Bad battery charger on old QT02016?

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SFurst
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Fri May 03, 2019 11:33 am

Model: QT02016ANSN
LP Gas, Single Phase

I inherited an old (pre-Nexus) Generac 20kW liquid cooled generator when I purchased our home. It has had yearly service and generally seems to run well (haven't yet had an outage to really put it to the test). The battery died recently (age unknown) but it got me wondering: how do I tell if the battery charger is working? There are yellow and green LEDs on the battery charger board; the yellow is always on and the green is never on. After 48 hours with a new battery the unloaded voltage is 12.3, which seems low. If I disconnect the battery and check for voltage across the battery leads (which, I assume, would be connected to the charger) I get 0v.

How do I test the battery charger?

Thank you!
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Chris
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Fri May 03, 2019 7:33 pm

There are 2 fuses of different styles on that charger that you should check. You can see them both in the picture you posted. One is the small brown mini blade fuse and the other is under the white plastic cap next to it. Disconnect the harness to the charger before you do however. These chargers are pretty simple to test. If there’s power in and no charge voltage out, it’s probably toast if the fuses are good.
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SFurst
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Fri May 03, 2019 11:15 pm

Thank you -- I'll check. But where can I check the output of the charger? Seems as if the board is coated with something -- can't make contact with the solder points for the wires.
Chris
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Sat May 04, 2019 8:59 am

If you're not seeing it at the battery terminals I'd say you have your answer. If you post the serial number I can look up the wiring diagram and find out where the harness connects to the battery so you can test, but the green power light being dark is a bad sign if the fuses are good.

Another simple question though... Is the battery 120V input actually connected in the control wiring section??
Generac tech for over 12 years. I'm here to help!
"The only source of knowledge is experience" -Albert Einstein
Looking for Generac parts? Gentek Power offers the full line of Generac replacement parts! Shop Gentek Power Generac Parts
A list of my favorite Generator & Electrical Tools! https://www.amazon.com/shop/gentek_power
SFurst
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Sat May 04, 2019 8:54 pm

I think you may have hit the nail on the head -- doesn't seem to be 120v feed into the charging board. I assume this comes from T1 from the ATS, which is connected (and live) at the generator so not sure why it isn't making it to the board. And yes, both fuses on the charger are good. SN 4844760. Thanks!!
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