Community Forums

Hrudey · 03-02-2014, 06:50 PM

I have found lots of great information on this forum for setting up a Toad to flat tow.
I am now setting up my Chevy Colorado for flat towing (I am going to sell my Master Tow Dolly).

I will be using a "Brake in a Box" sold by Camping World called Add-A-Brake (made by RoadMaster for CW).

The MH has a four flat plug that I will use for auxiliary lights on the Toad. The MH does not have preinstalled wiring for a 7 pin plug, so I will be running a 10 gauge charge line with two 20 amp auto resetting circuit breakers for a charge line.

My questions are:

1--Do I need to run a ground wire from the chassis battery negative post to the toad, or can I just ground the negative wire to the MH chassis at the rear of the coach?

2--Do I really need the charge line to be 10 Gauge or will 12 gauge be enough? Total distance to Toad battery from the MH battery is around 40 feet.

3--Instead of using separate spools of 10 gauge wire for the charge line & ground, I was thinking of using a quality 10 gauge contractors extension cord with the ends cut off. The advantage seems obvious to me. I get three insulated wires, wrapped in a weather proof casing that only need to be run once from the rear of the MH to the front of the MH.

Any helpful thoughts would be appreciated.

docj · 03-02-2014, 07:50 PM

I just installed this kit. In addition to wire and connectors the kit includes a circuit breaker for the MH battery bay and a charge controller which serves as a diode and as a switch which only permits current to flow when the MH engine is running. This keeps the MH batteries from being drawn down if the toad is left connected overnight. IMHO it was well worth the money: LSL Products TOAD-CHARGE-40 Dinghy Vehicle Battery Charger 40' Wire Harness

Hrudey · 03-02-2014, 09:19 PM

Docj--thanks for the suggestion. I am familiar with the Toad-Charge. It looks like a good product and it could serve as a charge line for my Toad.

However, I was looking for an alternative that would be less costly. That is why I was thinking about using a 10 gauge contractor's extension cord for the wire needed for my charge line. I haven't seen any posts referring to extension cords used as a wire substitute.

Papa_Jim · 03-02-2014, 09:33 PM

I have been having the same ideas. The Toad Charge looks great, but I wonder if it's more than I need.

Providing the toad battery and coach batteries are fully charged when the connection is made between toad and coach, why would the wire need to be very heavy?

I think a fuse would be needed at each end.

I'm waiting to hear opinions regarding a ground wire.

Jim

Spinner · 03-02-2014, 10:29 PM

Your ground wire needs to be able to carry the same amperage as your 12v + wire. That being said, it's run might be much shorter if you have it attached to the frame at the rear of the MH. Google wire gauge ampacity.

Arch Hoagland · 03-02-2014, 11:14 PM

I like the idea of the contractor's extension cord.

I can't think of anything negative about it.

Hrudey · 03-02-2014, 11:37 PM

I really appreciate all of the comments so far. Keep them coming!

docj · 03-03-2014, 06:17 AM

Quote:

Originally Posted by Hrudey

Docj--thanks for the suggestion. I am familiar with the Toad-Charge. It looks like a good product and it could serve as a charge line for my Toad.

However, I was looking for an alternative that would be less costly. That is why I was thinking about using a 10 gauge contractor's extension cord for the wire needed for my charge line. I haven't seen any posts referring to extension cords used as a wire substitute.

Regardless of where you get the wire, you still should use a circuit breaker and, at least, diodes to prevent the toad from trying to charge the MH's batteries. A good contractor-grade extension cord isn't cheap; I wonder how much you'll really save.

wa8yxm · 03-03-2014, 04:35 PM

Running the ground line to the rear of the MH frame is just fine.. It's how I do it in fact.

Id use quality 10ga myself but 12 will simply give you a slower charge.. How much slower I do not know.

One thing I wished to post in another thread but could not re-locate the post I wished to attache it to as a reply is this:

Charge rate depends on 4 things

1: Voltage at source of charge (Alternator)
2: Gauge of wire and condition of connectors on wire.
3: Internal resistance of battery
4: State of charge of battery.

As the batteries (Towed and towing) Approach same state of charge current falls to a very very low level.

With your brake in a box.. it should never get very high.

Recommendation: Consider some other brake system, Like Inivisible brake or best US-Gear Unified Brake Decelerator.. includes charge line (They both include a method of charging towed) . Since these systems are installed, and stay installed, all you do is plug 'em in and they are ready to go. You have nothing to "Stow" save for the umbicial on the US gear (not even that on the Invisible brake) and it hooks up in like 2 seconds if you dog it.

Stealth01 · 03-06-2014, 06:07 AM

Quote:

Originally Posted by Hrudey

I really appreciate all of the comments so far. Keep them coming!

Hrudey,
I installed my toad charge circuit just as you are describing... save for the auto reset CBs, I used fuses on each end instead (if a fuse blows, I want to double check the system for faults). I simply ran a contractor grade extension cord from one of the coach batteries (Positive and ground) through a connector on the front of the toad to the toad's battery (positive and ground). I did not use diodes, I simply DO NOT run the toad with the coach shut down... If however, I did, the fuse would protect the toad alternator from damage. I've used this circuit for a year of towing with no issues and maintained a charged toad battery!!

Libero · 03-06-2014, 06:26 AM

If you have not committed to a brake that requires high current drain from your Toad yet, I suggest you look at other options. Such as "ready brake" - it is simple, no electrical to operate and nothing to stow away or insert everytime you go to tow.

I have had M&G, Brakemaster and ReadyBrake and I towed a friends car using is Brake Buddy, I found the "Brake Buddy" concept a PITA, albeit it did work and it did drain the toad battery somewhat.

Good luck on whatever you decide to do.

doc · 03-07-2014, 11:23 AM

I ran the charge line on my Jeep and pulled two wires through a run of heat shrink (had the wire and shrink and needed to get it run that PM) works fine except a bit of a pain to keep everything in order. The 12 volt (lighter plug) in the Jeep does not stay hot with the switch so it looks like I will be using a battery jump box as a power source for the Brake Buddy so I can turn the ignition off.

Starsekr · 03-07-2014, 01:38 PM

A couple of thoughts for you. What you are going for is a trickle charge to the battery, enough to keep it up and replace what the lights/braking system uses, not recharge it. There is a reason that they make jumper cables pretty large, and its not to start your car. Its so that a lot of current can pass quickly. When two batteries are hooked up, if there is a voltage difference between them, the only thing that stops that first rush of current is the internal resistance in the batteries and the resistance of the wire.
This offers you two choices. First I haven't done this <so YMMV>. But I will do this this month, because we are commissioning our toad.
1. If you go with diodes or separate lights, why not just power the brake system off the tow vehicle? Only power the brake system off the toad when the breakaway switch is active?
2. Use a smaller gauge wire with high temperature insulation (automotive rated, which is higher than house wire or extension cords) from the battery to battery, with fuses on each end, the small wire acting as a distributed resistor to limit the current. You do not run a ground return wire to the battery, because you want the loss of the chassis ground to help limit your current. You could see it this is viable by not running the wire under the coach yet, but just making a hookup with the length of wire you will need lying on the ground small gauge (14/16) on the +/+ leg and a heavier jumper cable frame to frame. Stick a fuse in each end. See how hot the wire gets. If it is uncomfortably hot, it's too hot. A better experiment would be to turn all the lights on in the toad for about an hour, to discharge the toads battery a little, and try the experiment again. Fusible link wire is usually 1/2 the size of the current carrying wire, 14 gauge main wire , 18 gauge fusible link <4 awg numbers smaller>and made with a high temperature, non-flammable insulation.
3. Comment on diodes used in charging, protective circuits. Most motorhomes have isolation diodes between the alternator and the house and starting battery. Your toad alternator will not damage the RV alternator. When you do a jump start of a car, if the polarities of battery connections are ok, then the alternators of both cars are not damaged. Diodes will reduce 1.5 volts or so from the alternator output. For example, put a diode in the circuit between toad and RV, the RV battery will have 13.7 volts and the toad battery will see 12.2, which will not be enough to start charging the toad until its battery drops to 12.2 If the RV engine is running, the RV battery sees something like 14.2 and the toad will see 12.7. So the only way to use a diode in a circuit to charge your toad is to connect to the RV alternator output, just like the house and starter batteries. .And put in fuses

docj · 03-07-2014, 01:57 PM

Quote:

Originally Posted by Starsekr

3. Comment on diodes used in charging, protective circuits. Most motorhomes have isolation diodes between the alternator and the house and starting battery. Your toad alternator will not damage the RV alternator. When you do a jump start of a car, if the polarities of battery connections are ok, then the alternators of both cars are not damaged. Diodes will reduce 1.5 volts or so from the alternator output. For example, put a diode in the circuit between toad and RV, the RV battery will have 13.7 volts and the toad battery will see 12.2, which will not be enough to start charging the toad until its battery drops to 12.2 If the RV engine is running, the RV battery sees something like 14.2 and the toad will see 12.7. So the only way to use a diode in a circuit to charge your toad is to connect to the RV alternator output, just like the house and starter batteries. .And put in fuses

From your numbers, using diodes pretty much prevents current flowing to the toad unless the MH alternator is running (or the toad battery ~<12.2 V). To me that seems perfect because it means there's pretty much no way for the toad to drain the MH batteries. This is exactly how the Toad Charge system is designed. If the toad is kept connected overnight there's little chance that leaving something on in it will result in a discharged MH battery.