As part of the giant power bank that gets dragged to all my major camping trips & festivals, there is an old Eberspacher Diesel heater, a D1LCC from at first guess somewhere in the mid 90’s. At only 1.8kW heat output this is a little small for our current tent, and it struggles to keep the temperature comfortable at night, so with Chinese clones on the market these days much cheaper than the Eberspacher or Webasto units, a replacement was up! Still, the old Eberspacher is in working order, and will probably get used for some other project.
After removing the old D1LCC & placing it next to the new one, the size difference is obvious! The new heater is a Chinese clone of the Eberspacher D4 unit, allegedly uprated to 8kW. (In reality, it’s probably around 5kW heat output at full tilt). Luckily, it’s not that much larger than the old one, so it’ll go into the same space.
The port layout on the bottom of the heater is identical apart from intake port size, a quick attack of the baseplate with a grinder to remove the old hole pattern allowed the supplied mounting plate to fit correctly into place for the new heater. The duct size on this unit is also bigger than the old 60mm – 75mm duct is used on these large units. No modification to the vent hole was required, as the 75mm vent already fit perfectly. To clear the fittings on the top of the fuel tank, which is just underneath the hot air exhaust cowling of the heater, the mounting plate is fixed using 10mm nylon standoffs, this also helps get a bit more natural airflow around the base of the heater, as the mounting gets to 90°C in operation at full power!
These heaters don’t use the Eberspacher standard switch wire for control – there are only 3 pins in the loom to the controller, for 5v power & an odd UART which uses gated TX/RX to avoid having a separate line for each.
The stock controller has quite a nice looking LCD display, but it’s less than responsive & the backlight is always on at full tilt. It’s also much larger than the Eberspacher 701 controller so would require some rejigging of the control panel on the trolley. The built-in thermostat is also inaccurate, being almost 5°C high no matter what the room temperature. Ray Jones from Down Under has designed an open source ESP32 based controller for these heaters, and one of these is currently being built to control the unit. More to come on this bit!
A quick teardown of the controller reveals pretty simple internals, there’s a microcontroller, probably an STM8 device by looking at the programming header, but the markings have been scrubbed off the IC. There’s a standard LCD controller IC, a RTC which isn’t battery backed, and a 433MHz receiver IC with PCB trace antenna.
I wasn’t able to get the remote control function working with any of the remotes I have, any attempt at pairing a remote didn’t give any response from the controller unit. I also tried a 315MHz remote, but that didn’t work either. Not an issue since I’m building a much better open source controller.
Under the base is the exhaust system & the fuel dosing pump. There’s a small filter in the feed line from the tank to keep crap out of the pump, and nylon fuel line then runs the fuel to the heater inlet. The exhaust is made as gas-tight as possible with foil tape & exhaust paste, to keep the exhaust fumes contained in the pipework until they’re vented outside. The rest of the exhaust after the right hand silencer is done in brazed 22mm copper pipe, and a piece of Eberspacher exhaust duct is removable from the final exhaust tail for storage. The black pipe is the combustion air intake, which is simply fed into a silencer cable tied to the trolley frame.
The 3 ports are visible under the mounting plate, the square hole cut out of the trolley base to accommodate everything.
Since I do festivals every year, along with a couple of other camping trips if the weather is good enough, I’ve been taking equipment with me for years in flight cases to make things more comfortable. Things like a large battery to power lights & device charging, an old Eberspacher diesel heater for the times when the weather isn’t great, and an inverter to run the pumps built into airbeds.
Red Diesel / Heating Oil is my fuel of choice for camping purposes, as it’s about the safest fuel around, unlike Butane/LPG it is not explosive, will not burn very readily unless it’s atomized properly & it’s very cheap. Paraffin is an alternative fuel, but it’s expensive in the UK, at about £12 per 5L.
The Hexamine-based tablet fuels the UK festivals promote is nasty stuff, and the resulting combustion products are nastier still. (Things like Hydrogen Cyanide, Formaldehyde, Ammonia, NOX). They also leave a sticky black grok on every cooking pot that’s damn near impossible to remove. Meths / Trangia stoves are perfectly usable, but the flame is totally invisible, and the flammability of alcohol has always made me nervous when you’ve got a small pot of the stuff boiling while it’s in operation in the middle of a campsite filled with sloshed festival goers. A single well-placed kick could start a massive fire.
Over the years the gear has evolved and grown in size, so I decided building everything into one unit on wheels would be the best way forward. I’ve been working on this for some time, so it’s time to get some of the details on the blog! Above you can see the system used for last year’s camping, the heater is separate, with a 25L drum of heating oil, the battery is underneath the flight case containing all the power components, and it’s currently charging All The Things.
Above is the new unit almost finished, the bottom frame is a standard eBay-grade 4-wheel trolley with a few modifications of my own, with a new top box built from 12mm hardwood marine plywood. This top is secured in place with coach bolts through the 25mm angle iron of the trolley base. The essential carbon monoxide detector is fitted at the corner.
The inside gets a bit busy with everything crammed in. The large Yuasa 200Ah lead-acid battery is at the far end, with it’s isolation switch. Right in the middle is the Eberspacher heater with it’s hot air ducting. I’ve fitted my usual 12/24v dual voltage system here, with the 24v rail generated from a large 1200W DC-DC converter.
The hot air duct for the heater is fed out through a standard vent in the front. Very handy for drying out after a wet day.
Here’s a closeup of the distribution bus bars, with both negative rails tied together in the centre to keep the positives as far away from each other as possible, to reduce the possibility of a short circuit between the two when working on the wiring. The EpEver Tracer 4210A MPPT Solar Charge Controller is on the left, tucked into the corner. This controller implements the main circuit protection for the battery, having a 40A limit. Individual circuits are separately fused where required. Solar input on this unit is going to be initially provided by a pair of 100W flexible panels in series for a 48v solar bus, the flexible panels are essential here as most of the festivals I attend do not allow glass of any kind onsite, not to mention the weight of rigid panels is a pain.
I’ve stuck with the 3-pin XLR plugs for power in this design, giving both the 12v rail, 24v rail & ground.
Tucked under the DC outputs are a pair of panel sockets for the 600W inverter. This cheapo Maplin unit is only usually used to pump up air beds, so I’m not expecting anyone to pull anything near max output, but a warning label always helps.
Behind the front panel is the hardwiring for the power sockets. The DC jacks are connected together using 2mm solid copper wire, bent into bus bars.The mains wiring underneath is a simple radial circuit straight from the inverter. The large cylinder on the left is a hydraulic pump from a BMW Z3, which runs a hydraulic cylinder for lifting the lid of the top box, used simply because I had one in the box of junk.
External fuelling is dealt with by a small gear pump, this is used to fuel up the Optimus Stove & Petromax Lantern. This is in fact a car windscreen wash pump, but it has coped well with pumping hydrocarbons, it currently has a small leak on the hose connections, but the seals are still entirely intact.
There’s a small remote relay module here, for switching the DC output for lighting & the heater from afar. Very useful when it’s dark, since there’s no need to fumble around looking for a light switch. A car-style fob on my keyring instead.
Since the Eberspacher 701 controller I have is an ex-BT version, it’s very limited in it’s on time, a separate timeswitch is fitted to control the heater automatically. Being able to return to a nice warm tent is always a bonus.
Just to the left can be seen the top ball joint for the hydraulic cylinder that lifts the top of the box.
The final large component is the battery charger. This unit will maintain the battery when the trolley isn’t being used.
On the left side is the old Atom motherbaord used to provide a 4G router system. This unit gets it’s internet feed from a UMTS dongle & provides a local WiFi network for high speed connectivity. The bottom of the hydraulic cylinder is visible in the bottom right corner.
Since the Eberspacher obviously needs fuel, a tank was required. In previous years I’ve used jerry cans for this purpose, but this trolley is supposed to have everything onboard, for less setup time. The tank is constructed from 3mm steel plate, MIG welded together at the seams to create a ~40L capacity. The filler neck is an eBay purchase in Stainless Steel. No photos of the tank being welded together, as I was aiming to beat sunset & it’s very difficult to operate a camera with welding gauntlets on 😉
The tank is the same width as the trolley frame, so some modification was required, having the wheels welded directly to the sides of the tank. This makes the track wider at the rear, increasing stability.
A quick view inside the tank through the level sender port shows the copper dip tubes for fuel supply to the heater, and an external fuel hose for my other fuel-powered camping gear. These tubes stop about 10mm from the bottom of the tank to stop any moisture or dirt from being drawn into the pumps.
The top of the tank is drilled for the fuel fittings & the level sender and has already been painted here. The 1mm base plate has yet to be painted.
Touching up the paint & fitting the sender is the last job for this part. The mesh bottom of the trolley has been replaced by a 1mm steel sheet to support the other parts, mainly the heater. Fuel lines are run in polyurethane tubing to the fuel pumps.
All the instruments & controls are on a single panel, with the Eberspacher thermostat, external fuelling port & pump switch, inverter control, the solar controller monitor panel, cover buttons, router controls, compressed air & fuel gauges.
As is usual behind instrument panels, there’s a rat’s nest of wiring. There’s still the pressure gauge to connect up for the compressed air system, and the nut on one of the router buttons is such a tight fit I’ve not managed to get it into place yet.
The support components for the Eberspacher heater are mounted underneath the baseplate, with the fuel dosing pump secured to a rail with a pair of cable ties, and some foam tape around to isolate the constant clicking noise these pumps create in operation. The large black cylinder is the combustion air intake silencer, with the stainless steel exhaust pipe to the left of that. Silencing these heaters is essential – they sound like a jet engine without anything to deaden the noise. Most of this is generated from the side-channel blower used in the burner.
Bolted to the underside are a pair of exhaust silencers, one is an Eberspacher brand, the other is Webasto, since the latter type are better at reducing the exhaust noise. Connections are sealed with commerical exhaust assembly paste, the usual clamps supplied do not do a good enough job of stopping exhaust leaks.
Next update to come when I get the parts in for the air compressor system.
Some time ago I did a couple of posts on cheapening up the maintenance of Eberspacher hot air heaters by making the glow plug screens myself. Now one of my pieces of stainless mesh has been in the heater for nearly a year, and the heater is starting to get a bit smoky on a cold start. This is usually a sign that the screen isn’t allowing the fuel to vaporise quick enough for the glow plug to ignite the flame, because it’s becoming blocked. So far the heater has had about 150L of diesel through it with my DIY screen.
After removing the plug, here’s what’s left of the screen. The bottom end has completely disintegrated, but this is to be expected – OEM screens do the same thing as this end is exposed to the most heat in the burner. There’s quite a bit of coke buildup on the top end of the screen around the fuel nozzle, again this isn’t surprising, as this is the coolest part of the heater not all the heavier fractions of the diesel fuel have the chance to vaporise.
Looking further down into the mixing tube of the main burner, everything looks good. There’s a coating of soot in there, but no tar-like build up that would tell me the unit isn’t burning properly. Another advantage of making my own screens is that they’re much easier to extract from the hole once they’ve been in there for months. The OEM screens have a stainless ring spot welded to the mesh itself to hold it’s shape, and once there’s enough fuel residue built up the entire mess seizes in place, requiring some sharp pokey tools & some colourful language to remove. The single loop of mesh held in place by it’s own spring pressure is much easier to remove as it collapses easily.
I’ve decided to change the mesh size of the screen while I’m in here, in this case to 80 mesh, which is much closer to the OEM screen size. There doesn’t seem to be much of a difference so far in either the starting or running capability of the heater, although the thicker wire of this screen might last longer before disintegrating at the burner end.