Truck to Camper Electrical

[Clark]

Okay. So my wife and I are going to be picking up an Alaskan in may. It is a 1997. Pretty excited! I want to make sure I do the right things to my truck to make this a easy and fun experience right from the start. I have a 1999 dodge 2500 diesel truck. The Alaskan camper comes with two AGM marine batteries. I would like the truck to charge these batteries while it is running. When the truck is off and we are using the camper I would like to ONLY draw power from the AGM marine batteries and not my truck batteries for obvious reasons. I have read alot of information about using big wire etc.. but really it is greek to me. I guess I am looking for some handholding..need to know exactly what wire to use, connectors etc.. and how to set this up properly. We do not have solar panels and probably won't get them...

My questions : How should I hook up the electrical from my truck to the camper? Also I would like the configuration to also allow the batteries in the camper to be charged when plugged in to "shore" power.

I have a female electrical port wired into the bed of my truck, it was there when I bought it. The cover reads 6 - 8 - 12v. It is in the Front drivers side corner of my truck bed, so it would be right under where the female port is on the camper.

I have attached two pictures. The first is the female plug in my truck, the other is the camper plug. Well I can't attached pictures b/c they are "too big" but if it would help I can email them

THANKS!!!

 

[Casa Escarlata Robles Too]

Welcome,Clark.Sounds like you are set up for charging power from the truck.Just a plug in to the camper.
Does the camper have a "battery separator"? You will need one if there isn't one.This lets the truck charge the battery in the camper but the camper won't draw off the truck when you are parked.This is a must.One of the most common separators is the Surepower brand.Check in your new camper,there might already be one there.I am sure someone with an Alaskan will be able to give you that info.
Good luck with your new camper.Send pictures when you can.To post photos try to size them at medium,that usually works.
Frank

 

[Clark]

Thanks Frank. As soon as I get the camper on the truck I will post some pictures. Where do you resize a photo? I have emailed the current owner of the Alaskan and asked if he had a battery separator. I remember him saying everything was wired on the "truck" side, he mentioned he had something called a solonoid that would basically restrict the current flow to one direction, which apparently makes it so the camper will not draw power from the truck batteries...

We will see what reply I get.

Thanks!@!!

 

[ntsqd]

I know this has been covered before, but there are three basic ways to separate the camper battery(ies) from the truck when the engine is off, and connect them when the engine is on.

The simplest is a constant duty solenoid. This is the ages-old solution. It's not very smart, but they're pretty reliable if a little clunky.

The next idea to come along is to use power diodes. These are commonly called "Battery Isolators." They have a voltage drop penalty that results in the camper battery(ies) never reaching a full charge unless the alternator's regulator has it's voltage limit offset to compensate for this. These have mostly fallen out of favor.

The current idea is some voltage sensing electronics combined with some form of the constant duty solenoid (or a solid state equivalent). These all have varying forms of logic that delays connecting the camper battery(ies) until the starting battery has had at least a chance at getting fully recharged. Different mfg's go about this in different ways. Some look at the starting battery voltage and won't connect until the starting battery is at some nearly full charge status. Others use a timer and won't connect until the starting battery has had the sole benefit of the alternator for some programed time period. Still others combine both methods. Some of these are called "Voltage Sensing Relays", others are called "Automatic Charge Relays." The name depends on the mfg. The better units are made by companies that specialize in deep ocean marine applications. BEP Marine and Blue Seas are two that come to mind. Gigavac makes a very, very nice one built on a MIL-Spec assembly line, but I'm not sure about availability.

Your electrical socket in the bed probably has a contact intended to charge the camper battery(ies). It most likely is a 10 gauge wire, max. To my thinking that is nowhere near big enough. I do not think that I over-killed the wiring on our camper by using 6 gauge wire for both the hot and the ground.

If the camper will not live full time on the truck, and perhaps even if it will like ours, you will need or want some easy way to connect and disconnect any wiring not in the light connector. I used a pair of the charge plugs for electric fork lifts. They're made by Anderson and are available lots of places, but the best local price that I found was at Grainger.

 

[Clark]

Thanks for the advice thus far. I am not sure what wiring you are referring to when you say "you will probably want some easy way to connect and disconnect any wiring not in the wire connector". Does this mean the plug in the bed of my truck will infact plug into the camper, and will be used for the brake light etc. only. Then I will have another heavier gage wire (6) that will go from my truck batteries (or alternator?) to the batteries in my camper? And it is that connection that I will want so sort of easy method to connect and disconnect. The camper will not live on my truck, it is my daily driver.

Is this the gigavac product I need

http://www.gigavac.com/products/contactors/datasheets/gx16/

 

[ntsqd]

That's not the Gigavac product that I was thinking of. They offer one with voltage sensing electronics on-board.
Easier to get is the Blue Seas products. I would look at something like this: Blue Seas ACR

Anytime you take power off of a battery it needs to be protected with a fuse or a breaker, so you'll need something like this breaker:

Or this fuse assembly:

at both batteries or you risk an electrical fire.

This is my camper disconnect:

This is the wire that I used:

Two of these make up the disconnect:

(Note that different colors of these connectors will not mate, nor will connectors of different amperage series.)

The socket provided in the bed is mostly for lights. The 7 contact "RV" sockets, which yours likely is, do have a contact for battery charging. However, they are typically limited to a max wire size of 10 gauge. That would be OK for a trickle charge, but it will not carry enough current to do bulk charging without a pretty large voltage drop. Given that the voltage difference between a fully charged battery and a 50% discharged battery is about 0.5 volts, you want to minimize any voltage drop as to as little as possible. Some here probably think my choice of 6 gauge power and ground wires is over-kill, but I wanted as little voltage drop as I could get without adding unnecessary weight. I feel that 6 ga. is sitting on the cusp of becoming excess weight, but I'm confident that the voltage drop is very small.

 

[Clark]

Do you have any pictures of your fuse assemblies at your batteries? Thanks for all the help thus far.

I was looking at this :

http://www.allbatterysalesandservice.com/browse.cfm/4,6120.html

Does that product do the same thing as the Blue Sea product you mention?

Also, b/c I will have 4 batters (two starter batteries in my truck, and then 2 AGM marine batteries in the camper) do you think I should upgrade my alternator? Like a 200AMP alternator of some sort?

 

[Clark]

I really want to see pictures of your entire Battery, electrical setup!

 

[pods8]

(Note that different colors of these connectors will not mate, nor will connectors of different amperage series.)




Bolded part isn't true. The same amp/model series mate up and they come in various colors.

 

[pods8]

So lots of ways to skin the cat on things. But lets step back for a second and look at the WHOLE system. You've got nice expensive dual AGMs, you should take care of them. My personal belief is somewhere in the system there needs to be a stage charger to properly fully charge/condition the batteries. The easiest/most common would be the shore power charger (solar and DC-DC charger being the other and/or options).

1) You say you want it to charge off shore power. Do you know if the camper has a convertor/charger already in it? If not you should add one since this will be your reliable charge source ideally, top off the batteries when you get home.

2) On the truck ntsqd covered most it already I will just state my current preferences (I'm not a politician I get to flip flop ). For starters I'd never consider using the RV plug unless I had a DC-DC charger in the camper to boost the voltage back up, likely too much voltage drop for good charging.

On my build I'll have both shore and solar stage chargers so I'm going to go more simple on the truck connection. I'll be using an ACR like ntsqd linked above (I plan to add a switch in the ground line to the ACR so I can shut it down even in conditions it would otherwise connect, more on that below). I'll likely be using some 6ga welding wire (a guy on ebay has a decent deal on 25'ea of red/black right now for like $35 if I recall right, I just need to confirm length needed). At the moment I'm thinking of using some 50amp manual reset stud breakers (Manual Reset Circuit Breakers with Mounting Bracket) I opted for manual reset or auto reset so if there is a short it doesn't keep reconnecting I'll see how I like it in practice. I'll be using some anderson powerpoles like ntsqd. Here's a good selection: Anderson Powerpole and SB Connectors | Powerwerx I'll likely use the SB50 series but not committed yet. That generally lists my plan, I can go into more detail if you want. The main thing is I'm starting from scratch and putting in what I want, you can just plug your camper into your current truck connection but you may not be happy with the results.

On the manual override of the ACR: Batteries ideally like charge stages and it takes a higher voltage than the battery is to push amps into them. There is a bulk stage usually in the 14.4V range (+/- a bit) that is to dump amps into the battery. Then an absorb stage which ideally is a little higher voltage, but not all charges increase the voltage, where its held for a while to keep pushing amps into the battery to top it off. AFTER all that though it should drop down to a float voltage (usually mid 13V range) which keeps the battery from self discharging and also squeaks in any last charge needed w/o overcharging (if the higher voltage is kept applied to a fully charged battery it has the potential to overcharge and vent the battery which is doom for an AGM). Now looking at an alternator its a generally singular charge voltage, usually in the 14.1-14.4V range. Its usually a little low for bulk/adsorb and a little high for float, not IDEAL for an AGM but we work with what we got. In my case I'll be using decent sized 6ga wire to limit wire losses so I can dump amps at a decent rate to bulk charge my battery when needed. However I personally don't want my AGM batteries to see my alternator voltage 100% of the time the truck is running, for instance on a 12hr drive or such I think there would be some minor overcharge potential, so I'm putting in a manual over ride. I'll leave the ACR connected for reasonable drives and when leaving camp with drawn down batteries but after a while on the road I'll shut it down. I'm a tinker'r though and that isn't for everyone. Additionally I'm not relying on the truck for all my charging, I'll have solar for charging/conditioning w/o me doing anything and also I'll have my shore power charge to plug into when I get home if I'm still low.

 

[Clark]

THanks alot so far guys. The camper does have an inverter so shore power should be taken care of.

I think we will be on very long drives (12hours or more) with the camper and truck. Also, I doubt we will go to many "camp" grounds that have available shower power hookups, mostly the shore power will be used at home when the camper is sitting.

So what I gather this far, is I need a battery isolator, something like the Blue seas one, then I need heavy gage wire, and I need a breaker at each AGM battery.

How does the hook up configuration go? Alternator to isolator, isolator goes too both starting truck batteries, and isolator goes to camper batteries (via a connect/disconnect powerpole mounted for easy access when removing camper from truck). Then at each camper battery I have a breaker..

Is that correct? Also, I have a 1999 dodge 2500 diesel, with a stock alternator. Given my stated uses (no solar, possibly 1-2 week trips without shore hook up) will the alternator be adequate for charging AGMs while driving, or if not driving somewhere i can just start the truck for awhile...

I am also thinking of replacing all interior lights with LEDs. I would also like to add 1-3 exterior lights, one on the back and one on either side. Any thoughts about that?

Thanks for the help thus far.

 

[pods8]

My preference is:
Truck battery -> Fuse/breaker very close to battery -> ACR -> wire to camper with powerpole connector -> fuse/breaker close to camper battery -> camper battery.


You'll likely never fully charge your batteries off the truck, esp. when just idling for a while (alternator needs higher RPMs for decent current production). But with decent wire gauge you can hopefully keep the batteries in the upper end of charged and top off/condition them when at home.

If you'll be sitting a lot on your 1-2week trips and think you'll pull down your batteries perhaps consider solar after all, you can get a panel and controller for under $200... Hardest part would be chasing the wiring from the roof if you're putting it on the roof. Some folks are setting up their panel separate from the camper at camp though.


LEDs are a lower draw with is nice. What's the question? I bought some Kaper II units for mine, no comment on performance of those yet (still in the box ).

 

[Clark]

Okay. I think I got it. So I do not really need a bigger Alternator. With two deep cycle batteries for camper I do not think we will draw them all the way down. We are pretty conservative when camping. Really will only be using 12v fans and LED lights... Maybe water pump a few times as well.

I think I am figuring out what I need. So for ACR, which one do you have? I was thinking of the Blue Seas one, or this one

http://www.allbatterysalesandservice.com/browse.cfm/4,6120.html

is that sure power one overkill, or not what I need?

 

[Casa Escarlata Robles Too]

. Where do you resize a photo?

I see there are helpful electrical people there to help you.
I re size my posted photos before I send them to desk top.I post all my pictures from desk top.That's how I do it ,there may be other ways.This method works for me.
Frank

 

[pods8]

I don't know what your alt does for performance so no comment there.

Keep in mind if you have X AH of listed battery capacity you can't/shouldn't use it all. 50% max is recommented, ideally only 20-30% of it most of the time. The lower you pull them and the more frequently you do the quicker you'll kill off your batteries (there are battery life vs discharge curves out there).

I haven't ordered my ACR yet, but likely a bluesea 7610 or 7611. The 7610 is dual sensing which means when either bank gets over a certain voltage it'll open, what this means is my solar would top off my truck battery too in that case. Not sure if I desire that or not.


That surepower is an isolator with diodes, avoid it (causes voltage drop). Are you near allbatterysalesandservice? I used to live right there and would stop in for my odds/ends, it was nice having them close by.

 

[Clark]

Thanks for all the input guys. I am a few hours from All Battery.

So, I think I will go with the Blue Seas ACR, some 6 gage wire, and some connectors... as well as breaker at each battery (this means 4 breakers, 2 for truck battery and 2 for camper batteries..?)

I am wondering if this is a wiring project I can do, or if this is something best left to a shop?

I am excited to get the truck ready and get the campEr!

 

[pods8]

You only need fuses/breakers on the positive wire, so one on each end for a total of 2.

Here's that 6ga welding wire I was thinking of getting: http://www.ebay.com/itm/50-6-gauge-AWG-EXCELENE-WELDING-CABLE-25-FT-RED-25-FT-BLACK-USA-MADE-BATTERY-/350766392071?pt=LH_DefaultDomain_0&hash=item51ab4e6307 (There are listings for other sizes too).

Biggest potential hurdle for the novice is likely putting the lugs onto the cable ends, off hand you're look at about 8 of those (+/- at each battery is 4, then 2 at the ACR, and potentially 2 more at the fuse/breaker depending on what the connection style is there). Could potentially figure out lengths and bring the wire in somewhere to have crimped. I haven't investigated the large size crimpers yet for something affordable but I likely will when the time comes (ideally I'd like to crimp and maybe backfill with solder depending on the crimp quality I can do) and I'll be using adhesive lined heat shrink all around.

This is where smaller typical 10ga connectors are more forgiving, though most folks only have a crappy $5 crimper which suck honestly. This ratchet one from all battery works pretty good on insulated terminals for an affordable price: http://www.allbatterysalesandservice.com/browse.cfm/4,6999.html

 

[Clark]

I have two starter batteries for truck and two batteries in camper, wouldn't I need a fuse for each positive line? So 4 fuses, or are these batteries treated as a bank (of two batteries) and therefore only need 1 fuse per bank?


So right now my shopping list is (does it look correct?) :

30' ft each Black and Red 6gage wire.
Battery terminal connectors ( I have 4 total batteries, so I think I need 4 sets..? this goes back to the battery bank question)
Connectors that go from 6 gage wire to the blue sea 7610
Fuses (what size?) and still trying to figure out if 2 or 4 are needed
A set of SB50 powerpoles


Will anything need to be done with the charger/inverter that is already in place on the camper? Or can I just run wires from truck battery to ACR to camper battery?

 

[pods8]

You'll only be connecting one set of wires between each battery bank, so no only 2 fuses/breakers. On your camper batteries I'm going to assume they are 12V in parrallel? If so the best method of connecting to them is connect the charge wire to the + on one battery and the - on the other. On the truck you should just be able to connect up to one of the batteries as I presume each has an alternator feed.

Recommended max fuse size for 6ga is 80amps I believe. I just went with 50amp breakers as I don't expect the batteries to pull that much, I'm using heavy wire for the low voltage drop not to try and carry a big draw.

You current charger would just be connected to the battery posts as well. If you had solar it would also be tied to the posts. Long story short its not uncommon to have a few ins/outs connected up.

 

[Clark]

Awesome. I am going to order it all. I am not sure where I will route the wiring yet from the engine compartment to the bed of the truck. I also am not sure where to mount the powerposts. Ideally it would be nice to have the truck wired with the power post ready. That way, when I go get the camper i can just make the wires for the camper battery and plug right into the power post and be off and running.

Thanks. EEveryone has shed a good deal of light on this for me.