Yeah, the Sprintergen people pulled back from the Sprinter application and have moved strictly to watercraft applications. There is a Kubota 2.5KW generator (which is essentially what the Sprintergen was supposed to be) that's small enough to go into a Sprinter, but there are drawbacks to using it in expediting.
There are several Sprinter RV conversions that have the generator installed at the side-rear of the vehicle, but those are on dually Sprinters with extended (wide) bodies, where there is room for the generator. With the Expediting need to be able to carry 48-inch wide skids, that doesn't leave enough room to mount (and sound baffle) a generator. Another mounting options is under the vehicle, between the rear axle and the fuel tank, but it's a really tight fit when the weather/sound enclosure is added, and getting to it for routing maintenance is a nightmare. The other option is on the roof, with maintenance on that being only a semi-nightmare. A small diesel generator is gonna run you about 5 grand.
You do have propane generator options, but then you have to deal with propane tanks. Propane generators seem to burn an awful lot of propane under a full load, like when running an air conditioner, and of course, you'll absolutely run out of propane when you're most asleep or when it's raining the hardest. There are also issues with the routes where you can transport propane.
A cheap generator alternative are the small gas-fired generators from Honda and others. You sit them out back of the van and run a power cord to the inside and you're good to go. Rain can be a problem when the generator is outside, tho. And you're dealing with gas instead of diesel, which is a PITA. And they burn nearly as much fuel under a full load (an air conditioner) as idling. Yuck.
After much too much research, trial and error, and cost analysis until I'm blue in the face, I have come to the conclusion that a generator in a Sprinter used for expediting is simply not worth it. No matter what you do it's a kludge. Difficult maintenance, very limited mounting options, having to deal with a different fuel than what's in the tank, a lot of things.
What you want to do is eliminate idling, for many reasons. And you want to get heat, air and auxiliary power in the most long-term cost effective manner. This means good, high quality, high end, off-the-grid-caliber AGM deep cycle batteries for power. Stay away from "marine" batteries or anything else that's cheap. You'll get exactly what you pay for.
You're going to be sleeping with these batteries (I literally sleep on top of mine, as they are under the bunk), so there are many things to consider other than price, or even that they are AGM batteries.
For heating, hands down, the Espar heater wins. When you order a Sprinter with the auxiliary heater, it's an Espar heater. When you order one for the passenger configuration with the passenger heater, it's the Espar heater. The Espar heater is the heater of choice all over the world, but for some reason it's been slow to catch on in the US. I don't know why, because it really is all that
and a bag of chips.
If you have a sealed, permanent bulkhead, and only need to heat the front of the van, the Espar Airtronic D2 will suffice, at $1500 installed. If you want to heat the entire van, like I do, the Airtronic D4 will do it, at $1900 installed. The D4 puts out just about twice as much heat and airflow at all 4 heating levels (boost, high, medium, low) as the D2, and uses essentially the same amount of diesel fuel (they have a gas model, too) and power amps as the D2 at each level.
Heat Output BTU's
D2 D4
Boost 7,500 13,50
High 6,150 10,200
Medium 4,100 6,800
Low 2,900 3,400
Boost last maybe 5 minutes, to get things quickly warmed up. Then it cycles down through the other levels as needed. I have my van well insulated, so it spends the vast majority of time at the Low level.
Power Consumption amps
D2 D4
Start 8.3 8.3
Boost 2.8 3.3
High 1.9 2.0
Medium 1.0 1.1
Low 0.7 0.6
Fuel Consumption US Gal per hour
D2 D4
Boost 0.07 0.13
High 0.06 0.10
Medium 0.04 0.07
Low 0.03 0.03
I have found that mine uses just about 1.5 gallons per 24 hours, when the outside temp is between 20-30 degrees F. That's an average of 0.06 per hour. When the temp drops down to the low teens or single digits, it's about 0.10 per hour, or about 2.5 gallons over 24 hours.
Make no mistake - this is a serious heater. Well constructed, and extremely well performing. The temperature control doesn't have numbers on it (they do have a real thermostat option, tho) but if it did mine would show it being set on about level 2 or 3 most of the time. Never even had it as much as a 5. I don't wear a spacesuit and 3 layers of pajamas and 4 pair of socks and my hiking boots in here. I can sit around or sleep in the van wearing nothing but a smile, and am completely comfortable, with nary a cold spot anywhere. My toes are toasty, which is the main thing.
You're going to need an auxiliary battery for the heater, as even the small amount of amps it draws will run the starter battery down in a day. A little planning for the battery size is necessary. One important thing about deep cycle batteries is, the general rule is to never discharge them more than 50% of their rated power. A good AGM will last 7-10 years if never discharged more than 50%. If you routinely discharge to 70% or 80%, expect the batteries to die in 3 years, if not sooner.
You'll want to figure out your energy consumption. How many amps you will draw from the battery (or battery bank) over a given period of time. In expediting, especially in a van, you can often count on dropping off a load on Friday and not getting another one out until Monday, or even Tuesday. You'll want to figure out how many amps you'll need in order to be able to sit there all weekend without having to recharge the batteries (from the engine's alternator). I have a refrigerator, microwave, lights, computer, the list goes on. Figure out how many amp hours each of these will use over a 24 hour period, for example.
Then, because you don't want to discharge more than 50%, double the amp hour requirement figure. Worst mistake most people make, other than discharging too deep, is skimping on the amp hours of the batteries. Always get at least twice as much as you'll need. My energy consumption is relatively high, particularly when I sit for extended periods. Over a 24 hour period, I pull at an average of 25 amps per hour. The refrigerator is the biggest culprit. It runs from 1/3 to 1/2 of the time, and pulls 13 DC amps when it's running. If you have a small cooler or something else, you'll use much less amps per hour. But at a 25 amp per hour draw, that's 600 amp hour a day. For a 50% DOD (Depth of Discharge) I need 1200 amps hours with of batteries. That's a lot.
I actually have 1320, which is even more than a lot. Many people out here with much less power requirements do well on 440 amp hour batteries. Your mileage will vary. The main thing is to do the best you can at figuring out what your requirements are, including things you will invariably add on later, and use a battery monitor.
Make sure you get a battery monitor to let you keep track of exactly how many amps are going into and out of the battery. Trying to live on a battery bank without a battery monitor is like trying to make a living expediting without a fuel gauge. It will scream at you when your batteries are 50% discharged. Battery monitors are expensive, but when compared to just one time of discharging the batteries to the point where the lights dim and the fans start to make noise, and the price of a battery monitor is cheap at twice the price.
The Xantrex Battery Monitor is the one I recommend, with the temperature sensor. It also has a computer interface option that is very kewl.
Another little ditty that will help, especially initially when trying to size a battery bank, is something called a Kill-A-Watt Meter. You plug something into it and then plug it into the electrical outlet, and it will let you know how many Watts (and amps) that a particular appliance uses. Just multiply the amps used by 10 to get the amount that will be drawn from a 12 volt battery. It's like $25 and worth its weight in gold. It's lets you see "phantom" loads, or loads that take place when an appliance is turned off. Like the TV that uses 30 Watts when turned off in order to keep the channel memory and stuff, or the DVR or satellite box. Lots of little things like that need to be accounted for, as they can add up in a hurry. A few small phantom loads can add up to a couple of amps, and over 24 hours that's 24 amp hours poof (which is another reason a battery monitor is crucial).
Also, don't start off with one or two batteries, thinking you can always add more batteries later. It doesn't work that way. When you add fresh new batteries to used batteries, the new batteries have to work much harder to overcome the diminished capacity of the old batteries, and the old batteries try to work twice as hard to keep up with the new boys in town. It would be much more humane to just take the batteries out back and shoot them and be done with it.
You want all of the batteries to be the make make, amp hour capacity, and age. Even to the point of having the same Date of Manufacture on each of them.
I have Concord Lifeline batteries. I have their "golf cart" batteries that are 6 volts, with pairs wired in series to make a single 12 volt battery. Each one is 220 amp hours. I have 12 of them. Weight is an issue, and at 65 pound each, I'm right on the edge of being able to carry the required amount of freight. But extra batteries versus fewer batteries and a generator was just about an even swap, all things considered.
I chose Lifeline for several reasons. One is they can handle rapid discharge better than most, and can handle the occasional accidental deep discharge better than most. Another is they can handle a rapid charge way, way, way better than any other battery. Most AGM's require charging at 25% of their rated capacity. So, a 220 amp hour battery can be charged at a rate of 55 amps. Lifelines can be charged at 400% of their capacity, so long as the voltage is a constant 14.4-14.4 volts, which means you can recharge them very fast if you have a high output alternator (replace that 90 amp alternator, if that's the one you have, with the drop-in 150 amp Bosch replacement, and then have an alternator guy tweak or replace the voltage regulator to put out 14.4 volts instead of 13.8). Another is the 5 year warranty (1 year full replacement, plus another 5 year pro-rated). Concord also makes the Sun-Xtender batteries, which are essentially the same as Lifeline, only they are $30 cheaper and you don't get the same warranty when used in mobile applications. But the biggest factor in my choosing Lifelines is that they dramatically exceeded the military specs for AGM batteries (the Concord Lifeline AGM's were invented as a result of the military's request for such a battery), and to my knowledge, while other AGM's meet the specs, only the Lifelines exceed them to such degree.
The specs, in a nutshell, is that they be deliberately overcharged (as can happen by accident) at 17 volts until they nearly melt, and outgas hydrogen gas. The level of hydrogen that is released must not exceed 4%, as that is the amount of hydrogen that will explode, which is kind of important on an aircraft or under the seat of a Hummer. On top of that, after all that abuse, the batteries must still work. The Concord batteries never exceeded even as much 1% hydrogen outgassing, and they continued to perform the same as new batteries did. Since I literally sleep on these batteries, I wanted them to be as safe as possible.
Now, as for air conditioning. I actually have enough amp hours to run a rooftop AC for 8 hours. Something like a Coleman or a Duo-Therm. But those are 120 volt air conditioners. They pull about 10 amps AC, which when inverted from 12 volts is 10 times that, or 100 amps from the battery. Sucking amps out of batteries is like miles per gallon, the faster you drive the fewer miles you'll get out of a gallon of fuel. The faster you suck amps from a battery, the less capacity, or amp hours, the battery will have. This is known as the Perkert Effect, and there's an algorithm that will let you know just how dismal your batteries will operate at high amp draws.
For example, the amp rating of a battery is figured at the 20 hour rate. That means that whatever load you put on the battery, if it's a load that will suck the battery dry in 20 hours, that's the amp hour rating of the battery. If you draw 20 amps continuous for 20 hours, it's a 400 amp hour battery. If you can draw 5 amps for 20 hours, it's a 100 amp hour battery.
But, you can't draw 20 amps an hour out of a 100 amp hour battery for 5 hours, even though that's the math. You're drawing the amps out faster than the 5 amp hour rate, which means you're speeding when you draw 20 amps. The Peukert Effect turns that 100 amp hour battery into an 85.86 amp hour battery, and you can draw 20 amps for 4.29 hours instead of 5.
This is why electric heating and cooling, things that draw heavy amps, are not suited to batteries. So, a real world example of a 440 amp hour battery bank: An efficient Coleman or Duo-Therm will pull 100 amps, plus the 10% efficiently loss for the inverter, which is 125 x 1.1 equals 110 amps. From a 440 amp hour battery bank, you'll run the battery dry, not 50% DoD, bot 100% DoD, in 3.35 hours. (an electric space heater is even worse - 1500 watts is 125 amps x 1.1).
My 1320 battery bank can run one of these air conditioners for 11.34 hours if I want to kill the batteries, or for about 6 hours if I go to 50% DoD. Then there's the matter of recharging. At 50% DoD I've used 660 amp hours, which has to be put back in the bank. I have a 150 amp alternator, of which 40 goes to the van, so I get 110 amps to the battery bank. That would mean it would take 6 hours to recharge the batteries, after having run the AC for 6 hours. And that's if I ran only the air conditioner, and not anything else, like the fridge, or the lights, or the computer, or, well, you get the idea. Basically, I'd be able to run the AC and everything else in here for about 4 hours, then recharge for 6 hours. Well, isn't that special.
Obviously, a more efficient, 12-volt DC air conditioner is needed. The problem is, efficient, well made DC appliances are ming numbingly expensive when compared to their alternating current counterparts. But after careful consideration and more cost analysis than I care to admit, they are actually way more cost effective than the alternatives. There is the popular DC Airco unit, that comes in 4400 BTU's (for cooling something small, like the cab of a truck) and the 9900 BTU model for a cab and sleeper, or a full cargo van. It's about $3700.00, plus installation. Yeah, I know. Man, that's a lot of money for a rooftop air conditioner. Whew.
The 9900 model draws just 39 amps under a full load, and at night or if your van is well insulated, it'll run at a half duty cycle and draw only 20 amps or so. Even 39 amps is a considerable improvement over 110 amps, especially when you take the Peukert Effect into account. At a 110 draw, the Peukert Effect turns a 440 amp hour battery into a 368.61 amp hour battery, and you can run it for 3.35 hours to 100% DoD. At 39 amps, the 440 amp hour battery becomes a 413.14 amp hour battery, and you can run that for 10.59 hours. When you double that to an 880 amp hour battery bank, a 39 amp draw makes the battery 891.75 amp hours, more than the 880. You're driving more efficiently the larger the battery bank (balanced with GVW, of course hehe).
The DC air conditioner costs out at pretty cheap when you start putting it all together and look at it over time. A diesel generator and a regular rooftop AC is gonna cost you about 5 grand. Espar of Michigan will install batteries and the DC Airco for about the same amount of money. They won't install 1320 amp hours of batteries for that, tho, so if you're thinking of going that route plan accordingly And don't forget the battery monitor! I cannot stress that enough!
OK, so the plus of the generator is that you've got a generator, duh, but you have to run it all the time the AC is running, and they burn way too much fuel when under a heavy load like an AC. You've got plenty of power when you need it, but you've also got maintenance to deal with, and unless the generator is very easy to get to, maintenance will be ignored. It always is. Over time, generator maintenance and burned fuel will cost considerably more than properly monitored and cared for batteries and a DC air conditioner. The more electrical appliances you add the more cost effective things get, provided you have your battery bank properly sized. Whatever you figure for your amp hour requirements, it's gonna be more than that, so plan on starting out with more batteries than you think you're gonna need. Again, you can't simply add capacity later.
I stay out 2-3 months at a time. For me, the above works well. Your situation may be very different. I wanted mine to be, essentially, a freight-capable RV.
We actually have more in common with a sailboat than an RV. The only difference is the sailboat will occasionally have to fire up the generator to recharge batteries, and we simply have to pickup and deliver a load to do that in most cases. On a sailboat they will figure out their battery bank size based on a 50% DoD for 24, 48 or 72 hours, which is what we do (or should) do out here, as well. When I run everything in here that I have hooked up (not including the DC Airco) my battery bank is sized for 30 hours at 50% DoD. But because I occasionally sleep and don't always run everything, I actually get between 48 and 50 hours before I hit 50%.
Hopefully this will let you make a more informed decision about what your needs are. Out here on the road we pretty much dry camp, without hookups. Or a sailboat. When it comes to power and living out here, that's the mindset to get yourself into. Straight trucks and big trucks have room for a generator. Vans don't. A balance between storage space, GVW, power requirements, and battery capacity must be met, and compromises will certainly have to be made. For me, it was about $5700 worth of generator, air conditioner and batteries, versus $2000 worth of batteries and a $2700 DC air conditioner. Either option weighs the same, actually, or close to it. Price-wise it's about a wash, but not having a fuel-burning generator that requires maintenance was a major consideration. And I just traded the weight of a generator for the same amount of extra battery weight. Many can certainly get by with less per requirements, and if so, the DC air conditioner and batteries make even more sense in the long run.
Just resist the temptation to go cheap. You'll wind up spending good money two or three times before you finally get it right. I have the t-shirt to prove it.
The Espar heater, to me, is a no-brainer. If you idle even relatively minimally, and aren't out here on the weekends, over the course of a winter you'll spend just about the same amount in idling fuel as you will for the heater. Next year it's all money in your pocket. At $1500 a year, it adds up fast over a few years.
And if you don't burn all that fuel idling, and if a lot of people don't idle, then the oil companies will see a reduction in demand, and they'll lower fuel prices. Hey! Did you see that monkey that just flew out of my butt?
I don't actually have the DC Airco, yet. I just got the van last July, so there was no point (or time, really), and I just very recently got the battery bank situated. So now I'm ready for the AC, and that'll be installed in April.
Whether anyone does what I did or not, at least, hopefully, this will give someone some ideas, and a point of reference.
Oh, and one last thing... if you're using deep cycle batteries for power, get a battery monitor.
Batteries don't die. People kill them.
