Power options?

[UberTramp]

Hello to all.. I might have to explain my situation to give you an idea of why I'm asking this, open to new suggestions too!
So I'm currently living in my van, as a van.. like tin walls n'all that. I'm pretty cushy in there, I seem thrive roughing it!
I have a fair idea of the end goal with the van, but of course funds are the only thing holding me back, and with winter coming I have to be savvy with how I do things.. I'm less worried about heating than I am ventilating the van. So I want a decent fan in there, ideally as the insulation goes in. (I work in construction so this part is going to be cheap and relatively easy for me)
But, with xmas coming and other financial commitments I dont think I can afford the solar to power it until the new year.. so I was wondering, what can I power the fan with?
My first thought was to get a couple of those small sealed lead batterys, those 12v 7ah ones. have one power the fan and the other charging off the altinator somehow? Then just keep swapping them over.
Or is there another option?

Sorry if that was too long! thanks though.

 

[pappajohn]

A 4" computer fan may be OK but a decent 12v fan will last about an hour or less on a 7ah battery
Charging from the alternator is going nowhere, it could take hours.
The only way that would work is a B2B charger which tricks your alternator into outputting it's full amps..... But that's going to cost more than a decent solar panel and controller which, in winter, is frankly going to be pretty useless anyway.
If you're well away from other people and houses a small generator will be your best bet.

 

[Boringfrog]

Do you need a fan? A couple of roof vents or even just crack the driver and passenger windows will give you fresh air.

 

[HandyAndy]

a few large 120mm computer fans would be cheap as chips and just wire in a resistor to set the speed you want or a four position switch with a different sized resistor on each and have a variable speed
Couple of Large lead acid batteries connected to the van battery via a split charger (so you can still start the van in the morning if you do flatten them) they will charge from the alternator without you having to swap anything around.
As for heating get a diesel heater rather than anything propane / butane powered as condensation and killing yourself will be less of an issue.
The diesel heater of choice would be the chinese copy of the eberspacher thingy..

UK 5KW diesel Air Heater Planar 5000W 12V For Motorhome Trucks Boats Silencer 682698075937 | eBay

SPECIFICATIONS Heater Power: 5KW Fuel Gasoline:Diesel Car Air Conditioning Type: Heating Rated Voltage:12V Fuel Consumption(L/h):0.64 Working Temperature of the Heater:-40℃~+50℃ Working Temperature of the Oil pump:-40℃~+0℃ Tank:10L Item Size:39*14*15cm Color: Black PACKAGE INCLUDING 1X 5KW...

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In fact thinking about the fan you could butcher the 12v computer fan into the frame of a "bathroom extractor fan" assembly and sikaflex that into the roof...

As pappajohn says, forget the 7ah battery idea and just get a couple of car batteries from the scrap yard if money is super tight!

 

[Potty]

Silver screens on the cab windows will cut condensation there. If you have glass windows elsewhere, insulation screens on the outside would help there too. Make sure you have window and roof vents open when cooking, even when just boiling the kettle.

Actually, can’t see why you think a fan would help with ventilation. It would only move the air around inside the van, not bring in fresh air or remove damp and stale air.

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[UberTramp]

Yes I did think of the small desk fan thing, I could use a small battery pack to run it through the night. Can charge them really easy at work. And yes, I'm already cracking the windows!
Maybe I'll just bave to install the fan while putting the inso in and hook the power up later.

 

[pappajohn]

A 12v desk fan may draw 7 or 8 amps.
A 100amp battery will give you maybe 6 hours use without permenantly damaging the battery......then take up to 24 hours to fully recharge on a mains charger.
There's no easy option to this problem.

 

[UberTramp]

The fan would be extracting air out the van via some ducting over the bed, which is where I'd think most of the moisture in the night would come from. With the windows cracked, I'm sure it would be much better than nothing. Sounds like I'll just have to madmax something together like HandyAndy suggests!

 

[Figaro]

That van is going to be very cold over the winter and condensation a big problem, not just on the glass.
What insulation are you using, Celotex ? get it in asap followed quickly by that diesel heater.
We don`t want to loose a funster to hyperthermia

Welcome to the forum by the way

 

[pappajohn]

Only one post left then you need to subscribe to continue or just read the posts for free.

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[UberTramp]

Wouldn't I need a power source even for a deisel heater?

 

[Figaro]

Wouldn't I need a power source even for a deisel heater?

You would, but surely it`d be worth it, especially if your planning to convert it into a proper camper van eventually ?
Your surely going to need basic comforts if your living in the van.

 

[Malcolm Bolt]

Wouldn't I need a power source even for a deisel heater?

Yes it would take a fair bit of power when running but the idea is to bring the van temperature up to a comfy level before snuggling down for the night. This would be a relatively short time and so would not drain the battery.

I have to say that is a brill price.
I had a replacement webasto fitted and it was over a grand.

 

[Malcolm Bolt]

I reckon you will need to extract air rather than rely on cracked windows. Provide an intake vent low down and some level of extraction at roof top.

 

[HandyAndy]

yes the diesel heater will need power to run the fan that blows the hot air round the van.
I can't see a cheaper way to stay warm than a couple of car batteries and a split charger.
Split charger kit with all wires, cable crimps, conduit, connectors and zipties will set you back about 70 quid for a 140amp capable splitter.

7mtr Professional Split Charge Kit Durite 12v 140amp Relay 110amp Cables T4 T5 | eBay

7mtrs 110amp 16mm2 Red Power Cable. 1mtr 110amp 16mm2 Black Earth Cable. 2 x Fuse holders & 100amp Fuses including spares. Heat shrink to protect all the connections. 2mtrs Split Black plastic conduit to protect cables in Engine bay.

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Batteries from scrap man will probably be no more than £20 but they wont last forever as they are not designed to be deep cycled (flattened) but should get you through winter safely and get you going on your project.

And just for reference the reason I promote a diesel warm air blower is that it is dry heat, unlike a gas heater like propane or butane, they give off a lot of moisture when burning and not only that, would most likely kill you from either carbon monoxide poisoning or setting fire to the van while asleep, neither of which is a great long term plan ?

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[pappajohn]

A 30amp relay will be just as capable at a fraction of the cost

 

[HandyAndy]

If they are totally flat in the morning and he starts the van with a 120 amp alternator... that poor 30amp relay is going to get a fright. ?

 

[pappajohn]

If they are totally flat in the morning and he starts the van with a 120 amp alternator... that poor 30amp relay is going to get a fright. ?

But it won't be 120amps as the engine battery is fully charged reducing the output considerably.
Why does it take many hours of driving just to top up a leisure battery via split charged.

 

[Misterg]

I'm less worried about heating than I am ventilating the van. So I want a decent fan in there, ideally as the insulation goes in

IMHO: Get a diesel heater (cheap, Chinese if you must), *but* take the heated air inlet from outside the van so that you get a supply of heated, fresh air that pushes the stale, damp air out. It will still be plenty warm enough, even with a 2kW heater, and the heater itself will be happier working harder (granted, you will use a bit more diesel).

Diesel heaters take most power on start-up. I've measured our current Planar heater and it takes 2 Ah to start-up and cool-down, but less than 1Ah to run for an hour. (Our previous Eberspacher was similar.) The moral of the story is that if you need to start it up, you may as well let it run.

My first thought was to get a couple of those small sealed lead batterys, those 12v 7ah ones. have one power the fan and the other charging off the altinator somehow

If you'll be running the engine often enough to do that^^^ then you can charge a much bigger habitation battery with a split-charge relay.

 

[Misterg]

the reason I promote a diesel warm air blower is that it is dry heat, unlike a gas heater like propane or butane, they give off a lot of moisture when burning and not only that, would most likely kill you from either carbon monoxide poisoning or setting fire to the van while asleep

Diesel or gas both produce water when burned and both have the capability to generate carbon monoxide in the right/wrong circumstances. Indirect heaters (like most diesel heaters, Propex gas heaters, Truma combis, etc. ) separate the combustion air from the heated air, so give "dry" heat inside the van and dump all the nasties outside.

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[HandyAndy]

Oh I fully realise that.
I took it as a given that the diesel heater would be installed correctly with the exhaust vented to the exterior but what quite a lot of people don't realise is the danger of camp cookers / burners when used without ventilation.
Personally I think the heater would be more efficient if it was sucking the previously heated warm air from the inside of the van instead of introducing cold air (as long as you did have a suitable amount of fresh air inlets) which the standard van, pre being insulated and boarded out would have.

 

[Misterg]

I think the heater would be more efficient if it was sucking the previously heated warm air from the inside of the van instead of introducing cold air

Yes, I'm sure that the heater will use less fuel if it is set up to heat recirculated air, but then the ventilation needs to be dealt with separately (and any cold air introduced will need heating up).

My main point was that installing the heater to draw in outside air kills two birds with one stone - forced ventilation and heating for very little electricity usage (the Planar, and I guess most others, will run in ventilation only mode if heating isn't needed).

We had an Eberspacher D2 installed that way on a boat, and it kept the interior warm, fresh and dry, even in the face of a steady supply of soggy waterproofs, etc. There was plenty of power in the 2kW heater to make the incoming air warm enough. Admittedly, this was only tested to a few degrees below freezing - maybe the best solution is an adjustable flap that can be used to blend fresh and recirculated air...

 

[HandyAndy]

But it won't be 120amps as the engine battery is fully charged reducing the output considerably.
Why does it take many hours of driving just to top up a leisure battery via split charged.

Not it'll be about 50 amps at a guess with decent cables.. Depends on the setup.
I've got 0.2v drop across my 250 amp manual switch and 50mm2 cabling from front to rear on a 250amp mega fuse just after it leaves the Main battery.. Post to post (between front positive vehicle battery and post positive on the switch was nigh on the same, difficult to be any more accurate as I had to walk from one end of the vehicle to the other )
I've seen 70 amps on mine (The Land Rover, not the MH)

 

[pappajohn]

And these are 16mm2 cables plus we know leaving a diesel on idle, even a fast idle, for long periods does it no favours.

 

[HandyAndy]

And these are 16mm2 cables

He hasn't said so I wouldn't have a clue... or do you mean the "kit" I suggested as an idea, as they were indeed 16mm2 but 5m long so could probably double them up if he kept the hab battery at the front under the seats.
Anyway, semantics.. 30 amps is a little low for longevity IMO. Yes it would work, but I would always fit something that the switch might in theory see for safety if nothing else. otherwise it's just wasted money when you have to buy it twice because the first one got hot and packed up.
I think Tramp needs to work out a better plan than the one he was thinking though, that's for sure. 7ah "swappable" batteries is way out there in "not the best plan of action". I think we can agree on that.
We still don't know what he is thinking of doing for heating, it won't be long before that is needed either judging by the sudden disappearance of the hot thing in the sky.

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