I am new to the forum and owning a 2003 Lance 815. Vehicle is 1992 F-250 7.3 IDI. Also inexperienced with electrical systems.My plan for the setup is almost always dry camping. So I am really wanting to get the battery charging system dialed in. I have already bought Lance's unique truck side male plug which I quickly learned I needed. My model does not have a built in battery isolator/separator.I hoped I could wire the lance plug directly into my 7 pin in the bed of my truck, but the trailer wiring has smaller than 8 gauge wire for the power wire and ground wire. I tried this and the running lights work, but I now know the smaller gauge hot wire and ground won't charge the camper battery. What do I need to do to successfully and safely wire my camper to the power generated when the engine is running? Some say wire 8 gauge or bigger directly from the truck battery via an isolator, some say from the alternator via an isolator. While others say just wire it directly to the windshield wiper motor. I will also have a solar panel (being shipped now), so ideally this will not be the only way my camper battery gets charged. Any advice, links, or previous posts I didn't find would be greatly appreciated. And apologies for my ignorance on what seems like such common knowledge info for experienced folks.

Check out Anderson Connectors.Linkaroonie

“I will also have a solar panel (being shipped now), so ideally this will not be the only way my camper battery gets charged”An adequate solar system will be all you need to recharge your house battery on sunny/semi sunny days. What system did you buy? Will it fit on the roof?

Search constant duty solenoid will bring up a few old threads, also a couple in the TCU sticky. Simplest and effective is using constant duty solenoid-triggered by ign hot. constant duty solenoidalso KKELLE14K post w/picOursI tied into battery, fused lead goes to solenoid, solenoids out goes thru thermal breaker then on to separate plug for camper. (ours will only accept 10ga)

Some very good basic information here:The 12volt Side of Life- Part 1.The 12 volt Side of Life- Part 2.

I use a 250 amp blade switch, mounted on the bolt that tightens the positive battery terminal on the truck. Then a 10 gauge wire to a lift gate connector, wired direct to the camper batteries. with a pair of 10 gauge wires for the ground. THe 10 gauge wire seems to be enuff, but I'm sure 8 or 4 g would be better. I only open the switch to protect the truck battery when I am going to be dry camping in one spot for more than 2 or 3 days without much sun to run the solar panels. What I like about the blade switch is that it is simple to install, reliable, I can take advantage of the truck battery capacity, and there is no measurable voltage drop. What I don't like is I have to open the hood and do it. I use a combo deepcycle/starting battery in the truck and a pair of 6v golf cart batts in the camper with 200w solar. I have never ran the batteries down enuff that the truck did not start, but I figure if I did, it should still start the generator to charge it back up.https://www.awdirect.com/knife-blade-battery-switches-for-side-terminal-batteries/battery-tools-accessories/

Truck to camper wiring questions | Good Sam Community

33 Replies

KKELLER14K
Explorer II
Mar 22, 2018
Wow..lol. I still believe that isolating the charge wire makes good sense and go big.Thanks for the revisit and shout out AnEv942. I can't believe some of my how to's are still out there but pictures are worth a thousand words and these subjects will always come up. Happy trails!!
bb_94401
Explorer
Mar 22, 2018
For those who want to learn way more than they ever knew existed about VRLA (Valve Regulated Lead Acid) batteries, a company called C&D Technologies has a "Resources Page" on their website where they have the following Technical Bulletins as PDF files.

By extension you'll also learn a lot about agm, gel and regular flooded batteries. For the most authoritative source for your particular battery, the "good" manufacturers have technical bulletins and technical people you can talk to if you have questions or need to put technical information in perspective.

VRLA Batteries

41-2128 Charging Regulated VRLA Batteries
41-2129 Constant Voltage Charger Selection for VRLA Batteries
41-2130 Recharging Time Determination for VRLA Batteries
41-2131 Charger Output AC Ripple and the affect on VRLA Batteries
41-6739 Gassing and Ventilation
41-7135 Capacity Testing VRLA Batteries (20 to 200 Ah Capacity)
41-7264 Integrity Testing
41-7271 Impedance and Conductance Test
41-7272 Self Discharge and Inventory Control
41-7327 VRLA Battery and their Application
41-7329 Life Expectancy and Temperature
41-7334 UPS Applications and VRLA Battery Sizing
41-7471 Operational Qualification and Warranty Registration Checklist
41-7546 10 Year VRLA Periodic Maintenance Instructions
41-7745 Lead Acid Battery Terminology Glossary
41-7944 Thermal Runaway In VRLA Batteries - Its Causes and Prevention
41-7952 Parallel Operations Lead Acid Batteries
41-7953 VRLA Batteries Electrolyte Freeze Protection
41-7954 VRLA Batteries Extended Run Time
41-7955 VRLA Batteries Engine Starting Applications

For those concerned with the causes and how to prevent thermal run away (aka blow the battery) you might find bulletin 41-7944 interesting.
cewillis
Explorer
Mar 21, 2018
Kayteg1 wrote:
cewillis wrote:
Those that want to learn -- will.

Not that easy. There is a lot in electricity that even professional electricians don't understand.
Like household wiring where 2 hot wires use single common.
Some houses had fire after electrician did some additional wiring.
With TC battery charging you have several factors, who interact and you can't judge one without considering the other.
- truck charging voltage (that on older trucks changed with rpm)
-voltage drop on long wire (that is changing depends on the amperage)
-max amp output the truck alternator can send
- max amp charge the battery will take without exploding
-time you have to charge the TC battery
- your choice of faster charge and shorter battery life, or the other way around?
Those are the issues I learned the hard way, even I never had intention to become electrician. I bet real pro will have more to add.

And those that don't -- won't.
Kayteg1
Explorer II
Mar 21, 2018
Grit dog wrote:
You’re blowing the whole exploding battery thing out of proportion. What makes you think the alternator will send more amps to the camper battery than it does to the truck batteries?

See, that is where subject knowledge apply.
And take it from the guy who did manage to blow the battery with high charge ;)
Coming to the point, truck batteries are always well charged, or they will not turn the engine over. So when alternator delivers ca 14V, the batteries being at 12.5 + V don't take high amperage.
Now when you run thick cable to TC battery discharged down to 10V, the full alternator power will go straight to it.
High amp = lot of heat and lot of potential something will blow.
Grit_dog
Navigator III
Mar 21, 2018
You’re blowing the whole exploding battery thing out of proportion. What makes you think the alternator will send more amps to the camper battery than it does to the truck batteries?
Kayteg1
Explorer II
Mar 21, 2018
cewillis wrote:
Those that want to learn -- will.

Not that easy. There is a lot in electricity that even professional electricians don't understand.
Like household wiring where 2 hot wires use single common.
Some houses had fire after electrician did some additional wiring.
With TC battery charging you have several factors, who interact and you can't judge one without considering the other.
- truck charging voltage (that on older trucks changed with rpm)
-voltage drop on long wire (that is changing depends on the amperage)
-max amp output the truck alternator can send
- max amp charge the battery will take without exploding
-time you have to charge the TC battery
- your choice of faster charge and shorter battery life, or the other way around?
Those are the issues I learned the hard way, even I never had intention to become electrician. I bet real pro will have more to add.
Kayteg1
Explorer II
Mar 21, 2018
The cigarette pack-sized jump battery alone will start my Honda 3000 generator.
Good flashlight too and saved my photo session when I run low on android charge.
Hemi_Joel
Explorer
Mar 21, 2018
mellow wrote:
Hemi Joel wrote:
I have never ran the batteries down enuff that the truck did not start, but I figure if I did, it should still start the generator to charge it back up.

I thought this myself, surprisingly the Onan generator takes a bit of juice to turn over. Ended up Having to get a jump start from a friend as I didn't feel like waiting for the solar to charge it.

After that I installed a Low voltage disconnect switch to my truck battery so it won't happen again.

I also carry one of those remote jumper packs that has a built in air compressor, 12v and 110 volt outlets as well. Just in case. I don't know how well it would do starting the cummins, but it should at least start the generator.
mellow
Explorer
Mar 21, 2018
Hemi Joel wrote:
I have never ran the batteries down enuff that the truck did not start, but I figure if I did, it should still start the generator to charge it back up.

I thought this myself, surprisingly the Onan generator takes a bit of juice to turn over. Ended up Having to get a jump start from a friend as I didn't feel like waiting for the solar to charge it.

After that I installed a Low voltage disconnect switch to my truck battery so it won't happen again.
cewillis
Explorer
Mar 20, 2018
Those that want to learn -- will.