My poor man's Earth Roamer design.

L

Lovetheworld

Active member
I have some experience in this field in that I am building a 48V offgrid house, and have built a 48V scooter before.

Some points:
- Try to use the Victron Multiplus (hmm, what is available at 110V?) instead of Quattro, as that gives you the freedom to charge from grid power, for just a small price difference. Even though it is not your intended use.
- I have a Victron Multiplus on a 12s lithium system (so bit on low voltage side) and it allows me to pull 6000W

- Regarding the BLDC idea, just like the batteries, you have to reuse components from electric vehicles.
I have also played with the BLDC idea for my smaller camper van. If I take a 2KW electric motor from my electric scooter, it is cheap.
At these power levels (lets say below 10KW) a Kelly controller is not that expensive either. And these motors allow for belt drive I think but you can also solve it in different manners.

- Regarding the batteries: At this time I am using a module from a BMW i3. Which is 12s and a nice size. Reusing the original BMS board inside.
I am assuming you are aware of proper battery management systems so that you don't burn down your truck?
I am unhappy with buying more at 200 Euro per kWh. Same for Tesla modules.
The only way to get it cheaper is to buy possibly degraded batteries in complete shape.
Meaning you buy a Leaf pack of 24kWh and get in worst case 17kWh (if it is a 2012 model, they degrade because no thermal management)
Other option is Outlander PHEV, but they are the heaviest per kWh.
Model 3 packs are interesting because of availability but their modules are at 100V level.

- Regarding heating and cooking. If you're doing that amount of solar panels and batteries, why mess with diesel?
Get rid of the smell :p
Induction cooking it is, and try to get a A/C (in roof or in bench) that can also heat. That is much more efficient that heating directly electrical.
But with electric heaters in such a small compartment and with 40kWh is storage, you will also get away with it in many occasions, unless you are talking overlanding in long winter areas.
 
Joe917

Joe917

Explorer
CappyJax said:
How are you measuring that?
Click to expand...
Measured with a Bogart Trimetric.
I use Amp hrs
The 2520 Watt hrs would be 210 Amp hrs. In perfect conditions I have seen 40Amps off the panels, but only at mid day. morning and evening those numbers drop drastically. Don't base your projected power on 12 hrs of the peak output.
Are you living off solar with your trailer now?
 
C

CappyJax

Member
Lovetheworld said:
I have some experience in this field in that I am building a 48V offgrid house, and have built a 48V scooter before.

Some points:
- Try to use the Victron Multiplus (hmm, what is available at 110V?) instead of Quattro, as that gives you the freedom to charge from grid power, for just a small price difference. Even though it is not your intended use.
- I have a Victron Multiplus on a 12s lithium system (so bit on low voltage side) and it allows me to pull 6000W

- Regarding the BLDC idea, just like the batteries, you have to reuse components from electric vehicles.
I have also played with the BLDC idea for my smaller camper van. If I take a 2KW electric motor from my electric scooter, it is cheap.
At these power levels (lets say below 10KW) a Kelly controller is not that expensive either. And these motors allow for belt drive I think but you can also solve it in different manners.

- Regarding the batteries: At this time I am using a module from a BMW i3. Which is 12s and a nice size. Reusing the original BMS board inside.
I am assuming you are aware of proper battery management systems so that you don't burn down your truck?
I am unhappy with buying more at 200 Euro per kWh. Same for Tesla modules.
The only way to get it cheaper is to buy possibly degraded batteries in complete shape.
Meaning you buy a Leaf pack of 24kWh and get in worst case 17kWh (if it is a 2012 model, they degrade because no thermal management)
Other option is Outlander PHEV, but they are the heaviest per kWh.
Model 3 packs are interesting because of availability but their modules are at 100V level.

- Regarding heating and cooking. If you're doing that amount of solar panels and batteries, why mess with diesel?
Get rid of the smell :p
Induction cooking it is, and try to get a A/C (in roof or in bench) that can also heat. That is much more efficient that heating directly electrical.
But with electric heaters in such a small compartment and with 40kWh is storage, you will also get away with it in many occasions, unless you are talking overlanding in long winter areas.
Click to expand...
The Quattro is more expensive than the multiplus as they not only allow charging from the grid, they also allow charging from a generator and have an automatic transfer switch. Not that I plan to have a generator, but I’d rather have the option than not.

And I will be using electric for everything except for heat below around 0F. That is when the heat pumps stop working well. Also, when it gets that could, there probably won’t be a slow of solar available. So it will have as Espar for heat and hot water. Also nice to preheat the engine.
 
C

CappyJax

Member
Joe917 said:
Measured with a Bogart Trimetric.
I use Amp hrs
The 2520 Watt hrs would be 210 Amp hrs. In perfect conditions I have seen 40Amps off the panels, but only at mid day. morning and evening those numbers drop drastically. Don't base your projected power on 12 hrs of the peak output.
Are you living off solar with your trailer now?
Click to expand...

Are you running down the batteries enough that they can take a full days charge?
 
Joe917

Joe917

Explorer
40 amps is best case, full sun, mid day, batteries accepting full charge.
Are you living with solar now?
 
Joe917

Joe917

Explorer
On another point, I think the hallway shower is a bad idea. A shower or shower wet room does not take much space. All high end overland trucks have them. they are also a great place to hang and dry wet gear after a hike.
 
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C

CappyJax

Member
Joe917 said:
On another point, I think the hallway shower is a bad idea. A shower or shower wet room does not take much space. All high end overland trucks have them. they are also a great place to hang and dry wet gear after a hike.
Click to expand...
I have been leaning that way as well. I decided to have a shower area and just hang a closet organizer in the show when not in use. Then just swing the closet organizer out of the way when I need to take a shower.
 
Joe917

Joe917

Explorer
CappyJax said:
Yes, I have 800W of Solar on my TT.

Ok, so 40A comes out to around 576W of solar, and you have 630W of panels. That is 91%
Click to expand...
Yes and that is peak output, mid day in Columbia. Not typical output. You have the solar, keep track.
 
L

Lovetheworld

Active member
Great, I am also currently running a SimpBMS between my BMW i3 battery module (now just one module, will expand) and Victron. Having a Cerbo screen on it, battery state becomes visible.

Regarding solar controller, I went with one of the most powerful ones of Victron. It allows me to connect up to 5000Wp of solar.
The ones with MC4 connectors are convenient. However, don't take one big one for a sliding roof.
They come with 3 sets of MC4 connectors, but unlike most grid connected inverters, in this case it is all connected internally I am pretty sure.
This means you don't get 3 separate strings with their own MPPT process. Which you would get in most grid connected inverters.
Don't be fooled by that, and by 3 physically separate controllers.
Probably the 150/45 MC4 model for you. However, don't forget you can even partition it even further, and that the 100/20 48V is quite small and cost effective.
 
C

CappyJax

Member
Lovetheworld said:
Great, I am also currently running a SimpBMS between my BMW i3 battery module (now just one module, will expand) and Victron. Having a Cerbo screen on it, battery state becomes visible.

Regarding solar controller, I went with one of the most powerful ones of Victron. It allows me to connect up to 5000Wp of solar.
The ones with MC4 connectors are convenient. However, don't take one big one for a sliding roof.
They come with 3 sets of MC4 connectors, but unlike most grid connected inverters, in this case it is all connected internally I am pretty sure.
This means you don't get 3 separate strings with their own MPPT process. Which you would get in most grid connected inverters.
Don't be fooled by that, and by 3 physically separate controllers.
Probably the 150/45 MC4 model for you. However, don't forget you can even partition it even further, and that the 100/20 48V is quite small and cost effective.
Click to expand...

I am going to use multiple mppt controllers to counter shading losses. It isn’t that much more expensive to have small controllers for each panel over one large one.
 
Alloy

Alloy

Well-known member
CappyJax said:
70% is based on a flat panel and full sun exposure. I didn't think I needed to explain that.
Click to expand...

The numbers I mention are with tilted panels. We get nothing if the panels are left horizontal.

.....edit 1/2 are fixed and 1/2 are portable
 
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