Kohler 20RESAL Whole house generator.

[drf256]

Good morning,

Looking for anyone familiar with these. Had a generator tech here who is a bit dumbfounded.

The generator runs well, but the controller shuts down if a charged battery is not connected. It is receiving 120V to the unit and to the clip to the controller, but the controller will not light up unless a charged 12V battery is connected. The battery will be drained by the unit quickly, as the unit isn’t trickle charging the battery back, nor is the controller being powered by anything but the battery.

The tech thinks it may be corroded connections, but I don’t see that. He is bringing a spare controller by to check it. If it’s the controller, a new one is $1200. A new unit is $4200. My unit is 7.5 years old already, but has under 200 hours on it.

My quick fix is gonna be a battery tender hooked up inside the unit to the battery from the 120V leads. If I can get another few years out of it, why not. Used controllers are around $500 on eBay, but I may be buying someone else’s problem.

Wondering if anyone else has been having this issue?

Thanks in advance.

 

[Deets066]

How else would generator fire up if it didn’t have a charged battery?

 

[Al Smith]

Just as a general rule ,any time you deal low voltage especially from a battery it doesn't take much corrosion to cause you problems .
About year ago I gave Georgia's oldest daughter a motorized tread mill my wife used before her health got bad .All it had done was sat in a dry garage .I thought the controller was bad but it turned out to be the clip on quick connections .I cut them off and pressed on new and that cured it .

 

[Stevetheboatguy]

Not sure if it is the same design as our generac. But ours had the voltage regulator go out and cause the same issue. What happened to ours was the blocking diode was fried by the battery maintainer running maxed out and the fix was a new tender, battery and rectifier. Was only about $150 for everything.

The maintainer was running maxed out because the battery had gone weak. Guess the extra amps were too much for the diode.

We learned our lesson and replace the battery every three years now.


Steven

 

[drf256]

I did have a battery go in the first 5 years. It may have taxed the unit.

After some research, and help from a few here, I came to find out that it’s a common issue. The Generac has a separate rectifier/trickle charger, but the Kohler charger is integrated into the controller unit.

The only thing that makes any sense is that the AC voltage coming in gets changed to 12-14DCV to power the controller. If it weren’t, the controlled would lose total power when the house power failed and therefore not be able to start. The battery back feeds or is in loop with this circuitry.

The tech is gonna try a replacement board, just to make certain that the pigtail connector is actually feeding the controller 120ACV. If a new controller works without battery voltage, it should be good presumptive evidence that the integral rectifier failed.

Batter Tender branded trickle charger is on order and will be added to unit in lieu of a $1200 controller.

Thank you for all the help.

 

[Al Smith]

I know nothing specific about this unit .How ever if it uses a small battery like a 20 plus HP lawn mower they don't last that long .You'll do good if you even get three years out of them .An automotive size maybe 5 at best .
Lead acid batteries do better if they are "exercised " in other words used on a regular basis rather than sit idle .Even with a trickle charge they aren't like being slightly discharged on start up and as a result gain some charge once in service . In essence you don't "buy " a battery you just rent it .