battery questions on my RF 176 mac Popup

[benfox49]

I have a 2018 Chrysler Pacifica TV. When I ordered a prewired 4 wire trailer wiring kit from e trailer the kit has an adaptor ,small sealed box , which needs a 12 volt input directly from the battery of TV.

The reason for this adaptor is to feed trailer lights from this adaptor instead of from TV taillights. A lot of newer vehicles use these ,they say to keep from overloading TV wiring.

So, the #12 wire I connected to battery to power this adaptor box, is only pulling enough current to power trailer tail and side lights.

So, when I bought my PUP camper I needed a 7 wire trailer connector, I bought an adaptor that plugs up to my existing 4 wire flat trailer connector on my TV to convert it to a 7 wire connector.

There are 3 extra wires on this adaptor plug, 1 is used to charge the battery
and needs to be connected to the TV battery.

So, my question is ,can I tap the #12 wire I already have connected to the TV battery to power both the trailer tail lights and charge the trailer battery?

I hope this explains it better.

Thanks,

ben

[jimmoore13]

Originally Posted by benfox49

Maybe you can answer another question I have about battery charging --
I have a #12 wire connected to TV battery feeding 12 volts to the trailer plug adaptor that comes in the wiring kit for TV .

Can I tap onto this wire to feed my battery charging connection pin on 7 wire trailer plug or will I need to run another #12 wire from TV battery to power this?


In other words will the #12 wire handle current to power both the adaptor on TV and the charging of battery?


Ben

If properly wired, your TV's 7 pin connector should already supply charging current to the trailer. Supplying that power directly from the battery to the socket with a dedicated, fused 12 AWG wire is fine, and it may supply more charging current than a conventionally wired system can. Note that it's highly unlikely that the harness to the 7-pin socket is 12 AWG. More likely 14 AWG.

But I would NOT CONNECT DIRECTLY TO THE RV BATTERY!! Your battery could easily suck 30 amps thru that connection if the battery is low...say at the end of your camping trip. See more below.

I do not know this for a fact, but it's my understanding that the Aux/Charging leg typically delivers about 7 amps. 14 AWG is massive overkill for 7 amps. I do NOT know how the draw is regulated, but I presume this is done at the trailer, and it's VERY unlikely that the Aux/Charging leg goes straight to the battery. A low battery is capable of drawing HUGE amps...thus the very large diameter "battery cables" on your TV's battery.

Others here should chime in, but I presume the Aux/Charging leg (pin 4) must be routed through the RV's converter/charger/fuse panel so that it controls charge rate pulled from pin 4...otherwise your RV battery could pull 30 amps or more and blow fuses or melt wires. 12 AWG would become a puddle with 30 amps flowing thru it.

Going REALLY far afield here, it's also important to note that a 3-way RV fridge running on 12 volts might easily consume all 7 amps and more. I no longer use the 12 volt function on my fridge, because when I arrived at my destination, my battery was always low....and that's starting cold with 24 hours on shore power before departure. The RV fridge is a HUGE power hog, because it must make heat to perform the conversion of the refrigerant to make the fridge cold. It's not a compressor system. It uses heat to achieve the refrigerant change of state. That's why it can run on propane...heat. Shore power is fine (essentially unlimited and 10x the voltage), and so is propane, but 12 volt draw can be 11 amps!!

A single 12-Volt Group 24 Battery...your run of the mill deep cycle typical with a small PUP...is rated at 75 to 80 AMP HOURS. You get to use about half of that before you start wrecking the battery. That means you get to use about 40 AMP HOURS TOTAL before you must recharge.

Driving down the road, delivering 7 amps from the TV and sucking 11 amps for the fridge PLUS the parasitic loads from the CO/Propane detector, your stereo head (if connected), and so on, let's say you're sucking a net loss of 5 amps. Over an hour, that's 5 AMP HOURS (AH). Let's say you drive 3 hours. You've drained 15 of your 40 AH before you get there. If you're boondocking, you're screwed! If you plug in to shore power, no big deal. Otherwise, you must have solar and/or a generator to restore your battery to survive the night and run the furnace and other draws.

Some will argue that, once cold, the 12 volt draw will be lower. Perhaps. My experience is that my battery is ALWAYS somewhat drained if I run my fridge on 12 volts while on the road. Once, when at my destination, I had trouble firing up the propane, and my battery was tapped out by the time I got it running. I had to run the generator for hours to charge the battery. I have solar, but it's useless if you arrive at your destination in late afternoon or early evening and your battery is tanked. In CO, in the mountains, the furnace runs in JULY, and then there's the pump, lights, ignition for the furnace, hot water heater, and fridge, parasitic draws, and, and, and. Starting the trip with a nearly dead battery is no fun.

But, if you do as most do and run the fridge on propane on the road, the only draw is that tiny amount to run the spark igniter. You arrive at your site with a fully charged battery. There are many threads about using propane on the road....you can search those out and weigh the options for yourself, but the broad consensus is to use the propane on the road. If you hit a tunnel or other "obstacle" that requires you to shut down the propane, run on 12 volts, or let the fridge act like a cooler for a short time, and shut it off.

So returning to your question. If you want to DIRECTLY charge your RV battery from the TV Alternator, you need to run HEAVY DUTY battery cable (due to the distance) directly from your TV battery ALL the way to the RV battery...with a super-heavy duty connector in the loop. This is typically 1/0 or 2/0 wire. (Plug)

This is why I presume the Pin 4 connection goes through the RV converter/charger/fuse system and trickles a charge to the RV battery while on the road. Without that regulation, your RV's heavily drained battery (on the home trip) would vaporize that connection to your TV.

[benfox49]

Jim & Renee,


I guess you didn't see my follow up post where I explained in more detail.

You say the 7 pin should already have Power to charge the battery, but as I explained in follow up post, my TV has a 4 pin connector that I converted to a 7 pin. So, I need to feed the 12 volts to that 7 pin charge wire on connector.
I assume my charging circuit goes through the trailer controller and not directly though battery.
So, I already have a #12- 12 volt wire hooked to TV battery which was needed to power the small control box that came with my 4 pin trailer wiring harness.[see my follow up post]

So, will this #12 wire handle the current draw from the trailer tail and marker lights and the charging circuit for trailer battery.
[assuming the charging goes through the trailer/ camper controller ,not a direct connection to TV battery]


Ben

[Bama Rambler]

Originally Posted by benfox49

I have a 2018 Chrysler Pacifica TV. When I ordered a prewired 4 wire trailer wiring kit from e trailer the kit has an adaptor ,small sealed box , which needs a 12 volt input directly from the battery of TV.
<snip>
So, when I bought my PUP camper I needed a 7 wire trailer connector, I bought an adaptor that plugs up to my existing 4 wire flat trailer connector on my TV to convert it to a 7 wire connector.

There are 3 extra wires on this adaptor plug, 1 is used to charge the battery
and needs to be connected to the TV battery.

So, my question is ,can I tap the #12 wire I already have connected to the TV battery to power both the trailer tail lights and charge the trailer battery?

I hope this explains it better.

That explains it a lot better!
The 12 awg wire that you have ran to the taillight adapter should be enough to keep the battery on the RV charged. The taillights on that RV isn't going to draw much current.

If it doesn't already have a fuse inline, I would be sure to fuse it.

[benfox49]

Originally Posted by Bama Rambler

That explains it a lot better!
The 12 awg wire that you have ran to the taillight adapter should be enough to keep the battery on the RV charged. The taillights on that RV isn't going to draw much current.

If it doesn't already have a fuse inline, I would be sure to fuse it.

I thought it should work, just wasn't sure how much current the charging controller on trailer pulled.

The 4 wire trailer wiring kit included a #12 wire for the adaptor I mentioned ,it came with an inline fuse ,but was only fused at 15 amps. #12 wire should handle 20 amps ,but maybe they didn't want the adaptor to be able to pull more than 15 amps.


I plan on replacing my trailer tail lights with LED lamps ,that should reduce current draw a lot. I wouldn't think lights and charging would pull more than 20 amps.


Ben

[pgandw]

Congratulations on your 176. It's a great way to camp without sleeping on the ground. And it's easily towed and managed.

I am not trying to be insulting, but the 176 is the Flagstaff entry level pop-up. Standard features on other models were options, or were not available on the 176. The option list includes electric brakes, a converter to charge the battery (comes with some options), the fridge, heater, electric water pump, and A/C. So the normal pop-up 12V electrical system could be a factory-installed option, or a home brew in a used 176. If you have the fridge, heater, or electric water pump, the electrical is a normal pop-up 12V system with a converter. If you have electric brakes, but no fridge or heater or electric water pump, they install a motorcycle battery to power the brakes, and no converter (it charges from the tow vehicle).

In pop-up and A-frame wiring using black/white wires, white is ground (negative), black is positive. When red/black wires are used (like boats and cars), black is ground (negative), red is positive.

In the Forest River plant, they often wire with wire pairs that have one white wire, and one with a color stripe. In that case, the color stripe should be positive, and the white is negative. That is actually not a bad system, as they use a different color stripe for each branch from the converter fuse panel. Of course, this assumes the Amish "electrician" understands the intended color coding.

You were given some misleading info regarding wire sizes and battery charging. Charging from a tow vehicle is voltage and voltage drop dependent. You have 2 batteries with very different charge and usage profiles both connected to the same alternator. The alternator senses the battery voltage(s) and regulates the charge voltage accordingly. The RV battery normally needs 13.7V or better to charge. 13.2V is a trickle charge to maintain an already full battery.

The problem with small wire sizes running the length of the vehicle is that the voltage drop because of the wire resistance masks the true voltage of the camper battery. #12 wire is very good, #12 wire is rated for 20amps in a non-enclosed space. #10 wire (rated 30 amps) would be even better (the biggest wire that will fit in most plugs, wire nuts, connectors, crimpers, etc).

A size 24 RV battery will not take more than 20 amps in charging current, no matter how much is available. However, if your fridge (if you have one) runs on 12V while towing, it is probably taking 10 amps. Whenever you stop for meals, refueling, etc., that 10 amps is flowing out of your battery without being replenished. With the resistance of the wiring, connectors, etc., very seldom will you see more than 15 amps actually going to the camper. And if the TV battery tells the alternator its fully charged, the alternator drops back to about 13.2V (from 13.8V), really reducing the charge going to the camper battery.

In my first A-frame, the fridge would not stay lit on propane while towing - the wind would blow the flame out - so I had to use 12V. I bought a wireless thermometer and put the sensor inside the fridge, and the readout in the minivan. While towing on the interstate, the fridge would usually drop into the 20s after a few hours. So when we stopped, I would turn the fridge off (if it was cool enough) to conserve battery.

Running and brake lights on the camper - I recommend converting to LED. The LED "bulbs" are readily available at car parts (relatively expensive) or on Amazon (much cheaper). If buying from Amazon, make sure the LEDs are rated for automotive use so they can take 14+ volts without frying. Also, pull a bulb out of the marker lights and measure size before ordering - some of the LEDs were too big to fit inside the marker light lenses on my A-frame. This reduces the lighting load from 6-7 amps (depending on number of lights) to less than 2 amps. Test to make sure your TV flasher handles LEDs OK (a few older ones do not).

Your proposed method of powering the 7 pin is fine. Again, I recommend #10 wire with a 30 amp normal fuse, or #12 with a 20 amp slow-blow fuse.

hope this helps
Fred W
Electrical Engineer, Purdue
prev: 2000 Coleman Lakewood PUP (12ft box)
prev: 2014 Rockwood A122 A-frame
now: 2019 Flagstaff T21TBHW A-frame
prev: 1993 Ford Explorer, no WDH (never again with no WDH)
now: 2008 Hyundai Entourage minivan, E2 600/6000 WDH, 205K miles
when the minivan dies: 2018 Kia Sorento V6, E2 600/6000 WDH
camping Colorado and adjacent states one weekend at a time

[Flybob]

Originally Posted by benfox49

I have a 2018 Chrysler Pacifica TV. When I ordered a prewired 4 wire trailer wiring kit from e trailer the kit has an adaptor ,small sealed box , which needs a 12 volt input directly from the battery of TV.

The reason for this adaptor is to feed trailer lights from this adaptor instead of from TV taillights. A lot of newer vehicles use these ,they say to keep from overloading TV wiring.

So, the #12 wire I connected to battery to power this adaptor box, is only pulling enough current to power trailer tail and side lights.

So, when I bought my PUP camper I needed a 7 wire trailer connector, I bought an adaptor that plugs up to my existing 4 wire flat trailer connector on my TV to convert it to a 7 wire connector.


ben

Be very careful accepting statements that "ALL" RVs use to a specific wire color standard. Most do but when in doubt check as some don't.

Also unless I am reading this incorrectly, you did not make any connections for trailer brakes. If your pup has electric brakes, you must connect them. 4 male to 7 pin female converters are not readily available as they allow unsafe connections.

[bikendan]

Yep, if the popup has electric brakes, you'll have to have a brake controller installed, including the 7-pin wiring to power the brakes, since it's obvious your minivan doesn't have the factory tow package.

[benfox49]

Originally Posted by pgandw

Congratulations on your 176. It's a great way to camp without sleeping on the ground. And it's easily towed and managed.

I am not trying to be insulting, but the 176 is the Flagstaff entry level pop-up. Standard features on other models were options, or were not available on the 176. The option list includes electric brakes, a converter to charge the battery (comes with some options), the fridge, heater, electric water pump, and A/C. So the normal pop-up 12V electrical system could be a factory-installed option, or a home brew in a used 176. If you have the fridge, heater, or electric water pump, the electrical is a normal pop-up 12V system with a converter. If you have electric brakes, but no fridge or heater or electric water pump, they install a motorcycle battery to power the brakes, and no converter (it charges from the tow vehicle).

In pop-up and A-frame wiring using black/white wires, white is ground (negative), black is positive. When red/black wires are used (like boats and cars), black is ground (negative), red is positive.

In the Forest River plant, they often wire with wire pairs that have one white wire, and one with a color stripe. In that case, the color stripe should be positive, and the white is negative. That is actually not a bad system, as they use a different color stripe for each branch from the converter fuse panel. Of course, this assumes the Amish "electrician" understands the intended color coding.

You were given some misleading info regarding wire sizes and battery charging. Charging from a tow vehicle is voltage and voltage drop dependent. You have 2 batteries with very different charge and usage profiles both connected to the same alternator. The alternator senses the battery voltage(s) and regulates the charge voltage accordingly. The RV battery normally needs 13.7V or better to charge. 13.2V is a trickle charge to maintain an already full battery.

The problem with small wire sizes running the length of the vehicle is that the voltage drop because of the wire resistance masks the true voltage of the camper battery. #12 wire is very good, #12 wire is rated for 20amps in a non-enclosed space. #10 wire (rated 30 amps) would be even better (the biggest wire that will fit in most plugs, wire nuts, connectors, crimpers, etc).

A size 24 RV battery will not take more than 20 amps in charging current, no matter how much is available. However, if your fridge (if you have one) runs on 12V while towing, it is probably taking 10 amps. Whenever you stop for meals, refueling, etc., that 10 amps is flowing out of your battery without being replenished. With the resistance of the wiring, connectors, etc., very seldom will you see more than 15 amps actually going to the camper. And if the TV battery tells the alternator its fully charged, the alternator drops back to about 13.2V (from 13.8V), really reducing the charge going to the camper battery.

In my first A-frame, the fridge would not stay lit on propane while towing - the wind would blow the flame out - so I had to use 12V. I bought a wireless thermometer and put the sensor inside the fridge, and the readout in the minivan. While towing on the interstate, the fridge would usually drop into the 20s after a few hours. So when we stopped, I would turn the fridge off (if it was cool enough) to conserve battery.

Running and brake lights on the camper - I recommend converting to LED. The LED "bulbs" are readily available at car parts (relatively expensive) or on Amazon (much cheaper). If buying from Amazon, make sure the LEDs are rated for automotive use so they can take 14+ volts without frying. Also, pull a bulb out of the marker lights and measure size before ordering - some of the LEDs were too big to fit inside the marker light lenses on my A-frame. This reduces the lighting load from 6-7 amps (depending on number of lights) to less than 2 amps. Test to make sure your TV flasher handles LEDs OK (a few older ones do not).

Your proposed method of powering the 7 pin is fine. Again, I recommend #10 wire with a 30 amp normal fuse, or #12 with a 20 amp slow-blow fuse.

hope this helps
Fred W
Electrical Engineer, Purdue
prev: 2000 Coleman Lakewood PUP (12ft box)
prev: 2014 Rockwood A122 A-frame
now: 2019 Flagstaff T21TBHW A-frame
prev: 1993 Ford Explorer, no WDH (never again with no WDH)
now: 2008 Hyundai Entourage minivan, E2 600/6000 WDH, 205K miles
when the minivan dies: 2018 Kia Sorento V6, E2 600/6000 WDH
camping Colorado and adjacent states one weekend at a time

Fred, WOW!

Thanks for taking the time to share all this good info. my camper does have the heater ,fridge ,water pump, converter,but no AC.

My battery wiring is white -ground and red-POS. I will either run my fridge on propane while driving or not at all. If I need to run a #10. wire I would just run another #12.


Ben

[benfox49]

Originally Posted by Flybob

Be very careful accepting statements that "ALL" RVs use to a specific wire color standard. Most do but when in doubt check as some don't.

Also unless I am reading this incorrectly, you did not make any connections for trailer brakes. If your pup has electric brakes, you must connect them. 4 male to 7 pin female converters are not readily available as they allow unsafe connections.

Mine does not have brakes. The 4 pin to 7 connector isn't any more unsafe than the connector between the trailer and the TV. Although I do plan to remove the connectors and hardwire them as soon as it warms up.

Ben

[jimmoore13]

I DID miss your follow-up post about the 4-pin to 7-pin conversion.

My thoughts:

• Your 4 pin connector's wires are adequate for the jobs they must do: ground, tail lights, and brake/signal lights.
• If you're going to run wire, while you're at it, run 3 separate wires from the new 7 pin connector to a spot under the hood, then run at least one of them into the driver's footwell to feed a future brake controller. Frankly, your Pin-4 Aux/charging circuit could be attached to a free spot on your TV fuse panel. And the "backup lights" circuit could easily power an LED backup light on the rear bumper of your PUP.
• All wires should be 12 AWG.
• If your rig has a converter, then it probably comes with a 7 pin male connector. If so, trust the factory wiring. If not, get instructions to properly install a 7 pin connector on the trailer. If it has a converter, I would be very surprised if it has a 4-pin connector on the trailer, because it would sacrifice on-road charging.
• I had a late '90's Viking PUP - 10' tub, no brakes, 12" wheels, very basic: but it did have a fridge, converter, charger, etc. It had a 7 pin connector. Your rig deserves one. It's not a utility trailer.
• Do not kluge some direct-to-the battery charging FUBAR. Do it correctly, and you won't have regrets.
• Also, if you don't have a brake controller (I know you don't need one), mark the wire you ran into the driver's footwell for future use....and DISCLOSE that your 7 pin connector is prewired for a brake controller when you sell your TV one day.
• If you must splice on more wire to extend the length of wires that feed your 4-pin connector (to reach the new 7-pin female), learn to solder, and use heat shrink tube to cover the solder joint. Crimp connectors are NOT well suited to "weather" duty. They are fine inside in the dry, but hanging out in the weather around the rear bumper is a horrible place to use them. If you don't know how to solder, it's worth it to learn and do a good job.

If you are going to run one wire, there's no reason to not run 3. Your TV can probably tow 3500 pounds. If so, your next rig may have brakes, and if you sell/trade your TV, the buyer will see the 7 pin connector and quite reasonably expect it to be wired correctly. It's no more work and little more expense to run three wires instead of one.

I wish you well with your "project." It may require a bit more effort than you expected, but you'll be glad you did it "according to Hoyle."

COMPLETELY UNRELATED TIP:
If you like to boondock, these PUP shake themselves apart. I've learned that Gorilla Glue on wood screws is a kind of "Loctite" for wood screws in wood or particle board. Every arrival begins with a scan for screws, nuts, bolts and camper pieces on the floor. Every time I replace something, I use Gorilla Glue. High stress items get bolts with nylock nuts. Sooner or later, everything that's going to fall apart will, and if you use Gorilla Glue, the next size up screw, and/or a bolt/nut, also sooner or later stuff will (almost) stop falling off. ALMOST.

[bikendan]

jimmoore, our two popups had no brakes and had a 4-pin connector harness. and they both had a converter.

[benfox49]

Originally Posted by jimmoore13

I DID miss your follow-up post about the 4-pin to 7-pin conversion.

My thoughts:

• Your 4 pin connector's wires are adequate for the jobs they must do: ground, tail lights, and brake/signal lights.
• If you're going to run wire, while you're at it, run 3 separate wires from the new 7 pin connector to a spot under the hood, then run at least one of them into the driver's footwell to feed a future brake controller. Frankly, your Pin-4 Aux/charging circuit could be attached to a free spot on your TV fuse panel. And the "backup lights" circuit could easily power an LED backup light on the rear bumper of your PUP.
• All wires should be 12 AWG.
• If your rig has a converter, then it probably comes with a 7 pin male connector. If so, trust the factory wiring. If not, get instructions to properly install a 7 pin connector on the trailer. If it has a converter, I would be very surprised if it has a 4-pin connector on the trailer, because it would sacrifice on-road charging.
• I had a late '90's Viking PUP - 10' tub, no brakes, 12" wheels, very basic: but it did have a fridge, converter, charger, etc. It had a 7 pin connector. Your rig deserves one. It's not a utility trailer.
• Do not kluge some direct-to-the battery charging FUBAR. Do it correctly, and you won't have regrets.
• Also, if you don't have a brake controller (I know you don't need one), mark the wire you ran into the driver's footwell for future use....and DISCLOSE that your 7 pin connector is prewired for a brake controller when you sell your TV one day.
• If you must splice on more wire to extend the length of wires that feed your 4-pin connector (to reach the new 7-pin female), learn to solder, and use heat shrink tube to cover the solder joint. Crimp connectors are NOT well suited to "weather" duty. They are fine inside in the dry, but hanging out in the weather around the rear bumper is a horrible place to use them. If you don't know how to solder, it's worth it to learn and do a good job.

If you are going to run one wire, there's no reason to not run 3. Your TV can probably tow 3500 pounds. If so, your next rig may have brakes, and if you sell/trade your TV, the buyer will see the 7 pin connector and quite reasonably expect it to be wired correctly. It's no more work and little more expense to run three wires instead of one.

I wish you well with your "project." It may require a bit more effort than you expected, but you'll be glad you did it "according to Hoyle."

COMPLETELY UNRELATED TIP:
If you like to boondock, these PUP shake themselves apart. I've learned that Gorilla Glue on wood screws is a kind of "Loctite" for wood screws in wood or particle board. Every arrival begins with a scan for screws, nuts, bolts and camper pieces on the floor. Every time I replace something, I use Gorilla Glue. High stress items get bolts with nylock nuts. Sooner or later, everything that's going to fall apart will, and if you use Gorilla Glue, the next size up screw, and/or a bolt/nut, also sooner or later stuff will (almost) stop falling off. ALMOST.

Jim,

My trailer does have a 7 pin connector. Unfortunately , my 2018 Chrysler Pacifica is only rated to pull 1500 lbs as it didn't come with a trailer towing package.


Your suggestion of using my fuse panel to power the charging circuit and backup lights is interesting because my 7 pin connector on TV has a back up light and buzzer and I want to connect it.

The backup lights are on my liftgate and wiring is routed through the headliner and tapping that wire is not an option.


I looked at fuse block but don't see a way to get a wire into it , looks like all the wiring goes into the bottom of block. Didn't want to unscrew the block to see underside ,too much of a chance of screwing up something,


If you know of a simpler way to get a wire into block I'm interested.


As far as learning to solder ,I've done a fair amount of it , I worked 40 years as a field service engineer for Bell&Howell and then for Eastman Kodak after they bought Bell&Howell co.
I'm also a cabinet maker and will be rebuilding the cabinets in camper when this damn cold weather ends. Trailer will fir in my garage but I only have 8" ceilings and top won't go up all the way.


thanks for your help and advice.

Ben