Question on Energy Panel

[VACMAN]

On my MAGNAM energy panel.. 2008 DSDP.

Line one--------FLOAT CHARGING
Line two--------DC 13.8V 28A

My question is: I am plugged into a 120v 20 amp breaker. The last is for amp, I know that . But that 28A will change from time to time. Sometime I go by and it will be 17A.....5 Min later it may be 26A. This morning it said 0A..Why does it change etc. Explain

[Spikester]

Its the output of your battery charger that is part of your inverter/charger/power supply.

Spike

[VACMAN]

Do you mean the charger on my coach is putting out the different amps.. Not the power coming from my shore plug

[RVDude]

The charger will output different currents depending on battery needs/demand and which of the charger phases it is operating in (bulk, absorb, float, saver). Try this, boondock for a night and then plug in and the charger will probably output somewhere around 120amps in bulk charge mode (it's max depending on the model). Over time the charge will move through absorb charge (roughly the same higher amps as in bulk but at higher volts) and then into float/saver. As it moves into float mode it'll wiggle around between 0 and maybe 20 like you indicate depending on if you have a couple lights on or even the battery temperature (the colder it is the higher the "maintenance" amperage. It might even have an battery saver mode which is 0 amps until there is a change in the battery state.

To be clear, the display is indicating charger output, not shore power input.
To get an idea of what the charger is drawing from the shore use this example based on your display above...

13.8V * 28A = 386Watts ....
Most chargers have about an 80% efficiency rating so.... 386W/.8 = 482W are required from the shore - (the extra shore watts goes into heat generated by the charger itself)...
482W/120V (the incoming voltage to the charger) = 4.0A are being drawn from the shore line just for the charger at this (28A) charge level.

[VACMAN]

RVDude.......Thanks a lot.. Makes sense now

[John-D]

Quote:

Originally Posted by VACMAN Do you mean the charger on my coach is putting out the different amps.. Not the power coming from my shore plug

That is reading the output of the converter/charger, It is a combination of current flowing into the batteries (Charging) and any lights, or appliances that are drawing current in the coach.

As for power (or rather current) through the shore plug, The is a relationship, roughly 10 to one between 120 volt IN to the converter and 12 volt out. HOWEVER.. your shore power also involves power to the heat element in the fridge, VCR, Sat receiver, TV, Air conditioner, Microwave and a whole bunch of other things

So this display is kind of meaningless when it comes to shore power current or power