Author Topic: battery question for cafe bike (i searched...)  (Read 7994 times)

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KingCustomCycles.com

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Re: battery question for cafe bike (i searched...)
« Reply #25 on: January 27, 2009, 11:34:29 AM »
WARNING: Battery threads are much worse than oil threads. It is snowing here so have at it.  ;D

eldar

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Re: battery question for cafe bike (i searched...)
« Reply #26 on: January 27, 2009, 11:38:10 AM »
HA HA YOU GOT SNOW!!! ;D Oh wait, we are freezing are asses off here.  :P

Offline timdhawk

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Re: battery question for cafe bike (i searched...)
« Reply #27 on: January 27, 2009, 11:42:16 AM »
Eldar,
Im just West of you over in Billings. It is about 5* with 5" of snow and 20-30mph winds... FREAKIN COLD!!!!!!!!!!!

anyway...thanx for all the input.
In deeper than I should be...

eldar

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Re: battery question for cafe bike (i searched...)
« Reply #28 on: January 27, 2009, 11:55:03 AM »
Well we do not get all the snow but we get air from the canadian interior all winter long. I think our average temp for december was below zero the whole time and wind chills averaging about 30-40 below, averaging! BLAME CANADA! BLAME CANADA! ;D

Offline bwaller

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Re: battery question for cafe bike (i searched...)
« Reply #29 on: January 27, 2009, 12:02:37 PM »
Well we do not get all the snow but we get air from the canadian interior all winter long. I think our average temp for december was below zero the whole time and wind chills averaging about 30-40 below, averaging! BLAME CANADA! BLAME CANADA! ;D



Well, you are welcome my good man. We fool-hardy tough mother Canucks come to life in this kind of weather.

eldar

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Re: battery question for cafe bike (i searched...)
« Reply #30 on: January 27, 2009, 12:07:27 PM »
Yeah IF you come out of your igloos! ;D

Offline jonbuoy

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Re: battery question for cafe bike (i searched...)
« Reply #31 on: January 27, 2009, 12:10:35 PM »
It IS standard practice but in most of those cases, the batteries are designed for that purpose. An average battery is not. yes it will work fine but its life may not be as long. Plus you cannot deny the fact that if 1 goes bad that the draw is greatly increased on the other batt(s).

Also as for changing internal resistance, that is well known. FOR EXAMPLE: in ANY battery pack if you have 1 cell at 1.5 volts, lets say resist is 10 ohm and amps are 1. If you add another in series, you jump the voltage to 3, BUT your resist DROPS to 5 and amps stay at 1 HOWEVER; as the resist has dropped, power can flow faster and the battery will die sooner.
This is fact. Why do you think electricity is cranked up to high voltage to transfer? Resistance is lower and thus less line loss.
So my point is that a standard lead-acid batt is made to offer fair life when used in a steady state for which it was designed. It is not designed to be charged/discharged all the time. Also a powersupply, flashlights, backup batteries and such are NOT lead-acid. They are most likely a bi-metal based battery and as such, react differently than a chemical based battery.

Besides, for the sake of simplicity, drop the starter and get a smaller 12V batt.

The voltage on transmission lines is increased to compensate for losses in cables and so it can be sent over thinner conductors - higher voltage less current, thinner conductor.  Nothing to do with batteries - the losses in two small 6v cells in series are insignificant.  Backup batteries ARE lead acid - sealed lead acid,  the one thing they are not designed for is taking high currents for short periods of time - ie the cold cranking amps that a motorcycle battery can provide.  A motorcyle battery is not a deep cycle battery, a deep cycle battery is designed to be able to cope with being run flat and then recharged.  A motorcyle battery is a start battery - high current output for short periods of time.  Although on the 750's it does do some cycling if the revs are low as they don't charge much at lower revs.
« Last Edit: January 27, 2009, 12:27:43 PM by jonbuoy »

Offline jonbuoy

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Re: battery question for cafe bike (i searched...)
« Reply #32 on: January 27, 2009, 12:21:16 PM »
For the record connecting batteries in parallel INCREASES the capacity by DECREASING the total resistance.

Offline Joksa

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Re: battery question for cafe bike (i searched...)
« Reply #33 on: January 27, 2009, 12:45:29 PM »
I am not sure whether LiFePo4 batteries would work with alternator, but something that might work with kick start only bike:
http://www.1000rr.net/forums/showthread.php?t=54463

eldar

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Re: battery question for cafe bike (i searched...)
« Reply #34 on: January 27, 2009, 01:03:19 PM »
Sorry but I have a degree in power plant operations which encompasses power transmission. The higher the voltage the less resistance and thus less line loss. Also, if you use OHMs law, you see that if you decrease resistance, you WILL increase voltage as that does not happen in parallel, then you are not decreasing resistance.

http://www.batteryuniversity.com/partone-24.htm some info but not much.

Transmitting electricity at high voltage reduces the fraction of energy lost to Joule heating. For a given amount of power, a higher voltage reduces the current and thus the resistive losses in the conductor. For example, raising the voltage by a factor of 10 reduces the current by a corresponding factor of 10 and therefore the I^2R\,\! losses by a factor of 100, provided the same sized conductors are used in both cases. Even if the conductor size is reduced x10 to match the lower current the I^2R\,\! losses are still reduced x10. Long distance transmission is typically done with overhead lines at voltages of 115 to 1,200 kV. At extremely high voltages, more than 2,000 kV between conductor and ground, corona discharge losses are so large that they can offset the lower resistance loss in the line conductors.

So you see, I was right on high voltage lines.

Just too add more. In a battery, power flow from the negative post to the positive.
When the battery is connected to a circuit, electrons produced by the chemical reaction at the anode flow through the circuit to the cathode. At the cathode, the electrons are consumed in another chemical reaction. The circuit is completed by positive ions (H+, in many cases) flowing through the solution in the battery from the anode to the cathode.

http://physics.bu.edu/~duffy/PY106/Capacitors.html

but whatever, he would still be better off with a smaller batt and losing the starter or doing what king did behind the tire with an agm. imo.

Offline TwoTired

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Re: battery question for cafe bike (i searched...)
« Reply #35 on: January 27, 2009, 01:48:33 PM »
Maybe i should clarify, my intent was not to run a smaller battery in power, only in size. I want stock battery abilities in the smallest package possible.
Ah, you seek the grail.  Just like all the electric car advocates.  ;D

Battery technology is on the verge of breakthough toward that goal (has been for 10 years now  ::) ), but it is not readily available yet.

i have found a 12v 10Ah this size: 5.94" L x 2.56" W x 4.37" H
and the same but in 21Ah in this size: 7.14" L x 3.03" W x 6.59" H

If you plan on using the electric starter, you must add another specification to your search parameters, and that would be CA or CCA or Cold Cranking Amps.   Starting batteries have a different plate and separator technology used within the battery.  Starting batteries maximize plate area and contact with the electrolyte (sometimes with thinner plates).  This allows them to deliver higher currents than their power durability rating (such as what you have posted).  However, because of the "more open" plate and separator design, their life is shortened by deep discharging.  Deep cycle batteries, on the other hand, have a plate and separator design that promotes depositing lost metals during discharge, mostly back where the metals came from, while recharging.  Such batteries do not deliver high currents of starting motors very well, without heating, distorting, or damaging the current crop of deep cycle battery plate and separator technology designs.  Conversely, deep discharging a starting battery frequently, removes metal from the plates and allows holes to form in the plate material far sooner as metal is not redeposited onto the plates during recharge where it came from on the internal plate.

Please note that the starter motor on the SOHC4 draws 150 amps or more during start operation.  This draw is well beyond the rating specs you've listed.  A starting battery can supply this load and still maintain a usable voltage to power the ignition components.  A Deep cycle battery used in this same application will drop the voltage more during starting operation, which may or may not effect you ignition system's spark capability when the battery is new.  However, as you increase the amount of time that a deep cycle battery as been overloaded, it will have more difficulty supplying the amps that the starting motor demands AND the voltage delivered during the high amperage draw will get lower.  So, while it may still spin the starter, it will do so slower and the spark voltage will get lower as well.  Of course, it the spark potential gets low enough, spark does not occur.  You may still kick start the bike with a weakened battery, and turning the lights off on the bike would help the spark voltage potential.

however, from all the sites i've looked at (a lot now), 3" is about the "thinnest" i can get keeping within or above the 12-14Ah minimums.

A 12 V 14AH battery, ostensibly, can sustain a 14 amps load for 1 hour.  (Ah, if life could be that simple.)  However, the voltage will not be maintained at 12v for that entire duration.  As the time advances the voltage depletes (to zero).  In fact, the battery will not be usable for that entire 1 hour duration, as that is a calculated rating, not a demonstrated rating.  Instead, the battery is designed to deliver 1.4 amps for 10 hours (if the spec was using a 10 hour rate) before the battery voltage level depletes to 10.5V.  If the spec was using a 20 hour discharge rate, you could place a 0.7 a load on the battery for 20 hours before the output falls to 10.5V.

Note this excerpt from:
http://www.logwell.com/tech/shdwe/vehicle_battery.html

Quote
Battery Ratings

There are a dozen or more vehicle battery rating methodologies.  The Society of Automotive Engineers (SAE) has established two ratings for domestic made batteries - Reserve Capacity (RC) and Cold Cranking Amperes (CCA).  The Cranking Amps (CA) rating is also still commonly used.  Industrial batteries often specify Ampere Hours (AH) and marine batteries may carry a Marine Cranking Amps (MCA) rating.  Definitions of these more common rating systems are given below:


RC - Rating in minutes a battery will carry a 25 amp load at 80ºF and maintain a minimum terminal voltage of 10.5 volts.

CCA - Rating in amps which a new, fully charged battery at 0ºF can continuously deliver for 30 seconds and maintain a terminal voltage equal to or higher than 1.20 volts per cell.

CA - Rating in amps which a new, fully charged battery at 32ºF can continuously deliver for 30 seconds and maintain a terminal voltage equal to or higher than 1.20 volts per cell.

AH - (@ 20 hours) a battery having a 100 AH rating must carry a 5 amp load for 20 hours and maintain a terminal voltage of 10.5 volts at 80ºF (100 ÷ 20 = 5 amps).

MCA - Rating in amps which a new, fully charged battery at 30ºF can continuously deliver for 30 seconds and maintain a terminal voltage equal to or higher than 1.20 volts per cell.

Ratings Conversions:      RC = 1.75 x AH          AH = (RC ÷ 2) + 15.5


Cheers,

Lloyd... (SOHC4 #11 Original Mail List)
72 500, 74 550, 75 550K, 75 550F, 76 550F, 77 550F X2, 78 550K, 77 750F X2, 78 750F, 79CX500, 85 700SC, GL1100

Those that learn from history are doomed to repeat it by those that don't learn from history.

eldar

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Re: battery question for cafe bike (i searched...)
« Reply #36 on: January 27, 2009, 02:18:11 PM »
Quote
Battery technology is on the verge of breakthough toward that goal (has been for 10 years now  Roll Eyes ), but it is not readily available yet.

Been hearing this for a few years now. Lithium based if I remember right. Would be nice if battery tech caught up a little but energy storage will always lag I think. Would be great though to have a battery that was half the size with less weight and equal power!


One other thing, with the battery behind the wheel, now it may not have been a problem for king, but I would be tempted to create a light shield of some sort to protect from rocks tossed by the rear tire. Nothing thick and heavy but enough to stop small rocks. Some light gauge tin perhaps.

KingCustomCycles.com

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Re: battery question for cafe bike (i searched...)
« Reply #37 on: January 27, 2009, 02:50:29 PM »
Lithium Polymer technology is ongoing but has yielded many advantages.  Weight and power output have made huge strides.  Cost has not.  Our UAS (model airplane with camera, think Predator) has a power pack that is 26 volts at 8 AH.  Cost?  $800.  We have two of those packs and they are good for about 2 years.  Flyin ain't cheap.

Offline jonbuoy

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Re: battery question for cafe bike (i searched...)
« Reply #38 on: January 27, 2009, 09:48:08 PM »
Sorry but I have a degree in power plant operations which encompasses power transmission. The higher the voltage the less resistance and thus less line loss. Also, if you use OHMs law, you see that if you decrease resistance, you WILL increase voltage as that does not happen in parallel, then you are not decreasing resistance.

Transmitting electricity at high voltage reduces the fraction of energy lost to Joule heating. For a given amount of power, a higher voltage reduces the current and thus the resistive losses in the conductor. For example, raising the voltage by a factor of 10 reduces the current by a corresponding factor of 10 and therefore the I^2R\,\! losses by a factor of 100, provided the same sized conductors are used in both cases. Even if the conductor size is reduced x10 to match the lower current the I^2R\,\! losses are still reduced x10. Long distance transmission is typically done with overhead lines at voltages of 115 to 1,200 kV. At extremely high voltages, more than 2,000 kV between conductor and ground, corona discharge losses are so large that they can offset the lower resistance loss in the line conductors.

So you see, I was right on high voltage lines.

Just too add more. In a battery, power flow from the negative post to the positive.
When the battery is connected to a circuit, electrons produced by the chemical reaction at the anode flow through the circuit to the cathode. At the cathode, the electrons are consumed in another chemical reaction. The circuit is completed by positive ions (H+, in many cases) flowing through the solution in the battery from the anode to the cathode.

http://physics.bu.edu/~duffy/PY106/Capacitors.html

but whatever, he would still be better off with a smaller batt and losing the starter or doing what king did behind the tire with an agm. imo.

Well thats great for you  - if you want to masturbate about your vast theoretical knowlage go right ahead.  But were talking about the practicalities of putting two smaller 6 volt batteries in series to give 12v which will be fine IF:

the batteries are identical
the leads between them are short
you don't want to use the starter

I was thinking of doing the same on my 750.

Offline TwoTired

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Re: battery question for cafe bike (i searched...)
« Reply #39 on: January 27, 2009, 10:57:04 PM »
Well thats great for you  - if you want to masturbate about your vast theoretical knowlage go right ahead. 
Dang, that's probably funnier than you intended.   ;D  Having read the prior drivel, I nearly spewed beverage out my nose.  I pity anyone who actually took the contrivance seriously.

But were talking about the practicalities of putting two smaller 6 volt batteries in series to give 12v which will be fine IF:

the batteries are identical
the leads between them are short
you don't want to use the starter
I largely agree with you.  But, to put a finer edge on the conditions, the leads don't necessarily have to be short.  It's just that the interconnects need to have low resistance offered to the currents that are expected to be delivered through the circuit.  Longer interconnects would require a larger cross section electrical conduit, in order to offer low resistive voltage drops.
Further, if the batteries are starting function rated, you could still use an electric start and expect decent battery(s) longevity.

Cheers,
Lloyd... (SOHC4 #11 Original Mail List)
72 500, 74 550, 75 550K, 75 550F, 76 550F, 77 550F X2, 78 550K, 77 750F X2, 78 750F, 79CX500, 85 700SC, GL1100

Those that learn from history are doomed to repeat it by those that don't learn from history.

Offline Joksa

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Re: battery question for cafe bike (i searched...)
« Reply #40 on: January 28, 2009, 06:19:49 AM »
It makes no difference if a cable is between, before or after the batteries.

eldar

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Re: battery question for cafe bike (i searched...)
« Reply #41 on: January 28, 2009, 06:26:42 AM »
And I pity you tt for thinking you are so smart when you really are not. I guess everyone else has accepted your smoke so you get by with it. Sorry If I posted info found on many different electrical power sites. Sorry if you use outdated material and have no freaking clue. I know you are in your fifties and that means you get a certificate from aarp that means you know it all. Sorry I forgot. I remember shutting you up a few years back about batteries, I thought you might have learned then. I guess not. I even quoted the exact college texts my info came from then. In this case I took the info from a number of different websites, I did post a couple of links but I am sure you still think you are right. I could present scientific proof that night is dark and if you did not think so, you would argue it. Well whatever tt. I know you are full of yourself, others do too. Almost everything I posted can be backed up but I know you will not look, that way you can still think you are right. Even if I did post links, you would still not read it. Clearly jonbouy did not otherwise he might have a different tune. SO clearly posting facts here means nothing. The only thing that mean anything here is apparently age and the ability to bulllshiit others into believing what you say.

Thats ok, I checked out what I posted to make sure it was not way off, I only have a degree in power generation, power plant operation, and transmission. I only worked on farm machinery that uses multiple batteries but since I am only 33 and live in ND, I do not know anything.

So I guess I will take terry from Oz's advice when dealing with tt and just tell you to piss off.

Oh wait.... Cheers  

What a phony.

Offline Joksa

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Re: battery question for cafe bike (i searched...)
« Reply #42 on: January 28, 2009, 06:49:25 AM »
It is kinda like speakers. 2 8ohm coils together drop ohms to 4. Same principle more or less.

As stated many times in parallel you get double capacity (with same voltage) and in series you get double voltage (with same capacity). It really doesn't matter whether a certain capasity battery is in one or two containers (only make sure the voltage drop stays low in cabling - as also stated in this same thread earlier).

Offline timdhawk

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Re: battery question for cafe bike (i searched...)
« Reply #43 on: January 28, 2009, 07:03:17 AM »
Sweet Jeebus!!! :o :o
I just want to power my bike with the smallest footprint possible... didn't know i was starting such a hot topic.

« Last Edit: January 28, 2009, 07:07:11 AM by timdhawk »
In deeper than I should be...

Offline jonbuoy

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Re: battery question for cafe bike (i searched...)
« Reply #44 on: January 28, 2009, 09:27:08 AM »
Well to be honest I mean no malice in my comments to Eldar.   My snappy responses are partly due to me having been working away from home in Saudi Arabia since before christmas and being in this godless and beerless  WTF  ???  land has made me into a grumpy bastard, and given me a little insight into  reasons why anyone would want to turn themselves into a not very smart bomb   ;)  Happy new year guys.

 

bollingball

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Re: battery question for cafe bike (i searched...)
« Reply #45 on: August 10, 2010, 01:43:52 AM »
How many batteries will I need if I take out my engine starter also?