Topic: Is it my CB or a battery?

[skiri251]

75' CB750K5

I just had the second AGM battery died on the CB. It's a Chinese made Scorpion. It lasted only a year and a half. I don't remember about the first one but it lasted two years or so. This battery had been on Battery Tender while in garage.

I measured the voltage at the battery while reving the engine (~4000 RPM) and the reading was 14.9V or so and according to the manual that's okay. I didn't test rectifier but if I get 14.9V that should be okay too, right?

I guess it's the battery.. Any one has experience with Scorpion?
I ordered Motocross (Yuasa made in USA) for the replacement this time.

[Tugboat]

I got a Scorpion for my 750 about this time last year. Still works fine. The thread that I found the recommendation on said they should last about 2-2.5 yrs, so maybe you got a dud?

[TwoTired]

75' CB750K5

I just had the second AGM battery died on the CB. It's a Chinese made Scorpion. It lasted only a year and a half. I don't remember about the first one but it lasted two years or so. This battery had been on Battery Tender while in garage.

I measured the voltage at the battery while reving the engine (~4000 RPM) and the reading was 14.9V or so and according to the manual that's okay. I didn't test rectifier but if I get 14.9V that should be okay too, right?

I guess it's the battery.. Any one has experience with Scorpion?
I ordered Motocross (Yuasa made in USA) for the replacement this time.

I've watching experiences about AGM batteries.  So far, it seems to be trading off "maintenance free" for overall lifespan.

What manual is telling you that 14.9V is OK?  Not the Honda shop manual.  Anything over 14.5V is going to stress it, particularly over longer stretches of time, and it shouldn't be maintained at that voltage.  That voltage level is the restorative charge cut off, after that is achieved, maintenance in the 13.5-13.8V range keeps the battery from harm and full charge, as removed from the charger, the battery should stabilize at about 12.6-12.8V before it begins the slow self discharge.

If your bike is charging at a 14.9v cut off, I suspect someone has futz'd with the Vreg adjustment (and didn't understand what it was for).

Cheers,

[skiri251]

75' CB750K5

I just had the second AGM battery died on the CB. It's a Chinese made Scorpion. It lasted only a year and a half. I don't remember about the first one but it lasted two years or so. This battery had been on Battery Tender while in garage.

I measured the voltage at the battery while reving the engine (~4000 RPM) and the reading was 14.9V or so and according to the manual that's okay. I didn't test rectifier but if I get 14.9V that should be okay too, right?

I guess it's the battery.. Any one has experience with Scorpion?
I ordered Motocross (Yuasa made in USA) for the replacement this time.

I've watching experiences about AGM batteries.  So far, it seems to be trading off "maintenance free" for overall lifespan.

What manual is telling you that 14.9V is OK?  Not the Honda shop manual.  Anything over 14.5V is going to stress it, particularly over longer stretches of time, and it shouldn't be maintained at that voltage.  That voltage level is the restorative charge cut off, after that is achieved, maintenance in the 13.5-13.8V range keeps the battery from harm and full charge, as removed from the charger, the battery should stabilize at about 12.6-12.8V before it begins the slow self discharge.

If your bike is charging at a 14.9v cut off, I suspect someone has futz'd with the Vreg adjustment (and didn't understand what it was for).

Cheers,

Maybe I misunderstood the shop manual...
I read 8-3 Regulator (pages 100-101). The note says: "The voltmeter indicates an output of 14~15 V at 5000 rpm at no load, the circuit is satisfactory".

The "no load" here means with the battery disconnected?

So with everything connected, I should see 13.8V max at the battery terminals?

[TwoTired]

Maybe I misunderstood the shop manual...
I read 8-3 Regulator (pages 100-101). The note says: "The voltmeter indicates an output of 14~15 V at 5000 rpm at no load, the circuit is satisfactory".

The "no load" here means with the battery disconnected?

So with everything connected, I should see 13.8V max at the battery terminals?

No load testing is not achievable on a running bike.  Honda Tech writers probably took that number from the bench technicians, where the bikes wiring and operating loads really weren't factored.

For an on bike test check out the chart on page 98.  You'll note that load or no load, the battery voltage should never go above 14.5V.

Under load, the vreg will oscillate, turning the alternator on and off rapidly.  Depending on the voltage sampling device, you may never see 14.5 V on the display, unless the meter reads peak voltage.

All the on bike tests and voltages in that chart assume a fully charged and rested battery before checking the voltages.  Depending on your measurement device, 14.5V should be achievable.  Back when the manual was written analog meters were prevalent and their movements couldn't move fast enough to track the Vregs oscillations,  The point is, you should never see voltages above 14.5V on the bike.

Note: I don't have any AGM batteries, yet.

Can you tell us about your charger/tender?

My research has mentioned that AGM batteries need to be "equalized" if not properly maintained.  Here is and excerpt from one manufacturer:

[skiri251]

No load testing is not achievable on a running bike.  Honda Tech writers probably took that number from the bench technicians, where the bikes wiring and operating loads really weren't factored.

For an on bike test check out the chart on page 98.  You'll note that load or no load, the battery voltage should never go above 14.5V.

Under load, the vreg will oscillate, turning the alternator on and off rapidly.  Depending on the voltage sampling device, you may never see 14.5 V on the display, unless the meter reads peak voltage.

All the on bike tests and voltages in that chart assume a fully charged and rested battery before checking the voltages.  Depending on your measurement device, 14.5V should be achievable.  Back when the manual was written analog meters were prevalent and their movements couldn't move fast enough to track the Vregs oscillations,  The point is, you should never see voltages above 14.5V on the bike.

Note: I don't have any AGM batteries, yet.

Can you tell us about your charger/tender?

My research has mentioned that AGM batteries need to be "equalized" if not properly maintained.  Here is and excerpt from one manufacturer:

Thanks!

I used cheapo digital multimeter from Harbor Freight. I don't think it responds quicker than analog ones. Plus I wonder how accurate its voltage reading is. Maybe I should somehow calibrate it? (I don't have any accurate voltage source though..)

I use Battery Tender Jr. from Deltran.

Here's what they say how good they are:

http://batterytender.com/resources/why-battery-tender

They also say somewhere it's safe for AGM batteries.

I can't tell what they say is correct or just a sales pitch.

[TwoTired]

I used cheapo digital multimeter from Harbor Freight. I don't think it responds quicker than analog ones. Plus I wonder how accurate its voltage reading is. Maybe I should somehow calibrate it? (I don't have any accurate voltage source though..)

Digital meters don't have a "constant read" algorithm.  They sample the source in smaller time increments, AND they update the display in time intervals.  There is little issue with this method in a pure/constant DC measured source.  But, if the DC level is changing, the frequency of the source and the frequency of the measurement device can play a role in the reading displayed.
For example: If the DC source is varying between 15V and 10V at a 100Hz frequency and the measuring device samples the source at the same frequency, it may display either 10V or 15V depending on how the two devices sync up.  This is called "aliasing".  And all digital samplers can fall prey to this phenomena, with the added complication of display update intervals playing a part.  There are other "false" display reading possible with other combinations of source frequency variation, and meter sampling/display update frequencies, as well.

Without knowing how your particular meter's operating parameters relate the varying DC levels possible on your bike, there is a level of uncertainty about the readings you've taken.   However, having said all that, none may be a factor in your measurement reports.  (There are few absolutes in this world.)  I also have an older DMM from Harbor freight.  It has given good service even though I have not "characterized" its function or accuracy.  The main uncertainty, is that I know that with full battery, the Vreg switches the alternator on and off to achieve an "average" level at the Vreg sense terminals.  This frequency can be random.  And the lows, to highs ratios can also vary.   Sometimes, unlikely events can align and fool you (and me).

I use Battery Tender Jr. from Deltran.

Here's what they say how good they are:

http://batterytender.com/resources/why-battery-tender

They also say somewhere it's safe for AGM batteries.

I can't tell what they say is correct or just a sales pitch.

Those chargers have a good reputation.  Unfortunately, they don't provide much in the way of specifications on their web site.  It is mostly marketing hype.  Perhaps there is more data on the owner's operator's manual that came with the unit? 
The ones I'm familiar with, didn't have a very high bulk charge rate.  While they may be safe for AGM use, they may not be able optimally charge it.
Have you considered that your battery may need to be "equalized"?  (Heavily discharges and aggressively charged.)

What does your battery measure after it has been fully charged, then disconnected, and rested for 2 hours?

How did you determine that your battery "died"?  Was it cold? Hot?

Cheers,

[Skunk Stripe]

I won't comment about chargers and such but 14.9 is high. As for lifespan, The last agm I got made it 4 years and was topped off 1 every couple of months with no other maintenance.

[ofreen]

I don't know anything about the Scorpion battery, but I do know that AGM batteries can give excellent service life.  I've used only Westco branded AGM batteries in my CB750F, CBR1000F, and R100GSPD.  They all have lasted at least 8 years.  The one I have currently in the 750 originally went into service in the CBR in November of 2001.  It has lasted 9 years and still cranks the bike strongly at 25 degrees F.

One of the advertised benefits of the AGM is slow self-discharge rate while sitting.  I have found this to be true.  My bikes may sit 2-1/2 months in the winter without starting.  I no longer bother to put the charger on them periodically when the bikes are idle in the winter.  It is unnecessary.  This assumes the bike's charging system is healthy and adequately maintaining the battery.

If your batteries are crapping out prematurely and your charging system is up to snuff, I'd say it is the quality of the battery that is the problem, not that it is an AGM.  All batteries are not created equal, AGM or otherwise.

[Skunk Stripe]

Thats for sure. Walmart batteries would crap out in less than 2 years on average.

[skiri251]

Digital meters don't have a "constant read" algorithm.  They sample the source in smaller time increments, AND they update the display in time intervals.  There is little issue with this method in a pure/constant DC measured source.  But, if the DC level is changing, the frequency of the source and the frequency of the measurement device can play a role in the reading displayed.
For example: If the DC source is varying between 15V and 10V at a 100Hz frequency and the measuring device samples the source at the same frequency, it may display either 10V or 15V depending on how the two devices sync up.  This is called "aliasing".  And all digital samplers can fall prey to this phenomena, with the added complication of display update intervals playing a part.  There are other "false" display reading possible with other combinations of source frequency variation, and meter sampling/display update frequencies, as well.

Without knowing how your particular meter's operating parameters relate the varying DC levels possible on your bike, there is a level of uncertainty about the readings you've taken.   However, having said all that, none may be a factor in your measurement reports.  (There are few absolutes in this world.)  I also have an older DMM from Harbor freight.  It has given good service even though I have not "characterized" its function or accuracy.  The main uncertainty, is that I know that with full battery, the Vreg switches the alternator on and off to achieve an "average" level at the Vreg sense terminals.  This frequency can be random.  And the lows, to highs ratios can also vary.   Sometimes, unlikely events can align and fool you (and me).

Yes. I understand that Nyquist sampling theorem. I will take your word that my cheapo HF multimeter's reading is somewhat acceptable. I don't have an oscilloscope so there is no way for me to see what is going on exactly.

I adjusted the regulator. Now the voltage at the battery is a little less than 14.5V. Hopefully this new Yuasa USA AGM battery will live a long life.

Have you considered that your battery may need to be "equalized"?  (Heavily discharges and aggressively charged.)

What does your battery measure after it has been fully charged, then disconnected, and rested for 2 hours?

How did you determine that your battery "died"?  Was it cold? Hot?

I put an HF battery load tester on it. W/o load I saw 12. something volts. With load, 0V.
I then tried to charge it with a manual charger. The current reading was almost zero.

[skiri251]

I don't know anything about the Scorpion battery, but I do know that AGM batteries can give excellent service life.  I've used only Westco branded AGM batteries in my CB750F, CBR1000F, and R100GSPD.  They all have lasted at least 8 years.  The one I have currently in the 750 originally went into service in the CBR in November of 2001.  It has lasted 9 years and still cranks the bike strongly at 25 degrees F.

One of the advertised benefits of the AGM is slow self-discharge rate while sitting.  I have found this to be true.  My bikes may sit 2-1/2 months in the winter without starting.  I no longer bother to put the charger on them periodically when the bikes are idle in the winter.  It is unnecessary.  This assumes the bike's charging system is healthy and adequately maintaining the battery.

If your batteries are crapping out prematurely and your charging system is up to snuff, I'd say it is the quality of the battery that is the problem, not that it is an AGM.  All batteries are not created equal, AGM or otherwise.

I have Scorpions on my two other bikes. So I will see if it's a battery or something else. At this point, it appears to be not the battery.

[Gaither]

I've always hated wiring and now, I'm beginning to hate batteries!

The 14.9 amps on Two-Tired's chart amazes me. I was under the impression that a 2 amp charging rate was about all these small bike batteries would stand for any length of time. (I wonder how long that is?). Every time I think I've finally learned something, I get blown away! I assume the high charge rate only applies to an AGM battery that has been badly discharged [?].

My Battery Tender JR lit states it charges at a rate of "0.75 amps per hour". (From the same lit the Plus model charges @ 1.25 amps/hr.) It further states it is OK for non-sealed (flooded), AGM and GEL batteries.

From Two-Tired's chart, it would appear a Battery Tender might not always serve to maintain an AGM battery (Which I was considering buying by spring).

So, now, I'm just confused. The more exposure I get the less I know!

[scottly]

This is called "aliasing". 
Cheers,

Please explain this phenomenon? I have never heard of "aliasing" before. I have heard of quantizing distortion, during the analog-to-digital conversion of much higher frequency analog signals.  

[TwoTired]

I put an HF battery load tester on it. W/o load I saw 12. something volts. With load, 0V.
I then tried to charge it with a manual charger. The current reading was almost zero.

Yep. It "died" .   

[TwoTired]

The 14.9 amps on Two-Tired's chart amazes me. I was under the impression that a 2 amp charging rate was about all these small bike batteries would stand for any length of time. (I wonder how long that is?). Every time I think I've finally learned something, I get blown away! I assume the high charge rate only applies to an AGM battery that has been badly discharged [?].

The chart was from a "Lifeline" battery website discussing their AGM types.  I don't know what size AGM battery they were referring to.  What I learned, was that they sometimes need to be equalized, which is a discharge cycle followed by a brisk charging regime to get all the cells back to a level playing field.  I think the equalization process described is only for AGM batteries (well some other battery technologies, too.) but, it not normally applied to Flooded cell batteries.

My Battery Tender JR lit states it charges at a rate of "0.75 amps per hour". (From the same lit the Plus model charges @ 1.25 amps/hr.) It further states it is OK for non-sealed (flooded), AGM and GEL batteries.

I thought all the Battery tender series were at least 2 stage chargers.  Could be they quoted the bulk charge rate, not a constant charge rate.

From Two-Tired's chart, it would appear a Battery Tender might not always serve to maintain an AGM battery (Which I was considering buying by spring).

It is usually best to follow the battery manufacturer's recommendation about charging.  Rather a pity Scorpion doesn't have any info on their ordering web site.  Maybe they deliver some info along with the battery?  I don't know, I have bought any scorpions batteries.

Cheers,

[TwoTired]

This is called "aliasing". 
Cheers,

Please explain this phenomenon? I have never heard of "aliasing" before. I have heard of quantizing distortion, during the analog-to-digital conversion of much higher frequency analog signals.  

I thought I did explain part of this.  Be aware, I've been out of the lab for about ten years, now.  Some equipment has no doubt gotten "smarter"
But, way back when our labs were starting to convert from analog scopes and other measuring equipment, to digital, were were taught by the equipment reps about what they termed "aliasing".

Digital equipment does not have a direct link to the display that you see.  The input being measured is "sampled".  There are several functional blocks in the equipment that take care of certain functions, and these pass data between them to get the overall job done.
The A to D converters, have a clock frequency (sometimes interactive with the time base selection on scopes).  This freezes the data read on the converter, for a duration that allows it to be passed on to a buffer for computational analysis, or a display processor.  So the actual voltage level being measured is sampled at some rate an interval.  The display processor has it's own update interval, which may or may not be in sync with the voltage sampling.

The display has a response time. LCD displays were often slow, which doesn't matter as the human eye is slow, too.  So sample rates can be higher that the display rates.  If the voltage you are measuring has a periodic component.  It may or may not be in sync with the display interval, or the sampling rate of the A to D converters.  So, measuring a signal or changing input level accurately will depend on the frequency response and clock frequencies of the sampling equipment distributed among the functional blocks.

An example.  Lets say that that your display is updated once per second.  You provide a measuring signal to test, that changes from 12 v to 13 volts every 1 second.  Your display could read either 12v or 13v depending on how the two independent time bases  synchronizes or "beats" against each other.  What you see is an "alias" of the actual signal or level on the input line.  Equipment such as this may be perfectly adequate for the task, provided the line level is not critical in operation given 12 or 13 V.

Generally, you want all the internal house keeping and transfer of data between the functional blocks of the equipment to be as fast as possible, or at least faster than the subject being tested.  But speed costs money.  And cheaper equipment is usually cheaper for a reason.  So, you have to be wary that your equipment doesn't present an alias of what is really present on the line input.

It gets far more complicated with oscilloscopes where you can control sampling time bases, buffer sizes allotments, etc.

Does this help?

[skiri251]

I guess cheapo HF multimeter is not equipped with anti-aliasing filter of any sort..

[754]

  I have never seen long life out of cheap batteries.

 I used to sell Yuasas back in the 89s, they held up well.

 In fact, I had one in a Kawi chopper sat in the shed for a few winters, maybe more, and it would have gotten below Zero F a few times.. The Kawi was not charging. I charged the battery, and amazingly it held charge. Then I proceeded to ride the bike running total loss.. charge and discharge.. repaeatedly.. and it kept working.. battery was 5 or 6 yrs old at that point..

[Gaither]

As an amusing, worthless side note:

In '55 I had a '50 mercury (6 volt with generator). It sat outside (winter) and I had to "roll it off" every morning. Then, it would start OK until I parked it overnight. The battery showed a dead cell and I was too broke to buy a new one.

A "county boy" I knew rebuilt batteries for a living. He told me to put a heaping teaspoon of epsom salts in each cell, roll it off and drive it. I did so. After that, the Merc would start each morning. I got another year on the battery before it finally gave up completely.

I assume it desolved the sediment in the bottom of the battery that was shorting the bad cell [?] - although it always read to have a dead cell every time I tested it.