Voltage reading for a freshly charged 12V battery

[Dresden Guy 24]

Can anyone tell me the correct reading (or range) that I should get on my voltometer for a battery after charging for 24 hours. I am using the 0 - 20V DC range on the meter. Is 12.3V enough or should it be in the 13 - 13.5V DC range?

[JackC 617]

Full charge on a 12v battery is 12.6-12.8 volts. (2.1v per cell). If you want to know the condition of a battery it is best to have it load tested at a place that sells batteries.

Advance Auto will test for free and the test printout has a $5.00 coupon towards a new battery if you buy from them.

[BOWTIE 226]

IF YOU JUST UNHOOKED THE CHARGER AND TESTED RIGHT THEN. IT WILL BE 13-13.5 VOLT, IF YOU TEST IT AFTER YOU PUT A SMALL LOAD ON IT WILL DROP DOWN TO 12.2-12.6 VOLT. CHECK THE BATTERY CHARGER OUTPUT ALSO. GOOD LUCK

BOWTIE IN OHIO

[Save Old Iron 1,568]

Bowtie is correct, right off the battery charger, the battery will have a "surface charge" from the charger voltage being higher than the battery fully charged voltage. Right off the charger, a lead acid battery will show 13.something volts. If you drain the battery slightly by putting a small load to it, such as turning the headlights of the tractor on for a few minutes, the false "surface charge" is removed and the true voltage of the battery is seen.

One statement I disagree with is the "range" of 12.2 to 12.6v for final charge acceptability. A lead acid battery should read 12.6 volts fully charged. Even at sub freezing temperatures, the fully charged voltage remains over 12.5 volts.

On the state of charge graph below, a 12.2 volt reading (intersection of red lines) results in only a 40% charged battery. The intersection of the green lines show a 12.6 voltage reading at a 100% charge.

The orange and blue lines represent the voltage of a 100% fully charged battery measured ON THE CHARGER.

The c/40 charge ratio is the battery amp hours divided by 40. The c/20, c/10 and c/5 rate is battery amp hours divided by 20, 10 an 5 repectively. For the purpose of understanding, the c/40 rate would be a trickle charger around 1 amp. The C/5 rate would be a fast charge setting on the charger.

On a trickle charger, the 100% charged voltage would be (follow the orange line to the left) 13.5 volts.

On a fast charger, the 100% charged voltage would be 16 volts. This would represent charging the battery at over 6 amps of current.

The assumption here is a LGT battery is about 30 amp hours capacity. So if you are quick charging a dead battery on a 50 amp setting and the current flow thru the battery is higher than 6 amps, you better disconnect the charger when the battery terminal voltage gets to 16 volts. DO NOT DEPEND ON THE TIMER ON THE CHARGER - WATCH THE BATTERY TERMINAL VOLTAGE.

[Dresden Guy 24]

Thanks to SOI and Bowtie ........ I think I have it.

I think it's time I enroll in SOI University - is there an age limit? Do you accept Medicare A or B? Will a federal college loan be acceptable?

Parenthetically, my voltmeter is malfunctioning,(Greenlee multi-range + temp, etc.), specifically the 0-20VDC range. It will not "0", but fluctuates and the

"-" stays on indicating polarity. I replaced the 9V battery, but I see that there is a small fuse inside. Any thoughts what's wrong? That is of course the range I need for checking my battery, or even a fuse - aaargh!!

Also, now that I know you're back at the "Help Desk": My frustration all started after plowing our village sidewalks for 2 hours and then the tractor just quit. I needed the headlights, and shortly after turning them on, the battery would'nt crank S/G fast enough to start. After charging a battery to about 12.3VDC (had to use the 20-200VDC range to get this reading), that battery also would no start it. I could hear the solenoid clicking, but the S/G turned maybe 20rpm's but only for 10-15 seconds. I will check all the connections (maybe rusty/corroded), and check that the battery I install falls in the volt parameters. HELP!!!

[Rock farmer 41]

Dresden guy,

You will need to think of your electrical circuit as a loop from your positive battery post to your negative post.

Battery post to ignition key switch.

Switch to solenoid.

Solenoid to starter.

Starter to engine ground.

Engine ground (thru frame?) to negative battery post.

A bad connection anywhere along the path will give a bad result!

Also, voltage is not the same as cold cranking amps. Cold cranking amps is what turns the starter.

If your trouble started when you turned on the lights, I would suggest dis-connecting the lights.

That's my thoughts! Hope it helps!

Joe

[smoreau 658]

Sounds like your charging system is not up to par. It should run the head lights and charge the battery at full throttle. If your just at idle, or just above, it will not be enough power generated to charge the battery with the lights on. If this is your c160 that you have in your signature, It should have a 15 amp charging system. that is at full throttle for the 15 amps. the lights should be around 10 amps depending on what style you have. so with the lights on I always run 3/4 throttle or higher. connections at the regulator have always been a issue on my tractors if they are not tight.

[Dresden Guy 24]

Sounds like your charging system is not up to par. It should run the head lights and charge the battery at full throttle. If your just at idle, or just above, it will not be enough power generated to charge the battery with the lights on. If this is your c160 that you have in your signature, It should have a 15 amp charging system. that is at full throttle for the 15 amps. the lights should be around 10 amps depending on what style you have. so with the lights on I always run 3/4 throttle or higher. connections at the regulator have always been a issue on my tractors if they are not tight.

smoreau,

I'm think you are exactly right, but I need to sort out the PO's wiring labyrinth. Everything is vitually brand new, just not wired correctly. After looking up the original B-60, it had a K161, 7HP (recoil start - I believe), with an 8-speed unidrive.

The tractor is a B-60 that the PO restored, including changing the engine to what appears to be off an 856 or an 876, complete with S/G - Reg. - Solenoid. The PO also added an LED to the lights circuit. And I found that a wire from the lights switch was hooked directly to the "Neg" battery post. I need to find a S/G wiring diagram with solenoid. The only dash switches are the ignition and the toggle light switch.I will attach a couple of pics (not the best).

I have 7" of snow on the ground and my tractor won't start. I also can't bet my C-160/8 going (carb problem I think).

I'm frustrated, because I have always cleaned all the sidewalks in our village, but my only "seat time" is here writing for help to RS!! :banghead:

[smoreau 658]

Ok from the pics I can see that the ignition switch is wrong, that's why the relay was installed as the ignition switch can not hold the current for a starter generator. But wired right it should work just fine. I need some more pics of the wiring on your tractor. I will try and find the wiring diagram for my 875. that should work for yours.

[smoreau 658]

Can't find it any ware. You can down load it from the manual section near the top left of this screen. I used to 856 manual to kind of check your wiriing from your pik and it looks like it should work, except the loose wire tha'ts near the negative cable of the battery. Is that a ground? You should be able to run the tractor for a few hours on a fully charged battery. for know just charge it and get your plowing done.

[Dresden Guy 24]

Can't find it any ware. You can down load it from the manual section near the top left of this screen. I used to 856 manual to kind of check your wiriing from your pik and it looks like it should work, except the loose wire tha'ts near the negative cable of the battery. Is that a ground? You should be able to run the tractor for a few hours on a fully charged battery. for know just charge it and get your plowing done.

The loose wire is the lights that were connected to the Neg post of the battery. I have looked for a S/G wiring diagram that includes a solenoid. Any ideas which schematic that would be? Looks like none of the 60's, or even the early 70's. I will take a few more pics and try to actually make a schematic drawing....... I am going to try and get my C-160 going, it's likely a stuck float with the rubber needle valve. It did it once before..... a "skillfully" placed tap with a screwdriver handle.

Maybe I'll just hire the little old lady across who's out shovelling her sidewalk to do mine!!! "If it was raining soup, I'd have a fork" ARRRGH!!

smoreau, thanks for your input

[smoreau 658]

Ok from the pics I can see that the ignition switch is wrong, that's why the relay was installed as the ignition switch can not hold the current for a starter generator. But wired right it should work just fine. I need some more pics of the wiring on your tractor. I will try and find the wiring diagram for my 875. that should work for yours.

from what I see, it looks right. It has a solenoid because it has the wrong ignition switch. your switch can not handle the current of the system with out burning out. that's why you have a solenoid in your wiring. You will not find a wiring diagram for your set up as WH never wired one up like that. The correct switch is a Col-Hershey switch. it has larger screw terminals that can handle the current. It is possible to wire it with out the correct switch, and I think that is what the PO did. The lights power should have been powered from the far left terminal of the regulator. but off the battery will work also. This system does not put out a hole lot of power to charge a dead battery, it was more just to maintain a battery. As for your c160 I would recommend you take the bowl off and check for fuel and dirt in it. if there is a lot of stuff in it, then take a screw driver and screw in the needles and count the turns so when you remove them you can put them back in the same place. blow out the passage ways with compressed air. reinstall the needles and put a coffee can under the carb with the bowl off and crank the engine over. You should have fuel spilling into the can. if not you have a fuel delivery problem.

[Save Old Iron 1,568]

Not the best diagram but in a pinch

As a work around,

with a fully charged battery, you should be able to jump start the tractor by taking jumper cables from a good battery and grounding the black jumper cable directly to the bare metal on the engine block. The red jumper cable can be touched directly to the SG terminal with the large red battery cable from the solenoid. This will bypass the solenoid and ignition switch and start the tractor. Of course the ignition switch needs to be in the RUN position to allow voltage to power the ignition coil. Set your throttle and choke at appropriate settings prior to touching the red battery jumper cable to the SG "A" terminal ( the one with the large red wire attached leading to the starter solenoid).

SG should spin , tractor should start. When the tractor starts, remove the red jumper cable from the SG , remove the black jumper cable from the engine ground. The tractor should run long enough on battery charge to get most of your work done.

We will try not to eat the entire elephant in one bite. Let's get your major issue solved first - your plowing - then work on the starting issue - then the charging issue.

I'm back home for a few days - if you need help - just ask.