2016 Cub Cadet Challenger 750 Crew Battery Issues

[McMURDY]

Just joined this forum. I am a new owner of a used 2016 Cub Cadet Challenger 750 Crew. I bought it from a friend's wife after my friend suddenly passed away this Summer. We hadn't run it much since when he passed in July and I used it to do some light plowing on my driveway last month and a handful of times during hunting season. Then, we got blasted with bitter cold and 2 feet of snow last week and it wouldn't start. I assumed the battery was low (from JUN 2018) and put another lawn and garden battery on I had which was relatively new and unused. It runs a plow and a front and rear LED light too. It started right up with the new battery, but when my wife plowed with it for 10-15 minutes, it ran dead. It has 250 CCA (the previous one had 350 CCA). Not knowing any better, I jumped it with my car running and let that charge it for 1/2 hour but got the same thing....a few swipes with the plow and it was dead again. I left it on the charger overnight, hoping that will give it a full charge and that will take care of the problem but I don't want to find out it doesn't work when another storm comes. Should I get a new battery? What do you guys recommend that will run the motor, the plow and the extra lights and do you charge it often during cold weather? Wish my friend was around to ask him what he did but he's gone and I'm new at this.  Thanks!

[Travis]

The charging system should be taking care of that. Most UTV's come with at least a 10 or 12 amp charging system. usually around 15-20 amps,

When it's running at idle, check the voltage on the battery, it should be at least 13Volts DC and rise to about 13.5 or 14 when you raise the RPM's,  or you can find the stator(alternator) wires, they should read around 28volts AC at idle. also  most auto part stores should load test the battery for free to determine if the battery is bad.

[McMURDY]

Thanks Mule! The battery I pulled off it that my friend had been using was an Interstate with 350 CCA. I've got that on the charger and will meter test that. What is a reasonable charge without hooking it up to the UTV for idle? 10-12 amps? With two and a half years of sporadic use (though he was meticulous about maintenance), should this battery be recycled?

[Travis]

i always charge batteries up to around 12.5 volts before installing them.

What Horsepower is the engine?

[Ben1098]

You toasted the regulator.....NO CHARGE......motor running charge test voltage will be sitting at the battery's present terminal voltage......discharged say to 11.7v.  The regulator is a shunt type------dumps EXCESS voltage, thus current to GND.  The stator and the rectifier/regulator's output is "puny" compared to a light trucks RUNNING (100A area) alternator and 800 CCA battery.  NEVER hook up to a smaller system EVEN right after pulling into location to give a jump as the host battery is still at 13.6Vv  to 14.2V after shutting down engine.  The poor regulator is trying to HOLD it's setpoint regulated output voltage by dumping the excess.  POOF!  The potting shatters when a F350 Diesel with 2 batteries and 120A alternator (running of course) is the host.

Do a regulator diode test checking for F/B voltage on the 6 diodes from Y-Y-Y to R & B    i.e.   DIODE FUNCTION on digital meter to Y to R, Y to B.....times 3 for each alternator leg input......  .6v and OPEN.  This does NOT test the SCR (switches) that do the actual dumping of excess current.....might show up in test as .0000001v instead of .6v.

Killing off only 1 diode will result in only 1/3 the possible rated output.  SO, you could be charging at idle with lights and engine electronics load     BUT     the winch motor will take more than the system can recover BETWEEN the adjustments to the snow plow height....slowly discharge to a no start condition.   

[Ben1098]

Sorry, I forgot to mention that a shorted Regulator can overheat and burn off the insulation on the stator winding coils....usually takes out every 1/3 pole piece around the clock as it is a 3 Phase system.  Do a resistance test on the Y-Y-Y pigtail (regulator disconnected).  R = .3 ohm Y to Y (3 times).  If all 3 R readings are close, do a load test to mimic what the stator windings have to do in real life.  Test with engine running----no load VOLTAGE will be 25-30 VAC at idle and up to 80 or so at 4000 RPM.  LOAD TEST involves drawing current (POWER) off the 3 Y-Y stator pigtail leads.  I like a 40 W incandescent bulb screwed into a pigtail socket available at electrical/hardware/HD/Lowe's etc.  Touch any 2 of the stator output legs combinations (3X) and the bulb will glow at idle...30 VAC on a 120 VAC rated bulb.  SLOWLY raise the engine RPM....brighter and brighter....that is good.  On a hot 2 Phase system like H-D, you will be  buying a new bulb if not careful.