Re: [ST] Flat Battery

[Neil Lindsey <Neil.Lindsey@xxxxxxx>]

Thank-you Chris



----- Original Message ----- 
From: "Chris Harwood" <Chris@xxxxxxxxxxxxxxxxxx>
To: <ST@xxxxxxxxxxxxxx>
Sent: Wednesday, March 07, 2007 4:48 PM
Subject: Re: [ST] Flat Battery


> Rick
>
> I've studied electricity for over 40 years including at university and 
> some of your comments there make me cringe.  You could connect a 
> billion-amp charger to your battery and the charging current will be 
> determined by the battery's internal resistance and the difference in 
> voltage between the open-circuit battery and the open-circuit charger. 
> That could be milliamps.
>
> Incidentally, we dispensed with amp-hours over here some years ago and we 
> rate lead/acid car batteries in cranking amps now.  It's all part of 
> progress and we are clearly more advanced than the rest of the world 
> (not).
>
> Chris Harwood
> 00 RS UK
>
>>>> drbrant@xxxxxxxxxxxxxx 08/03/2007 00:05:06 >>>
> Neil,
>
> Actually Kevin explanation is a rather good.  As a basic rule you can 
> divided a batteries amp hours, the rating on the battery, by the charging 
> amps to determine the maximum total time to charge the battery.  Note 
> typical car batteries range from 500 amp hours to 800 amp hours.  Most 
> motorcycle batteries are in the 10-20 amp hours range.  I think the amp 
> the middle numbers on a Yuasa Battery.
>
> The major risk associated with using an running automobile to charge a 
> motorcycle battery is too many amps over heating the electrical system and 
> damaging components.  I sold a GS650 to an in-law many years ago who was 
> an automotive mechanic.  He attempted to charge the battery with an 8-0 
> amp hour automotive charger and destroyed the regulator rectified in the 
> bike.  An alternator in a car will produce similar results.  It is also 
> possible to short a battery out by exposing it to too many amps.
>
> If you don't believe us you can either study electricity some or go and 
> hook a high amperage charger to you motorcycles electrical system.
>
> Rick B
> Pfafftown, NC
> -----Original Message-----
>>From: Neil Lindsey <Neil.Lindsey@xxxxxxx>
>>Sent: Mar 7, 2007 6:42 PM
>>To: ST@xxxxxxxxxxxxxx
>>Subject: Re: [ST] Flat Battery
>>
>>Kevin -- 
>>
>>sorry, but you have no idea what you are talking about
>>
>>----- Original Message ----- 
>>From: "Kevin Dicks" <kdicks@xxxxxxxxxx>
>>To: <ST@xxxxxxxxxxxxxx>
>>Sent: Wednesday, March 07, 2007 12:14 PM
>>Subject: Re: [ST] Flat Battery
>>
>>
>>> Agreed.  What I should have said is that a car battery needs more 
>>> current
>>> to
>>> charge it compared to a bike battery given the same time period - 
>>> another
>>> effect of this is, as you point out, it has a higher AH.  If you leave a
>>> battery on a 20mA charger for long enough, given the correct voltage, it
>>> will probably eventually charge (as long as the battery is in good
>>> condition
>>> etc).  The point I was trying to make was that even though a car battery
>>> and
>>> a bike battery have the same voltage, they are very different when it
>>> comes
>>> to current (and therefore the AH each can provide).  Given this
>>> difference,
>>> the charging system of a car can (because it has to) provide far more
>>> power
>>> (Volts *  Current) than a bike charging system can.  Given that,
>>> jump-starting a bike from a car with the car engine running, 'may' lead 
>>> to
>>> problems with the bike due to the higher current the car charging system
>>> provides.
>>>
>>> -----Original Message-----
>>> From: st-bounces@xxxxxxxxxxxxxxxxxxxx
>>> [mailto:st-bounces@xxxxxxxxxxxxxxxxxxxx] On Behalf Of Eoin Kirwan
>>> Sent: Wednesday, March 07, 2007 3:08 PM
>>> To: ST@xxxxxxxxxxxxxx
>>> Subject: Re: [ST] Flat Battery
>>>
>>>
>>> On Wednesday 07 March 2007 03:23, Kevin Dicks wrote:
>>>> Current is not the same as Voltage. Just look at the size of a car's
>>>> battery in comparison to a bike's.
>>>
>>> But it's the same voltage. The larger size means more amp-hours, so it 
>>> can
>>> power a given load for a longer time - or a larger load for the same
>>> length
>>> of time - before it becomes discharged.
>>>
>>>> The car battery needs more current to
>>>> charge it - even though the voltage is the same as the bike's (give or
>>>> take).
>>>
>>> It doesn't need more current to charge it, it needs more amp-hours to
>>> charge
>>>
>>> it. Whether you do that by using a larger charge current in the same 
>>> time,
>>> or
>>> use the same charging current for a longer time, is up to you. The
>>> *maximum*
>>>
>>> recommended charging current will be larger, but you don't have to 
>>> charge
>>> it
>>>
>>> at the maximum rate, it'll just take longer.
>>>
>>>
>>> Eoin
>>>
>>> '04 ST955i
>>>
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>>
>>
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