Help in designing an electrical system for an overland build!

[Atmadeep1993]

TLDR: Building an overland vehicle, need help with designing the electrical system.

Mechanical engineer here with basic knowledge of electrical engineering! I am in the process of designing an electrical system for my overland build. I will be using Mastervolt components as I will be getting a serious discount from them. The core structure of my build consists of the following:

Generate: Alternator, Solar, generator & 120V 50 Hz AC shore power.

Storage: 24V DC Lithium batteries.

Usage: 24V DC loads & 120V 50 Hz AC loads

Management, Communication: Czone, MasterBus for digital switching, and global monitoring

I would be really appreciative if the community provides any input in designing this system. I will ask very specific questions as the design progresses and share my build. Thank you, everyone!

If anybody has any questions as well, please let me know.

 

[Peter_n_Margaret]

What is the scale of the loads and the travel intentions?

Our system is designed for full time off grid, so the shore power is a complication that can be eliminated.
Generators are anti-social and not usable universally, so likewise it is eliminated from the start. If you can do without it sometimes, you can do without it always.
We maximise the use of solar with the alternator as back-up.
It is likely that some DC loads will need to be 12V.
Our new build will have no propane, just electric (DC 12V and AC via inverter) and diesel (for heating and hot water).
Cheers,
Peter
OKA196 motorhome

 

[Atmadeep1993]

I haven't zeroed in on the exact loads yet. Depending on suggestions, everything might change. The rough estimates are as follows:

AC Loads: Induction cooktop - 1800W, Convection Microwave - 1200W, Washer - 300W, Dryer - 800W
DC loads: Aircon - 900W, Water maker - 500W, lighting, fans, water pumps, consumer electronics, - 400W?

We camp quite a bit in RV parks as well so shore power would be great. Plans are to extensively visit Northern Canada, Alaska, parts of Greenland, Northern Europe so cannot solely rely on solar, going with a Onan QD 3200.

Comfortable with US standard, so 120V 60 Hz?

 

[Peter_n_Margaret]

No 120V in Europe. Another reason not to have shore power. There is lots of off grid free camping in many countries in Europe but it does vary a lot from country to country. RV parks tend to be expensive (and you will not be able to run the generator), except in Eastern Europe.
Northern Europe in summer is fine with solar. Low fridge loads and cool panels. They work exceptionally well. If the budget allows, an EFOY is a great silent back up.
The alternator will provide huge battery charging capability.
Be sure the lithium BMS can handle the amps you need for the inverter loads.
"Dryer 800W" ?? Cloths dryer? We can isolate our bathroom and heat it via hydronic diesel (which also provides hot water) to dry the cloths. The bathroom has a sliding window that allows it to be left open a little while driving to facilitate this.
I would suggest a small Mitsubishi Heavy Industries split system aircon. Much more efficient than any of the DC RV units and a fraction of the cost.
Don't know about water makers, maybe the same applies. We travelled all over Europe with chlorination treatment plus 0.5um carbon block filtration.
Cheers,
Peter
OKA196 motorhome

 

[unreng]

Find a victron wiring diagram and input your pieces to their puzzle:

https://www.victronenergy.com/blog/wp-content/uploads/sites/10/2022/12/Screenshot-2022-12-30-at-10.47.43_216243023.png

https://community.victronenergy.com/storage/attachments/19716-multiplus-ii-3kw-2x120vac-12vdc-400ah-li-lynx-smar.pdf

https://www.victronenergy.com/blog/wp-content/uploads/sites/10/2019/07/Screenshot-2019-07-08-at-12.57.09_106433036-e1562587369384.png

https://www.victronenergy.com/blog/wp-content/uploads/sites/10/2019/07/Screen-Shot-2019-07-15-at-21.22.59_107067951.png

can i get discounted mastervolt parts & pieces?????

 

[unreng]

Shore power plug = https://smartplug.com/

depending upon the size of your battery system, may need multiple macplus units to recharge the house batteries = https://www.mastervolt.com/products/mac-plus-serie/

you’ll need an appropriate inverter/charger = https://www.mastervolt.com/products/combis-inverter-charger/

solar charger controller (may want to go victron for this as mastervolt has limited selection) = https://www.mastervolt.com/products/solar-charge-controllers/

also consider BEP‘s Pro Installer series of switches & fuse holders & bus bars & etc for the cable connections. I did not know about BEP until after my build and it would have been a lot more compact and efficient. https://www.bepmarine.com/en/Products/Pro-Installer.

Use Ancor or other tinned copper for all cabling = https://www.ancorproducts.com/en/products/wire-and-cable

 

[Atmadeep1993]

Thank you so much, everyone. This really helps! So far this is what I have done. Please keep in mind that I am designing this electrical as an overkill system to compensate for future demands (like a recirculating shower & tap from orbital) as well, so some systems may appear absurd or too big. I will add components ordered with questions below it. I prefer to have a professional grade system so not going cheap on components or installation.

Batteries: Aiming for a 35 kWh system to have an usable capacity of 30 kWh. To that effect, I just ordered MLI Ultra 24/6000 - 6 units for a total capacity of 36kWh (1380 Amp-hours at 24V DC). Now do I need buy their Ultra connecting kit 24V for all the 6 battery units?

Inverter/Charger: CombiMaster 24/3000 - 70 (120V) - 2 units for AC load capacity of 6kW and a DC max charging current of 140A. Haven't ordered yet, so should I go with 2 units of this in parallel or a single CombiMaster 24/4500 - 120 HT (120V)? Does the DC Max Charge currents simply add up in a parallel connection? Like 2 70A units adding upto 140A max charge current?

Alternator: Alpha 24/110 - III with the Alpha Pro III charge regulator to have MasterBus/CZone control. Now, should I replace the OEM alternator on the truck with this and design a combined truck/habitat electrical system or mount this alternator separately for a complete separate electrical system for the habitat?

Solar Charge Controller: SCM60 MPPT-MB solar charge controller. Any recommendations on solar panels will be much appreciated, higher efficiency better! My plan is to have at minimum 2400W of rooftop solar. Also planning for a 600W deployable solar as well, how much complexity this will add?

Distributor & Shunt: Mastershunt 500 & DC Distribution 500.

Generator: ONAN QD 3200.

General questions: Watched a lot of YouTube videos, all with Victron systems. What is the Lynx distributor system and what is the Mastervolt equivalent? Secondly, why do I need the MacPlus units and how do they fit into the whole puzzle? Any other general recommendation as well?

Some musings, please tell me if this is crazy but is it possible to have shore power input in both 220V and 120V to account for majority global standard? Secondly, for secondary circuits it it a terrible idea to have both 120V AC and 220V AC? I want the sweet Camec wall mounted washer. Any similar washer recommendations in 120V AC? Lastly, some people have suggested having 12V DC as well. How difficult is it to incorporate a DC-DC converter for some 12V DC circuits?

Big thank you to everyone! Unreng, I will see about what I can do about Mastervolt pieces for you. I can get them for discount and maybe I can resale them back to you. Thanks!

 

[Peter_n_Margaret]

Solar Charge Controller: SCM60 MPPT-MB solar charge controller. Any recommendations on solar panels will be much appreciated, higher efficiency better! My plan is to have at minimum 2400W of rooftop solar. Also planning for a 600W deployable solar as well, how much complexity this will add?

Multiple solar controllers work well together and provide redundancy. Multiple smaller units are also often cheaper than large units. For my new build I will have a small controller for each large panel (about 2kW total).
This will also assist if some panels are getting different light due to angles or shade where diodes will cause additional losses.
The 600W extras can simply plug into a solar controller that has capacity via an Anderson plug. Don't be tempted to put a controller on the panels. They need to be close to the batteries.
Same philosophy applies to the inverter. I would choose 2 in parallel to provide redundancy.

Refrigeration..... I will be installing a domestic AC fridge/freezer (about 210L) with inverter motor and running on a small (300W) separate inverter. Small inverter because it needs to run 24/7 and I don't want the losses of running the larger inverter when it is not required. These modern units are better and cheaper than the traditional DC stuff.
Cheers,
Peter
OKA196 motorhome

 

[Peter_n_Margaret]

ps... If you insist on having shore power, why not limit it to feeding a battery charger (maybe 2? One 120V60hz and one 240V50hz). Then everything else is always constant.
Make every appliance possible AC. The few small DC things are easily handled by a 24V-12V step down transformer.
Cheers,
Peter
OKA196 motorhome

 

[unreng]

System schematics - Victron Energy

A system schematic shows schematically how Victron Energy devices are connected to each other. Find schematics for your product.

www.victronenergy.com

https://www.victronenergy.com/upload/documents/Catamaran-setup-Quattro-5KW-230VAC-24VDC-600Ah-Li-Lynx-Smart-BMS-&-distributors-Cerbo-GX-touch-generator-MPPT-Extra-Alternators-&-Alpha-Pro-III-regulators.pdf

Ummm… how large is your rig?? 2400watts of solar is 6 mondo panels. If there’s a roof hatch or rooftop a/c or maxxfan, that limits space.

600watts of portable solar??

3000watts of solar is skoolie territory…and a really long time to recharge 35kwh of battery.

try the bifacial panels from canadian solar https://www.canadiansolar.com/bihiku/

a dc step converter can easily be used to convert 24v to 12v.

A worthwhile resource https://www.victronenergy.com/upload/documents/Wiring-Unlimited-EN.pdf

lynx distributor = mastervolt distribution
lynx smart shunt = mastervolt shunt

macplus allows the house batteries to recharge with excess energy from the alternator that charges the starting batteries.

https://manuals.heartlandowners.org/manuals/Electrical/Basic%20Electrical%20Info/Understanding%2050%20Amp%20Shore%20Power%20System.pdf

Why the multiple levels of redundancy??

~620lbs in batteries (103 x 6)? Gonna need some heavy duty battery brackets with appropriate securement.
and each 230ah battery can take 80amps charging (recommended), so if you are at 50% capacity, that’s ~700ah’s or ~9 hours at 80 amps

MLI Ultra 24/6000 | Mastervolt

Compact 24V-5500Wh Lithium-Ion battery. High capacity. Ideal for running heavy loads for long periods. Short charge times. Saves up to 70 % in space and weight

www.mastervolt.com

the ultra connection kit is a compact battery switch & fuse that mounts to the battery. A switch is helpful if you ever need to disconnect a battery from the system without shutting down the entire system. If it helps, thank of it as a really big circuit breaker, you flip the switch to de-energize the circuit/battery. it’s a blue sea switch and class t fuse holder on a bracket that connects to the battery.

class t fuses are what should be used on any system with lithium batteries. The batteries can discharge at 500amps, so you need at least a 500 amp or 600 amp class t fuse.

https://www.grainger.com/product/BUSSMANN-Fuse-600-A-Amps-4XH34

regarding the alternator, without knowing the vehicle or engine, adding a second alternator can be quite difficult. if the engine is already capable of a second alternator, then go for it.

“TIP: A second alternator on the main engine, combined with a larger battery bank and inverter, could be an alternative for a generator.”

Alpha 24/110 III | Mastervolt

24V/110A Mastervolt Alpha alternator. Fast & complete charging of starter and service batteries. Power supply for all consumers. Includes charge regulator.

www.mastervolt.com

 

[unreng]

Fwiw,
The fuses linked here are for AC.
While probably be ok at 24V DC. But really should never use AC fuses on a DC system.
Further,
500A fuse should only be used if rest of the circuit conductors and/or devices will handle 500A.

huh??

Not sure what fuse you’re talking about.

Product Details
Catalog Page179
Amps600 A
AC Voltage Rating300V AC
DC Voltage Rating160V DC

 

[Peter_n_Margaret]

Ummm… how large is your rig?? 2400watts of solar is 6 mondo panels. If there’s a roof hatch or rooftop a/c or maxxfan, that limits space.

I avoid "stuff" on the roof. My new build will have about 2000W of solar, mostly from 430W light weight panels. The vehicle is 20ft long.
There is always somewhere else to put panels

I have been using 230V AC circuit breakers for 20 years. They are rated to 48VDC. On DC they will take root 2 times longer to trip.
Cheers,
Peter
OKA196 motorhome

 

[Atmadeep1993]

I am holding off on ordering more stuff from Mastervolt as less options and much less resources available for DIYers. A very specific question about inverter/charger combinations!

So, from the input side I plan on having at least two sources of AC power, shore power as well as generator. The Mastervolt CombiMasters have 1 AC input as compared to Victron Quattro with two inputs. Additionally, the Quattros have bigger capacity as well. If I end up using two Mastervolt CombiMasters, how do I account for two AC inputs?

Thanks!

 

[Alloy]

Shore power plug = https://smartplug.com/

depending upon the size of your battery system, may need multiple macplus units to recharge the house batteries = https://www.mastervolt.com/products/mac-plus-serie/

you’ll need an appropriate inverter/charger = https://www.mastervolt.com/products/combis-inverter-charger/

solar charger controller (may want to go victron for this as mastervolt has limited selection) = https://www.mastervolt.com/products/solar-charge-controllers/

also consider BEP‘s Pro Installer series of switches & fuse holders & bus bars & etc for the cable connections. I did not know about BEP until after my build and it would have been a lot more compact and efficient. https://www.bepmarine.com/en/Products/Pro-Installer.

Use Ancor or other tinned copper for all cabling = https://www.ancorproducts.com/en/products/wire-and-cable

BEP ANCOR BlueSea and a raft (or a boat load) of other brands are now owned by Navico.

Home | Navico Group

Navico Group is a global leader in technology for marine, RV & specialty vehicle and beyond. Explore integrated solutions from the most trusted brands.

www.navico.com

For a simple 200Ah system that might have a 400W inverter I'll use BEP. For larger systems I'll pick (especially buss bars) and choose from each brand.