Originally posted by MidwestCamper
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For the benefit of the larger group and to provide a different perspective I did attach my grounding to the chassis at the rear of the TV. I thought about this quite a bit and finally concluded that, since the truck wiring is doing this everywhere, it must be OK to do. I think it really comes down to how one does the grounding and where attach point is. Like another post here I used a grinding tool to carefully remove all paint and I used a copper washer between the lug and frame to ensure a good contact. I also used a substantial self drilling screw with a lock washer. This is all very similar to what the truck maker did when grounding directly from the battery to the frame. For good measure I intend to cover the connection with liquid electrical tape. I can't imagine this ever failing. Moreover I believe the Renogy negative input terminal from the TV is electrically protected from the negative output connection to the Trailer (they are independent connections after all). This would imply that, even if the ground failed, the DC-DC converter would disconnect well before the 7-way connector wire overheats and melts.
For me the biggest concern is protection of the TV alternator. In my case the OEM alternator (2021 Jeep GC) is made by DENSO. The alternator states 230A but the reality is that this spec is tied to a specific RPM and the available amps drops with RPM. Although unconfirmed I was informally told the 230A is rated at 2000 RPM (I could not get it documented though). My concern is whether running at idle for extended periods the DC-DC converter will cause the alternator to overheat. That is, what the continuous use alternator is rating is at, say, 750 RPM. I had purchased both the 40A and 60A Renogy converters (Amazon had a low price on both) intending on returning the 60A if it was too much.
One would think this would be straightforward to figure out. But that is not the case. I couldn't get any decent technical information from either Chrysler or Denso. On the other hand Renogy assured me there would be no issue at all but with no substantive technical information to backup that claim. The poor English from the representative I was emailing back and forth with eliminated my confidence in their claim (offshore help?). In the end I ran a thermal test measuring the alternator temp while charging my battery bank and feel somewhat comfortable that the 72A or so being drawn from the alternator while feeding the ~60A to the Trailer batteries would not cause an issue at idle. When I get some free time I'll try to post the results of that test in case others can benefit. However, I'd love to see if anyone else running the 60A DC-DC converter had alternator concerns and how they alleviated them.
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