Old Fleet 12 volt wiring updates

[fordjunky]

I have an older Fleet I am starting to refurbish for a mobile winter powder chaser.

For load my use will be the following:
- I will be replacing all the lighting with LED
- I will need to add some type of water heater (I assume these are electric but have not got that far).
- I will run the propane furnace (igniter and blower use electricity)
- I might need to run some type of electric heater on the bed for really cold nights.
- I will use an electric water pump.
- Charge my cell phone.


Currently there are 2 wires bare wires on the outside of the camper that control all 12v in the camper.

I would like to update this system in few ways, but I am open if people have better ideas.
1 - Add 2 batteries in the camper that are charged off the truck as much as that can allow.
2 - Prep my new wiring solution for adding solar. At this point I don't think it makes sense for winter camping. Hopefully my camper is covered in snow every morning.
3 - Add a fuse panel not just a single inline glass fuse. Potentially redo the wiring so not everything is fed off 1 circuit.
4 - Put a connector on the camper to plug into the truck in some way.

Here are my questions:
- Will my F350 (dual alternators) be able to charge the batteries with the factory wiring? I have read both yes and no.
- Should I be looking at going with 6 volt batteries in series or 12 volt batteries in parallel?
- I like the idea of having a marine switch to isolate batteries if necessary.
- What does the wiring look like so that I can charge batteries by truck or solar and then run the camper. I would guess I need some type of controller but I am not really sure how that part works.

I have been able to find most of these topics in some form but nothing that talks about the entire system starting with nothing. Thanks for everyone's help.

 

[ntsqd]

It is getting to the point where we might need an Electrical sub-forum with relevant stickied threads.

Avoid 120 VAC loads on the battery. Try to only use 12 VDC equipment. Inverters are terribly inefficient. Your electric blanket will suck the batteries dead regardless of voltage. Same would be true of running a 3-way fridge on 12VDC in conditions other than as described. Suggest looking at other options. The propane heater can do a pretty good job. If you're solo on these trips you might consider not raising the roof. Much easier to heat the smaller volume, but harder to pull yer pants on etc.

With the appropriate wire size (find the threads discussing the "Handy Bob" blog) your dual alts should be able to pull the batteries up without trouble, so long as you can let the engine run long enough. Alternators on an idling engine are at their lowest output.

Deep cycle batteries are what you want. Look for the combo of batteries that fits the space allotted with the most storage. Not being a battery expert I'm not sure which to give more emphasis to, the 20 min discharge rate or the amp-hours. You may wish to look into the newer battery chemistries as their storage is far greater, but at higher complexity and cost.

Search here for threads on "Voltage Sensing Relays" and "Automatic Charge Relays", sometimes abbreviated "VSR" & "ACR", for methods of keeping the camper batteries charged and not drawing camper loads from the starting battery(ies).

Fuse or breaker at both ends of the charge wires from the engine. I use the camper end Blue Sea Systems breaker to also separate the camper batteries from everything else.

For the connector between the truck and the camper search here for the "Anderson Connector", that should get you close.

Look to ocean going marine vendors for components. They're more expensive and only very rarely are not worth it. Blue Sea Systems makes fuse panels out the wazhoo. Suggest buying one that has an included ground buss because you're going to need that.

Find the wire ampacity vs. length chart on the resources page at ancor marine's page. I've linked it here many times. Once you know a circuit's amp draw and the length to and from the load you can look up the minimum wire gauge in the chart. Be careful with the online calculators as most of those are intended for AC loads and the same amps in DC needs a bigger wire (Root Mean Square issue).

Searching those suggestions here should open up a whole bunch of reading for you as a lot has been written here about all of this.

 

[Vic Harder]

Thom is bang on. Blowing my own horn, take a look at the "More Power Scotty" thread -

http://www.wanderthewest.com/forum/topic/13230-i-need-more-power-scotty/

It discusses a lot of solar, but also the basics of batteries, wiring, etc.

And ask more questions. You will get great responses from the folks on this forum.

 

[fordjunky]

Wow thank you, that is a huge help.

The more power Scotty thread never came up in my searches. Great information.

 

[fordjunky]

OK, after getting almost no work done today I have a better understanding of how I think this should work.

Please let me know if I am on the right track.

12v Truck Alternator ---(4ga wire)---> Truck Camper Plugs --->Battery Isolator /Controller ---> Monitor ---> Pair of 12v AMG Batteries

Truck Camper Plugs (100 amp Capacity)
https://www.napaonline.com/en/p/PHI15336
https://www.napaonline.com/en/p/PHI15326

Battery Isolator/Controller
CTEK D250s - DC/DC
- This will handle truck charging and the future solar

OR

Blue Sea ML-ACR - Blue Sea 7622 Automatic Battery Separator for Auxiliary Batteries 12V/500 Amps
- I am a little unsure how to add solar to this set up at a later date. Maybe use the Bogart SC-2030 but I don't know where it would connect in the system.

OR

Zamp PWM ZS-30AD
-Not sure how I tie into my alternator charging with this option.

Monitor
Powerwerx RM12-2 Single/Dual Bank Battery Monitor for Battery Chargers - Powerwerx RM12-2 Single/Dual Bank Battery Monitor for Battery Chargers

OR

Trimetric TM-2030-A Battery Monitor System - Battery Maintenance & Accessories - Batteries & Battery Storage - Residential | NAZ Solar Electric

 

[rando]

The combination that I, and several others here have used is:

Alternator -> Bluesea ML or SI ACR -> Victron BMV-702 -> Camper Battery <- Victron Mppt 75/15 or 100/30 <- solar panel

The CTEK is cool, but probably more than you need for alternator chargin, and has a couple of draw backs - it is not configurable for your battery (or a lithium battery in the future) and I don't think it will charge the starting battery from solar. I think you would do better with a bidirectional automatic charging relay (Bluesea and Victron make good ones) and an MPPT solar charge controller. If you don't drive your camper often the bidirectional charging is great because it allows solar to keep both your camper and starting batteries charged.

To echo what ntsqd said - buy marine components, not automotive or RV products where ever possible. The quality is typically far superior. Paul Kennedy Yacht Services (http://shop.pkys.com/) is a good source for much of this stuff at competitive prices.

 

[fordjunky]

Thank you, this ties everything together I think.

Is it a problem that both ACR and the MPPT would be charging batteries at the same time?

I assume people are charging dual house batteries with ML-ACR.

This is the diagram I found for the Blue Sea, would putting the house batteries in parallel allow both batteries to be charged at the same time?

 

[ntsqd]

In theory maybe it might be a problem to have two competing charge sources at the same time. In practice it isn't an issue and I've never heard or read of it being an issue anywhere.

Another good marine mfg. is BEP Marine. I thought their product superior to Blue Sea for purely subjective reasons, but Blue Sea bought them so shelf stock is dwindling. I mention them though as sometimes I still find their stuff NOS.

I suspect that as MPPT prices continue to drop that the PWM controllers will eventually die off or only be found in the cheapest of the cheap controllers, but I'm not convinced that MPPT solar controllers should be the current default. There are instances where a lower cost, high quality PWM controller is perfectly suitable.

I really liked the D250S until someone here pointed out it's short-coming. A more usual solar charge controller that could accept alternator input would be high prized by myself. The Alternate is to go with something like Balmar Marine's ARS-5: http://shop.pkys.com/Balmar-ARS-5-H-Regulator-12-Volts_p_1734.html to get multi-stage charging from an alternator. Not an inexpensive route to take though, and the alternator needs to be of a certain type that will allow easy connections or you're looking at much more cost.

 

[rando]

There is no issue with charging with more than one source at one time.

I tend to agree that MPPT won't get you a huge amount of extra power, but I can't see what you wouldn't use it as high quality MPPT controllers can be had for less than $100, and less than some PWM chargers.

 

[fordjunky]

Thanks everyone, I was making it more complicated than it needed to be.

How does only using a ACR between the alternator and battery (except with relays) not over charge the house batteries? Does this setup rely on the alternator not over charging the batteries?

I had a thought if I wire my alternator charge wire through a continuous duty solenoid and in the camper I connect it to a dc-dc battery charger is there any downside to this setup?

 

[rando]

Alternators are designed to charge batteries - it won't overcharge your camper battery any more than it will overcharge your starting battery. The main purpose of a DC-DC charger is to squeeze the last bit of charge into your batteries. As your batteries charge, their voltage rises, getting closer to the output voltage of the alternator. As a result the current flow decreases, and it can take a very long time to put that last 10- 20% of capacity into your batteries (this is also why you don't have to worry about overcharging) The DC-DC charger boosts the voltage to you batteries to force that last bit of charge in and generally charge a bit faster than just charging straight off the alternator. However, if you have a solar charger - that can provide the higher voltages needed to get to 100% charged - you don't really need the DC-DC charger.

 

[PaulT]

Think of the ML-ACR as just a smart switch that combines or separates two independent battery/charging systems. If it detects charging happening on either the truck system or the camper system, it switches to combine the two systems. Otherwise, they are separated.
The truck alternator/regulator determines its charging of the truck battery. The camper with its solar charge controller or Iota smart charger determines its charging of the camper batteries.
The ML-ACR sits between them monitoring the states of the two systems. If it senses that one side is charging as compared to the common ground, it connects the two systems so that the charging source can charge the batteries on both sides. Just as importantly, if the two systems have been combined because one side was charging and the charging stops, the ACR opens the switch to separate the two systems so that one side does not discharge the other side.

Paul

 

[Vic Harder]

As usual, Paul and Rando are right on!

And, as I just posted in a different thread, this is what I can say about dual charging scenarios:

I noticed today while driving back from a 5 day trip that solar and alternator work quite well in sync. What I saw was that when driving though a cloudy stretch of road, the alternator was putting about 10A into the camper batteries (98% SOC at the time). Then, when in the sun, the PV panels took over, and were putting the 10A into the camper batteries, and little or no current was flowing from the alternator to the camper batteries. Neat.

Once the camper batteries were full up (100% SOC) then the PV panels started charging the truck batteries! I may be just lucky, but the PV array puts out just a tad more volts than the alternator, so current tends to flow towards the truck batts.

Works out super well.

 

[fordjunky]

Thanks Vic, this makes me feel much better about going this route.

I noticed today while driving back from a 5 day trip that solar and alternator work quite well in sync. What I saw was that when driving though a cloudy stretch of road, the alternator was putting about 10A into the camper batteries (98% SOC at the time). Then, when in the sun, the PV panels took over, and were putting the 10A into the camper batteries, and little or no current was flowing from the alternator to the camper batteries. Neat.