Renogy 20A dc to DC report

pianotuna wrote:
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.

If you use large enough gauge cable, and your alternator voltage is high enough (relative to charge voltage), the Renogy dc to dc chargers can be almost 90% efficient. A 90% efficient 20a Renogy dc to dc charger would draw 22a from the alternator while producing 20a of charge current. A 40a Renogy dc to dc charger, 44a. A 60a Renogy, 66a.

Renogy's cable recommendations generally result in 70-80% efficiency. If you step up one gauge larger (physical size), one should get very close to 90%.

We have an approx. 20 ft run of 2 gauge cable from our alternator to our 40a Renogy dc to dc charger in our truck camper. It draws 44a from the alternator while producing 40a of charge current.