How can I power diesel heater since solar is probably going to be almost useless in winter when I want heat most?

[Gueyog8a7]

Check this out maybe it would work for you constructed properly

Yea I have watched another video from the outsider where he does similar. I just paid almost 1000gbp for a diesel heater and hob combo so I am not going to scrap that idea now .

 

[eXodus]

Yea I have watched another video from the outsider where he does similar. I just paid almost 1000gbp for a diesel heater and hob combo so I am not going to scrap that idea now .

You can get one of those Diesel Heaters for less then 200 from China.

There is youtuber in Van which has a ton of comparison videos:

https://www.youtube.com/@MispronouncedAdventures

 

[Gueyog8a7]

Fit insulation, this is the first stage of van conversion.


This the recirculating heated air, not the combustion air for the heater. Your hob/ heater will recirculate .


This takes a small amount of power once running but the start up cycle, around 10 minutes, takes more.
Using the Wallas Duo as an example, startup current is 8 to 10 amps and running current less than 1 amp, ( in the region of 0.8 amp).

Power needed. Regardless of battery bank capacity you will need a charging source. In UK winter, with horizontal panels and perhaps shade, there won't be much solar input. Off grid, the best solution is a battery to battery charger using alternator power.

Estimating electrical power for your heater. Example 6 starts per day, 12 hours run time. Startup power 6 x10 amps x 1/6 hours = 10 Ah.
Run time power, 12 hours x 1 amp = 12Ah. Total power per day heating, 22 Ah.

Engine run time with a 60 amp battery to battery charger, 25 minutes, to restore battery capacity.

With better insulation, including window insulation, the heating requirements will be much less. Self adhesive closed cell foam direct on the metal,

10mm Closed Cell Foam Car or Van Adhesive Waterproof Insulation

10mm Closed Cell Foam Car or Van Adhesive Waterproof Insulation This easy to install black closed cell foam waterproof insulation is ideal for roofs, doors, wheel arches, boot and parcel shelf applications. Once fitted this product will improve the ride quality in your vehicle by reducing engine...

www.carinsulation.co.uk

Trying to survive off grid in the UK winter is not easy. Heating will be the least problem, water, washing and toilet needs, doing the laundry , finding somewhere safe to park.

Hi. I find your posts are like good cheese. I have to let them mature and come back to them later .

I see you suggest 60a battery to battery charger but isn't that slightly too much for my fogstar drift 105ah? I read that 50% maximum is recommended of total battery capacity so isn't 50a what I want? Can you recommend one to me? It is especially useful as it seems you are also in the UK and doing conversions so you can point me to equipment that is available domestically.

Also what about this talk of isolated and none isolated for installation? I read that in an article yesterday but have not got my head around it yet.

 

[mikefitz]

60a battery to battery charger but isn't that slightly too much for my fogstar drift 105ah? I read that 50% maximum is recommended of total battery capacity so isn't 50a what I want? Can you recommend one to me?

The Fogstar specification recomends a 50 A charge but also suggests the maximum is 100 amps. For a 100Ah battery charging at 0.5 C is recomended for long service life.
With your situation where you want maximum energy Into the battery in the shortest time, charging over 50 amps is an option
attery to battery chargers available in the UK, Sterling Power, Victron, Renogy, Votronics

It's probable your van has smart charging so the chargers have to be comparable.

In a van, the house, leasure, battery has the negative connected to van metal as does the starter battery so non isolated chargers can be used , ( isolated types can also be used where the negatives are connected to the same point).

 

[Gueyog8a7]

The Fogstar specification recomends a 50 A charge but also suggests the maximum is 100 amps. For a 100Ah battery charging at 0.5 C is recomended for long service life.
With your situation where you want maximum energy Into the battery in the shortest time, charging over 50 amps is an option
attery to battery chargers available in the UK, Sterling Power, Victron, Renogy, Votronics

It's probable your van has smart charging so the chargers have to be comparable.

In a van, the house, leasure, battery has the negative connected to van metal as does the starter battery so non isolated chargers can be used , ( isolated types can also be used where the negatives are connected to the same point).

My van is ford transit connect from 2007 so not sure when smart charging was introduced.

 

[Gueyog8a7]

My solar has been a little better the past couple of days. I even broke double digits the other day with I think an all time high of around 16 watts for a few seconds .

We have just passed the winter solstice so things can only get better from here eh? I also have not fully depleted my battery yet and have been able to run the heating and/or cooking for hour or so a day.

The battery hovers between 13.1v and 13.2v and solar seems to generate 0.01kwh average per day so far had 0.02kwh a couple of times.

Getting a battery monitor shall be a priority though to see what is really going on.

 

[eXodus]

My van is ford transit connect from 2007 so not sure when smart charging was introduced.

"Smart Charging" was introduced somewhere in the 80-90s. It essentially gives the engine computer the ability to regulate charging.

Depending on the car/van model it smarter or less smart. Most designs only regulate charging when the battery gets full.
My 1996 Volvo for instance - reduced charging rate when full acceleration (full - throttle - no charging) to reduce the engine load for a minute.

Newer design even measure alternator temperature.

Contrary to popular belief most alternators do not burn up when charging lithium IF in parallel to the lead starter battery (very important!!)

Is it ideal charging? No - the alternator charging curve is different from LFP. Will it work ? Yes - make sure to properly fuse all cables at both ends.

 

[Reed Cole]

I have a different vehicle but I charge my lithium batteries with a direct parallel connection via a voltage sensing relay, which is a bit cheaper than a dc-dc charger.

Find a way to monitor the voltage of your alternator/starter battery while the vehicle is in operation, many vehichles run at 14.4v when the battery is fully charged, which is fine for lithium. Especially if you aren't driving much, your lithium batteries won't ever get to 14.4 unless they are close to being fully charged.

Though you will benefit from having a battery monitor for the lithium battery if you try this so you can make sure voltage and current going into it is within tolerable ranges.

If your vehicle's charging system puts out odd
low voltages, like ~10v, at times then you have a "smart alternator" and you'll need a dc-dc charger maintain a charge at the proper voltage.

Though you can probably do some internet searches to determine if you vehicle likely has a smart alternator or not. Chances are someone has tried charging a lithium battery off their alternator in the same vehicle as you and has posted about it.

 

[OM617YOTA]

Contrary to popular belief most alternators do not burn up when charging lithium IF in parallel to the lead starter battery (very important!!)

If anyone does this, make sure you know what you're doing and monitor everything closely.

There are two main issues with charging lithium batteries from an alternator directly, and having a lead acid battery in parallel only solves one of them - the battery getting full and BMS shutting off charging suddenly.

The other issue with charging lithium from a standard alternator is that a lithium battery can soak up every amp the alternator will produce for a lot longer than the average alternator has duty cycle to handle. This is where a dedicated battery charging alternator regulator or battery charging DC-DC converter comes into play, frequently monitoring alternator temperature and adjusting charging rate accordingly. Another idea might be an alternator that has 100% duty cycle, as many semi truck alternators are.

Just make sure folks know what they're doing, not burning up their alternators by thinking paralleling a lead acid battery solves all their issues.

 

[eXodus]

Just make sure folks know what they're doing, not burning up their alternators by thinking paralleling a lead acid battery solves all their issues.

correct, you should know what you are doing.

The other issue with charging lithium from a standard alternator is that a lithium battery can soak up every amp the alternator will produce for a lot longer than the average alternator has duty cycle to handle.

I actually had the opposite issue with a direct connection, my lithium's would not charge fast enough. I had a 180A alternator and could never get more then 80A going to LFP for extended time.

The Smart Alternator starts with 14.4V for the first ~5 minutes until the engine is warm and then goes down to 13.8V at this voltage - the amps flow slower - since it's just barely above the resting voltage of LFP.

 

[Gueyog8a7]

The dc-dc chargers do not seem massively expensive and am not strapped or cash so do not see much advantage with some other option which sounds more fineckety and perhaps more risky on my brand new lithium battery.

 

[eXodus]

The dc-dc chargers do not seem massively expensive and am not strapped or cash so do not see much advantage with some other option which sounds more fineckety and perhaps more risky on my brand new lithium battery.

if you only want a trickle charger - a DC to DC is fine. A Victron 20A DC to DC is about $150, it takes forever to charge decent sized battery bank.

I used to have a 300AH bank in my Van - do the math - 300/20A that would be 15 hours of driving. My not ideal direct connected would average about 60A going to LFP battery - 300/60 = 5 hours - still not great - but much better.

When I see it correctly you are looking at somewhere 100-200AH?
100AH is not a lot of power (1kWH), just running the a small fridge, laptop and some lights - that's barely one day.

 

[Dave911]

I have mentioned this before on this forum in other places, but the easiest way I have found to add a Lifepo4 battery to a vehicle is to use one of these:

Amazon.com

$52 US.

This is an intelligent device, not just a voltage sensing relay. It has nice heavy brass terminals and brass nuts.

I have the isolator mounted to the inside of a marine battery box lid. I have 10 ga wires running from the battery under the hood (bonnet) to the battery box that is in the back of the car. There is a 30 amp fuse at the battery. This setup runs a BougeRV refrigerator and it works great. For a while I monitored the current draw into the Lifepo4 battery. After sitting overnight and after starting it up. When the Isolator would detect that the voltage was sufficient for charging a minute or so after starting the car, 18-22 amps of current was flowing into the lifepo4 battery.
This setup prevents the Lifepo4 battery from discharging into the Lead acid starting battery when the car is not running. It also insures that the lead acid battery is charged before the Lifepo4 battery starts charging. A slick solution for $52
The refrigerator (you can see the end of it in the picture) draws a little over 4 amps.

FWIW, I never connected the one lead to the ignition switch. This isolator is smart enough to do the right thing without that connection. Verified with a clamp on meter and volt meter. This has been running for about 4 months now nonstop.

If I don't drive the car for 4+ days in warm weather, I plug in a small 4 amp LIFEpo4 charger to 120 VAC power. The charger is connected to the battery all the time. But I use the car almost daily so so I have only done that twice.

 

[Gueyog8a7]

if you only want a trickle charger - a DC to DC is fine. A Victron 20A DC to DC is about $150, it takes forever to charge decent sized battery bank.

I used to have a 300AH bank in my Van - do the math - 300/20A that would be 15 hours of driving. My not ideal direct connected would average about 60A going to LFP battery - 300/60 = 5 hours - still not great - but much better.

When I see it correctly you are looking at somewhere 100-200AH?
100AH is not a lot of power (1kWH), just running the a small fridge, laptop and some lights - that's barely one day.

I have a 100 lfp battery. I don't need a fridge. Heating, powering tablet ereader and phone and a few fans and that is about it. I don't think that is going to take much? One day is fine so long as I can replenlish day by day. I think 1 day is an overestimate for my small use case though?

 

[MisterB1959]

we have a rumor going around on this side of the mountains that you folks all have webbed feet is that true?

only on two of them .......

 

[Dave911]

I have a 100 lfp battery. I don't need a fridge. Heating, powering tablet ereader and phone and a few fans and that is about it. I don't think that is going to take much? One day is fine so long as I can replenlish day by day. I think 1 day is an overestimate for my small use case though?

FWIW, using that device I mentioned and a generic 12 volt, 100 ah battery, with a stock auto alternator, I have never seen more than 25 amps of charging current. The alternator is a modern car alternator likely rated at 140 amp or so (Lincoln MKZ, 2007) , so it could put out a lot more amps, but not at voltage sufficient to pump more amps into the LIFEPO4 battery. I don't know how long you want to idle your van to charge your LIFEPO4 battery, but idling for 4 hours to almost fully recharge a 100 ah battery seems like a long time. Unless you have a diesel, you will be using a lot of gas.
If they make 50 amp DC to DC chargers, that might be a better idea.
The other alternative is to get a small suitcase style gas generator and use that to drive a 50 amp charger. But that means keeping gas and another device, etc. In the US it is very common to see vans with a platform on the back end with a generator on it along with gas cans etc. The platform often is attached to the hitch which is a common 2" square socket, Reese style hitch.

 

[eXodus]

I have a 100 lfp battery. I don't need a fridge. Heating, powering tablet ereader and phone and a few fans and that is about it. I don't think that is going to take much? One day is fine so long as I can replenlish day by day. I think 1 day is an overestimate for my small use case though?

you are asking to run a Diesel Heater- those needs about 40w per hour - 40w * 24h = 960Wh
Your 100ah *12V = 1200WH - not a lot of extra room.

I know during the winter you don't need a fridge - but during the summer.

When it's cold you need to keep warm and when it's warm you need to keep things cool. It always needs energy.

 

[Gueyog8a7]

you are asking to run a Diesel Heater- those needs about 40w per hour - 40w * 24h = 960Wh
Your 100ah *12V = 1200WH - not a lot of extra room.

I know during the winter you don't need a fridge - but during the summer.

When it's cold you need to keep warm and when it's warm you need to keep things cool. It always needs energy.

Well I have no intention of running it 24 hours a day.

I don't like anything running when I am not in the van and I am outside most of the time, even in winter.

I want to run it the bare minimum to keep condensation at bay.

I am only running 1 hour or less in the morning and same in the evening. Granted this is still too low to keep condensation at bay but a lot of wiggle room between 2 hours and 24 .

I am looking at active fans now for the condensation issue as that may give more bang for my buck as the 2 I bought run at 0.16 watts.

I notice my mum's car parked next to mine doesn't produce condensation most times while mine does so it must be a product of my breath and cooking so venting seems like it could do the trick here. Perhaps run those through the night while sleeping to vent out the moisture from my body.

I started living in it in summer and was able to adapt to not having cooling. Just make food in the morning for the whole day and repeat each day. This did not change my lifestyle much anyway as I would only make for 1-2 days when in an apartment.

 

[Bob B]

I notice my mum's car parked next to mine doesn't produce condensation most times while mine does so it must be a product of my breath and cooking so venting seems like it could do the trick here. Perhaps run those through the night while sleeping to vent out the moisture from my body.

It is surprising the amount of moisture added to an enclosed space just from breathing .... and cooking definitely adds to it.

The key .... especially in the winter time .... is ventilation. Of course, that will require that the cold air be warmed enough to remain comfortable ... and, just as on the outside of a glass of ice water, moisture will condense on the cold metal or glass surfaces when the dewpoint is higher than the temperature and the RH reaches 100%. When you breath, you increase the dewpoint and RH of the air.

The outdoor dewpoint is one of the keys.
For instance, it the outdoor temperature is 55 deg F and the RH is 100% ...... warm that air up to 72 degrees and the RH is now only 50% .... but the dewpoint of the air will be 55 regardless of the temperature. This is why it gets so dry in a house at very cold outdoor temperatures .... Warming the air from zero deg F outside to 70 inside very significantly reduces the RH.
It's the opposite in the summer .... when outdoor air is brought in and the temperature is lowered, the RH increases over what it is outside .... That is why there is so much condensate off an air conditioning coil.
The dewpoint of the air, however, remains constant regardless of the air temperature. It's very important to understand RH and dewpoint when trying to reduce moisture.
As temperature rises, RH is reduced .... as temperature drops, the RH increases and once the dewpoint equals the air or surface temperature the RH will be 100% and there will be condensation .... or fog.
Studying a psychometric chart to understand how they interrelate is very revealing.

I have a truck camper and the risk of condensation ... and therefore mold is a concern. I always have a vent cracked open a little .... especially in the winter.
My brother and his wife have a larger camper and almost always blocked their vents so they wouldn't have to use so much heat .... and they always had a lot of condensation.

In order to dry out your van, you will need to bring in more outside air and run your diesel heater more to warm the air and dry it out .... If you continue to get condensation, you will get mold and that can be VERY bad for your health. As others mentioned, you will also need insulation, because when the warm air comes in contact with the a cold surface the RH drops radically and you will get condensation.
It would be ideal to know the dewpoint inside your van ..... or the temperature and the relative humidity so you can calculate the dewpoint. That way, you will know what outdoor air temperatures will begin cause condensation on the metal and glass..

That was a lot of rambling, but a kind of a quick psychometric lesson.

 

[eXodus]

I notice my mum's car parked next to mine doesn't produce condensation most times while mine does so it must be a product of my breath and cooking so venting seems like it could do the trick here. Perhaps run those through the night while sleeping to vent out the moisture from my body.

I started living in it in summer and was able to adapt to not having cooling. Just make food in the morning for the whole day and repeat each day. This did not change my lifestyle much anyway as I would only make for 1-2 days when in an apartment.

you might want to look into one of the many #Vanlife forums. All those questions you had are answered there. We are here more concerned with the Energy side of things.

I was living out of a Van for couple of years, you do not want to skimp on heating to dry out the rig. Depending how you built your van - all the moisture saturates the materials and it is difficult to get those out. At least every few days you want have it nice an toasty in there for many hours so that the water can move from the materials (carpet, wood, sheets, blankets, headliner insulation) into the air. - Then vent this air out. Otherwise you are going to have mold box very soon.
Just google "Vanlife mold"