Quote:
Originally Posted by John 070
I extensively tested now and I can safely say just go to Costco and get the battery tender, but do not confuse this device with a power supply for coding.
My power supply I confirmed it never went to bulk 14.4v (again this is a bonafide RV power supply by WFCO). If the amperage were low it was around 13.8v, and even 20 amps it was doing 13.2v.
So let's say at 13.5 volts or thereabouts a battery has begun to float at 0.1 amps. My WFCO that can deliver 55 amps is overkill and it cannot be 100% efficient. So by that definition, to deliver only 0.1 amps, it will use more current than a 1A battery tender.
I actually tested my 3A battery tender on my reasonably drained Lexus sitting outside for 4 weeks undriven--it was doing 2.88A at 13.4 volts--my measurement confirms it's doing what it is supposed to. So a person asking this question could walk into costco, drop $40, leave, and never ask again lol
Me I'm testing everything because I'm curious by nature. I have a APC 1500SMTC in the box for 2 years. I pulled it out, and the battery is at 95%. Amazing. I plugged the gas dryer into it 
And saw the load go to 55%. The battery alone for this UPS runs roughly $150. I think its specs are 12V and 18ah, not sure.
I also popped a particular 20A breaker in the house plugging in my WFCO, and my WFCO into the APC. I believe both may have capacitors as not plugged into the wall the WFCO's fan starts up when connected to a battery.
seriously, I wonder how your Dell would stack up to this
This set me back $126 and again I tested it connected to the 335i with ignition and lights on, and it was delivering 20 amps to the car, at about 13.2 volts, exactly what's published...
https://wfcoelectronics.com/product/wf-9855-55-amp/ |
voltage and current are not the only metrics by which you judge a power supply.
and I tested it to 59 amps at 13.8 volts before it's overcurrent protection freaked out. It does take minor modifications to defeat the over voltage protections, and a resistor to then set the voltage.
using my fancy wattmeter for model airplanes that's really just a voltage shunt.