Is this a terrible idea?

[Wocca]

Hoping to find some opinions from those in the know….

I’m in the earliest stages of bulid an L4H3 Relay campervan, and the over-cab space is calling me. I have a diesel combi heater. Is it a terrible idea to mount it there? Obviously the plastic will be replaced with strong stuff, and there’s plenty of room. The main issue I see is the exhaust being high on the side of the van.

I’m thinking hot exhaust rises, and by the time it cools it’ll be elsewhere - but I don’t know. As it involves cutting holes, I’d really approeciate any sensible thoughts before this ends up on ebay as a bodged half-finished effort for a quarter of what I paid!

Cheers!

 

[Raul]

You want the heat as low as possible to the floor, as it raises, it warms up the space. Over the cab it’s a bad idea in many way, let alone the challenges getting the exhaust sealed trough the roof, power cable to it, combustion air feed from outside, fuel etc.
Diesel heaters close to the floor is best.
Over the cab, it’s good space for bedding duvet, screen covers etc. general items, not appliances, that’s my opinion anyway.

 

[Wocca]

Good job I didn’t mention my first bright idea of 70kg of LiFePo4 up there then

Agreed, down low is best, I’ll stop trying to reinvent the wheel.

Thanks for the input

 

[Phill D]

Hi and welcome

In addition to the above points You really don’t want weight that high up.

You certainly don’t want batteries and fuel overhead.

 

[Googlebot]

I think it’s a bad idea, for the same reasons others have said.

I am more interested in the size of the lithium battery if it’s that heavy!

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[Wocca]

920AH, 2 large batteries in parallel. Heavy, but heavy duty

Planning on that plus the vans own diesel supply being the only fuels - it’ll be a 3 day max van, for a whole load of reasons!

Understand the rationale of heavy stuff low down - but that over-cab bit is massive in van terms, seems almost a waste.

Todays plan is batteries/inverter under one side of U-shaped dinette, water and waste tanks under the other, should stay fairly well balanced at that

 

[Suenliam]

The over cab may be huge but you will soon find masses of light weight stuff to store there when you use the MH.
Sue

 

[Phill D]

Wow that’s a lot of ah for 3 days!

 

[Googlebot]

Wow that’s a lot of ah for 3 days!

Not if you are cooking with it.

We can wallop 100ah in an evening with the hob.

 

[Pausim]

Not sure the Combi fuel lift pump is designed to raise the fuel that far up above the fuel tank, would need checking. Motorhome designers seem to go to great lengths to keep the heavy stuff as low as possible, you don’t want it falling over on the first bend.

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[Miggs]

Remember the pumps can be very noisy so place wisely.

 

[chaser]

Good job I didn’t mention my first bright idea of 70kg of LiFePo4 up there then

Agreed, down low is best, I’ll stop trying to reinvent the wheel.

Thanks for the input

Up there is for the air conditioning unit, that's where they are on ambulances.

 

[Wocca]

All good stuff

Aiming to mount the diesel pump in the cab area, possiblly under-seat, with the combi on the living side of the bulkhead likely hidden in a kitchen cabinet. I’m aware of the ticking - what do people do? I don’t want to mount it externally. Had some idle thoughts of a sound-dampened box but nothing really beyond that.

Agreed, 920AH sounds a lot, but for reasons of system simplicity and anticipated use, I’m not having solar or even DC/DC onborad charging. Cooking will be induction hob and electric multi oven, which will take me to the limit of the inverter, so 3 days of 2 or 3 cooked meals plus all the 12v stuff and the losses means - I think - adequate rather than overkill. I will have the ability to charge externally from AC ie campsite hook-up or possible EV station but need to investigate that more

Quite enjoy the geekiness of it all!

 

[Otter Spotter]

920AH, 2 large batteries in parallel. Heavy, but heavy duty

Planning on that plus the vans own diesel supply being the only fuels - it’ll be a 3 day max van, for a whole load of reasons!

Understand the rationale of heavy stuff low down - but that over-cab bit is massive in van terms, seems almost a waste.

Todays plan is batteries/inverter under one side of U-shaped dinette, water and waste tanks under the other, should stay fairly well balanced at that

Not A waste, it’s a great space for storing your window screens, tables, coats etc. You need somewhere close to sliding door that you can just throw stuff.
As you have now clocked it you need anything heavy low down for balance and the heater needs to exhaust on opposite side to sliding door, otherwise you will end breathing fumes back in van when you open door, and box the Chinese diesel heater in as they need to be silenced as they are really noisy.

 

[tacr2man]

Weight balance is quite important but, overall , and axle weights are more so especially if you are building on a 3500kg vehicle . Your batteries will be about 76kg for a start. inverter/charger 20kg

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[Otter Spotter]

Weight balance is quite important but, overall , and axle weights are more so especially if you are building on a 3500kg vehicle .

Good point, heavy stuff nearer to rear of van as much of front axle weight is used up by engine and gearbox

 

[Raul]

All good stuff

Aiming to mount the diesel pump in the cab area, possiblly under-seat, with the combi on the living side of the bulkhead likely hidden in a kitchen cabinet. I’m aware of the ticking - what do people do? I don’t want to mount it externally. Had some idle thoughts of a sound-dampened box but nothing really beyond that.

Agreed, 920AH sounds a lot, but for reasons of system simplicity and anticipated use, I’m not having solar or even DC/DC onborad charging. Cooking will be induction hob and electric multi oven, which will take me to the limit of the inverter, so 3 days of 2 or 3 cooked meals plus all the 12v stuff and the losses means - I think - adequate rather than overkill. I will have the ability to charge externally from AC ie campsite hook-up or possible EV station but need to investigate that more

Quite enjoy the geekiness of it all!

Please consider to subscribe here, and hang around. I wish I knew this place when I converted mine. You will never regret it. As a new member you will be limited to 5 posts, then you will need to subscribe to be able to further post.
I think your system will be nice but, a tad large for 12v. On large amperage lines, you will need great care and high quality connection, protections, design and good insulation’s. At 960ah it’s screaming for 24v. Now it all depends on appliances you already got.

 

[Outdoors Dad]

Why don't you want to fit solar panels and a dc-dc charger surely these could help maintain charge and lengthen your camp options. The huge batteries most of cost a fortune.

 

[Raul]

Yes, solar would be my first priority with the roof, then hatches windows etc.

 

[Otter Spotter]

Not sure why you need a diesel pump? Most diesel heaters draw the fuel direct using integral pump from chassis fuel tank. You may also want to consider an Air Fryer (doesn’t fry food !) most are around 1500w and would take up less space that your cooker.
Please subscribe so you can gain as much guidance from the many people on Fun who have already gone done the self build route and straightened out the kinks

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[Pausim]

Aiming to mount the diesel pump in the cab area, possiblly under-seat, with the combi on the living side of the bulkhead likely hidden in a kitchen cabinet. I’m aware of the ticking - what do people do? I don’t want to mount it externally. Had some idle thoughts of a sound-dampened box but nothing really beyond that.

I think the usual place for the pump is underneath the van, just below the boiler. I came across an Aussie video showing the installation of a Truma Combi D when I was researching the Combi. Might be worth looking for that.

As you have now clocked it you need anything heavy low down for balance and the heater needs to exhaust on opposite side to sliding door, otherwise you will end breathing fumes back in van when you open door, and box the Chinese diesel heater in as they need to be silenced as they are really noisy.

The OP refers to a Combi diesel rather than a noisy Chinese one. The Truma Combi D is reported to be no noisier or have more fumes than the gas version once it has fired up.

 

[Wocca]

This seems like a genuinely useful forum! Thanks very much for the replies, much food for thought.
Although I do have some experience of electrical systems, basic plumbing knowledge and some woodworking projects, I’ve never tried to combine these into one space before!

One thing that I am quite keen to do is have onboard water, both waste and fresh. I’ve also allowed space for a wetroom, and my intention is to employ a pumped waste system rather than gravity fed. So the (rough) idea is to have approx. 100kg of electrical stuff on one side of the bed area, and 2 x 70 (ish) low profile water tanks on the other so the van will stay balanced as most of the clean water tranfers to waste water but ends up in the same location.

Yes, it’s the Truma D6E which I intend to run in diesel mode only. I’ve discounted solar and alternator charging mostly because I don’t see a situation where it’s going to be needed. As much as a continous source of energy is a nice thing, with an adequate battery bank I simply wont need it, and the added complexity to the system is also a factor.

Cooking with be via a Ninja flip air fryer 8-in-combo thing, and and induction hob. The idea of 24v is very interesting, and something I’ll need to think about properly - thanks ideally I’d like a 4000w inverter (the batteries can take the continuous draw) but 12v inverters seem to top out at 3kW. Still to buy the inverter, was thinking Renogy/black friday Agreed, the wire gauge, switch gear and terminations need to be absolutley correct at that potential amperage, but only in the parallel battery connections, and on to the inverter - more standard from there out.

Lots of big ideas for someone who has only insulated the van and put a floor in at this point!!! But it’s a project to plod along with, and I’m very open to suggestions!

Cheers

 

[Otter Spotter]

I have a couple of questions;
1 Unless you are going to stay on EHU how do you intend to charge your batteries? if no solar or Alternator charging.
2. Are you intending to drive your vehicle with full tanks all the time? You shouldn’t, going from site to site you should consider 1/2 fresh water and little or no Grey water, why carry crap around with all the time. If you are not going to drive with full tanks then balance may be out.
3. Have you considered a Wallas XC Duo which is a combined heater and hob powered by diesel via cab tank ? I say this so you have cooking alternatives.

 

[Raul]

If solar is out, ( big mistake) and DC charging, then permanent EHU will give you less options for traveling. You will limit yourself to sites with EHU, and occasional of grid while you still have juice in the battery. A solar panel 300-360w its about £100 and a controller £180-200.
I'm skeptical of renogy for long term use reliability wise. Best value for money as it stands, nothing beats Victron.

 

[Suenliam]

I admire you for taking on a project like this but like others I can't work out why you need so much electrical storage etc. when you will need to use EHU to recharge the batteries. If I recall correctly you will only be doing short trips away but this may change and without solar etc. you will be confined to campsites quite frequently and limiting your opportunities to be a free agent if that is what you want.
Again as others have said - subscribe here and it will save you so much - not just money but also the agravation of finding out about alternatives after the event.
Sue

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[tacr2man]

Just relying on ehu for recharging will still take a fair while esp on limited 220v supply if a big hole to fill .
Victron combi unit rather than renogy JMHO B2B not that expensive or complicated .

 

[headlight]

If it were me I'd reduce the amount of lithium and use the savings to pay for solar and a B2B.
It will give you far my choices than loads of lithium on its own which can only be recharged from the mains.

 

[Richard n Ann]

I would fit a propane system for cooking, the gas lasts years if you have a compressor fridge. We last filled our LPG (2 x 6kg) up in Benidorm in 2021 and I haven't used 50% yet.

Then without the enormous drain for cooking, 200w of solar will be plenty for summer use (maybe 300 if you watch tv a lot) with a single battery.

 

[Tony50]

Bad idea.
But if you want to dry your hair good idea , me I don't have that problem!

 

[Aucheorn]

I use 4X100watt Solar panels 2 X 110 Amp hour gel batteries and a 1500watt Inverter. I have never used, or needed to use EHU. In winter keep the solar panels clean.

Works for me.