System Design Help

[Bigc3031]

I've been pouring over the forum and vendor web pages and I am having a hard time figuring out what I need. Would any of you be willing to share your experience and advise me a 12v buildout?

I have an F350 on the way and will be installing an AT Overland Atlas for the cap. The truck will have the dual battery/dual alternator system however I want my truck bed/living quarters powered completely independant to the truck. The cap will have a 170watt solar panel.

What will I need to power:
National Luna 60L fridge/freezer
Maxair fan in topper
Truma heater
BPAP machine
interior and exterior led lighting for camp
charging phones/tablets

I just ordered a sunfunkits 300AH LifePo4 battery for the system.

I would like to charge from solar, the trucks alternator and shore power.
I don't think I need an invertor at this time.
Light dimming is nice but not a must have.
A switch panel/touch screen would be ideal.
12v, USB and anderson plugs can be placed in the topper or in self built cabinetry.

For camping use I will be offgrid for up to a week however I use the truck daily and the fridge will be in constant use aside from the winter.

I want a quality system and have looked at victron and red arc but frankly I am just lost.

Thank you in advance for your help!

 

[dstefan]

You might consider this:

DC-25 Power Pack

The National Luna Power Pack DC25 blends the convenience of a portable battery system and the performance of a DC-DC battery charger with MPPT solar regulator. This combination results in a self-contained split-charge system that is at-home in the vehicle or in camp and can be used to power...

www.equipt1.com

I know Mario at AT specs these in some of his shell camper builds. I went this way and I’ve been very happy with it for 2 1/2 years. If you don’t feel like piecing together a system, this works extremely well. It looks expensive at first glance, but you’re getting a power distribution system, an MPPT controller, and a DCDC charger all in one package. They also include 20’ of 6 gauge cable for the starter battery/alternator connection. Nearly plug and play

I put a 100 ah Battleborn LIFEPO battery in it and I run pretty much everything you’ve listed, with the exception of the CPAP. I have had my battery last for as long as five days running it down to 40% without having move the truck or using any solar. In that case, I was really trying to test the capacity of the system, and we were running everything a lot.

I used to use a portable solar panel when we were parked, but I’ve quit carrying it with us because it’s just not necessary. This also has the advantage of being easily removed, and that’s partly why I got it so I could use it in our forerunner at times.

I also installed a BlueSea four switch distribution panel for permanent wiring, and I run a 8 gauge line to that from one of the 50 amp Anderson plugs in the NL DC pack.

If I ever need more amp hours, I can plug another Battleborn into one of the 50amp, Anderson connections and run two batteries in parallel through this.

You can see the green box under my bench in this picture as well as the BlueSea distribution box in the upper left-hand corner. I did add a Victron inverter. It’s mounted on the wall behind the box, but I don’t really need it, and I took it out because it was too heavy. The only other thing I added to the package was a Victron smart shunt, so I can monitor it on the phone. The one downside to this package is I don’t really think the monitor for it is that great, but its adequate.

 

[Bigc3031]

Thanks for the detailed reply! I was bummed about the battery box, it’s just a bit too small
For the battery I am getting. That would have been a pretty ideal set up. I like your idea with the blue sea switch, I’ll check those out.

 

[Peter_n_Margaret]

My first advice is to install as much good quality solar as you can fit.
It is cheap, silent and surprisingly effective, even when you think it will produce nothing, it will deliver.
Match the solar with a couple (for redundancy) of Victron MPPT controllers, a smart shunt and monitor.
Your battery is quite excessive for the stuff you intend to run, but with a good capacity reliable input you will quickly find other stuff to run from it, so installing an inverter is likely in the (near) future, so plan for it even if you don't install it initially.
Cheers,
Peter
OKA196 motorhome

 

[Alloy]

This site runs through the options

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[Bigc3031]

Awesome, thanks for all the links and advise!

I know my battery is big but our winter months mean very little sun and I do a lot in the winter and Northern Canada so my past experience with solar has been underwhelming. I own an inspection company and will likely charge the drones and other devices off this system in the field so you are all right, I likely will end up with an inverter.

The only reason I picked the 300 amp hour battery was the price was good compared to premade 200AH batteries and I like building things so it will be a fun project.

 

[dstefan]

One of my luxury buys was a proper electrical crimper and all the bits to go with it.

This ⬆️

Also, Powerwerx is good source for quality tools, connectors, wire, etc. They also build very nice custom cables for one offs that you don't want to buy lots of wire, or terminals or specialized crimpers (eg, 50amp Anderson or heavy battery cables).

https://powerwerx.com/

 

[fratermus]

I have an F350 on the way and will be installing an AT Overland Atlas for the cap. The truck will have the dual battery/dual alternator system

Heads up if you plan to shovel Monster Current into the 300Ah LFP bank from the alternator: the dual alt setup appears to rely on the primary alt until it is saturated, then adds capacity from the secondary.

At normal charge rates the dual-alt setup should be quite happy. Depending on how much you drive (or have shore power) I'd think the alternator will be doing most of the heavy lifting in the charging department.

I would like to charge from solar, the trucks alternator and shore power.

Normal stuff, no big challenges.

solar panels -> solar charge controller -> battery bank
alternator -> [insert choice here] -> battery bank
shore power -> converter/charger -> battery bank

The cap will have a 170watt solar panel...

I want a quality system and have looked at victron and red arc but frankly I am just lost.

A 15A controller (e.g. Vic 75|15) would be more than sufficient for that panel. In northern latitudes a 10A MPPT would probably suffice. In Canada I would consider 170w of solar to be "best effort".

You could likely buy 500w of used panels cheaper than a new 170w, if such a thing interests you.

Shore power charging choices will hinge on how much time you have connected to the grid. If you only have a few hours at a time a 0.4C charge rate (120A) multistage would be preferable to shovel Ah back in. If you have overnight or more then a gentler 0.2C rate (60A) at something like 13.4v {single stage} would be easier on the cells {and less expensive}.

Alternator charging has a few variables we should consider.

• how many hours/day do you typically drive (not idle)
• what kind of charge rate did you have in mind? 50A? 100A? 150A?
• how will the bank is {be} NEG returned ("grounded") to chassis electrical? We need a complete circuit from the alt to bank and back. Frame ground? Will the bank be in the bed under the camper shell or inside the cab?

however I want my truck bed/living quarters powered completely independant to the truck.

The alternator charging gear should automagically separate the two when charging isn't present.

The value play here might be something like a Kisae DC-DC w/mppt. Solar + 50A from the alt. Redarc is decent gear but not sure about bang-for-buck after importation to north america.

The somebody else is paying for it play is 2x Victron 30A DC-DC in parallel. Over twice the cost as the Kisae above after we figure in a separate solar charge controller but it seems to be a popular option.

If you want more than 60A of alt charging you can direct-charge with the alternator or spend big money on a big DC-DC from Sterling, etc. Victron makes a 100A DC-DC but it's not particularly popular. Maybe because it has no app, or maybe because it's not photogenic enough for influencer social media accounts. It's also >$1,000USD.

According to data I've collected and my own experience, direct-charging 300Ah of LiFePO4 in the broad middle section of the voltage curve with frame ground would pull ~95A. [spectators screaming in the background: "...but what about that victron video?!??!??!"]

What will I need to power:
National Luna 60L fridge/freezer
Maxair fan in topper
Truma heater
BPAP machine
interior and exterior led lighting for camp
charging phones/tablets

I'd do the math on this to find daily power requirements if you haven't already. Ideally that happens before buying anything.

I just ordered a sunfunkits 300AH LifePo4 battery for the system.

Hopefully we have a warming solution in mind for those cold Canadian winters.

{corrections in brackets}

 

[jonyjoe101]

For solar controller I recommend the makeskyblue 60amp mppt. Its one of the few controllers that has battery voltage calibration (for voltage drop) purposes. I paid 120 dollars for mine 3 years ago and has been very reliable and use it on my 220ah lifepo4 bank 24/7.
For solar panel, 170 sounds too small for areas with limited sun. During winter I was using a 240 watt solar panel and it couldnt keep up with my battery. I upgraded to a 365 watts LG panel and havent had anymore problems. I have a 220ah lifepo4 and also a 312ah li-ion battery bank both of them power my fridge and other devices. The 365 watts easily keeps both batteries at 100 percent even in winter. No need for alternator/generator/shorepower on my system.
This is the makeskyblue 60 amp mppt producing 375 watts from my 365 watt panel.


For lifepo4 you need a coulombmeter. No need to spend hundreds on a victron, you can get a TK15 which does the same thing for less than 50 dollars. Its what I been using. This is the 50 amp model, but you can find some that can read up to 350amps.

 

[Bigc3031]

Thank you all for the amazing responses here!

With your help I’ve selected the following:
victron Orion 12/12-30 smart non isolated DC/DC charger
victron bmv712 smart monitor
victron mppt 75/15 smart controller
victron 12v 15amp smart charger

once these come in I’m going to see if it will fit in a large Milwaukee packout to make it somewhat portable. I’ll dive into powerwerks stuff, I’ve used them before.

what is your suggested wire types?

you guys rock!

 

[fratermus]

one of the few controllers that has battery voltage calibration (for voltage drop) purposes.

Voltage calibration accounts for scenarios where the controller consistently reads low or high. Example: Vbatt + 0.2v across the board. The MSB manuall alludes to this: "If you have accurate device and need to calibrate the battery voltage, then calibrate it by D06"

Current-induced voltage sag is a different matter; it increases as current increases. Voltage sensing aka battery sensing (comparing bank voltage to controller terminals) accurately adjusts controller output to account for current-induced sag. It's usually done with a separate voltage sense wire that carries no meaningful current and therefore has no sag:

* victron - networked smart battery sense or smartshunt
* epever (supported models) - sense wire
* renogy (supported models) - sense wire - example of premade wire
* xantrex - sense wire
* morningstar - sense wire
* etc

 

[Alloy]

what is your suggested wire types?

I use ( Ancor, Vertex ) tinned wire that is UL1426 with tinned lugs/terminals and everything gets heat shrink. Reason is the plastic/vinyl insulation is vapor permeable. I've stripped old (5-10 year) wire back 1', 2', 5', 10' and found the copper to be brown and a few times green.

Vertex Marine | International Distributors | Marine Hardware

www.vertex-marine.com

Products

ancorproducts.com

I try to stay away from welding (SAE J1127 with a EPDM cover) cable but sometime is the best solution when when dealing with heavy cables.

 

[dstefan]

Thanks for the detailed reply! I was bummed about the battery box, it’s just a bit too small
For the battery I am getting. That would have been a pretty ideal set up. I like your idea with the blue sea switch, I’ll check those out.

Just occurred to me that NL sells the interface, MPPT, DCDC charger and everything else that’s on the box . . . without the box. If you want to not DIY, this wouldn’t be a bad idea. Just have to cable it to you battery, and it allows for a remote/separated placement. Just a thought

DC-25 Distribution Box

The National Luna DC25 Distribution Box is ideally suited to fixed installations such as trailers, caravans and campers where the auxiliary batteries are separated from the charge system. The DC25 Distribution Box features a high-performance 25A DC-DC charge system that offers charging from the...

www.equipt1.com

 

[fratermus]

multiple sleeping bags is my go to

for keeping LiFePO4 banks warm?

 

[fratermus]

think lead acid.... -40 is not an issue

Just so we're clear about what's being discussed in the thread: