Battery or other problem?

Discussion in 'Mechanic and Repair' started by hdtvluvr, Nov 17, 2007.

  1. hdtvluvr

    hdtvluvr LawnSite Senior Member
    Messages: 505

    Engine: Kohler Command Pro 25 CV730S

    A week ago I had difficulty starting the engine. It finally started before the battery died.

    Yesterday, I decided to put a charger on the battery before attempting to start it. This is the first time I have used a charger on that battery. The charger was set for 2 amps and it was on for about 15 minutes. The mower started and ran fine. I mulched leaves for about 1.5 hours without incident.

    Today I needed to finish mulching leaves so I started the engine without needing to charge it. I mulched leaves for about an hour and the mower died. When I tried to restart it, the engine would not turn over - like a low battery. I removed the battery and checked it with a voltmeter. It read 10.6v. I put it on the charger for about 40 minutes, put it back on the mower and mulched for about 30 minutes before the engine died again. I removed and charged the battery for about 20 minutes. It now read 12.6 v. This allowed me to get the mower started and I was able to get it to my shop.

    While the engine was running, I checked the battery with a voltmeter. It read 14.1v. The engine is on a 2004 dixie chopper. It does not have an electric clutch or other electrical accessories.

    Why does the battery voltage drop during use such that it will not start the mower? It seems that the charging system of the mower would keep it topped off especially since it appears to be working fine (puts out 14.1v).

    Is this a bad battery or do I have another problem?
  2. Restrorob

    Restrorob LawnSite Fanatic
    Messages: 11,029

    Take the battery to your local auto parts store and have them load test it, It sounds like you have a bad cell or a strap inside fixing to blow.

    Once you install a new battery re-check your charging system.
  3. hdtvluvr

    hdtvluvr LawnSite Senior Member
    Messages: 505

    So a low battery will cause the engine to die? I thought that the alternator on the engine would keep it running.

    I'll get the battery tested tomorrow.
  4. Restrorob

    Restrorob LawnSite Fanatic
    Messages: 11,029

    You must have battery voltage to activate the fuel cut-off solenoid on the carb, If the voltage drops too low it will shut the fuel flow off.

    The charging system puts out amps for charging, Not enough dc voltage for running equipment with a bad/no battery.
  5. hdtvluvr

    hdtvluvr LawnSite Senior Member
    Messages: 505

    Now I see why the engine would die. Thanks.

    The battery was the original one. I got a little over 3.5 years out of it. I guess it was time to go.
  6. fixer67

    fixer67 LawnSite Silver Member
    Messages: 2,098

    Almost all rectifier/regulators that are used on small engines are of the "Reference Voltage" type. They do not put out any power until they can 'see' the battery. If the rectifier/regulator does not detect at least 6 volts it does not switch on. You lose Reference Voltage and the rectifier/regulator switches off and the engine dies. Most common cause of this is a bad ground. If your bad has a lose plate in it this can cause this as well. WARNING=a lose plate can arc and cause a battery to explode. Have you battery test would be a good ideal

    By the way about 1 year is all most people get out of a mower battery
  7. hdtvluvr

    hdtvluvr LawnSite Senior Member
    Messages: 505

    Thanks for the information. I went to Northern Tools and got the same brand/size battery tonight. I haven't had time to install it yet - probably won't till after Thanksgiving.

    I have a wally world battery in my other mower. I hope I don't jinx it but I got it in March of 2005. I do not use a battery maintainer or charger on either of them with the exception of my original post above.

    I like the one from Northern tools. There hasn't been any corrosion on the terminals. While both of my batteries are maintenance free, the wally world one has 2 caps that aren't supposed to be removed. The Northern tools battery has a flat top and no caps. I clean corrosion off the wally world battery about once a year.

    I guess I've been extremely lucky with batteries.

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