Engineer In Residence
Those aren't terribly expensive to operate if you can find a way to get the ultra pure methanol on the cheap. The EFOY branded methanol is crazy expensive.
That would be the trick. I haven't looked into fuel cells much, but one powered by unleaded gasoline would be easier to feed. I think it's pretty cool that 50 years after the moon landing, I can buy a powerful, suitcase sized fuel cell for my camper.Those aren't terribly expensive to operate if you can find a way to get the ultra pure methanol on the cheap. The EFOY branded methanol is crazy expensive.
This is quite interesting and intriguing. But does this not seem to further complicate matters? Why not just consider a genset to charge batteries? Aside from the fact these are more efficient of course. I have long wondered when fuel cell tech will reach the automotive market.. It still seems to be years off which is a shame really. I guess with what seems to be a stage of still in development, I would be hesitant to try something so costly.Out of left field, a methanol fuel cell is another option. Size the battery bank & fuel cell to complement each other, and you could go all-electric, even if solar charging isn't reliable enough, and you want unattended operation (no alternator charging).
If starting from scratch, I really think electrical power is becoming the way forward for everything, with the possible exception of space heating. A powerful LFP battery bank can be carried by even smallish vehicles, and it can be coupled to solar & alternator charging (or fuel cell) to meet most power demands. Especially when solar power is the primary charge source, electrical power comes with no fuel penalty, and it's the most flexible form of power available.
How do yo like the composting? I've read mixed reviews...-- Toilet - dump. Our composting toilet needs to dump about once a week.
The weight and bulk, and danger, of LPG is what makes me wanting to look at another idea, even though it's 'easiest'. I do like the loop idea and already was thinking of something similar. It would be awesome to have a radiant floor heating effect, and also keep tanks/pipes warm in sub zero temps. As for the cooking, I really am thinking that induction/electric for cooking is opening up more complications that will work. In the winter, I basically would have to run a genset every time I cooked. That would probably get a bit annoying. I already plan on having to do so when using a micro - which would be the biggest electrical consumer I have (other than AC in summer). I would hope that the power consumption from 2 12v fridges, a heater (whether it be LPG or diesel), and other normal things, would be 'easy' to manage via solar/genset. Adding induction just seems to require much more robust systems. But, DiploStrat clearly does it and it works great! So I will consider it more before making a decision.Nothing wrong with LPG, but it gets heavy with the weight of large ASME style tanks. Its also large, as the density of the fuel is lower than diesel.
If you are planning on leaving this rig unattended for long periods, you need to address the risk of a heating failure. This can be with a water system that is tolerant of freezing. This would include lines/fittings which can tolerate it, or a system that will self purge. Or you need some type of backup heat.
This loop would heat all underbody tanks (interior tanks are the most desirable though).
For cooking you could just opt for a portable LPG bottle in a storage box for safety. You could also go with induction, but that requires significant charging/batteries, or a genset running. In the winter solar charging would be signficantly reduced, and getting a lead bank to full several times a week will be challenging without regular shore power. If you went down the route, and plan to keep the cabin warm 95% of the time or more, I would suggest a lithium bank, as that eliminates the rapid degradation a lead bank would see due to abusive partial charge cycling.
How do yo like the composting? I've read mixed reviews...
... Also, what kind of electrical provisions would be necessary to run a computer frequently? I believe the input (consumption) is 1.3a. But use it extensively between work/fun planning.
I believe you could set up a fuel cell for unattended charging triggered by a battery management system when the battery reached a desired state of charge. A generator could do that, but not at the same size, weight, and noise level. Having another type of fuel to carry would be a complication. Portable fuel cells have been available long enough that their pitfalls should be easy to find with a little research.This is quite interesting and intriguing. But does this not seem to further complicate matters? Why not just consider a genset to charge batteries? Aside from the fact these are more efficient of course. I have long wondered when fuel cell tech will reach the automotive market.. It still seems to be years off which is a shame really. I guess with what seems to be a stage of still in development, I would be hesitant to try something so costly.
I use diesel for air and water heating. I plan on adding some plumbing to my hydronic heater so I can keep my gray water tank from freezing. The rest of my plumbing is inside the heated envelope. I would not use anything but a 12V fride for our usage. The space and weight sacrifices for an LPG fridge would be too significant.May I ask if any of you utilize the diesel heat, LP cooking, 12v fridge combination, and how well it works? Also, what kind of electrical provisions would be necessary to run a computer frequently? I believe the input (consumption) is 1.3a. But use it extensively between work/fun planning.
The AC would only be used during hot summer days when needing to cool things off for a bit in the afternoon, or after cooking (if inside) and would have to be ran of gen or shore of course. I dont think batteries could even reliably run AC.You say a/c in summer, so do you mean from a genset or batteries? If the latter then all other battery draws will be tiny compared to that!
Our diesel camper will have;
- A composting toilet, so no external black tank or too small cassette.
- An internal grey tank sunk in the insulated floor. This not only hopefully stops the water freezing but keeps shower water heat in the camper. Vented outside of course!
- Room for two but probably just one 12kg propane bottle just for a marine hob+grill, giving six months cooking. So spare heat source too. No oven apart from an omnia, maybe a dutch oven too. Sealed but internal gas locker directly under the hob so minimal plumbing. Externally vented locker of course.
- Espar hydronic heater with calorifier and air blown heat exchangers for camper and cab. No engine connection. I think there's a post here somewhere proving that underfloor heating can't provide enough heat from the floor area available in a camper so you need another source too?
- Modest fridge/freezer 12/24v only. I think compressor fridges can tolerate not being level when parked, lpg/12v ones less so.
- Mains a/c maybe added later depending on solar and battery performance.
- Washing machine from batteries.
- A portable mains induction hob. Cheap, additional cooking space if needed, can use it outside, if the glass top breaks not a deal breaker.
- Whole roof solar.
- Small petrol/gas genny to charge batteries and run a small heater if required. Lithiums I believe can't be charged when very cold.
- 400l of water.
That was pretty much the set up in our last camper which we lived in full time for three years and worked well. That did have external waste tanks which were an issue when cold, as was an Espar without the altitude kit which coked up at and above 1000m altitude. Cleaning out is easy but a faff. We did have a 24v microwave to start with but that was very power hungry so got ditched.
Thank you for the link! Billings is quite a ways east of me. I'm on the western side. Still more sun than my old home are of WA, but quite cloudy so the locals say. I have not been here through a winter yet, but excited to!! Would it not be easier to just put some of your air heater directed toward your water tank? Or is it exposed? I do like that idea, but seems having it enclosed and insulated, just having some of the hot air going that direction would be easier than plumbing more lines. Less chance for leaks or problems as well?I use diesel for air and water heating. I plan on adding some plumbing to my hydronic heater so I can keep my gray water tank from freezing. The rest of my plumbing is inside the heated envelope. I would not use anything but a 12V fride for our usage. The space and weight sacrifices for an LPG fridge would be too significant.
Running a laptop uses between 20-80W on average. Generally its not a problem with a decent solar array. Note that solar arrays are more efficient in lower temperatures. Assuming you have clear skies, and you aren't near the arctic circle, you should be able to get 4 hours of decent solar output, even in the winter. This requires tiltable panels. At 50 degrees latitude, you may need 65 degrees of panel tilt.
Look here for solar estimates for various US locations.
Estimates the energy production and cost of energy of grid-connected photovoltaic (PV) energy systems throughout the world. It allows homeowners, small building owners, installers and manufacturers to easily develop estimates of the performance of potential PV installationspvwatts.nrel.gov
In Billings MT, a 300W premium system tilted at 60 degrees would yield about 900 watt-hours per day in January.
With your needs, it makes sense to use a lithium battery pack, assuming you can keep the interior warm when you need to charge. A lithium pack would charge very quickly from the genset, and will not need long tapering absorb to keep it from dying an early death. It will also take maximum advantage of any solar charging you have available.
I might have been reading old reviews, or reviews from people who were using them wrong. One thought though is how they do bouncing around off highway. Aside from dumping the liquids tank, maybe theres no real issue at all, and was all just subjective comments from using them incorrectly. I do love the idea of not messing with a black tank. I always worry about my current tank cracking, or leaking, or the dump hose ripping apart mid emptying. That would be SO bad.... and a bio hazard for wherever I dumped it too. However, the one benefit is being able to use a mensuration pump to pump the waste into a pit toilet. Then again, I see no reason you can't do the same with a composting unit.Composting toilet, never read a bad review from someone who lives with one. We have lived with ours 5 years.
We have Webasto diesel heat, NovaKool 12v full size fridge freezer and a Smeg propane cooktop. The cooktop is next to go, replacing with induction.
Propane tanks are heavy(we have two 55l tanks,it requires inspections and makes shipping difficult. I do like cooking on propane but for us its not worth it.
The fridge is the biggest draw. In summer it Draws a lot more but we are also making more solar power so it evens out.
If you are going to use a coolant heater the only reason to not connect to the engine coolant is a de-mountable camper, even in that case you can use hydraulic quick disconnects.
Gen charging a lead bank will use lots of fuel.
Both excellent points - edited to shorten quote length....It is misleading to say generator charging lead takes a lot of fuel.