across the poles to check for a voltage drop after a day or two - shouldn't go noticeably below 12 volts.

FZRMutt · #30 25th June 2010, 05:07 PM

15 volts is awful high from an alternator. I don't know much about Deauville's.
13.5 - 13.7 Volts would be more reasonable. You are reading 15 v and no current, If you rev the engine and it goes to 16 or 17v either your regulator is gone or there is a problem with the field winding on your alternator.

Would give more help right now but my brother is gone to a wedding and I have to milk the cows
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But if you want skype me after 7.30 and I can talk you through how to test an alternator. I'm an unemployed electronic engineer, I'll help if I can

FZRMutt · #31 25th June 2010, 05:09 PM

Originally Posted by jimgoose

Looks like a reasonably sane voltage for a bike on fast idle and charging well. What RPM was the bike doing while this was going on, and how accurate is that meter? Note that much over 15v charging voltage is too much for a 12v battery - you could be looking at a faulty regulator on the bike.

Some bikes run fine with the battery disconnected, some don't. Something to do with the Roswell Incident (
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).

Are you sure? If you used something like the 20A scale a bothersome current draw mightn't show. Assuming not, OK - that means you're probably OK for shorts. That's good to know.

Right. You can put the voltmeter across the poles to check for a voltage drop after a day or two - shouldn't go noticeably below 12 volts.

Roswell never happened! FZRMutt

jimgoose · #32 25th June 2010, 06:26 PM

Originally Posted by FZRMutt

Roswell never happened! FZRMutt

The truth is out there! 15v isn't high for an alternator, but it's at the upper end of what's acceptable as charging input. I agree that at the moment BTs regulator is looking like a borderline case - I'm interested in how the battery trial goes. BTW, I'm using Skype for Symbian these days - it's the blind bollocks.

Brother Thadeus · #33 30th June 2010, 04:15 PM

OK lads - the saga continues.
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Re-connected the battery yesterday after 4 days off the bike and it started first time so it doesn't look like the battery is the problem. If I leave the battery connected it won't start the bike after more then 2 days.

So, I guess the problem is either -
1. A short to ground somewhere on the bike or
2. Regulator not charging the battery properly

I have to add (2) above because I fully charged the battery with a charger before leaving it sit for the few days.

At this stage, should I be looking at bringing her in somewhere?
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jimgoose · #34 30th June 2010, 04:18 PM

Originally Posted by Brother Thadeus

OK lads - the saga continues.
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Re-connected the battery yesterday after 4 days off the bike and it started first time so it doesn't look like the battery is the problem. If I leave the battery connected it won't start the bike after more then 2 days.

So, I guess the problem is either -
1. A short to ground somewhere on the bike or
2. Regulator not charging the battery properly

I have to add (2) above because I fully charged the battery with a charger before leaving it sit for the few days.

At this stage, should I be looking at bringing her in somewhere?
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Well, we saw no current leakage the other day with the ammeter, right? Your charging voltage looks a tad high - at this stage I'd say you might have a dodgy reg/rec. Take 'er to a good spanner-spinner for a proper check-up.
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