The stock 12 volt wire on the 7-way plug.

[Priherd]

Originally Posted by JerryP

Most of this post was a response in another thread about the Orange and black wires that run from under the drivers dash back to wiring harness near the 7 pin trailer plug. The wires stop 1 foot from the trailer plug. The rest of this response seemed like it belonged in this thread too. Regards, Jerry

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I have just completed adding a power wire to my 7 pin trailer plug. I will use this wire to charge the battery on my Toad (Toyota Tacoma). My Tacoma is wired with an RVI "Towed Battery Charger". This charger will draw a maximum of 15 AMPS at 12V. Normally it pulls much less.

The orange and black wires route up under the drivers dash near the emergency brake release. Mine had a label that said "Tow Plug Trailer Wiring". I used the orange wire to run my power to the Toad. You have to dis-assemble the trailer Plug. All pins except one will have a wire attached. The empty plug pin matches the standard for the +12V trailer power feed. I attached the orange wire to this pin. My trailer plug was attached to the coach with pop rivets. These will need to be drilled out and replaced with #10 machine screws. You will also need a couple of feet of 14 gauge stranded wire to extend the Orange wire. You can buy this wire by the foot at Home Depot. (they sell Orange wire too)

There is another bundle of 5 or 6 wires under my dash. These are for wiring a Trailer Brake controller. The Blue wire in this bundle also runs back to the trailer plug. It is connected to the standard brake controller pin.

Getting the +12V power under the dash is pretty easy on my Baystar. Newmar has an auxiliary fuse box located under the dash just above the drivers left foot. It's a rectangular box with several automotive fuses installed. There are several open slots for fuses. I picked an "AUX" fuse position near the bottom of the fuse box. It was also labeled 15A. Just to the edge of the fuse is a lug that a spade lug will push over. These are standard crimp on lugs that you can get at any auto store or Home Depot. Crimp a lug on the Orange wire. Push the spade lug over the lug post on the fuse box. I installed a 15 AMP fuse in the AUX position. This 15 AMP fuse matches the wire gauge and trailer plug current capacities. I ordered a special fuse that is resetable. If an overload occurs, the fuse opens up. When the overload fault clears, the fuse restores itself. A regular fuse should work too. The 12V is only active when the ignition is on. When you turn the key off, the 12V is removed.

I went through several complicated options before I discovered this approach. It is actually pretty simple.

Hope this helps.

Jerry - 2013 Bay Star 3002

Jerry, I have a 2011 Newmar Canyon Star 3920. I spent today figuring out most everything you said here! (wish I would have seen this post first) Anyway, a lot of people talk about putting a Auto Reset Circuit Breaker between the power supply and the 7 pin plug. Is the 15AMP resettable Fuse providing the same protection?
Thanks for your post!

[Algoma]

Well, according to Newmar there is no 12v on that 7-pin socket. I am attaching the Newmar engineering drawing to confirm what they told me. Luckily I discovered that Freightliner had installed that 12v on their chassis but I don't know what Ford provides on the gas chassis.

[JerryP]

Yes this resetable fuse provides protection. By putting it in the fuse box, it provides protection for the full wire route under the motorhome and onto the toad. Here's the full product name: "15 Amp Bussmann ATC Circuit Breaker Modified Reset"

I purchased it from wiringproducts.com

Here's the product link:

15 Amp Bussmann ATC Circuit Breaker Modified Reset - Wiring Products

[JerryP]

Originally Posted by Algoma

Well, according to Newmar there is no 12v on that 7-pin socket. I am attaching the Newmar engineering drawing to confirm what they told me. Luckily I discovered that Freightliner had installed that 12v on their chassis but I don't know what Ford provides on the gas chassis.

I talked to Newmar twice and Ford F53 Motorhome tech support also. No one seems to know exactly what's on each coach when it come to this wiring. The Newmar engineering is correct that +12V is not on the 7 pin plug. What they didn't tell you that a usable wire is only 1 foot away and the other end of the wire is also 1 foot from a fuse panel with spare locations.

Regards,

Jerry 2013 Bay Star 3002

[Mr_D]

Originally Posted by HicksRA

Not sure about your Bay Star, but I was surprised to find that there is no 12v wire tied into the 7 way plug on my 05 DSDP. The factory did not run one. I had to run a new wire into the plug to supply 12v from it over to my toad for charging its battery. I figure if it's even a trickle, it should help keep the battery up.
This is what I installed on mine:
Robot Check

Yep, found that with our '02 DSDP on Spartan. Got 2 30 amp resetting fuses and wired one in at the MH end and one at the towed end. Used 10GA wire although 8 would have been better but not necessary. In fact the 30 amp fuses are overkill! But it works so I'm not going to change it out.

[JerryP]

In a previous reply I said:

"Yes this resetable fuse provides protection. By putting it in the fuse box, it provides protection for the full wire route under the motorhome and onto the toad. Here's the full product name: "15 Amp Bussmann ATC Circuit Breaker Modified Reset" "

I probably need to expand on this a little more. I decided this after reading some of the early posts on this thread. Someone suggested that the resetable fuse could be of similar use as a diode or other protection device. These don't really do the same thing. The resetable fuse protects from high currents caused by some type of short or other electrical malfunction. This is very important. The fuse will open up before the wire decides to fry or burn.

It's also important to isolate the toad electrical system from the RV electrical system. I use the RVI-Brake Towed Battery Charger. This provides proper charging of the toad battery system and provides isolation between the toad and RV. Either RV or Toad could have it's engine running or turned off with no ill effects. Running a heavy gauge wire with no other protection between the RV and Toad is asking for problems. A Diode between the RV and toad prevents the Toad from damaging the RV, but the RV could still do a lot of damage to the Toad electrical system. I don't have any affiliation with RVI, I just use their product. I was an electrical engineer in my pre-retired life.

Regards,

Jerry 2013 Newmar Bay Star 3002 / 2004 Toyota Tacoma

[Dutch Star Don]

I liked the idea of the toad charging systems that have all of the protection built into one kit. There are several. What I didn't like about them is that they typically require their own wiring harness. The first one I bought, years ago, had it's own harness, but really cheesy plug ends.

I like to keep things simple. I prefer to wire everything through one umbillical cord. If that requires a seven pin plug on both vehicles, so be it. On my vehicles that required charge power, I added a fuse at both ends of the wire and a diode in between. One way charge to toad and protection at both ends. Just my preference.

With all that said, I've found that none of my three toads ever needed power. I also run separate bulbs versus using diodes.

[BFlinn181]

Originally Posted by JerryP

In a previous reply I said:

"Yes this resetable fuse provides protection. By putting it in the fuse box, it provides protection for the full wire route under the motorhome and onto the toad. Here's the full product name: "15 Amp Bussmann ATC Circuit Breaker Modified Reset" "

I probably need to expand on this a little more. I decided this after reading some of the early posts on this thread. Someone suggested that the resetable fuse could be of similar use as a diode or other protection device. These don't really do the same thing. The resetable fuse protects from high currents caused by some type of short or other electrical malfunction. This is very important. The fuse will open up before the wire decides to fry or burn.

It's also important to isolate the toad electrical system from the RV electrical system. I use the RVI-Brake Towed Battery Charger. This provides proper charging of the toad battery system and provides isolation between the toad and RV. Either RV or Toad could have it's engine running or turned off with no ill effects. Running a heavy gauge wire with no other protection between the RV and Toad is asking for problems. A Diode between the RV and toad prevents the Toad from damaging the RV, but the RV could still do a lot of damage to the Toad electrical system. I don't have any affiliation with RVI, I just use their product. I was an electrical engineer in my pre-retired life.

Regards,

Jerry 2013 Newmar Bay Star 3002 / 2004 Toyota Tacoma

Originally Posted by Dutch Star Don

I liked the idea of the toad charging systems that have all of the protection built into one kit. There are several. What I didn't like about them is that they typically require their own wiring harness. The first one I bought, years ago, had it's own harness, but really cheesy plug ends.

I like to keep things simple. I prefer to wire everything through one umbillical cord. If that requires a seven pin plug on both vehicles, so be it. On my vehicles that required charge power, I added a fuse at both ends of the wire and a diode in between. One way charge to toad and protection at both ends. Just my preference.

With all that said, I've found that none of my three toads ever needed power. I also run separate bulbs versus using diodes.

Could you explain to me what protection is needed beyond a current limiting auto reset circuit breaker on each vehicle? JerryP, you said you connected to an ignition switch circuit. Doesn't that isolate the two vehicles when the RV engine is off? You also recommend two 15 amp modified reset circuit breakers. Beyond the switched source and circuit breakers, what does the +$50 RVI-Brake Towed Battery Charger do to protect the system?

Two 12 v battery systems, charged up, will have minimum current flow between them when connected together. As the toad battery is depleted, the charging system of the alternator in the RV will replenish it. The only time a large imbalance would happen when the RV starter is engaged. The circuit breakers would limit current to no more than 15 amps. As soon as the RV engine is started, the breakers would reset and charging and equalizing of the batteries would result. Even if the toad where started still connected to the RV, again the circuit breakers would limit current flow, but having it wired to an ignition switched circuit would also prevent back feed unless the RV ignition was left on.

I'm just wondering, what extra 'protection' does one of these devices add? The LED light(s)? I'd mount it under the hood so the light wouldn't be visible unless the hood was up? They might have a diode in them to prevent current flow back from the toad to the RV, but that's not needed unless connected to a not-switched 12v source in the RV. I'd really like to know what the 'protection' is in these devices over the auto reset breakers.

TOAD-CHARGE Dinghy Vehicle Battery Charger/Maintainer

RVibrake Towed Battery Charger, charge line replacement

By the way, since they don't actually charge, only 'regulate' the charging current from the RV alternator, I think they are wrongly named 'chargers.'

[USMCRET]

Sometimes I buy things and use products because I know they work and give me a certain level of confidence and peace of mind. I don't always completely understand them nor care to. My toad charge fits this category, as would just about anything 12V related. YMMV.

[Dutch Star Don]

Bob......The idea is to keep both units safe. Theoretically, if the toad's battery or the RV battery(s) went dead while parked overnight, one could draw down the other. Since it's a relatively large charging wire, you certainly don't want to accidentally short it to ground, hence the fuse protection on both ends, since you have current flowing at both ends.

Realistically, you could just run a large wire between the two vehicles without any protection. The units that are being sold are made primarily for people who want the protection and don't want to make their own or have the expertise to make their own. As I said, I like the products, I just don't like running extra umbilical cords and I didn't care for the cheesy connectors on the one I bought.

[JerryP]

--> Bob, I put your text first and "-->" before my responses that follow.....

Could you explain to me what protection is needed beyond a current limiting auto reset circuit breaker on each vehicle? JerryP, you said you connected to an ignition switch circuit. Doesn't that isolate the two vehicles when the RV engine is off? You also recommend two 15 amp modified reset circuit breakers. Beyond the switched source and circuit breakers, what does the +$50 RVI-Brake Towed Battery Charger do to protect the system?

--> A current limit of 15A is pretty large. In the case of the RV and the Toad running their engines at the same time, both regulators in the alternators would be fighting each other. This can confuse their regulation circuitry and possibly cause damage. Also, I think that I only put one reset circuit breaker in my circuit. The RVI Towed battery charger is a regulator that is designed to charge an automotive battery. It will provide a heavy charge, when the battery needs charging, but cuts back to a trickle once it come up to voltage. The Towed Battery charger is not damaged when the Toad alternator drives the battery to a higher voltage than the RV provides.


Two 12 v battery systems, charged up, will have minimum current flow between them when connected together. As the toad battery is depleted, the charging system of the alternator in the RV will replenish it. The only time a large imbalance would happen when the RV starter is engaged. The circuit breakers would limit current to no more than 15 amps. As soon as the RV engine is started, the breakers would reset and charging and equalizing of the batteries would result. Even if the toad where started still connected to the RV, again the circuit breakers would limit current flow, but having it wired to an ignition switched circuit would also prevent back feed unless the RV ignition was left on.

--> The problem with both vehicles running, is that the regulators in each alternators would be fighting each other. There could be damage.


I'm just wondering, what extra 'protection' does one of these devices add? The LED light(s)? I'd mount it under the hood so the light wouldn't be visible unless the hood was up? They might have a diode in them to prevent current flow back from the toad to the RV, but that's not needed unless connected to a not-switched 12v source in the RV. I'd really like to know what the 'protection' is in these devices over the auto reset breakers.

--> An alternator/regulator combo is somewhat similar to a power supply. The alternator gets its voltage/power from a drive belt from the engine and it generates 12VDC, while a power supply gets it power from 120V AC plug on the wall. Some power supplies are designed to be run in parallel, but they are much more expensive and have special circuitry to insure that the output regulators don't destroy themselves. Since I don't know the characteristics of your RV or Toad, I can't really say for sure if tying them together with a 15A fuse will cause damage or not. I can guarantee that using a RVI Towed Battery Charger between the RV and Toad that you will not have any problems. There may be other chargers out there besides RVI, I am only familiar with them. You also mentioned the LED on the RVI Charger. It's just an indicator that the RV is supplying voltage to the charger. It's helpful when you are checking your wiring and connections to the RV.

By the way, since they don't actually charge, only 'regulate' the charging current from the RV alternator, I think they are wrongly named 'chargers.'
-->True - all chargers are regulators. They are designed to charge your Toad battery and not damage it by overcharging.

Regards,
Jerry 2013 Newmar Bay Star 3002 / 2004 Toyota Tacoma

[BFlinn181]

I'd like to know how, "The RVI Towed battery charger is a regulator that is designed to charge an automotive battery. It will provide a heavy charge, when the battery needs charging, but cuts back to a trickle once it come up to voltage." the RVI device creates the extra energy to provide a heavy charge? If true, they could solve all the world's energy issues!

All the other protections you mention would be covered by one simple action: Disconnect the umbilical cord before starting the toad. That's what I always do, never been an issue or caused an inconvenience. Just as I have to remove the auxiliary brake from the driver's floor to access the clutch pedal, I disconnect the umbilical cord.

[Dutch Star Don]

Bob....I think you're taking some terms literally. Obviously, it's not the unlimited power source the world is looking for. Your RV charges your batteries while it's going down the road. If connected to your toad, it will also charge the toad at the same rate it's charging your RV batteries. On a night where you boon docked, your batteries could be low and as you drive away in the morning, your batteries will be getting a heavy charge. If you didn't drive your toad and the battery is fully charged, it could be overcharged by the coach.....hence the RV1 or other systems that regulate what's coming from the coach to the toad, by sensing the toad's state of charge.

I doubt many people start up both vehicles while both are running, but it does happen. On those cars that require a start and idle every 200 miles or so, people could leave the coach running while doing so. This is not the primary reason for the protection between the two vehicles. It's really designed to stop feed back from one battery system to another (toad to coach).

Like said, you could run a battery jumper cable from your coach to your toad and let it dangle between the two and it will work, but with todays electronics, you REALLY have to be careful of frying something on the toad, not so much on the RV.

[BFlinn181]

Don, the maximum difference in voltages between the two battery systems is a matter of a volt or two, perhaps only a fraction of a volt. I think lead acid batteries can handle those differences, I'm still not convinced a toad charger offers any extra protection. I guess we'll have to agree to disagree. Happy travels.