Renogy 20A dc to DC report
Hi All, Regarding the Renogy 20A DC to DC Battery Charger 12V, the unit puts out 20 amps, but draws 30 amps when doing so. This is the result of bench testing.
Forum Discussion
otrfun wrote:
The 3-4a drop in output current at idle vs. driving would concern me. This potentially indicates the alternator is unable to sustain the proper current/voltage at idle. In other words, the dc to dc charger may be overloading the alternator at idle. Every dc to dc charger I've installed has exhibited negligible to no drop in input current to the dc to dc charger when the engine is idling at, say, 750rpm vs. driving at 2000 rpm.
It is not an amperage issues.
As long as the alternator can sustain the MINIMUM input voltage to the DC-DC charger, it is a non-issue. Most of these chargers have a way to determine if the engine is running or not to prevent discharging the vehicle starting battery OR they need to be wired to a KEY-ON circuit.
An adjustable minimum input voltage might be useful.
