Charging a trailer battery from my current National Luna PPP feed?

dgarber

New member
I have a National Luna Portable Power Pack in the bed of my truck. I am getting a camping trailer and would like to charge the trailer battery while driving. Can I plug into the 50a High Output gray connector on the Portable Power pack with a National Luna or Redarc DC to DC charger to charge the trailer battery? I would locate the DC to DC charger on the trailer. Or, would I be better or installing an Anderson Y plug and bypassing the PPP for the trailer charger? Please let me know how this can be done. Thank you.
Doug
 

john61ct

Adventurer
OK, let's start by saying no uses one battery to charge another.

Yes the physical connections are often attached within the source circuit directly at the terminals of a battery on that side, for good reason.

But, the actual **source** of the charging energy is the alternator, a mains charger, a solar setup etc.

The connecting device (e.g. DCDC charger, but not necessarily) only closes (combines) the two circuits when a source like that is active, usually by a direct external switch (solenoid / relay / contactor opening, electronic signal) or by an internal circuit with VSR/ACR functionality.

OK.

So, I take it you want whatever source(s) keep(s) your power pack (battery) in your bed charged,

(your stock truck alternator?)

to also charge the House bank in your trailer?

There is no reason for the power pack to participate in this, since the more robust and cheaper Starter batt is already available to act as a buffer.

You need a robust and very thick gauge wiring infrastructure from the alt circuit, perhaps direct from the Starter posts, all the way back to the trailer House bank.

Likely you will need / want a DCDC there to overcome the resulting voltage drop.

Andersons do make good connectors.

If the connection from the starter circuit to the power pack is **very** robust and thick gauge wiring, it would be possible to charge both target banks at the same time, but I'd actually check the continuity, resistance and voltage drop of all the components carefully, at every point along the way.
 

dgarber

New member
OK, let's start by saying no uses one battery to charge another.

Yes the physical connections are often attached within the source circuit directly at the terminals of a battery on that side, for good reason.

But, the actual **source** of the charging energy is the alternator, a mains charger, a solar setup etc.

The connecting device (e.g. DCDC charger, but not necessarily) only closes (combines) the two circuits when a source like that is active, usually by a direct external switch (solenoid / relay / contactor opening, electronic signal) or by an internal circuit with VSR/ACR functionality.

OK.

So, I take it you want whatever source(s) keep(s) your power pack (battery) in your bed charged,

(your stock truck alternator?)

to also charge the House bank in your trailer?

There is no reason for the power pack to participate in this, since the more robust and cheaper Starter batt is already available to act as a buffer.

You need a robust and very thick gauge wiring infrastructure from the alt circuit, perhaps direct from the Starter posts, all the way back to the trailer House bank.

Likely you will need / want a DCDC there to overcome the resulting voltage drop.

Andersons do make good connectors.

If the connection from the starter circuit to the power pack is **very** robust and thick gauge wiring, it would be possible to charge both target banks at the same time, but I'd actually check the continuity, resistance and voltage drop of all the components carefully, at every point along the way.


john61ct,
Thank you for the quick detailed response. Your knowledge is appreciated. The portable power pack came with a wiring kit. It included 7m of 16mm2 (6awg) red/black cable along with a 100amp fuse. One end of the wires is terminated on my main battery posts, with the fuse on the hot side. The other end runs to the bed of my truck and has a 50amp Anderson plug. Would this wiring be considered robust enough to use for charging my truck bed battery and the trailer battery? Could I use an Anderson Y splitter? I would then run an extension cable to the trailer that would plug into a DC to DC Charger or some sort of isolation solenoid. By the way, my truck is a 2016 RAM 2500 with a 220amp alternator.
Thanks again for you assistance!
Doug
 
Last edited:

dgarber

New member
This is the setup I am looking at. Sorry for my crude drawing. My question is...what is the best way to connect the trailer to the truck? Y adapter on current 6awg feed in back of truck or do I need to run another set of of cables from the truck battery to the truck bumper? Also, if I used a Y adapter, is the current 100amp fuse ok or should I install a 40amp fuse on the side feeding the trailer?
Thanks.
Doug
 

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