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Author Topic: The Autonomous Electric Motorhome (with an ICE(concept))  (Read 4022 times)
« on: June 18, 2016, 01:56:39 AM »

This is inspired by LG's bifacial solar panels and a relative of this thread.,26968.msg309015.html#msg309015

A few things combined between me giving out about cr@p vehicle habitation electrics, and putting some drafts together of the right way to do things for a friend then I got totally carried away and engineered the bejaysus outtov it.

So if you want a live-aboard you want something big, so straight away we're into 7.5ton territory which is great because that affords us some roof space and payload.

So I figure one of these road warriors (also available in 4wd) is the entry vehicle size class for this rig.

The potential for this goes beyond the scope of a live aboard vehicle. Given enough moxie this machine could power a house build, or a site office, or a log cabin or a shipping container what-have-you, all the while being a kitchen, living and sleeping quarters.

You can get five modules on that roof. That's a good start. .

1.5kWp PV.
1.75kWp with 15% bi-facial gain over white reflector.
1.87kWp temp comp @ 10C.
Tristar60 MPPT.

Flat panels are great for all day generation but pretty ineffective in Winter.

Let's make them tilt adjustable!

On board loads:
  • 3 x Induction Hobs.
  • 1 Halogen Grill/Oven
  • 24VDC/250VDC compressor fridge/freezer.
  • Usual Motorhome/Domestic loads; television, radio, computers, life support etc.
  • A toaster.
  • An electric 500W kettle.
  • A hot fill Washing Machine.
  • A 5HP 24V Winch
  • 2 x 4.5kN PV Actuators

Features & Generators:
  • 32A Single Phase Inlet.
  • 16A Single Phase Inlet.
  • 32A Single Phase Throughlet.
  • 16A Single Phase Outlet.
  • 3kVA Low frequency True Sine inverter with 60A Charger and Genset Autostart.
  • 300VA TS Inverter (backup if preferred).
  • 7kVA Diesel Genset with Electronic Ignition.
  • 700W Turnip.
  • Dual Alternators 150A on Habitation Battery & Stock Alternator for Auto-Electrics
  • 700Ah C20 @ 24v Battery (16.8kWh, 8.4kWh to 50% DOD): 12 x 2V Forklift Cells / OPzS.

~5.37kWh Day average minimum PV gain (Spring to Autumn).
Peak Solar Gain: 12kWh.

Expected Average Daily Loads:
  • 40Ah p/d compressor fridge
  • 15Ah p/d inverter self consumption
  • 40Ah p/d electronics, lights
  • 150Ah p/d electric kitchen: induction hobs, halogen grill/oven 3.75kWh
  • -100Ah per day gain using gas hobs to allow battery to recuperate.
Total Load: 245Ah p/d

Generation Ability
  • 223Ah p/d average min. solar gain.
  • 37.5Ah p/d alternator gain; 30 min. drive.
  • 125Ah p/d Wind Harvest in average 5 m/s.
Design load: 6kW per day.

Designed with inherent redundancy and minimum parasitic loads.

« Last Edit: June 18, 2016, 02:19:30 PM by Scruff » Logged
« Reply #1 on: June 18, 2016, 02:10:59 AM »

Dual Alternators

« Reply #2 on: June 18, 2016, 02:13:14 AM »

1.5kWp + Bifacial Gain + Tilt Adjustable Actuators + MPPT + Constant Current PSU boost.

« Last Edit: June 18, 2016, 02:15:00 AM by Scruff » Logged
« Reply #3 on: June 18, 2016, 02:19:09 AM »

700W Wind(or Hydro) Turnip with diversion control for indirect hot water, a circulation pump for direct hot water and a tank reserve low, rainwater harvest refilling pump. A resistive full load dump load in case water is already at optimal temperature.

« Last Edit: June 19, 2016, 01:27:12 AM by Scruff » Logged
« Reply #4 on: June 18, 2016, 02:22:29 AM »

24VDC Distribution
Note a lot of information is repeated here, it's in the format of an installation cabinet in contrast to the rest, which are circuit formats.

« Last Edit: June 21, 2016, 01:49:31 AM by Scruff » Logged
« Reply #5 on: June 18, 2016, 02:24:55 AM »

AC Circuits, Lighting Changeover Circuits.

« Last Edit: June 21, 2016, 01:12:41 AM by Scruff » Logged
« Reply #6 on: June 18, 2016, 02:29:32 AM »

Schemetics in .pdf

* 24V Goliath.pdf (260.46 KB - downloaded 120 times.)
* Dual Alt.pdf (49.28 KB - downloaded 104 times.)
* PV Dual Source Controller Mains Support.pdf (197.49 KB - downloaded 91 times.)
« Reply #7 on: June 18, 2016, 02:56:21 AM »

more pdf

* Wind Water.pdf (65.15 KB - downloaded 88 times.)
* AC Changeover Distribution and Lighting.pdf (153.23 KB - downloaded 105 times.)
* DC Bus & Distro.pdf (105.26 KB - downloaded 175 times.)
« Last Edit: June 21, 2016, 01:41:15 AM by Scruff » Logged
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« Reply #8 on: June 18, 2016, 09:43:57 AM »

 genuflect genuflect genuflect genuflect genuflect

Kidwelly South Wales
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« Reply #9 on: June 18, 2016, 10:44:20 AM »

That is pretty impressive Scruff,
                             A lot of thinking,planning involved. genuflect genuflect

An unpaid Navitron volunteer,who has been living off-grid,powered by wind and solar,each year better than the last one.
« Reply #10 on: June 18, 2016, 01:06:03 PM »

Aboot 10 nights Biff anna few days too, my poor 6volts are hammered with all the late nights on the laptop. All drawings powered by photons from a live-aboard with a 150W PV rig.  Grin
I left my camper for a week to her own defences with the battery sitting at 62% SOC Cry . I think that's a new record low for me, outside of controlled discharge testing, followed by prompt recharging. I don't think I've ever seen solar insolation this bad in Summer before.
« Reply #11 on: June 19, 2016, 04:19:46 AM »

Oops..fergot aboot this one..

Less efficient (for a battery) but a whole lot cheaper run a domestic fridge though.
« Last Edit: June 19, 2016, 04:26:07 AM by Scruff » Logged
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« Reply #12 on: June 19, 2016, 08:44:53 AM »

Hi Scruff, would those 12v silent fans work connected in series? It'll save you some wire and a 24/12 converter  Smiley

1.140kW mono south-facing at 49*
EpEver 4210A at 24v
New (Old) 8S7P LiFe battery, 105Ah @ 26.4V
EpEver STI1000-24-230 pure sine inverter
Of course it'll work. (It hasn't caught fire yet).
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« Reply #13 on: June 19, 2016, 10:17:56 AM »

 Smiley  heavy engineering ... ,

I guess one could do with some more PV   for a  6 kWh daily  consumption  perhaps ...

I came across  these role able /flexible  PV  panels that used to be quite expensive  now at about 32 pence per watt  and only 1.5 kg per ~100 watt

I just dont like the high voltage  , but in an AC coupled  idea perhaps  a nice solution ...


1.6 kw and 2.4 kw   PV array  , Outback MX 60 and FM80 charge controller  ,24 volt 1600 AH Battery ,6 Kw Victron inverter charger, 1.1 kw high head hydro turbine as a back up generator , 5 kw woodburner, 36 solar tubes with 360 l water tank, 1.6 kw  windturbine
« Reply #14 on: June 19, 2016, 05:13:34 PM »

Smiley  heavy engineering ... ,

I know right, you see "concept", drawing rendering software and Re tech together and it's automatically... facepalm   wackoteapot
Whereas the industry would have us all using float maintainers tethered to mains "hook-ups", running everything on 2.5mm cable with 20A blade fuses, charging voltages of 2.37V p/c.  with a parasitic load equivalent to 6% of usable storage and a voltmeter that says fully charged at 75% SOC. wackoold

I understand there is a middle ground but that's not worth posting unless somebody asks.  Wink
To be honest you could save a lot of money ground mounting extra PV, using regular 60 cell modules and a PWM controller which is probably what I'd do, but the whole point of the exercise is to see how much power I can get in a relatively small space and how versatile I can make it.

As a whole I aim to be conservative with the gen. figures and generous with the load figures. You can for example get far more efficient fridges.

The other option is of course conserve energy but I guess that's a lifestyle choice. I generally use 2.5kW per day including gas cooking, water heating and another 2kW powering a stoopid absorption fridge on buthane. Only 300Wh of that are refined electrical loads and I don't use an inverter.

Regarding other complications. I am not a fan of throwing all the chargers on the battery and letting them at it. I know some people say it's all fine and they stop charging when the battery is full, it's my experience that this never works or only does to a point.
Usually what happens is one charger reads the other charger's charging voltage as the battery state of charge voltage and throttles to absorption early, screwing up the absorption duration as it's usually derived from the bulk duration. The reason for the redundancy mains charger CC PSU through the solar controller is actually as a personal preferential primary low current charger when time is available, as slow charging is far more effective than fast. Possibly this is controversial but I'll put penny to a pound a mains powered MorningStar solar controller will charge a battery far better than a combi charger or any other porpoise built charger. I'm happy to stand corrected and even invest in one soon as I see a mains charger hold absorption for > 2 days like a TriStar will. In the meantime I've decommissioned every dedicated mains charger I've met on end of charge state of charge termination accuracy.

Complexities have been added to ensure that the battery side of things aren't running parasitic loads like relay coils, there are no "always on" SMPS's, DC loads are not powered by charger load compensation limiting charger current to battery when mains is available.
Also catering for redundancy and manual enables (overrides) does make for a more elaborate system but I think it's justified in a go-anywhere fix-it-with-a-hammer-vehicle.

N2, I'm not sure about running 2 x 12v fans in series for 24V operation it's probably a case of suck it and see. Gone are the days of stringing 20 MR16's in series for 240v, I've tried 4 x 12V leds (different makes) for 48V with no success.
These modern brushless jobs are a little more sophisticated than initially meets the eye. The other problem is voltage regulation; the charging system will push 30.2V in absorption that's close to 25% over-voltage for them and they won't last long (1 year). I just use a resistor on mine (which have wide operation voltage) which means the fan speed is proportional to ambient heat as it's got a direct relationship to the PV voltage. The trick with that is to ensure they are never powered while torque stalled otherwise the windings will let the smoke out.
A little buck regulator on Eblag is only aboot 2 anyways with 5% loss (10s of mA).
As regards the power saving with active cooling; my fridge including fan consumption runs for about 33% less power with forced air vented to the atmosphere.  
« Last Edit: June 20, 2016, 12:48:24 AM by Scruff » Logged
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