How To Install A Roadmaster Hy-Powered Diode On Trailer 7-way
Question:
I have the RM-690 diode. I have a trailer and installed lithium batteries and a new power converter. Ive read conflicting installation procedures for the RM-690 diode. Could you please be explicit with instructions? So far: 1 connect the positive wire from the trailer to the anode side of the diode and the other side to the positive wire of tow vehicle 2 connect the diode in the positive of the trailers 7-pin connector with the anode side facing towards the tow vehicle and, 3 severe the 12 volt hot lead from the deep cycle battery between the battery and 7-way connector. No reference to direction. One says: allows power to flow from tow vehicle to trailer batteries preventing backfeed to tow vehicle Second says: ensures that power can only flow from the trailer to the tow vehicle preventing reverse current Where should I place the diode and which direction? I would like to place it between the batteries and input to trailer if possible. Please help
asked by: Randy
Expert Reply:
Hi Randy,
Are you just trying to charge the trailer batteries from the tow vehicle's 7-way? If so you're using the 12v aux pin on the 7-way and could place the diode on the trailer side just before the junction box to prevent any current from backfeeding to the tow vehicle. The face of the diode has an "in" and "out" labeled on it. The "in" will be power coming in from the tow vehicle. The "out" would be the power going to the batteries. With these diodes current can only flow from in to out, if it ever went both ways then you'd know that the diode has failed and needs to be replaced.
That being said, you're not going to get a good charge for your batteries using just the 7-way. The 12v pin on the 7-way is typically low amperage so if you're needing more than just a trickle charge you'd want to look into a DC to DC battery charger like the Redarc BCDC. These come in a few different amperage ratings so you'd really want to determine your power draw/demand to size the charger. The smallest option they offer is 12 amps with the # RED96FR. If this is for a camper that you'd have plugged into shore power the trickle charge from your 7-way would likely be enough to get you by though.
If you have any other questions just let me know and I'd be happy to help.
Products Referenced in This Question
Redarc In-Vehicle BCDC Trailer Battery Charger - Single Input - DC to DC - 12V/24V - 12 Amp
- Battery Charger
- Battery Charger
- Dump Trailer
- RV/Camper
- Trailer
- Charges Only
- DC to DC
- 12V
- 24V
- Vehicle Battery to Auxiliary Battery
- Redarc
more information >
Product Page this Question was Asked From
Roadmaster Single Park Light Diode
- Accessories and Parts
- Flat Tow Wiring Harness
- Diodes
- Roadmaster
more information >
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Randy
11/13/2024
Kevin, I don't necessarily need to charge the lithium batteries from tow vehicle. My issue is that I seem to have received differing connection issues via research on the internet: a) It is generally recommended to install a diode between a trailer with lithium batteries and the tow vehicle to prevent reverse current flow and protect the to vehicle's electrical system. b) Install a diode to ensure that power can only flow from the trailer to the tow vehicle, preventing reverse current from the tow vehicle battery potentially damaging the trailer's lithium battery system. This seems to show a current flow in different directions. Am I correct? Also, a previous response to another customer question was: In your case, you will want the Roadmaster Single Park Light Diode part #RM-690 (which is what I have) to eliminate back feed. To install the diode, you will need to severe the 12 volt hot lead from the deep cycle battery between the battery and 7-way connector. The diode will need to be placed on the trailer. (Direction not stated.) This would be easiest for me if it protects the system. Would the "IN" be from the batteries and "OUT" towards the trailer 7-way connector? Sorry to be so confused on this one. ;)