Electrical hookup questions on 2018 Grandby Flatbed

[Durango1]

Time is (slowly) marching forward and Denny says our Grandby flatbed is arriving late March! We'll be mounting it on a new regular cab Ram 3500 Chassis Cab. (Arriving in a week or two.) We ordered the Grandby with the 160 watt roof solar panel and the two battery set-up.

This will be our third FWC in six years so we want to 'do it right'. So a few questions from an 'electrical dummy':

1) What gauge/type of wire should I run from the alternator to the camper for maximum recharging efficiency? We ordered the 'heavy duty' alternator. (220 amps)

2) Will it be OK to just run the supply wire to the 'pigtail' from FWC outside the camper or should I try to have it run all the way to the connection inside the camper?

3) Anything else we should do during installation to tweak the electrical?

4) Denny has offered to buy the two batteries FWC supplied so I can install my own if I wish. We basically have unlimited space since there will be a large under-bed aluminum box mounted below the existing battery space in the Grandby. So we can just drill through the floor and the aluminum deck, install rubber grommets and lengthen the cables- voila! So any battery suggestions given 'unlimited space and weight'? (The box can be vented easily too.)

Many thanks in advance for your suggestions, Steve

 

[ckent323]

Questions:


I assume you have the IOTA charge controller with IQ4 or equivalent (if not there is a lot more to discuss)

It would be appropriate to ask FWC what the wire size is from the controller to the battery bank. In my camper the wires are only 10 ga. :-(

As I recall the standard wire size FWC uses internal to the camper is only 10 Ga. My camper is a 2007 Keystone which did not have factory solar but did have a factory battery bank and the wiring sizing may not be the same as the newer campers.

At any rate here is what I did:

The previous owner of my truck installed a surepower 1202 battery isolator (he used the truck to tow a 5th wheel camper which had house batteries). It was disconnected. Since I rarely tow a trailer when I have the camper on, but I have a 7 pin trailer electrical connection, I ran 6 ga wires from the surepower isolator in the truck engine compartment to the unused pins in the 7 pin trailer connector . I made a pigtail to go between the camper connector and the trailer connector. As I recall, I only seem to get about 7 A of current to my battery bank through that connection but it is sufficient to run everything in the camper and slowly add charge to the house batteries.

It may make sense to put a battery isolator in your truck as well as an in-line fuse if those are not already part of your set-up

Again I would first ask FWC for recommendations since it is a newer camper and perhaps they have learned a bit more about wiring these systems and have improved the way they are doing the wiring.

Hopefully a few others who have set up the truck to camper with battery bank will comment.

Regards,
Craig

 

[Vic Harder]

Hey Durango/Steve!

Unlimited space? Woot! And vented too it sounds like. Easy to get at? Do you want to check battery electrolyte every month? Add water? If you are ok with that, dual 6 volt flooded lead acid batteries are way less expensive than AGM or LiFePo4. If all that sounds like greek, go with dual 6v AGM batteries. I like Rolls/Surrette but Crown batteries are very good as well.

I put in 2g wire, all the way from the truck batteries to the camper batteries. I can get 80+ amps over that wire, no problems. As Craig says, you will want fuses on both ends. I used 100A. And some Anderson Power Pole connectors to break the connection between truck and camper when I need to take the camper off.

Part numbers and more details are available if you think this is the direction you want to go.

Vic

 

[Durango1]

Thanks, guys!

Vic, once I bolt my flatbed campers on they are more-or-less permanent so they can be wired in without the connectors. And I'm not super great about checking water levels. So I better go with the AGM's. Are the dual 6v AGM batteries going to be that much better than the batteries that come standard from FWC?

And given that I've got lots of space where would be the size and capacity 'sweet spot' taking into consideration the 160 Watt solar (I also carry a 100 watt portable solar suitcase too) and the 220 amp generator?

Thanks in advance!

Steve

 

[Durango1]

So Vic (and all you other electrical geniuses) which of the dual 6v AGM Rolls/Surrette batteries should I get? Taking into account the 160 watt solar (and sometimes a 100 watt portable solar) and the 220 watt alternator hooked to the camper with 2 gauge wire. I guess I'm asking where is the balance on 'generating (solar or alternator) vs. storage'?

The batteries would be housed in a underbody aluminum box 36" long x 18" deep x 18" high. All thoughts for this electrical neophyte welcome!

Thanks! Steve

 

[Vic Harder]

So many variables... Your alternator only comes into play if you move campsites, and are driving for an hour or more. Solar, ideally, is 2x the amount of battery. As in 160W solar = 80AH battery. That assumes you are draining the batteries every day.

So, are you? Draining the batteries every day? That depends on draw... what's attached and powered on?

Taking a complety different approach, knowing the size of the box means you can just buy batteries to fit, and start there. If you need more solar later, you can add it later. Batteries weigh the most, and arguably also cost the most. You have LOTS of room in that underbody box. You could easily fit these:
http://www.rollsbattery.com/wp-content/uploads/batteries/S6-370AGM.pdf
and have the biggest battery bank of anyone on WtW. Do you need that much? Well, at 335AH, you would have 50% of that usable = 170AH. If you didn't start up the truck and had no sun and draw 60AH a day, you could park for 3 days before needing to charge.

See... lotsa variables.

I doubt that helped.

P.S. I'm no genius!

 

[ckent323]

Steve,

I wrote a thought process down in the following link that I hope will be helpful.


http://www.wanderthewest.com/forum/topic/15467-solar-power-for-your-camper-%E2%80%93-where-to-start-hint-the-solar-panels-are-last-in-this-list-of-steps/


Regards,

Craig

 

[pvstoy]

I had a private conversation with Steve and feeling it would be ok to post it here to gather more advice. The conversation is about wiring and battery for his new setup Grandby / Dodge 1 ton. Please jump in and add any corrections and advice you may have. Steve is in "red" text and I'm in "blue" text. Thanks!

Wiring:
For my Hawk model I bought from you I do plan on replacing wiring from engine all the way back to the camper batteries with heavier gauge and add solar panels.
​ Patrick, this one is driving me crazy. Denny Saunders son, Steven, is installing the campers for Denny know. I asked him what gauge wire he normally installs. he says "10 gauge" I explain I've always heard it should be much heavier. ​Steven responds, "10 gauge wire is rated for 30 amps and all the FWC is rated for is 15 amps so why do you need a heavier gauge?" (I took notes.) So who is right, Patrick? (Remember I'm a dummy!) And what wire size would you recommend?





Yes the camper itself from the battery to everything inside the camper is a 15 amp system and 10 gauge works and they drop wire size to fans and pumps and such. 10 gauge from the inverter / charger to battery is fine for what it puts out and relativity short distance it travels.


.


The problem and issue is from the alternator to the camper battery. Yes the 10 gauge wire can handle 30 amps but for 10 feet there is 5% loss at 12 volt DC. It is recommended that you keep the losses down to 3% for critical stuff like charging the battery bank. You need to realize how many amps your alternator is capable of putting out, of course 220 amps is the max at certain RPM and how much can the battery bank take at a given time. That is where the newer smart truck charging systems read what the battery need and feeds it. Also there is concern going along with the wire loss it is generating heat, and we know heat is a bad thing. So it comes down to how long of wires from alternator to the battery bank? How many AMPS can you get with your system? Need to size breakers ( resettable fuse) good to have one on both ends on positive side.


.


Ask on WTW, those guys are great with their knowledge, Give them your distance of wire and what the truck is capable supplying amps to the camper battery. They should give you a wire gauge that should carry the volts and amps and maintain a 3% loss. That would be the sweet spot.


Link you can enter info and calculate percent loss, ok to enter say about 14.5 volts what voltage the alternator might put to the camper batteries.


http://www.calculator.net/voltage-drop-calculator.html?material=copper&wiresize=3.277&voltage=14&phase=dc&noofconductor=1&distance=10&distanceunit=feet&amperes=30&x=78&y=19

.
Batteries:
One other big question, Patrick. FWC is supplying these ​batteries in the 8A24 size. (I don't know if they are what you have or not.) However, since I want to drill down and install batteries in the aluminum under body box below I have virtually unlimited space. They said two 6 volt batteries like these would give me more capacity. But I could also get bigger 12 volt batteries. My input power is: standard factory installed 160 watt roof panel and occasionally a 100 watt portable panel if needed. I do hate running short on and obsessing over power. Where is my 'sweet spot'? My head hurts. Any thoughts?

The 2015 Hawk has 2 Fiamma 80 amp/hr AGM. So that puts them in parallel for 160 amp/hr 12 volt system. You are looking at 2 6-volt in series to give you 12 volt system. And looks like 213 amp/hr? In series you do not add the amp/hours, only in parallel. At 213 amp/hr you are better than what the 8A24 gives you. Why don't FWC use group 27 or 31 series? Why the smaller 24, maybe it fits better in a wider campers they build.

The 6-volt system gives you a bigger battery with larger plate system, bigger depth to draw from. But they come with a higher cost. Did you ever run down the Hawks batteries or needed more? Then up sizing makes sense.

Solar it is recommended battery amp rating be half of panel wattage. 160w x 90% = 144w
you may never have to deploy the portable panel but just be aware that whatever you draw from the battery the solar may or may not replace it. Your alternator will do a good job if you travel often. Or if you sit for a long time the generator. Generator does good to 90% then solar can pack in the rest.

 

[klahanie]

^ I'd go way heavier than 10ga. But again it depends on the plan for recharging and the requirements of the batteries.

Myself I rely on alternator(s) so I want to as many amps sent through and as quickly as possible during the constant current stage of charging (bulk, stage 1). If I'm only driving a hour or two at least I've thrown a bunch of amps at the batteries (the Lifelines can take a 1C charge rate, 105Ahr batt, 105 amp charge current)

My Lifeline's want 14.3v for the constant voltage stage (absorption, stage 2), fortunately my alternator outputs a higher voltage, But not by much so voltage drop is very important here. 3% might be a good rule of thumb for running electronics but in my case I worked backwards from required absorption voltage. So using Patrick's calculator link but changing the output voltage to 14.5v (my alternator) 10ft of #10 at 30A result in terminal voltage of 13.9V, that's not going to charge my AGM beyond the bulk charge, say 80% capacity. Again, if the plan is to top up with solar that might work. But for me I'd have to go to 4ga to limit the drop to a terminal voltage of 14.3v. And that's at 30amps not the 100 or 200 that my alternators are supposed to be capable of (would also need a bigger ga).
** ON EDIT loss increases with current. so in the example above at 3A voltage only drops to 14.44 which could work, so what do I know??

Wire is expensive but going up a few sizes is not THAT expensive.

The third stage of charging is float. My batts want 13.3v, here's where a thinner ga wire can limit alternator voltage so batts aren't overcharging when full. In my case, I'm not worrying about it - can't have it all. **ON EDIT maybe a smart device could manage this. Definitely see why some eschew the alternator and only use solar, system capacity permitting.

For solar, I don't know much but seem to remember you want at least .2C charge rate for your batteries (1/5 of Ahr rating for the batt bank) or could be undercharging.

----

To Steve,

Is 10 feet long enough?

The added underhood, underbody wiring should be protected with nylon convoluted tubing (loom) or similar.

Finally, I didn't post before but am curious why you're not planning to use the FWC space for batteries. I'm thinking the under deck storage is premium real estate and lockable to boot. FWC space too small or other plans for it ?

 

[Durango1]

Finally, I didn't post before but am curious why you're not planning to use the FWC space for batteries. I'm thinking the under deck storage is premium real estate and lockable to boot. FWC space too small or other plans for it ?

God question. Remember that this is the flat bed model and the batteries are in a small compartment accessible from the outside via a cute little locked door! So since this will be a regular cab my wife has lost a lot of space for her junk that she uses when she gets out, of the truck. The idea is this battery space will become her outdoor 'glove box'.

And with two 36" and two 24 underbed boxes, a 6" high x 28" wide 'shovel box' running the length of the bed and a transverse 80" long x 20" wide 'garage' 42" high between the camper and the truck we shouldn't be hurting for storage space!

 

[Vic Harder]

10' is unlikely to be enough. My Hawk/GMC needed 50' (25' each way).

 

[paddlesurf.net]

Would something like a ctek d250s solve the charging problem without having to rewire from the truck alternator to the battery bank?

 

[pvstoy]

10' is unlikely to be enough. My Hawk/GMC needed 50' (25' each way).

Sorry Vic I just threw 10' out there as a number to show how much loss was with a 10 gauge wire for just 10 feet at 30 amps. The actual distance Steve will have to measure to calculate percent loss and pick the proper wire gauge to match. Thanks for giving a thought how much distance you had and you went 2 gauge for 25 feet?

 

[Vic Harder]

Sorry Vic I just threw 10' out there as a number to show how much loss was with a 10 gauge wire for just 10 feet at 30 amps. The actual distance Steve will have to measure to calculate percent loss and pick the proper wire gauge to match. Thanks for giving a thought how much distance you had and you went 2 gauge for 25 feet?

yes, 2G right from battery posts on truck battery, through a 100A Blue Sea resettable breaker (285 series i think) shunt for the Blue Sea mini-ammeter that sits in the overhead console of the truck's cab, 2G wrapped in flex cover and zip tied to existing plumbing/wires all the way back along the frame member to the truck bed, grommetted hole in bed to an Anderson 100A connector, into the camper (about 18" of dangling 2g coming out of the camper) and along the front window in the water tank/battery box to another 100A breaker, and into the ML-ACR and then into the camper batteries.

 

[ckent323]

Vic,

I have been planning to install the Blue Sea ML-ACR in place of the Surepower 1202 already in my truck.

I was going to bypass the IOTA charger controller with IQ-4 and take the wires directly to my camper bank. However, a consideration is that my truck only has a voltage regulator, no smart charger.

Further, the truck battery is a NAPA BAT-7235 1125 cca FLA. The camper batteries are a pair of Lifeline 220 A 6 V AGM.

from Blue Sea:

An ACR does not direct the charge to the battery that “needs it the most” or has the lowest terminal voltage. If there is a charge present on either battery, indicated by a high enough voltage, the ACR will combine the batteries.

One ACR will manage the charge between two battery banks. but the batteries need to be the same type (and probably manufacturer) because the ML-ACR can only handle one type of battery in a system.

Not sure how I am going to do this at the moment but posting this info so others also see the Blue Sea imitation to a single battery type.

Craig

 

[ckent323]

I found the Balmar Duo Charge while searching for a way to Automatically charge vehicle and house batteries of different battery types.

It seems this balmar unit is designed to accomodate that>

"The Duo Charge is designed specifically to enable its user to control charging voltage output -- making it possible to safely mix house and starting battery technologies. The Duo Charge features four different programs based on four battery technologies: Standard Flooded, Deep Cycle Flooded, Gel and AGM battery types. In addition, the Duo Charge can be programmed for 12-volt or 24-volt operation. When used with an optional Battery Temperature Sensor cable (MC-TS-B, the Duo Charge responds to a battery over-temperature condition by automatically discontinuing charging output."

http://www.balmar.net/products/digital-duo-charge/

I am going to start a new thread related to this device.

Craig

 

[pvstoy]

Craig this company has a lot to sell for complete systems for marine systems and I'm a little confused on two things.

1) The wiring diagram has the alternator wire going to the house battery then to the DDC unit. But there is a "S" wire from the battery post of the house battery going to what I think is a regulator. Then after the DDC unit it connects to the starter battery.

2) It is a 30 amp system meaning that is what the battery will get. But adds "An optional solenoid control enables higher start battery charging output when required."
.
.

Digital Duo Charge: DDC-12/24
[SIZE=large]Multi Bank Charging[/SIZE]

• [SIZE=medium]The DDC is a Solid-State Battery Combiner[/SIZE]
• [SIZE=medium]Control Voltage and Current between House and Start Batteries[/SIZE]
• [SIZE=medium]Eliminates the Need for an Isolator, Relay or Manually Operated Battery Switch[/SIZE]
• [SIZE=medium]Used in Concert with Max Charge or ARS-5 Regulators[/SIZE]
• [SIZE=medium]Can also be Employed without a Balmar Regulator[/SIZE]
• [SIZE=medium]Works in Both 12V and 24V Applications[/SIZE]
• [SIZE=medium]House and Start Batteries can be different technologies[/SIZE]
• [SIZE=medium]Start Battery Temperature Sensing Available with the MC-TS-B Sensor Cable[/SIZE]
• [SIZE=medium]4 Battery Programs Supported for the Start Battery:[/SIZE]
  [SIZE=small] Standard Flooded, Deep Cycle Flooded, AGM and Gel Cell[/SIZE]

[SIZE=small]The Digital Duo Charge[/SIZE] (DDC-12/24) provides a “hands off” solution for charging two battery banks without the use of problematic isolators or manual battery switches. [SIZE=small]During charging the DDC-12/24 monitors voltage at the house battery. When voltage exceeds the set minimum (typically 13.2V in a 12V system and 26.4V in a 24V system) the DDC-12/24 automatically engages, providing up to 30A charge current to the starting battery. When no charge source is present, the DDC-12/24 separates the batteries so the starting battery won’t be accidentally discharged into the house battery. An optional solenoid control enables higher start battery charging output when required.

[/SIZE]

 

[ckent323]

Pvstoy,

I realized my questions amounted to hijacking this thread so I started a new topic. Apologies to Durango1 and others.

All my subsequent comments about charging different type batteries will be at this new topic:

http://www.wanderthewest.com/forum/topic/16087-charging-vehicle-and-house-batteries-that-are-different-types-eg-fla-and-agm/



Craig

 

[pvstoy]

No worries. That is a piece of the puzzle that goes with the charging system. In my 2015 Hawk it has the Surepower 1314. I do have AGM in both places so thinking of a better system. Don't know what FWC is putting in Steve's new Grandby but I'm sure he has a similar interest.