Electric Hook Up

[mtbMike]

Hey folks,
Newbie here. Trying to fix up a 93 Grandby. It has a battery and the electrical system is intact but there is no hook up (umbilical?) to get power from my trucks system. I'm wondering exactly what sort of connector FWC/ATC uses. Seems like I just need a 2-prong connector but would be nice to have a flush mount female plug in the bed of the truck since the battery is up by the cab. I don't see any such thing for sale anywhere.

Also, I understand (cus someone told me) that I should run the power from the truck through a battery isolator and again, am curious what FWC/ATC uses. I see that isolators come to accommodate different amps but don't know how to figure out what I need. A guy at an auto parts store looked in a book and said my alternator (F250 diesel) puts out 135 amps but I'm thinking that's not the number to use.

Thanks for any help!
Mike

 

[camelracer]

The electrical connector on my '06 Grandby is a 3 prong twist lock made by Marinco. I'm not sure where you can get one but you might try the FWC factory. They sell them as part of the install kit.

To isolate the camper from the truck battery they use a Model 1314 battery separator from Sure Power Industries. This device monitors the truck electrical system and when the voltage exceeds 13.4 volts (engine running) it connects the camper to the truck. As for amperage I don't think the camper will ever see the rated alternator output. FWC uses a 30 amp circuit breaker and #10 wire for their connection.

Before you get a battery separator or isolator trace the battery wiring in your camper. It might already be there. I'm not sure what they used in'93.

 

[craig333]

A good place to look for connectors is marine supply stores. I get a lot stuff from West Marine. Marine stuff is usually pretty high quality and waterproof.

 

[WarpathEngineering]

If you do not already have one side of your umbilical, look for an electrical supply company in your area. 2, 3, & 4 prong twist plugs and sockets are fairly common in the electrical field although you may need to order a flush mount socket. If you want, look up hubbell.com on your web browser. This company make everything you'd need, it just may mean a little digging. I used a lot of these types of umbilical items when I used to work on fire trucks and ambulances for a living.

As to the battery isolator, you always want to match or exceed the amprage rating of your alternator or you run the risk of burning it and the wiring up. If you are just running 12 volts to supply power to the camper without a battery installed in the camper, you might get away with a 30amp isolator but if you add a battery for the camper later, you'll have to change out the isolator to match your alternator size. The only thing you waste in going to a larger isolator is cost and physical size.

 

[Sam]

Just to echo what Craig333 said, I go to West Marine for most of my camper mods, they cary Marinco products. They have a great selection and marine stuff is hands down higher quality than the crap made for the RV world.

If you don't have a store in your area you can order online as well, though it's nice to see the stuff in person.

www.westmarine.com

 

[Sam]

WarpathEngineering:
Sounds like you have a good grasp on the electrical side of things, let me ask you; I am using the + lead or battery lead on the 7 pin round trailer connection on my factory tow package to charge the batteries in my camper. Should I have an isolator in the camper or does the factory hitch (2000 GMC) wiring somehow address this?

Thanks,
Sam

 

[WarpathEngineering]

Sam,

After reading my last post I noticed I made an error.

Maybe I'll get it right if I start at the beginning. A battery isolator is nothing more than an heavy duty diode, or electrical check valve. It allows the flow of electrical current in one direction, from the alternator to the battery and seperates two or more batteries. In other words if you have a battery in your camper which is connected to your truck's wiring (like you have) and an isolator is NOT installed and you leave the lights in the camper on, you will drain both batteries. If you leave your truck lights on you will drain both batteries.

Now if you install an isolator between the camper & truck, your alternator will still charge both batteries but if you leave the lights on in the camper you will only kill the camper battery and if you leave the lights on in the truck you will only kill the truck battery. Make sense so far?

Now, your trailer connection from the factory, it will be fused in the trucks fuse panel. I doubt that it has an isolator inline but I'd check. If it is fused for say 20 amps and the camper draws 30 amps with everything on, you will blow the fuse when you turn everything on. If you have a 20 amp isolator and the camper draws 30 amps, there is the potential to burn out the isolator. Your isolator should be sized to at least the maximum load of the camper (in this example 30 amps).

Now, lets say you want to put an extra battery under the hood and it will serve only the camper's load, then 30amps would be enough for our example. But lets say you want to install Hela lights on your truck and want to hook them up to the secondary battery so as not to drain your truck battery. Then you'd be best to rate the isolator for the alternator for safety sake.

Am I making sense?

Hope this answers your question.

 

[Sam]

Perfect sence. I understood that with my set up I risk draining the truck battery, I usually remove the fuse(40amp) in the vehicle that feeds the camper once I reach my camp spot. You mentioned in your earlier post the risk of damagine the alternator, this was my main concern but it sounds like this is not the case with my set up?

Thanks,
Sam

 

[mtbMike]

OK. I think I get it...the isolator needs to be able to handle at least the max amps that the camper will draw (probably about 30) -- not necessary the amps that my alternator puts out. In case anyone was wondering, I heard from FWC today and they use a Sure Power 1314 when you get the aux battery option. This handles 100 amps. Read about it on the web and it sounds like you can flip a switch or something and possibly use your camper battery to jump start your truck if you need to. Could be handy.

Thanks for all the tips!
Mike

 

[camelracer]

mtbMike,

There are 2 types of battery isolators being discussed here. The one WarpathEngineering is talking about takes the alternator output and directs it to each battery keeping the batteries separated. This type of unit needs to have a current capacity that equals or exceeds the alternator capacity.

The Sure Power unit that FWC uses just disconnects the camper from the truck when the truck isn't running. It's capacity doesn't need to exceed the camper load. If you want to use the function that will help start the truck you need to also use appropriately sized wiring, probably #2.

I was in a Boater's World store today looking for electrical supplies and saw the connector FWC used on my Grandby. It's a trolling motor connector by Marinco - $15 for the set. This is a 3 prong twist lock with an o-ring seal.

 

[John D]

It is better to have a separate alternator for each battery.

Small alternators, such as made by Nipon Denso, are available but might require advanced gearhead skills. Mounting hardware is available through several sources, such as Summit Racing. Owners of late model trucks can buy well engineered off the shelf mounts for two or more alternators.

Standard alterators made for General Motors vehicles are probably the best to use because replacements and parts are available through every AutoZone across the nation. Whether you prefer an external voltage regulator or not, it is still much easier to mount one wire alternators like GM's. Two or more alternators provide excellent redundancy, especially if they are identical, but it is not essential. Using common off the shelf alternators is reliable, flexible, and economical.