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 > DC-DC Charging ?

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noteven

Turtle Island

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Joined: 02/13/2011

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Posted: 02/23/21 07:02am Link  |  Quote  |  Print  |  Notify Moderator

The cleanest connector I've figured so far is the trolling motor 3 pole - + and - from vehicle battery plus + wire to turn on the DCDC charger.

On my pickup there is no need to wire into the cab from the battery. I think I can get where I need to go by using long booster cables wire as it is joined and easy to protect inside loom.


I've seen a video where the owner jumped the DCDC turn on from the + battery cable coming in. He said this works but you have to remember to unplug the tow vehicle or the RV will continue to draw on the starting battery of the tow/haul vehicle.

DCDC chargers are also isolators so current on flows one way from the starting battery.

Again, any I've seen are supposed to be install close to the batteries they are charging.

Yes it would be super convenient to have it on the truck because I have 2 trailers with batteries and a truck camper.... I'm thinking of a weather proof enclosure where it can still cool somewhere near the rear of the truck.

When I'm done wasting time on that idea I'll throw hat on the ground and order more chargers [emoticon]

In Europe these are called "Battery to battery" or B2B chargers - which kind of explains what they are for.

vermilye

Oswego, NY, USA

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Posted: 02/23/21 08:11am Link  |  Quote  |  Print  |  Notify Moderator

Do remember that if you have a TT with a break away switch and add a DC to DC charger in the 7 pin charge line, since it is a one way device the trailer battery will no longer be connected to the switch. Same problem if your electric tongue jack is connected to the 7 pin charging wire. You will need to add a new wire from the trailer battery to the break away switch.


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BFL13

Victoria, BC

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Posted: 02/23/21 08:11am Link  |  Quote  |  Print  |  Notify Moderator

Keeping the charger to house battery wires short will help preserve the charger's voltage settings for each type of battery as instructed in the manual for using the dip switches.

Voltage variations on the longer run from the unit to the starter batt should be taken care of by the unit's buck/boost as I understand it.

You could make the unit portable by using MC4s on its input and output wires?

EDIT--the breakaway on a trailer puts the trailer's brakes on right from the trailer's batt (not to be fused), nothing to do with the 7-pin.


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vermilye

Oswego, NY, USA

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Posted: 02/23/21 08:29am Link  |  Quote  |  Print  |  Notify Moderator

BFL13 wrote:

Keeping the charger to house battery wires short will help preserve the charger's voltage settings for each type of battery as instructed in the manual for using the dip switches.

Voltage variations on the longer run from the unit to the starter batt should be taken care of by the unit's buck/boost as I understand it.

You could make the unit portable by using MC4s on its input and output wires?

EDIT--the breakaway on a trailer puts the trailer's brakes on right from the trailer's batt (not to be fused), nothing to do with the 7-pin.
While I agree that the break away switch should be an unfused run from the trailer battery, (and mine now is), my trailer came with the break away switch connected to pin 4 of the 7 pin connector. Maybe this is allowed in Canada?

BFL13

Victoria, BC

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Posted: 02/23/21 08:44am Link  |  Quote  |  Print  |  Notify Moderator

Good that you fixed that! Not allowed anywhere AFAIK.

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