F350 Super/Dual Batts/Lance camper questions.

Danny,

What year is the F-350? I have a 2000 F-550 with the same diesel engine and spent a good amount of time tracing the wiring down of the dual batteries. In my truck they are definitely wired in parallel (to double amperage). I've heard that sometimes one battery is isolated for starting only, but that is not the case in my F-550. I assume all of the F-series diesels have a similar setup due to the large amount of starting amperage required. If that is the case then both batteries will be drained by the fridge.

Is it possible to switch out the fridge to one that also runs on propane? When I bought my 2003 RV, they told me it runs on AC and propane. I asked why it also does not run on DC and they said those models typically leave you with dead batteries. Something to consider.

Charlie Changin' Gears A web site about the recreational vehicle (RV) lifestyle

The batteries are wired in parallel. The fridge will kill them both if the batteries are not kept charged. The proper setup should have a separate house battery for the Lance. A much lighter wiring connection will be necessary to connect that battery to the truck charging circuit through an isolator. The isolator will allow the Lance house battery to charge from the truck but, will not allow the fridge to discharge the trucks two starting batteries.

This is a mixed blessing because unless you add at least two batteries to the camper, you will have very short battery charge life as 2 batteires in parralel last longer than 2 x longer because of battery efficencys gain at lower discharge rates per battery in a parallel setup. What you should do first is to actually measure what draw ir being placed on the batteries by the camper with a clamp on amp meter and then we can go from there once we better understand the amount of power that is being used rather than guessing at a good fix at this stage.

As others have stated, the correct way to provide 12vdc to the camper is a third battery charged through an isolator. The isolator allows the alternator to recharge the third battery but prevents discharging the two truck batteries required for starting. Three way reefers (ac, dc, gas read propane) have gone out of popularity in most rvs, the exception being slide in truck campers. However, even when running in the gas (propane) mode 12vdc is required to hold the propane inflow valve open while the fridge burner is lit. The same applies to your furnace in the camper. As you can see, a separate battery is really "de rigeur" unless you are very careful or have a very strong arm and heavy duty crank to start your truck. <G>.

Dave D

Hi Dave, and all who have replied.

I checked with my dad-in-law, he has a third battery in the camper. I'll see if it has an isolator. If there's a battery in the camper, why would the dealer need to run a line from the other batteries? Shouldn't the camper battery be sufficient to hold the propane inflow valve open when parked?

Thanks, we're getting there.

Donny

Again, if you have dual batteries I would not even bother unless you have dual batteries in camper because it will have a much shorter charge life. Figure out what is being drwn from battery then decide because it is the load that determines the correct solution not guessing.

The dealer ran a hot line from the truck batteries to the camper batteries so that the latter will be recharged when the alternator is turning. The isolator separates the truck battery from the camper batteries until the alternator is providing charge voltage, then it allows flow to the camper batteries to recharge them. When this is not the case it prevents the camper battery demand from draining the truck batteries. This way you don't wake up to a no start situation.

///snipper snipper///

Sorry about the previous post, Donny, I had a senior moment and depressed the send button long before I was ready... Ah, well...I hope that post cleared up any questions...Good luck...

Dave D

He was right in requesting an isolator from the dealer, then. Right now he doesn't have one, so the fridge, when parked, draws from all three batteries, right? I can see where this would be a problem.

They're on their way home now. I'll call them and make sure they get one installed as soon as possible.

Thanks to all who replied, and have a good summer.

Donny

I'm coming very late on this, but, there should be a pair of relays somewhere around the Master Brake cylinder that will only connect when the ignition is on. When the ignition is off the relays open isolating the camper battery from the truck batteries. When the ignition is on, the alternator charges the camper battery.

: >> Just stopped in for a few questions for my dad-in-law. : >>

: >> He has a late model F-350 Super Duty with the 7.3 deisel. He has dual : >> batteries and the : >>

: >> When they hooked up the wiring for his new Lance camper, they needed a : >> direct line from the battery to the fridge so it would run when : >> parked. He had to talk them into putting a 40 amp breaker inline, they : >> weren't gonna. : >>

: >> They ran the line from the battery on the drivers side. His questions : >> are: : >>

: >> Should they have used the battery on the other side instead? Is it : >> like a dual battery setup on a boat, where one is for starting, the : >> other is for "house" use? : >>

: >> My thoughts were that the batteries are probably in parallel, and they : >> would both be drained by the fridge draw when he parks too long. (He : >> has a Norcold fridge, which I think is propane as well, so maybe it : >> switches over automatically so this drain doesn't happen?) : >>

: >> Thanks for the help : >> Donny : >

: >As others have stated, the correct way to provide 12vdc to the camper is a : >third battery charged through an isolator. The isolator allows the : >alternator to recharge the third battery but prevents discharging the two : >truck batteries required for starting. Three way reefers (ac, dc, gas read : >propane) have gone out of popularity in most rvs, the exception being slide : >in truck campers. However, even when running in the gas (propane) mode 12vdc : >is required to hold the propane inflow valve open while the fridge burner is : >lit. The same applies to your furnace in the camper. As you can see, a : >separate battery is really "de rigeur" unless you are very careful or have a : >very strong arm and heavy duty crank to start your truck. <G>. : >

: >Dave D : : : Hi Dave, and all who have replied. : : I checked with my dad-in-law, he has a third battery in the camper. : I'll see if it has an isolator. If there's a battery in the camper, : why would the dealer need to run a line from the other batteries? : Shouldn't the camper battery be sufficient to hold the propane inflow : valve open when parked? : : Thanks, we're getting there. : : Donny :