17 Navion Towing CRV

CoreyinWP · 01-05-2021, 06:41 PM

Getting ready to set CRV up for towing. Am I understanding correctly there is no 12v available in the 7 pin on the Navion to use for charging? Any workarounds if that is correct?

Winterbagoal · 01-05-2021, 06:51 PM

My understanding is that most 7 pin connectors do have a "hot" 12V DC pin. It's position may vary by manufacturer. Whose towing setup are you going to use? My Blue Ox rig has a charging circuit/pin. I had it installed by my RV dealer, and my Wrangler's battery does get charged while towing it.

CoreyinWP · 01-05-2021, 06:59 PM

I am referring to the sprinter/Navion trailer plug. Some postings have indicated there is no 12v to get for charge line.

Winterbagoal · 01-05-2021, 07:50 PM

Can you see my signature? I'm not sure which pin/hole it is in my Navion, but there is a 12V DC "hot" pin/hole. The Blue Ox rig uses it to charge my Wrangler's battery while we're traveling.

CoreyinWP · 01-05-2021, 07:56 PM

Excellent...thanks for clarification. Will start working on early next week.

Winterbagoal · 01-05-2021, 08:06 PM

Try doing a search for 2017 Sprinter View/Navion 7 pin connection diagrams. It will show you which one is the"hot" pin/hole. IIRC, it may be the 12 o'clock postition?

BigTexEd · 01-06-2021, 07:46 AM

My 2020 View chassis owners manual says to NOT use it for charging a battery. I'm trying to come up with a DC to DC boost charger to do this very thing.

CoreyinWP · 01-06-2021, 08:27 AM

My 2016 manual says a little different.

"You can connect accessories with a maximum power consumption of 240 w to the permanent power supply. You must not charge a trailer battery using the power supply"

Goes on to talk about complete discharge when trailer is not switched off.

Think it would be ok for a toad and trickle charge though??

Winterbagoal · 01-06-2021, 08:31 AM

Quote:

Originally Posted by BigTexEd

My 2020 View chassis owners manual says to NOT use it for charging a battery. I'm trying to come up with a DC to DC boost charger to do this very thing.

That's interesting. Just about everyone does it.
I wonder why? I'm thinking something has been lost in the translation between German engineering and North American functionality. If you aren't supposed to charge the "trailer battery" with it, then what is it's purpose?
Where will you get the DC power to run the DC to DC charger?
Perhaps, if you're not going to use pin 4 to charge your towed's battery, a simple mechanical disconnect on the towed's negative battery terminal will preserve it's SoC while traveling.

Winterbagoal · 01-06-2021, 08:37 AM

Quote:

Originally Posted by CoreyinWP

My 2016 manual says a little different.

"You can connect accessories with a maximum power consumption of 240 w to the permanent power supply. You must not charge a trailer battery using the power supply"

Goes on to talk about complete discharge when trailer is not switched off.

Think it would be ok for a toad and trickle charge though??

That's what my manual says, more or less. See my other post.
I'm using pin 4 to charge the Wrangler's battery while underway, with no discernable negative effects, whatsoever. It's simply a bridge connection from one 12V DC battery to another 12V DC battery, afaik.

BigTexEd · 01-06-2021, 08:49 AM

Quote:

Originally Posted by Winterbagoal

That's interesting. Just about everyone does it.
I wonder why? I'm thinking something has been lost in the translation between German engineering and North American functionality. If you aren't supposed to charge the "trailer battery" with it, then what is it's purpose?
Where will you get the DC power to run the DC to DC charger?
Perhaps, if you're not going to use pin 4 to charge your towed's battery, a simple mechanical disconnect on the towed's negative battery terminal will preserve it's SoC while traveling.

I'm an electrical engineer, so I can postulate.

You are not supposed (in my professional opinion) to use the "+" from the 7 pin to charge any battery no matter the chassis. It's unregulated. It's very little current. I have measured 1 to 3 amps on many occasions. You can maintain a motorcycle battery with this, but not a deep cycle automotive battery. No way. It's fools gold to think you can use this wire to magically charge your toad battery.

You can use this same wire to boost the DC current (voltage). As an input to a boost circuit, this works. The input current is 1-3Amps (max 5) and the output is 15 Amps to 20Amps. This is the amount of charge that is needed to charge a battery.

Winterbagoal · 01-06-2021, 03:21 PM

Quote:

Originally Posted by BigTexEd

I'm an electrical engineer, so I can postulate.

You are not supposed (in my professional opinion) to use the "+" from the 7 pin to charge any battery no matter the chassis. It's unregulated. It's very little current. I have measured 1 to 3 amps on many occasions. You can maintain a motorcycle battery with this, but not a deep cycle automotive battery. No way. It's fools gold to think you can use this wire to magically charge your toad battery.

You can use this same wire to boost the DC current (voltage). As an input to a boost circuit, this works. The input current is 1-3Amps (max 5) and the output is 15 Amps to 20Amps. This is the amount of charge that is needed to charge a battery.

I'm an actual user with 3 years of anecdotal experience, and I can tell you with complete confidence, that I've done it with 2 different motorhomes, one Ford and one Sprinter with no discernable negative effects. When I get to my destination, I unplug the towed. If I need to go somewhere in the towed, I put the key in the ignition, start the engine, and off we go. The Wrangter's electrical system isn't running anything except my Patriot II brake system, and it doesn't draw much current from the Wrangler's battery during travel.
Good luck with your DC to DC charger plan.

CoreyinWP · 01-06-2021, 03:47 PM

Excellent discussion and feedback from all. I am now armed with the info to do my install! Thanks to all.

Elkman · 01-08-2021, 12:06 PM

For charging using the trailer wiring it is a good idea to replace the power wiring with 10 gauge wire running to the 7-pin connector. The wiring provided is meant to power the running and brake lights and not to do a DC to DC charging of the trailer. Also a good idea to have a relay installed so the toad does not drain the coach batteries or to remember to disconnect it whenever possible.I would expect that this would be covered by the people doing the installation work.

There should be no need though to charge the battery of the CRV as it has its own alternator to charge the battery while the engine is running. I would take a small 6 amp battery charger and an extension cord to charge the battery if it cannot hold a charge and to replace the battery before it fails completely.

With my 2021 Navion a car as heavy as the CRV puts me 1000 lbs well over the GCWR for the Sprinter 3500. At best our Navion could tow something like the Fiat 500 or the Honda Fit and safest with a Smart ForTwo that has a curb weight of 1,800 lbs.

If planning to have a toad with a Class C motorhome one built on the Ford F-450 chassis is a wiser choice as there is a gain of 4,750 lbs of GCWR or more as compared to the Sprinter cab chassis vehicles. This is something that no one mentions when comparing various motorhomes.

AZ Okies · 01-10-2021, 09:28 PM

We towed a Honda Pilot with a 2014 Navion, and now tow a CRV with a 2019 View, both towed fine and have never had to charge the battery on the toad. We take out the brake controller and charge it inside the MH at night when on the road. On the pilot we had to start it every 350 miles anyway but the 2014 CRV we don’t have to. We use a Blue Ox tow pkg and brake assist.

ldfeat · 01-11-2021, 08:25 AM

Quote:

Originally Posted by Winterbagoal

I'm an actual user with 3 years of anecdotal experience, and I can tell you with complete confidence, that I've done it with 2 different motorhomes, one Ford and one Sprinter with no discernable negative effects. When I get to my destination, I unplug the towed. If I need to go somewhere in the towed, I put the key in the ignition, start the engine, and off we go. The Wrangter's electrical system isn't running anything except my Patriot II brake system, and it doesn't draw much current from the Wrangler's battery during travel.
Good luck with your DC to DC charger plan.

Ditto on that! I've been doing this for 20 years with 2 coaches and several toads. But I think the term "charging" is overused here. I'm really not "charging" my toad battery, but just maintaing the SOC while going down the road. The small 2-3 amp "tricklecharge" is enough to keep my toad battery topped off over a couple two or three days of unhooked-overnight towing. Larry, 2014 Reyo P

Shedboy · 01-11-2021, 09:58 AM

Quote:

Originally Posted by Elkman

For charging using the trailer wiring it is a good idea to replace the power wiring with 10 gauge wire running to the 7-pin connector. The wiring provided is meant to power the running and brake lights and not to do a DC to DC charging of the trailer. Also a good idea to have a relay installed so the toad does not drain the coach batteries or to remember to disconnect it whenever possible.I would expect that this would be covered by the people doing the installation work.

There should be no need though to charge the battery of the CRV as it has its own alternator to charge the battery while the engine is running. I would take a small 6 amp battery charger and an extension cord to charge the battery if it cannot hold a charge and to replace the battery before it fails completely.

With my 2021 Navion a car as heavy as the CRV puts me 1000 lbs well over the GCWR for the Sprinter 3500. At best our Navion could tow something like the Fiat 500 or the Honda Fit and safest with a Smart ForTwo that has a curb weight of 1,800 lbs.

If planning to have a toad with a Class C motorhome one built on the Ford F-450 chassis is a wiser choice as there is a gain of 4,750 lbs of GCWR or more as compared to the Sprinter cab chassis vehicles. This is something that no one mentions when comparing various motorhomes.

Agree completely. Have a 2012 Navion, occasionally tow a flatbed trailer w onboard battery over Rocky Mountains. Installed 12VDC 10ga wire to trailer plug to power trailer electric brakes. The added trailer weight is clearly RV abuse and I feel relieved when I reach my destination with no problems.
An alternative is to install a "battery maintainer" in the towed vehicle and plug it in at each stop either to shore power or the RV generator.