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Orezona

Won't crank but battery checks out at 11.7 volts

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After I finished mowing yesterday I shut down the 655 and later tried to re-start and it wouldn't crank like the battery was dead.  I checked the battery with a multi-meter and it checked out to 11.7 volts.  I then checked the ignition switch and it was good.  So I put the charger on 2amp trickle on it for just a few seconds and it started right up.  Any ideas?  The engine is a 1970 K181S according to the serial number.

 

Thanks in advance.

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Bad connection someplace

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The wire wiggle should show you which one it is.

May want to clean the connections on the switch too.

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A 12 volt battery should have 12 volts at a minimum. My guess is the battery is on it's way out. Put a small load on it like the lights and what is the voltage?

 

Garry

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Believe it or not, A battery that reads 12.2 volts is all ready half discharged. At least the last automotive electrical seminar I went to said so.

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Time for a new battery?  You can take it to a store that sells batteries to have it load tested.

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A 2 amp trickle for a couple of seconds isnt going to help the battery, you may still have a battery concern but it should have tried with the voltage indicated. Bad connection.

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Orezona,

 

A weak battery is almost certainly at least part of your problem.  A reading of 11.7 volts indicates a battery that's only about 20% charged.  I would check the water level in all cells, top up with distilled water, charge with your 2 amp charger for a half hour or so, let it stabilize for an hour or so, and then check the voltage again.  If you're reading about 12.6 volts, you might be good to go, but do as some of the other guys have said here and check and clean as many connections as you can get to.

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Fully charged healthy 12 volt battery should show 12.6 volts.  11.7 is way low....

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Thank you for all the responses.  Haven't had a chance to mess with it yet (in the middle of moving).  It runs great.  I think I need to replace the valve cover gasket from what I can tell by the manual I found on here. Oil leak left and behind the carb.  But that is another thread...

 

Thanks again for all your responses.  This seems to be a great WH enthusiast forum.

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Thank you -all for the help. I charged the battery up real good. The sol will try, to spin, but it will not engage the fly wheel enough to make contact. Maybe the sol. is bad. I jumped the starter out and fired up the engine. But will have to check out some wireing. key switch will not kill the engine.

thanks

darg

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What should my Amp gauge read when running?  It doesn't seem to work.  Done packing for the day so I went out and checked the battery.  read 12.07 when off.  Started it and it read 11.7.  What do you all think?

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What should my Amp gauge read when running?  It doesn't seem to work.  Done packing for the day so I went out and checked the battery.  read 12.07 when off.  Started it and it read 11.7.  What do you all think?

Sounds like the charging system isnt working or you do infact have a shorted battery

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You might also have a charging issue if your battery is newer.  When you get the tractor running again, hold the voltage meter to the batter and it should be reading at least 14V, if not, then your battery isn't charging.  Temperature also has an affect on the amps, so your battery could be reading above 12V but still won't crank because the amps are too low.  The simplest solution for this is to throw it on a charger for a while, but the lower amps the charger it is the longer it will take.  At work we use a 50 amp charger for an hour if the battery is completely dead, and that just gives us enough to get it started and let it run and charge itself.

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Battery voltage at rest only tells part of the story here - a small part.

 

11.7 volts at rest is a NEAR FULLY DISCHARGED BATTERY as was stated earlier. Yes, the starter may try to turn at 11 or 12 volts BUT - and it's a big BUT - the battery may be sulfated and exhibit a very high internal resistance which prevents any significant current flow thru the starter system.  The graph below shows a state of charge estimation on a battery at rest - not under any load. Battery terminal voltage of 12.6 volts (green) shows 100% charge. A voltage of 12.3 indicates about 50% charge. A voltage around 11.7 shows battery only charged to 10% of full capacity.

 

 

117batteryvolts_zps290596ea.gif

 

 

Load testing will reveal the hidden inner secrets of the lead cell. Either load test the battery with a load tester or measure the battery voltage WHILE CRANKING. If the battery voltage drops below 10 volts while cranking, you can be assured the battery requires replacement or desulfation. No amount of charging will help recover a sulfated battery left sitting over a long cold winter. A discharged battery has electrolyte that will freeze at a much higher temperature than a fully charged battery. A full charge may allow the battery electrolyte to stay unfrozen below -30F. A depleted battery can freeze solid almost as quick as plain water. Frozen electrolyte can crack grid holders in the cells - cracked and distorted grid plates cause internal shorts and therefore a permanent drop in battery voltage (a dead cell). As spring is here, some folks who did not have their batteries on tenders thru the winter may indeed be in for a surprise.

 

Don't make me send the Battery Badger out to the flatlands !!  He looks friendly enough with his half in the bag swagger and willingness to pull up a chair and "have just one more with the boys" attitude, but he gets real cross when folks start ignoring the basics of good battery maintenance and troubleshooting.

 

 

batterybadger_zps00e510c0.gif

 

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Well, I put a new battery even though I new it isn't charging.  When running it only reads about 9.7 volts.  I threw a new battery in because we are in the middle of new-to-us house projects and I'm just trying to stay up with the yard while doing a lot of other need to be done stuff.

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I've been doing a lot of reading the last couple days and I understand the theory:

 

 

Posted by Save Old Iron in September of 2010

 

The regulator makes 3 "electronic" decisions in order to keep the battery charged AND protect the generator unit from overheating / frying. 

Decision #1 

Let's look at the output voltage from the generator. If the voltage out of the generator is less than a "cut in point", (tractor not running or tractor is just starting up at low RPM's) , do not connect the regulator to the generator. Wait until the generator voltage rises above about 10 volts before you allow the regulator to control the generator. This decision allows the regulator to disconnect the battery from the generator to prevent the battery from being discharged when the tractor is turned off. 


Decision #2

Ok, the engine is running and the generator output is above 10 volts - the regulator is now connected to and is able to control the output from the generator.

Now let's monitor the battery voltage to see if it needs to be charged. There is a "voltage monitor" relay adjusted to stop the charge current to the battery if the battery voltage rises above the "regulator voltage set point". When the battery voltage reaches 14.x volts, the regulator stops calling for generator output. Current from the generator to the battery (thru the ammeter) is reduced nearly to zero charge current. Not zero current , but close. 

If the battery voltage drops down below a minimum voltage set by the regulator, the voltage relay energizes again and turns the generator on full blast again. Current from the generator goes full blast and proceeds to charge the battery back up to the "regulator voltage set point".

This cycle repeats and repeats while the tractor is running. This keeps the battery charged to 14.x volts.


Decision #3

While the regulator commands the generator to produce current, the regulator also monitors the amount of current flowing from the regulator (thru the ammeter) into the battery. Please remember the voltage and current limits are being monitored at the same time.

If the current demanded by the electrical system or battery exceeds a "maximum current flow set point", a different relay in the regulator opens up the field voltage to the generator and brings the charge current back down to nearly zero. This "maximum current set point" limits the generator output to its design limit (somewhere around 10 amps sounds about right). When the charge current falls below the max setting, the regulator slams the current back on again until the current thru the regulator again exceeds the maximum setting and then slams the current off again. Think of the current sense relay as a 10 amp self resetting circuit breaker that can cycle several hundred times per second. You may also think of this process as dimming the lights in your room by flicking the light switch on and off rapidly. No real dimming is taking place, just how long they are on versus off and thus a perceived change in brightness. Crude by today's standards but workable. 

This full on / full off cycling is what you see in the ammeter indication. 


Sooooooo............

either your regulator is toast, or needs adjustment

or

the battery is not capable of maintaining a charge and demands a constant charge greater than the 10 amps the generator can supply. 

The regulator is slamming the current on to 10 amps then slamming off to nearly 0 amps when the 10 amp limit is exceeded. This "slam cycling" happens several times per second. This on / off cycling of current is the vibration you set in the ammeter needle. You can try this with your battery charger by connecting the + charger lead to the battery and then disconnecting and reconnecting it as fast as you can. You will see the battery charger ammeter jump the same as the tractor ammeter.


I would fully charge the tractor battery so little if any charge current will be needed to charge the battery when the tractor is running. With a fully charged battery, the regulator may need to drip in a small charge, tripping the over voltage relay in the regulator when the battery reaches 14.x volts. That's normal operation. 

The charge current to top off a fully charged battery should be very small so the over-current relay should never have to engage in the regulator assembly.

Do a load test on your battery if the ammeter swings keep happening with a fully charge battery. The battery may charge to 14.x volts but it may not be able to keep the charge under load. Replace the battery if a charge cannot be maintained.

 

 

Would somebody mind posting a "how to test the voltage regulator"?

 

Thank you in advance.

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the regulator has only one control function  - grounds and lifts the ground from the field terminal on the starter gen unit based on the electrical decisions discussed above.

 

in its most simple form, an SG system test would be

 

remove the field wire from the SG field stud 

start the engine

measure dc voltage across the battery

if voltage is less than 12.6 then SG field circuit is not shorted to ground - ok

if voltage is above 15, the SG field is internally shorted to ground - high charge voltage is not being caused by a defective regulator - SG unit is capable of producing a charge but is not capable of being controlled by the regulator.

 

so far so good?

 

with engine running,

ground the SG field stud (which should turn on the SG full force)

the battery voltage should start to rise rapidly and should rise above 15 volts - do not allow the battery to charge at this 15 volt or greater level for more than a minute or two

if the battery voltage rises above 15 volts with the SG field terminal grounded, the SG is functional

if the battery voltage does not rise above 15 volts, the SG is defective

 

all good so far ?

 

then the issue will be the regulator or the wiring to or from the regulator

 

In its simplest for, that's all the troubleshooting you need.

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Excellent post sir!  Thank you very much.  When we got back from dinner last night I had charged the battery up good and started the engine.  I checked the battery voltage with it running and it was jumping around above 12v and spiking up around 21.7!  Of course this was with the Generator Field Terminal on the regulator connected to the SG stud because I had not read your post yet.  I really want to keep this 655 running tip top and not give in to a box store mower.  The 655 cuts my half acre great and the rear discharge hardly leaves clippings at all compared to other new side discharge mowers in the area.

 

Thank you for taking the time to help me out.

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