Progressive Dynamics Charging at Lower Wattage

Updated 07/01/2025 | Published 09/25/2024

Question:

Hi there, Ive had the pd4135kw2b for a couple of years now, and its been working great. However, lately Ive noticed its charging my system at lower wattage. It used to be Id plug into shore power and see that its charging with over 100w, but lately at some point itll go way down to 20-30w. Last night I toggled the lithium switch to off, then on, turned on the system, and it started charging fast, at 135W. This morning I see its down to 32W, with batteries only at 80 Nothing else in the system is charging at the same time. Im using Lithium batteries, with a 12V system. Just wondering if this is normal somehow, or what I can look into next?

asked by: Timothy

Expert Reply:

Hello Timothy,

I contacted Progressive Dynamics for you and they said 135 watts would only be around 9 amps or less depending on where you are measuring the wattage. You can check the output voltage at the PD4135 with a voltmeter to see if it is functioning correctly.

With the switch set to lithium there should be 14.4 to 14.6 VDC at the output no load. The wattage would drop if connections have become loose or corroded. Also circuit breakers and switches can age and increase resistance, lowering current and therefore wattage.

expert reply by: Kyle S

Timothy

9/30/2024

Ok, I'll get in there with the voltmeter and check some things. Regarding the 9 amps. Is that considered low, high? The wattage I was referring to is from the display of my shunt.

Kyle S.

9/30/2024

@Timothy Nine amps would be considered pretty low.

Tim

9/30/2024

@KyleS I just checked the output directly coming out of the unit and I'm only reading 13.2-6 volts. If I disconnect my batteries all my 12 volt systems still work, powered off of the unit directly. So I'm not sure what's going on here. I've only had this thing for a couple of years The AC output also works fine

Kyle S.

9/30/2024

@Tim Yeah, I really do not know what the situation is with the converter. At this point I'll have to refer you directly to Progressive Dynamics, who has far better knowledge of the inner workings of their converters. At this point I'd just be guessing and don't want to lead you astray.