NL 8-11 Camper Upgrades

[lwgrubbs]

Super sweet setup. A little jealous of all the space in your camper compared to my Cirrus 620. I suspect in a few years we'll upgrade to a slightly larger truck camper that I can still get into the backcountry. Have you considered swapping to a 12v AC? I did this over the summer and it's an absolute game changer and I'm only running 400 AH of batteries. The heat option is a great backup or quick way to get heat in the camper in the mornings. Coupled with the DC to DC charger you can actually run this while driving down the road and not eat into the battery capacity, especially with all the solar you're running.

 

[ramv]

Short answer - DC-DC charging works great if you have a modern DC-DC charger. Old school ways are no longer acceptable.

In the really old days, when lead acid was the only choice, some people would directly connect the rv battery to the vehicle with a straight through cable. That worked, it would charge both batteries, but had a lot of down sides. Any short or draw would kill both batteries. The batteries had to be fairly well matched in capacity and age, or one would draw from the other. 2 batteries in parallel are a finicky thing.

To get around that, people then started installing relays and isolators. This helped get around the problem of one battery/vehicle having a problem and draining the other battery. But you still had problems with battery mismatches. Voltage drop over long runs was also a big problem as the rv battery would fail to full charge. This is why you can't just hook lead acid to lithium directly. They have very different voltages and internal resistance.

Then we get to actual dc-dc chargers. These handle all the previous problems. They isolate the batteries so one doesn't drain the other. The also boost the voltage at the RV battery to compensate for any voltage loss. Older dc-dc chargers can't handle lithium batteries.

But most of the newer ones can. Think of them as smart chargers. Newer ones will also limit current flow, which is critical as lithium batteries have low resistance. They will put a huge current draw on your vehicle alternate/battery and can do damage if not limited. Lithium batteries also need higher voltage than lead acid, so the dc-dc charge will give an extra boost in voltage up to what lithium batteries need over lead acid. Newer dc-dc chargers are needed to deal with smart alternators that can vary their charging, so that the rv batteries charge only when the vehicle is running and the alternator voltage is high enough to charge

This is really great information and a great summary. I do have a question that maybe is off topic, but if you buy a camper off the lot and plug into the 7 pin RV connection, assuming the camper is equipped with a lithium battery setup, does the truck or camper regulate the voltage or just rely on the fuses/CANBUS to shutdown excess draw of current? I have been considering a DC-DC setup for my RV as I already have 2 gauge wires to the bumper to a Anderson 175 connector with an isolator and relay triggered off the upfitter switches, but I am wondering the scenario just using the stock stuff.

 

[Phil314]

This is really great information and a great summary. I do have a question that maybe is off topic, but if you buy a camper off the lot and plug into the 7 pin RV connection, assuming the camper is equipped with a lithium battery setup, does the truck or camper regulate the voltage or just rely on the fuses/CANBUS to shutdown excess draw of current? I have been considering a DC-DC setup for my RV as I already have 2 gauge wires to the bumper to a Anderson 175 connector with an isolator and relay triggered off the upfitter switches, but I am wondering the scenario just using the stock stuff.

On older campers with lead acid, the 7 pin power is usually connected directly to a battery pos wire. Current in that case is somewhat limited by the small 7 pin wire and the vehicle. This is how my camper was setup. However when plugged into shore power, my converter/charger has a switch for SLA or Lithium. So shore power can charge either.

When I upgraded, I just completely disconnected the 7 pin. It only supplied 8-15 amps. With 600ah batteries, it would take weeks to charge them, so it's essentially useless. Plus many new trucks will turn off the 7 pin power after a few minutes.

If the camper come with factory lithium, then I'm guessing that either the 7 pin is disabled or it is run into the converter/charge just like the shore power is. Then the converter/charge will take care of it based on the SLA/LI switch. But that is still only charging at 8-15 amps, so not very helpful with a huge lithium batteries.

DC-DC converter really is the way to go with Lithium. My setup is #1 upfitter uses a solenoid to turn on power to my front bumper & bed mounted anderson connectors. Both wired with 1/0 cable to run a winch, sine wave inverter, or supply DC-DC power for the camper. I've got a 6ga wire from the bed to the camper and an Orion XS 50amp DC-DC inside the camper. It's fairly easy to hook up and takes care of everything. Can even turn it on/off with bluetooth as needed.

 

[ramv]

That makes sense, and I never really worried about it since all of my campers have onboard solar and I try not to travel at night so there is usually more voltage at the battery than the truck is providing anyway. DC-DC is the way to go for sure, it's not that expensive either other than the cables.

 

[Silverghost]

On older campers with lead acid, the 7 pin power is usually connected directly to a battery pos wire. Current in that case is somewhat limited by the small 7 pin wire and the vehicle. This is how my camper was setup. However when plugged into shore power, my converter/charger has a switch for SLA or Lithium. So shore power can charge either.

When I upgraded, I just completely disconnected the 7 pin. It only supplied 8-15 amps. With 600ah batteries, it would take weeks to charge them, so it's essentially useless. Plus many new trucks will turn off the 7 pin power after a few minutes.

If the camper come with factory lithium, then I'm guessing that either the 7 pin is disabled or it is run into the converter/charge just like the shore power is. Then the converter/charge will take care of it based on the SLA/LI switch. But that is still only charging at 8-15 amps, so not very helpful with a huge lithium batteries.

DC-DC converter really is the way to go with Lithium. My setup is #1 upfitter uses a solenoid to turn on power to my front bumper & bed mounted anderson connectors. Both wired with 1/0 cable to run a winch, sine wave inverter, or supply DC-DC power for the camper. I've got a 6ga wire from the bed to the camper and an Orion XS 50amp DC-DC inside the camper. It's fairly easy to hook up and takes care of everything. Can even turn it on/off with bluetooth as needed.

How do the camper brake and cab lights work without the 7-pin connection?