Renogy DC-DC Test Results-UPDATE 4 (Better!)
Updates 23 June--new test with Renogy input exposed for voltage readings Update 25 June more readings Update 4 - 27 June-- fewer amps with fat wire were noted this time! ----- I have the 20 ampe...
Forum Discussion
The 200AH bank at 50% SOC takes a long time to get up to Vabs at 14.7v. so it only got to 12.9v during the 45 min test with 15-20 amps of charging. If left on for hours and hours it would reach the 14.7 set on the Renogy.
After the test I turned off the Renogy and turned on the 55 amp converter set to 14.7v, which got it all done after a few hours.
The Renogy is buck/boost. An MPPT is buck only.
I didn't like the amps tapering down to 15 (could have gone lower if left running like that, don't know. ) Tapering was much slower by the time it got down to 15 so might have reached a bottom soon, don't know.
Also engine bay heat was climbing so truck voltage was also tapering. Might be related where input voltage got below the range the Renogy can convert (boost)
I could pull out the Renogy so I can access the input terminals, but would still need to install the ammeter somehow. I think the ammeter adds some R to the path, which I could measure across it (as taught here by Salvo back in the day), since you can see what the amps are.
It was out-putting max amps of 20 as rated showing 19.1 at the camper battery if you allow for some voltage drop on the wires from Renogy to the battery bank.
I don't care about the 30 amp draw as such for my scenario as long as I get the 20 amps out, but I need to run fatter wire to get that as seen in the test.
Those who want to reduce the amps draw on the alternator/engine battery by using fatter wire and still get rated output charging amps will not be able to use the OP test to see how that would play. Not sure I can re-arrange things to answer that. Have some other chores to get to meanwhile, so maybe somebody else can show that from actual results.
After the test I turned off the Renogy and turned on the 55 amp converter set to 14.7v, which got it all done after a few hours.
The Renogy is buck/boost. An MPPT is buck only.
I didn't like the amps tapering down to 15 (could have gone lower if left running like that, don't know. ) Tapering was much slower by the time it got down to 15 so might have reached a bottom soon, don't know.
Also engine bay heat was climbing so truck voltage was also tapering. Might be related where input voltage got below the range the Renogy can convert (boost)
I could pull out the Renogy so I can access the input terminals, but would still need to install the ammeter somehow. I think the ammeter adds some R to the path, which I could measure across it (as taught here by Salvo back in the day), since you can see what the amps are.
It was out-putting max amps of 20 as rated showing 19.1 at the camper battery if you allow for some voltage drop on the wires from Renogy to the battery bank.
I don't care about the 30 amp draw as such for my scenario as long as I get the 20 amps out, but I need to run fatter wire to get that as seen in the test.
Those who want to reduce the amps draw on the alternator/engine battery by using fatter wire and still get rated output charging amps will not be able to use the OP test to see how that would play. Not sure I can re-arrange things to answer that. Have some other chores to get to meanwhile, so maybe somebody else can show that from actual results.
