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Discussion Starter · #1 ·
I just ordered a charger for the camper trailer that allows the alternator charging to safely charge a lithium battery.
I only got a 20 amp, but got me to thinking - had I got the 40 amp one would it blow fuses in the truck? The lithium battery will suck as much power as it can unlike a lead acid that just takes what it is given (for lack of longer description). Possible the lithium battery can pull too many amps and blow fuses.
What is the amp limit for the stock Frontier 7-pin trailer plug charging ability?

The plan is to have the Dc-Dc charger in the camper at the battery (and onboard power supply) and just connect the 7-pin as normal.
 

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I just ordered a charger for the camper trailer that allows the alternator charging to safely charge a lithium battery.
I only got a 20 amp, but got me to thinking - had I got the 40 amp one would it blow fuses in the truck? The lithium battery will suck as much power as it can unlike a lead acid that just takes what it is given (for lack of longer description). Possible the lithium battery can pull too many amps and blow fuses.
What is the amp limit for the stock Frontier 7-pin trailer plug charging ability?

The plan is to have the Dc-Dc charger in the camper at the battery (and onboard power supply) and just connect the 7-pin as normal.
with ignition on, pin 5 (battery) on the 7 pin connector is fused at 30a through trailer tow relay 2 and pin 2 is the ground.
 

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Aside from the 30 amp fuse in your Frontier, I would be surprised if the 7-pin hitch receptacle, mating plug and umbilical on your trailer are capable of handling more than 30 amps without overheating.

Also, most trailers have a fuse or circuit breaker at the battery end of that charging wire that may be the limiting factor. For example, mine is just 20 amps.

The larger DC-DC converters are more commonly used on motorhomes, where there isn't a hitch connector involved.
 

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Discussion Starter · #4 ·
Thanks. yes, is my concern that a 30 amp fuse is mated to a 10 amp wire in the truck. I have a 20amp Dc-DC charger so at least is not going to be a huge draw. The trailer I built the electrical so it is ample other than the purchases 7-pin connector.

Thanks for the diagram.
 

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Thanks. yes, is my concern that a 30 amp fuse is mated to a 10 amp wire in the truck. I have a 20amp Dc-DC charger so at least is not going to be a huge draw. The trailer I built the electrical so it is ample other than the purchases 7-pin connector.

Thanks for the diagram.
fuses are always rated below the wire to protect the wire. the factory wire can handle a 30a draw or they would have fused it lower.
 

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Hopefully this is the case on Nissan, on other trucks it is not.
it would be criminally negligent for any manufacturer to allow more power (oversize the fuse) to flow in a circuit that the wiring can handle.

that is the sole job of fuses - to prevent too much power from flowing in a circuit and they are always sized to protect whatever is the weakest link in the circuit.
 

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I just ordered a charger for the camper trailer that allows the alternator charging to safely charge a lithium battery.
I only got a 20 amp, but got me to thinking - had I got the 40 amp one would it blow fuses in the truck? The lithium battery will suck as much power as it can unlike a lead acid that just takes what it is given (for lack of longer description). Possible the lithium battery can pull too many amps and blow fuses.
What is the amp limit for the stock Frontier 7-pin trailer plug charging ability?

The plan is to have the Dc-Dc charger in the camper at the battery (and onboard power supply) and just connect the 7-pin as normal.
I built a custom lithium pack for my small camper and decided to put a decent sized inverter in the front of the bed (I have a cap) and run 120 ac to the trailer. There's a transfer switch that gives me three types of shore power.
1 shore power
2 truck inverter
3 trailer inverter

I don't have a genny but this gives me lots of flexibility. I can charge everything that I have (300 AH) in 6 hrs of driving.

best wishes
 

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^That's an interesting solution.

There are some electrical losses in converting 12VDC to 120VAC in the truck - and in converting it back to 12VDC in the trailer - But you could still transfer a lot more power with it than you could at 12 volts through an ordinary 7-pin trailer hitch connector.
 

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^That's an interesting solution.

There are some electrical losses in converting 12VDC to 120VAC in the truck - and in converting it back to 12VDC in the trailer - But you could still transfer a lot more power with it than you could at 12 volts through an ordinary 7-pin trailer hitch connector.
Skibane-
thanks for the reply
and thanks for all the great stuff that you do here

With a 10 gauge marine grade cable , and nice movie industry connectors between the truck and trailer, I can easily get from the front of the box to the back of the trailer, because it's 120 v.

As a tradesman, I like having the 3000 w inverter in there. And the chargers all work off 120 anyways. The limiting factor in the system is the spare power produced by the alternator. There's not much at idle, but quite a bit once you get over 2500 rpms, as I understand it. When we're traveling, plenty.
 
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