# Battery not re-charging



## seandil

Hello,
I have a '99 model Yardman model # 13AT604G401. Its a 17HP 46in. riding lawn tractor. I can not find a free service manual. Does anyone have the .pdf file?
Also, the mower will start, but the battery is not holding a charge. We have two batteries. One is placed in the mower, and the other is placed on a re-charger since the mower itself appears not to be re-charging either battery. 
I have a voltmeter/ ammeter, and need to know where to check to see if the recharging system on the mower is working properly. I simply need a procedure for troubleshooting this problem and then repairing it. I want to test each part that needs to be checked in some order and replace myself, the problem part.
I work on my car, motorcycle, and other mowers which are Honda self-propelled. I feel I can do this if I can get some instruction. Please help.
The engine does turnover, and crank. When in use about a half acre is mowed at a time over a three day period. Then after two to three weeks, the yard is mowed again the same way. The mower is operated at full throttle as well. I mention this since some troubleshooting guides I have read suggest that the mower is not used enough to re-charge the battery in some cases. I want a procedure to test this.

Thanks for reading this and helping outBye


----------



## Mickey

Not know your machine or the engine in it I can only offer general comments. Glad to read you have a multimeter and know how to use it. First thing, is to measure the voltage at the battery. Fully charged and at rest you should see ~12.7V. With engine running and at least half speed, you should see something on the order of 14V. Should be NO AC component with engine running. Any AC noted means there is a failed diode in the charging system.

Not know the engine and its charging circuit I can't offer and further advise.

If the charging system is working properly, there should be no reason why the battery is discharged to the point it can't start the engine after setting a couple weeks, bad battery excepted. There should be NO discharge taking place when the tractor is shut down and self-discharge rates are VERY low.


----------



## jhngardner367

There are 3 types of engines used on that model.A briggs/stratton single, A Briggs/stratton twin, and a Kohler single. Without knowing the make and model,it will be difficult to tell how to test the charging system. thw model # of the engine tells what type of engine ,and what systems,bearings etc. are used. Please try to post the #s and Mickey,or one of us, can try to help.


----------



## seandil

Sorry Gentlemen,
I am a novice. I downloaded an owners manual which calls this mower a model 604. I looked at the engines illustrated in the manual, and what's inside my mower. Mine is DEFINITELY the Briggs and Stratton Twin. I can tell this for sure by where I got the following numbers off the engine, along with the hatch or door on top of the engine that has the two plastic-top screws holding it down. Only the Briggs and Stratton Twin had this door, and location on the engine where these number were located on top of a metal piece on the left side.

Here's what I got off the engine:

Model 407777
Type 0128 E1
Code 990S5YG

Hope this helps and thanks again along with another sorry for not providing more info.:lmao:


----------



## jhngardner367

*engine*

That engine uses a 9-13 amp ac stator,located under the flywheel.It puts out about 30 volts,ac,which is then converted to dc voltage of 12-14 dcv,by a diode in the wires from the stator.There should be 2 wires coming out ,(probably red and black),and one will have the diode near the connector end.That's the dc wire.The other is ac current for the lights.Locate the wire with the diode.Then,with the wires disconnected,using a volt meter,touich the pins in the connector,one at a time,with the + lead of the volt meter,and touch the - lead to a ground.It shouldread 12 to 14 volts,dc.If it reads 28-30volts,the diode is bad,and must be replaced.It won't charge the battery,since it's ac volts,and low amps.


----------



## Mickey

jhngardner367 said:


> That engine uses a 9-13 amp ac stator,located under the flywheel.It puts out about 30 volts,ac,which is then converted to dc voltage of 12-14 dcv,by a diode in the wires from the stator.There should be 2 wires coming out ,(probably red and black),and one will have the diode near the connector end.That's the dc wire.The other is ac current for the lights.Locate the wire with the diode.Then,*with the wires disconnected*,using a volt meter,touich the pins in the connector,one at a time,with the + lead of the volt meter,and touch the - lead to a ground.It shouldread 12 to 14 volts,dc.If it reads 28-30volts,the diode is bad,and must be replaced.It won't charge the battery,since it's ac volts,and low amps.


I question your comment about testing the DC lead. The diode will only drop the voltage ~.6v. It is the load that will pull the voltage down. Hope you are not suggesting to take that measurement with the DC load, battery, disconnected but you appear to be saying that.


----------



## jhngardner367

The wire with the diode will put out 12-14vdc.Connecting the +probe of the voltage tester to the pin connector,and the - to ground,does not cause any harm,and gives the true voltage out put through the diode. Any reading above 14v,will mean it is ac voltage,thus the diode is bad. Ive tested these things this way for 20 years,and was shown this test at the factory training school.


----------



## dangeroustoys56

Some of my tractors do that - since i dont have voltage regulators on them - im thinking its bad diodes ( one way electrical switch from stator lead) - you can get them from radio shack for like .50 - just make sure theyre the 12 volt style.

Since i havent gotten around to changing the diodes - i just unhook the battery when it sits.

Another question- how old are these batteries? And are they a large enough cold cranking amp to handle a twin cylender? I use a 650 CCA car battery on my GT II craftsman with a 18HP brigs twin- cranks it over with no trouble - i used smaller CCA batteries on another twin and it wouldnt even crank it over.


----------



## seandil

Thanks gentlemen for your help,
Dangerous toys, the batteries are just what the dealership gave my dad. If you want specs I will check it out and let you know. Its his tractor and I'm just trying to keep him from getting ripped off anymore than he has. He's old.
Mr. Gardener, sir I will try your check and see what happens. Its sounds like I just set to ohms in the two digit range, and ground one of the leeds while using the other one to do the check? I will let you know what I find. 
If need be, I just go to Radio Shack and tell them I need a 12 volt diode? I mean they most likely will not know anything about lawn mowers, so I was wondering what other info they may need form me? I will not have the lawn mower with me when I go. 
I really appreciate your insight and taking the time to describe in detail what I need to do. Thanks again, sir.Bye

Y'all keep the do it yourself-er, doing it,
Sean


----------



## seandil

Oh Mr John Gardener,
This may be a stupid question, but I am a novice. What you are saying is find the wires from the stator, and check the one with the diode as you explained so well. 
Now, I am assuming that this is done with the mower, on and the engine running or is it done with the ignition switch simply turned on? I am guessing that for the stator to put out any charge, the flywheel must be moving so the engine should be running while doing these checks. I mean its not like checking battery voltage which I can do while the mower is off?

Just wanna be safe,

Sean


----------

