Fitz’ 2016 Sprinter 4x4 RB 150S Build

[Fitz]

Doug,

I ordered the fixed full-width Box Shelf direct from Aluminess, the cost was $85 plus shipping.

The folding shelf came from forum member 1der, it was from the first batch of these custom shelving units he fabricated. The cost was $200 plus shipping. I do not know if Ray will be able to hold the same pricing on future runs, that's a question for him.

[Fitz]

General Electrical Thoughts

Posts 249, 251 & 254 above speak about electrical use in general terms. This, plus several questions that have come my way, got me to thinking and I decided I would get a bit more specific. An electrical engineer I’m not, (a good name for what follows might be an Idiot’s Guide) so if anyone wants to help fill in the blanks please feel free to do so!

Battery Storage Available

My Sprinter has a single 4D house battery with a capacity of 200 Amp Hours. For the best battery life, consider that 50% of the Amp Hours available are useable, thus the energy available is 100 Amp Hours. (A couple of other useful numbers to remember is that a fully charged battery will read 12.8 to 12.9 Volts and a battery at half charge will read 12.2 Volts. 12.2 Volts is the number to manage to, anything below this and it’s time to charge the battery.) See the graph below for a good visual to illustrate this:



Sprinter Engine Input

My Sprinter has a single 220 Amp alternator. From reading elsewhere, it appears that the Sprinter uses about 30 Amps just to support itself and all of its systems while running. 220 – 30 = 190 Amps available. Keep in mind when reviewing this that the van’s system will always give preference to the engine battery, which in my case will typically be fully charged when we quit driving for the day and begin to use the house battery.

Carrying this out for typical time durations, here is a look at the power being produced:

60 minutes = 1 hour, 190 Amps x 1 Hour = 190 Amp Hours
30 minutes = 0.5 hour, 190 Amps x 0.5 Hour = 95 Amp Hours
15 minutes = 0.25 hour, 190 Amps x 0.25 Hour = 47.5 Amp Hours
5 minutes = 0.083 hour, 190 Amps x 0.083 Hour = 15.8 Amp Hours
1 minute = 0.017 hour, 190 Amps x 0.017 Hour = 3.2 Amp Hours

Assuming either driving speed or high idle at 1,500 RPM’s, this is what you can expect to have available to charge the house battery.

Solar Input

My Sprinter has two 100 Watt panels, thus it produces 200 Watts
200 Watts / 12 Volts = 16.7 Amps (ideal)
16.7 Amps x 8 Hours = 133.6 Amp Hours (ideal)

Note I said (ideal). According to the SMB website, a good rule of thumb is that a 100 Watt panel will deliver 40 Amp Hours per day, thus my two panels can be expected to produce 2 x 40 = 80 Amp Hours per day, or expressed another way, an average of 10 Amps per hour over the course of an 8 hour day. Looking at the engine input figures above, that works out to be about 0.42 hours or 25.3 minutes of having the engine run at 1,500 RPM or above to produce the same amount of power as the two solar panels in a day. Hopefully this helps put the solar input into perspective.

Because of Michaelf’s prompting (thanks for the nudge Michael), I ran an experiment in January where I purposefully discharged the battery and then let the van sit without running for several days. The van had just been driven for several hours and thus the house battery was as full as the alternator could get it (approximately 80%, or what you can expect at the end of a day of driving). Starting from this point I used a measured 45 Amp Hours of power, or just under half (45%) of the battery’s useful capacity. These were mixed overcast days with a combination of sporadic light rain, clouds and sun with daytime temps in the high 50’s in the CA Bay Area, here is the solar gain I measured over the next four days:

Day 1: 8.1 Amp Hours
Day 2: 7.8 Amp Hours
Day 3: 9.1 Amp Hours
Day 4: 12.4 Amp Hours

Total: 37.4 Amp Hours

At the end of this time the battery was reading 12.8 Volts. I plugged the van into shore power and it immediately went into bulk charging, thus illustrating that the solar alone over the course of four winter days without the engine running and with all power consumers shut off was not enough to bring the battery back to a fully charged state.

FYI, this is an experiment I plan to run again this summer, I expect vastly different results.

Appliance/Microwave Use

The Sprinter has a small 0.7 Cu. Ft. 700 Watt microwave.

From the microwave specification sheet, the unit requires 1,500 Watts at 120 Volts to provide 700 Watts of cooking power.

1,500 Watts / 12 Volts = 125.0 Amps
125.0 / 0.91 (stated Magnum peak inverter efficiency is 90.6%) = 137.4 Amps

15 minutes = 0.25 hour - 137.4 Amps x 0.25 Hour = 34.35 Amp Hours
5 minutes = 0.083 hour - 137.4 Amps x 0.083 Hour = 11.5 Amp Hours
1 minute = 0.017 hour - 137.4 Amps x 0.017 Hour = 2.3 Amp Hours

It is usually fairly easy to find the rated power draw of an electrical appliance, using the above methodology will give you the ability to determine how much power you will use.

Appliance/Refrigerator Use

Here is a topic where you can get lost in the discussion of propane vs. all electric, efficiency, cycle times and etc. There is LOTS of information and discussion out there for anyone wanting to look.

As for us, we went all electric (no regrets) and stayed with a small size (no regrets), but we did go with a $380 upcharge to substitute the SMB standard 2.7 Cubic Foot Norcold for a more efficient Isotherm Cruise 65 (again, no regrets). Note that for many this appliance represents the major power consumer, thus for many this is the major factor in determining their energy budget, for us not so much. The Cruise 65 we have draws 2.5 – 2.7 Amps per Hour when running, when cycle time is considered it averages 0.7 Amps per Hour, negligible when the engine is on and we are driving down the road, something to pay attention to when parked for the night. With the engine shut down and the battery powering the refrigerator:

0.7 Amps per Hour x 8 Hours = 5.6 Amp Hours or 5.6% of the total of the 100 Amp Hours available in the house battery

0.7 Amps per Hour x 12 Hours = 8.4 Amp Hours or 8.4% of the total of the 100 Amp Hours available in the house battery

I encourage you to look closely at this. A larger refrigerator opening and closing a lot and a plan to stay put in one spot for several days will greatly increase the % of the energy budget dedicated to this one continuously-running appliance.

Espar D5/Electric Heating Element

When we heat water in Flint we typically do so with diesel, but don’t forget that with the D5 there is an option to use electric power to provide the heat source. The electric draw is 1,500 Watts, thus the power draw is the same as the example above for the microwave. I would not suggest using the electric power option unless connected to shore power (a really nice option when this is available, just not typical for us the way we use the van) or a generator, but I can see where you may find yourself needing to use the battery if you really need/want the hot water and your diesel tank level is below ¼ full. Remember, this is the level that the diesel tap for the D5 is set at in the fuel tank, it is designed this way so you can’t run the fuel tank too low and potentially strand yourself, thus a level below ¼ full = no D5 available for use.

Generator Use

I have a Honda 2000 generator, pretty much the gold standard for small portable generators. I thought I would be taking it everywhere with us, but I have yet to put it in the Aluminess box that was purchased for it and I have yet to wish I had it with us. If we camped a lot and stayed in one place off the grid for several days it would be a different story, but we are:

1) Travelers vs. campers, thus the house battery is typically fully charged at the end of the day, and
2) Not heavy electrical users, thus our daily electrical needs are typically easily served by the one 4D battery

For perspective, here is the power a typical small generator will produce:

Honda (or whatever brand you choose) 1000
1,000 Watts/120 Volts = 8.3 Amps available
Not enough for the microwave or the electric side of the D5, just a little bit more than the two 100 Watt solar panels will typically produce.

Honda (or whatever brand you choose) 2000
2,000 Watts/120 Volts = 16.7 Amps available
Double the typical output of the two solar panels, enough to run the microwave or the D5 electric heating element one at a time, with a bit left over for other uses.

System Monitoring

I did not have the Magnum Battery Monitor Kit (ME-BMK) installed as part of the build, a situation I will soon rectify as it looks to be an easy addition and the kit is in the garage waiting for me to get to it. From the ME-BMK documentation: “Monitoring your battery bank is easy…acting as a “Fuel Gauge” for your batteries, the ME-BMK monitors their state of charge (SOC) and then provides this information in an easy-to-understand display…the ME-BMK is an easy retrofit…the ME-BMK battery monitor uses a precision resistor known as a shunt to measure current flow into and out of the battery. The shunt provides a small voltage to the Sense Module that is proportional to the current flow. When current starts flowing into or out of the battery, the Sense Module measures the current flow and determines the amount of current removed from and returned to the battery. The amount of current (or amp-hours) removed or returned is displayed on the remote control as the AH I/O (Amp-Hours In/Out).

Conclusions

Here is where you need to draw your own conclusions based on your anticipated use. I suggest going through the exercise of determining your energy budget, especially if your style of using the van when the engine is not running is power intensive (ours is not). The SMB website has some good information to help you do this; other information is readily available from other sources. As for us and our typical use case, a single 4D house battery is sufficient and I will manage the system to keep the house battery from falling below 12.2 Volts. When the van is home and under cover it will be connected to shore power in order to take advantage of the Magnum MS2000’s multi-stage charging capabilities, and solar will be a bonus in the summer when we stop driving early enough to get enough solar gain to supplement what the engine has already delivered. And of course there is always the Honda 2000 generator sitting in the garage, the most likely use case I can see for it is if all of our (adult) kids and spouses want to meet and camp in one place for several days, then the additional power the generator will provide will be more for them than for us!

[michaelf]

^ Wow Tim, I'm exhausted just reading that. Thanks for all the info, it is much appreciated. I'll be looking at doing some more math (not my specialty) in the next few weeks to figure out the last of the details on my build.

[Fitz]

I think a meeting at El Charro is in order!

[velo47]

Originally Posted by Fitz

I think a meeting at El Charro is in order!

I was ready to head down south, but then I figured it must not be THE El Charro.
https://www.facebook.com/El-Charro-R...7566389622306/

[Fitz]

There is YOUR El Charro, and then there is OUR El Charro, El Charro Mexican Dining - Welcome
Matt, it looks like Michael and I need a road trip when he gets his SMB so we can compare the two!

[michaelf]

Funny drift these threads take. Tim, for sure! As I've told you, I grew up going there...some of my earliest memories are from around the tables and bar there (different times indeed). As it would turn out, today is my late father's birthday so seeing those words pop up in my email brought a huge smile to my face (and a small tear to my wifes). Sounds odd, but thanks for that...and yes the sooner the better. I should be down in the area in March so I'll touch base. Until then more research to be done.

[EmMay]

A fiine balance to weaving our way through Chumly's Charlie Travails. Hats off to both ya'll for fine documentation and attracting so much positive input and energy.
I read along, laugh and shudder, call out to granny to 'take a look at this...'and scribble our notes and leads down for future consult. We'll pay up at some future date during a meet-up with a hardy slap on the back, a beverage, both, we know how to cook too!
My brain needed a break so the bills pay routine rose up; the first thing we see is that a withdrawal was cleared Friday afternoon: a down payment to put us in the SMBw cue.
We talked about the long wait there; January '18 start date for build. It's on.
We going keep picking these forum threads for nuggets of great ideas and watch-outs too; We'll be begging some guidance at some time soon surely we will...

[Fitz]

Originally Posted by EmMay

....a withdrawal was cleared Friday afternoon: a down payment to put us in the SMBw cue. We talked about the long wait there; January '18 start date for build. It's on.
We are going keep picking these forum threads for nuggets of great ideas and watch-outs too; We'll be begging some guidance at some time soon surely we will...

EmMay,

Glad you are enjoying the read and I am especially glad you are getting something out of it. My goal is to document what I am doing and to hopefully provide a bit of insight to others who are contemplating doing something similar. If you have questions, feel free to ask and we will all share the information.

CONGRATULATIONS on getting in line for your SMB build. I was at SMB Fresno this past week and they are currently building about 80% Sprinters with a 16 month wait time...some beautiful rigs there to look at, I would encourage anyone contemplating taking the plunge to get to one of the three showrooms several times during the process of making your decisions.

There is one thing you will have to get used to once you take delivery - lots of people want to talk about SMB's! I went to the Home Depot earlier this morning, found a note with the following on the windshield when I came back to the van:

Please be so kind as to call me regarding this great rig! Looking for something like this - owned many MBZ's.

I called and we had a fine discussion. It turns out we live in the same East Bay town and I am confident we will get together in the near future. He closed with saying it looks like it's time for the Porsche to go...

[EmMay]

Halloo!
We currently camp and explore in our e350 rb 4x4. It's bare boned. A two piece platform bed, PH top for head room and storage on back panel (it's two piece bed design) an Engel 45 refer and Primus stove (burns from green bottles).
The seats swivel and it's loaded with window, which we love.
It is a beast and virtually unstoppable, more than we care to do or experiment with anymore; but we are torn to decide: EB or RB on this next set up! We still are attached to 4x4 and do have a few spots we frequent that require subtle 4x4 grinding to get into our preferred spots.
We've planned out simple sink, cook top refer space on drivers side designs with a couch in the rear for both sizes, EB and RB. We mapped out the interior free space on our kitchen tile and spend plenty of time talking, measuring, moving around each other in that zone. Kinda like a 21 century car camper square dance sometimes.
Ohhh, the extra length would be swell, but ahhh, the few spots that we do crawl up or over with 4x4 that might now be out!?
Like ya'll we're Eastern Sierra and Southern Sierra lurkers. We live about as far south in this great state as one can, Imperial Beach, but camp, climb and hike in the mountains.
We follow Vanessa and are prepping for maximum audio-visual-bc-navigation capacity over a shower or microwave.
I'm just a special education teacher, tons of Emotional IQ not tons of Builder-Electrician IQ. I can follow directions, we know what we can live in all ready and how we'd adjust it, we did plan and remodel our house to move parents in (drew the plans, submitted all on our own, got approved too and added 800 ft of two storied feet!). With this cadre of folks kicking in some advice, I'm positive it's going to fly...