Solar in winter

[Glynn]

What realistically would 400 watt of solar / victron 100/30 mppt produce in winter ?.
Just some idea ?.

 

[Langtoftlad]

Where?
Makes a significant difference

 

[Jev88]

UK. A quarter of the power if lucky in my experience

 

[oldiesontour]

Averag later autum maybe 10% also the hours of daylight are much shorter

 

[Mleabon]

I have 350W solar but it's not enough to keep the batteries charged in Dec/Jan in England. Towards the end of Feb it's OK if there's enough sun.

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[dunnah01]

Nowt

 

[Raul]

What realistically would 400 watt of solar / victron 100/30 mppt produce in winter ?.
Just some idea ?.

About 200Wh per day. Or, Half the amount of energy that a compressor fridge needs per day. A b2b is necessary.

 

[The joker]

About 200Wh per day. Or, Half the amount of energy that a compressor fridge needs per day. A b2b is necessary.

If only he knew where one was for sale at a reasonable price https://www.motorhomefun.co.uk/forum/classifieds/victron-orion-converter-12-12-30a.9950/

 

[TonyC123]

I live on a canal boat currently, but I'm planning to move into a motorhome within the next 12 months, and I've been pondering a solution to provide 'off-grid' power during winter, with a view to using the same solution in my future motorhome.
If you have an electric fridge (mine is a smallish 240v fridge), then solar will not do the job in winter, as I'm sure you know. Even with the 1400 watts of panels on my boat's roof, there is not enough power to keep my fridge running 24/7 in winter- let alone a laptop, diesel heater, and whatever else you might have.
For a few years, my solution for recharging the house batteries (lithiums) during winter has been to run the engine.
I have two alternators, and I used a 30 amp Victron B2B to take power from each alternator. At first glance a total charging rate of 60 amps seems pretty decent. But to replace the 120Ah of charge I use each day, it means I need to run the engine for two hours. That's fine on days when the boat is cruising because the engine is running anyway, but that happens only once per week usually, and I still need to generate power on the other six days.
In my future motorhome there will only be one alternator, and thus one B2B charger - so the house batteries will only get charged at 30amps.
As with the boat, there could be several successive days when I don't move my motorhome during winter, and I don't want to run its very expensive diesel engine at (or near) tickover for the 3 hours that would be needed to generate 90Ah of battery charge. It seems a very inefficient and expensive way to generate charge.
The other concern I have with B2Bs is their long term effect on the alternators.
After about 3 years of using B2Bs on my boat engine alternators, both of the alternators stopped working. They were 8 years old at this point, I must point out. And I don't know this to be the case, but my suspicion is that by taking a continuous 30 amps from the alternators whenever the engine was running, I have been overworking them, which I think contributed largely to their demise.
It's worth mentioning that the alternators supplied with canal boat engines seem to be very old-fashioned automotive types, and I would guess that many of the modern diesel van engines will come with much superior alternators.
But ultimately, most of these alternators are designed to work with lead acid starter batteries, and I'm not convinced they are all well-suited to long term use if continuously charging at 30 amps, 60 amps, or even more..
Anyway, whatever the truth of it, I have decided that a petrol generator is the way forward for charging batteries in winter, at least on the days when the vehicle doesnt move.
And bear in mind that even when it does move, at 30 amps it would take four hours of driving to generate the 120Ah charge that I use on most days.
Rather than put hundreds of extra running hours on an engine that is very, very expensive to replace, my thinking is that I can use a £400 generator instead. So I recently bought a maxpeedingrods 3500 watt genny, and it charges at 100 amps (and more if needed), so I can get my charging done quickly and without starting the main engine.
It's also pretty quiet and has a much less annoying sound due to its 150cc engine.
I've heard of people recharging their motorhome house batteries at EV charging points for very low cost, but you wont be popular if an EV turns up and wants to get charged. And in very rural areas the options for that might be limited.

 

[Glynn]

I live on a canal boat currently, but I'm planning to move into a motorhome within the next 12 months, and I've been pondering a solution to provide 'off-grid' power during winter, with a view to using the same solution in my future motorhome.
If you have an electric fridge (mine is a smallish 240v fridge), then solar will not do the job in winter, as I'm sure you know. Even with the 1400 watts of panels on my boat's roof, there is not enough power to keep my fridge running 24/7 in winter- let alone a laptop, diesel heater, and whatever else you might have.
For a few years, my solution for recharging the house batteries (lithiums) during winter has been to run the engine.
I have two alternators, and I used a 30 amp Victron B2B to take power from each alternator. At first glance a total charging rate of 60 amps seems pretty decent. But to replace the 120Ah of charge I use each day, it means I need to run the engine for two hours. That's fine on days when the boat is cruising because the engine is running anyway, but that happens only once per week usually, and I still need to generate power on the other six days.
In my future motorhome there will only be one alternator, and thus one B2B charger - so the house batteries will only get charged at 30amps.
As with the boat, there could be several successive days when I don't move my motorhome during winter, and I don't want to run its very expensive diesel engine at (or near) tickover for the 3 hours that would be needed to generate 90Ah of battery charge. It seems a very inefficient and expensive way to generate charge.
The other concern I have with B2Bs is their long term effect on the alternators.
After about 3 years of using B2Bs on my boat engine alternators, both of the alternators stopped working. They were 8 years old at this point, I must point out. And I don't know this to be the case, but my suspicion is that by taking a continuous 30 amps from the alternators whenever the engine was running, I have been overworking them, which I think contributed largely to their demise.
It's worth mentioning that the alternators supplied with canal boat engines seem to be very old-fashioned automotive types, and I would guess that many of the modern diesel van engines will come with much superior alternators.
But ultimately, most of these alternators are designed to work with lead acid starter batteries, and I'm not convinced they are all well-suited to long term use if continuously charging at 30 amps, 60 amps, or even more..
Anyway, whatever the truth of it, I have decided that a petrol generator is the way forward for charging batteries in winter, at least on the days when the vehicle doesnt move.
And bear in mind that even when it does move, at 30 amps it would take four hours of driving to generate the 120Ah charge that I use on most days.
Rather than put hundreds of extra running hours on an engine that is very, very expensive to replace, my thinking is that I can use a £400 generator instead. So I recently bought a maxpeedingrods 3500 watt genny, and it charges at 100 amps (and more if needed), so I can get my charging done quickly and without starting the main engine.
It's also pretty quiet and has a much less annoying sound due to its 150cc engine.
I've heard of people recharging their motorhome house batteries at EV charging points for very low cost, but you wont be popular if an EV turns up and wants to get charged. And in very rural areas the options for that might be limited.

You need a Victron Orion XS I think. 50amps.

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[oldiesontour]

You need a Victron Orion XS I think. 50amps.

Or 2

 

[Raul]

Or change to 24V and run orion XS1400, much faster charge at half the amps,
Large quantity of energy transfer, becomes efficient as you step up the voltage.

 

[Jays2]

My sterling power b2b is rated for 120A.

But with 1000 watts of solar on the roof and short drives/ plus being all electric ( not heating/water)

It does not always manage in the winter when in Spain. (Low as 30% only)( 600amp lithium)

We then top up via an aire with payed electric.

Even that takes time at 100 amp input.

 

[TonyC123]

I think before you look at taking more charge from your engine alternator (as you would do if trying to charge lithium batteries with a 50 amp Victron B2B) you should also take a quick look at what that alternator is capable of putting out.
When I first got the lithium batteries, I did a lot of testing of the charging using my domestic alternator. I found that although it was rated at 100amps, if I took more than 40 amps from it continuously, it would start to really warm up.
If I connected a 50 amp charger to it, it would rapidly heat up to 120 degrees and beyond.
I dont think it would have caught fire, but taking 50 amps of charge continuously would certainly have reduced its lifespan. The fact that both my original alternators died after just 3 years usage when charging via 30 amp B2Bs is something that causes me concern, and in future I will always check the capability/rating of the alternator before using a B2B.
Now in fairness, the alternators on modern vehicle engines are a world apart from the ones that came with my boat engine, which is now ten years old and is actually based on a 20 year old tractor engine design!
So it may well be that a 50 amp B2B like the victron would work really well on a MH engine- and maybe even two of them. But the thing is, it really depends on the capability and the quality of the alternator.
I think most boat alternators (and maybe vans too?) can safely put out about half of their rated charge, on a continuous basis. So to run a pair of 50 amp Victron B2Bs safely (and generate 100 amps of charge) you might need an alternator rated at 200 amps, or at least not far from that.
I suspect most vans wont have that kind of alternator as standard.
And anyway, on the days when you dont move your MH, why run its engine just charge the batteries, when you can run a cheap/disposable petrol generator for the same job?
Obviously noise nuisance is an issue to beware of with generators, but there are several quiet gennies on the market that cost less than £500, and will do your charging at 100 amps and more.
If I get an older MH, the last thing I want to be doing is running its engine just to charge batteries (which would be on the days when the MH doesnt need to be driven anywhere).

 

[Raul]

The only quiet genny I know of, is inverter type, and run at 1/4 load in a sound proof box. I run one Occasionally in the garage, during winter stormy weather. We have a house in Ro off grid, since 2016 ish. I'm well accustomed to off grid living.

In a van is different, I personally would not run a genny, but, I would fit a second high power alternator to service a b2b or two exclusively.

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[TonyC123]

Or change to 24V and run orion XS1400, much faster charge at half the amps,
Large quantity of energy transfer, becomes efficient as you step up the voltage.

I hadnt even considered changing the charging voltage, as I have a very poor grasp of most electrics.
But my concern with any B2B is the long term effects on the alternator of having it working hard continuously, having seen two of my alternators die after 3 years of use with B2Bs.
I dont have the technical ability to alter my alternator so that it charges at 24v, so unless I employ a professional I'm stuck with its limitation of 12v output and maximum (safe) charging current of 35 amps. So its putting out a maximum of 420 watts, is that right?
Apologies as I know its my ignorance about electrics, but I'm not seeing what I would gain from using a 24v charger? My alternator can only put out about 420 watts, so isnt 420 watts the maximum energy that is available to be put into the batteries, whether at 12v or 24v?

 

[TonyC123]

The only quiet genny I know of, is inverter type, and run at 1/4 load in a sound proof box. I run one Occasionally in the garage, during winter stormy weather. We have a house in Ro off grid, since 2016 ish. I'm well accustomed to off grid living.

In a van is different, I personally would not run a genny, but, I would fit a second high power alternator to service a b2b or two exclusively.

Gennies are very common among canal boaters, although there is a rule that you should not run them after 8pm.
As with any community, there are always people who break the rules and create noise nuisance, but the beauty of a boat is you can just move on a few hundred yards if you have a plonker next door running a genny at 11pm.
I dont like the idea of taking the genny with me into my future MH, but I honestly cant see a good, reliable and easily available alternative during the winter months.
I'll set up the charging system so I can use EV charge points on quiet evenings, but when in more rural areas that wont be easy.
I think a high-powered alternator would be a good idea for charging on the move, but my genny will be there as a fall-back option, and for days when the MH doesnt move far. I think the thing is run it as little as possible, always be conscious of the area and who is nearby, and dont run it after say 5pm.

 

[Raul]

I hadnt even considered changing the charging voltage, as I have a very poor grasp of most electrics.
But my concern with any B2B is the long term effects on the alternator of having it working hard continuously, having seen two of my alternators die after 3 years of use with B2Bs.
I dont have the technical ability to alter my alternator so that it charges at 24v, so unless I employ a professional I'm stuck with its limitation of 12v output and maximum (safe) charging current of 35 amps. So its putting out a maximum of 420 watts, is that right?
Apologies as I know its my ignorance about electrics, but I'm not seeing what I would gain from using a 24v charger? My alternator can only put out about 420 watts, so isnt 420 watts the maximum energy that is available to be put into the batteries, whether at 12v or 24v?

There are even 48v alternators, at cost, and will shift 4 times the energy compared to a 12v amp for amp.
However, the 24v agricultural or truck or even excavator alternator are cheap and plenty. A 24v will shift double the power of a 12v amp for amp. That is why higher voltage is preferable for shorter charge time.
A 55A 24v alternator is arround 60-70 quid. Run at 40A ( limited in the B2B), will have 1000w of charging power. The Orion XS1400 is actually capable of 1400W charging from 24v alternator to 24v battery bank.
All you need is a separate 100A ish 24v truck alternator, with custom fittings to the existing belt system on the van. That is my future plan for the coming winter.

 

[TonyC123]

There are even 48v alternators, at cost, and will shift 4 times the energy compared to a 12v amp for amp.
However, the 24v agricultural or truck or even excavator alternator are cheap and plenty. A 24v will shift double the power of a 12v amp for amp. That is why higher voltage is preferable for shorter charge time.
A 55A 24v alternator is arround 60-70 quid. Run at 40A ( limited in the B2B), will have 1000w of charging power. The Orion XS1400 is actually capable of 1400W charging from 24v alternator to 24v battery bank.
All you need is a separate 100A ish 24v truck alternator, with custom fittings to the existing belt system on the van. That is my future plan for the coming winter.

That sounds like a great idea in principle. One minor note I would make is that if I want an alternator that gives 40 amps continuously into a lithium battery, I would buy one rated at 80 amps, not 55 amps.
On a boat engine, its entirely normal to have a second alternator to charge the house batteries, in addition to the alternator that is used to charge the starter battery.
And in a similar discussion on a canal boating forum, I remember someone made the point that some specific controls on the alternator are very helpful.
For example, at low/tickover revs, my understanding is that you don't normally want the alternator to be putting out the full 40 amps that the B2B charger will accept.
I dont know if this is the case with vans, but on a boat engine, trying to pull too much current from an alternator at tickover revs is not good for the engine and crankshaft (apparently). And unlike vans, boats do spend a lot of their time at very low revs (and at low revs, the cooling of the alternator is not as effective as it is at higher revs).
So some of the boaters with lithium batteries have also installed intelligent alternator controllers. These will reduce the current output of the alternator at low revs. They also reduce current output if the alternator temp rises above specified levels.
For me these alternator controllers are too expensive (£700 plus fitting costs), in relation to the benefits they give. But it would be great to have a way easily switching the B2B on and off remotely, e..g if stuck in a traffic queue at tickover).
In terms of adding a second alternator, the challenge for me is that I'm hoping to buy a modern 6.4m van conversion (the shortlist includes: Autosleepers Kemerton, Dormobile D2B, Wildax Constellation XL), but I want one that is less than 5 years old.
On that kind of engine (hopefully the Fiat 2.3), how easy would it be to fit an additional alternator for the house batteries? one imagines the more cost effective option would be to upgrade the existing 12v alternator to a 200 amp unit?
Again though, I'm looking for year-round off grid solutions, and if I'm parked up for say 3 days without hookup in winter, I'll need some way of charging that doesnt need the vans engine to be running, which brings me back to the generator.
PS - I should have explained that I wont regularly be using the van for short journeys.
On the boat, I currently use an ebike to visit local places within 3-5 miles, and I am hoping I can use the same approach when I am living in a MH.
So I am expecting that there might be two or three days at a time when the van sits idle and the engine is not used, and I use the ebike to get around.

 

[TheMobileWanderer]

That sounds like a great idea in principle. One minor note I would make is that if I want an alternator that gives 40 amps continuously into a lithium battery, I would buy one rated at 80 amps, not 55 amps.
On a boat engine, its entirely normal to have a second alternator to charge the house batteries, in addition to the alternator that is used to charge the starter battery.
And in a similar discussion on a canal boating forum, I remember someone made the point that some specific controls on the alternator are very helpful.
For example, at low/tickover revs, my understanding is that you don't normally want the alternator to be putting out the full 40 amps that the B2B charger will accept.
I dont know if this is the case with vans, but on a boat engine, trying to pull too much current from an alternator at tickover revs is not good for the engine and crankshaft (apparently). And unlike vans, boats do spend a lot of their time at very low revs (and at low revs, the cooling of the alternator is not as effective as it is at higher revs).
So some of the boaters with lithium batteries have also installed intelligent alternator controllers. These will reduce the current output of the alternator at low revs. They also reduce current output if the alternator temp rises above specified levels.
For me these alternator controllers are too expensive (£700 plus fitting costs), in relation to the benefits they give. But it would be great to have a way easily switching the B2B on and off remotely, e..g if stuck in a traffic queue at tickover).
In terms of adding a second alternator, the challenge for me is that I'm hoping to buy a modern 6.4m van conversion (the shortlist includes: Autosleepers Kemerton, Dormobile D2B, Wildax Constellation XL), but I want one that is less than 5 years old.
On that kind of engine (hopefully the Fiat 2.3), how easy would it be to fit an additional alternator for the house batteries? one imagines the more cost effective option would be to upgrade the existing 12v alternator to a 200 amp unit?
Again though, I'm looking for year-round off grid solutions, and if I'm parked up for say 3 days without hookup in winter, I'll need some way of charging that doesnt need the vans engine to be running, which brings me back to the generator.
PS - I should have explained that I wont regularly be using the van for short journeys.
On the boat, I currently use an ebike to visit local places within 3-5 miles, and I am hoping I can use the same approach when I am living in a MH.
So I am expecting that there might be two or three days at a time when the van sits idle and the engine is not used, and I use the ebike to get around.

You could do worse than to check out 'cleversolarpower' where the guy explains stuff quite well.

Aside from your alternator-specific question, you should consider habitation battery storage. It should be big enough to power you for say, 3 days off-grid stationary. So, work out your likely electricity consumption per day in the moho - fridge, microwave, kettle, not forgetting induction hob, usb chargers and heating, for example, and multiply by 3 (days). That'll show you how much battery you might need. It'll also show what size inverter you'll need, optimally.

Eg. 2000W * 3 / 12V = 500Ah storage needed and a 2000W - 3000W inverter.

I suggest you consider upping the voltage to 24V or even 48V (that's what I'll be running with), to reduce amperage and wiring cost, component costs and storage amperage too.

Once those numbers regarding demand are established, I'd check the output of the vehicle alternator and upgrade as necessary.

I think I have read that two alternators should not be used together, to charge any batteries so, in case I'm correct, please double check that.

Hth

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[TonyC123]

You could do worse than to check out 'cleversolarpower' where the guy explains stuff quite well.

Aside from your alternator-specific question, you should consider habitation battery storage. It should be big enough to power you for say, 3 days off-grid stationary. So, work out your likely electricity consumption per day in the moho - fridge, microwave, kettle, not forgetting induction hob, usb chargers and heating, for example, and multiply by 3 (days). That'll show you how much battery you might need. It'll also show what size inverter you'll need, optimally.

Eg. 2000W * 3 / 12V = 500Ah storage needed and a 2000W - 3000W inverter.

I suggest you consider upping the voltage to 24V or even 48V (that's what I'll be running with), to reduce amperage and wiring cost, component costs and storage amperage too.

Once those numbers regarding demand are established, I'd check the output of the vehicle alternator and upgrade as necessary.

I think I have read that two alternators should not be used together, to charge any batteries so, in case I'm correct, please double check that.

Hth

Thanks for that info, that's really useful.
I'll pipe down after this because I've already hijacked the OPs thread more than I should, but I can say that I'm fairly clued up on my energy usage already, because I've lived on a canal boat using lithium batteries for 5 years, with no mains electricity of any kind.
My victron BMV712 battery monitors have enabled me to monitor the exact energy usage of each appliance in real time, and I've made a decision about when each should be used.
But my approach to charging batteries does vary seasonally. E.g. in summer I use solar power to cook on the induction hob/air fryer, and even to heat a 35L tank of water each day for washing etc.
But in winter I tend to use gas for cooking, because it seems inefficient to run a big, expensive diesel engine for two hours each day (and burn 2 or 3 litres of fuel), just in order to generate the extra charge needed for electric cooking.
So I do have a good handle on my energy needs now, and I dont think those needs will change massively when I move into a MH.
What will change is that instead of my current 1,4kw of solar panels, I'll be lucky if I can fit 600 watts on the roof of a van conversion - so my ability to heat water from solar power will be greatly reduced.

Re the question of two alternators charging a single battery bank, I imagine the important thing is that they work at the same voltage. I did find initially that the domestic alternator was regulated at a slightly lower voltage than the starter alternator, which meant that the domestic alternator never became 'excited' enough to put out its full charge.
My solution was to run each alternator into its own lead acid battery, and from there into a B2B, and then into the lithium bank. Working through these separate charging routes, each alternator would put out its maximum (safe) charging current.
But after seeing two alternators fail after only 3 or 4 years of charging within this system, I'm now wondering if its best not to try and get the maximum charge from alternators- unless, that is, you can buy replacement units cheaply, and can fit them yourself.
In terms of safety, a couple of marine electrics professionals have checked over my setup and felt it was safe (including a boat safety inspector), and it has worked 24/7 for the last 4 years without fault, so I'm satisfied that charging from two alternators doesnt pose a specific or significant risk within my particular system - which is not to say that it isnt a factor in other setups of course.
When I move into the MH, I will only use a single alternator. But if its cost-effective, I might upgrade to a high power unit. I just dont know enough at the moment about how powerful the standard alternators are on the Fiat 2.2 and 2.3 engines.

 

[TheMobileWanderer]

Thanks for that info, that's really useful.
I'll pipe down after this because I've already hijacked the OPs thread more than I should, but I can say that I'm fairly clued up on my energy usage already, because I've lived on a canal boat using lithium batteries for 5 years, with no mains electricity of any kind.
My victron BMV712 battery monitors have enabled me to monitor the exact energy usage of each appliance in real time, and I've made a decision about when each should be used.
But my approach to charging batteries does vary seasonally. E.g. in summer I use solar power to cook on the induction hob/air fryer, and even to heat a 35L tank of water each day for washing etc.
But in winter I tend to use gas for cooking, because it seems inefficient to run a big, expensive diesel engine for two hours each day (and burn 2 or 3 litres of fuel), just in order to generate the extra charge needed for electric cooking.
So I do have a good handle on my energy needs now, and I dont think those needs will change massively when I move into a MH.
What will change is that instead of my current 1,4kw of solar panels, I'll be lucky if I can fit 600 watts on the roof of a van conversion - so my ability to heat water from solar power will be greatly reduced.

Re the question of two alternators charging a single battery bank, I imagine the important thing is that they work at the same voltage. I did find initially that the domestic alternator was regulated at a slightly lower voltage than the starter alternator, which meant that the domestic alternator never became 'excited' enough to put out its full charge.
A couple of marine electrics professionals have checked over my setup and felt it was safe (including a boat safety inspector), and it has worked 24/7 for the last 4 years without fault, so I'm satisfied that charging from two alternators doesnt pose a specific or significant risk within my particular system - which is not to say that it isnt a factor in other setups of course.
When I move into the MH, I will only use a single alternator. But if its cost-effective, I might upgrade to a high power unit. I just dont know enough at the moment about how powerful the standard alternators are on the Fiat 2.2 and 2.3 engines.

Start a new thread please because theres a few more things I'd like to add.

 

[TonyC123]

Start a new thread please because theres a few more things I'd like to add.

I've sort of hijacked the OPs thread with a side discussion about charging from engines and alternators - is that the topic you would like to discuss in a new thread?
Bear in mind I do feel like something of an interloper already on this forum. I am a tad concerned that people may not be very interested in the views of a boater who is planning to transition to a MH.

 

[TheMobileWanderer]

I've sort of hijacked the OPs thread with a side discussion about charging from engines and alternators - is that the topic you would like to discuss in a new thread?
Bear in mind I do feel like something of an interloper already on this forum. I am a tad concerned that people may not be very interested in the views of a boater who is planning to transition to a MH.

Well it's a motorhome forum and you're planning on owning one so, writing for myself, I've no problem discussing with you in a new thread. As for the subject, it should be about your complete solar set up.

 

[TonyC123]

Well it's a motorhome forum and you're planning on owning one so, writing for myself, I've no problem discussing with you in a new thread. As for the subject, it should be about your complete solar set up.

Tell you what - since this bit is about solar (and relevant to this sub forum), and since the OP has probably obtained the feedback he was looking for, I'll post on this thread (unless he objects, of course).
Currently I have two groups of panels. One group consists of four small panels (rated at 660 watts in total), which came with the boat. The second group consists of a pair of larger panels that I added, rated at I think 750 watts in total.
There are three lithium house batteries totalling 400Ah of charge, which seemed like enough 5 years ago, but in hindsight I should have opted for about 600Ah. The extra storage capacity would have given a bit more flexibility around when I need to charge etc.t least 4 days of charge with no need to run a generator
Each of the two groups of panels charges through its own victron 100/50 MPPT, and as you can imagine they provide a huge amount of power during summer. Generally speaking I get enough solar power to heat a 35L immersion tank to washing temp, between about mid-April and mid-Sept.
These boats tend to have calorifiers, so you can heat the water with electricity, or via hot water running through from the engine, or even via the hot water running from the diesel CH. Its ideal for off grid living really, but my impression is that van conversions probably wont have space for that kind of setup.
Its been disappointing to see how few of even the latest vans have diesel heating, or diesel water heating.
I can imagine if I used gas for heating, or to provide hot water, I'd be buying a new gas bottle every other week during winter. But in fairness, I suspect MHs are primarily designed with extended holidays in mind, rather than full time off grid living.
The solar kit might stay with the boat when it's sold, although most boat buyers would be happy to have just one of the two sets of panels - so I am toying with the idea of taking the original set of 660 watts (plus an MPPT) with me into the MH, as they are smaller, and I think I stand a better chance of fitting them around the roof vents of a van than I would with the bigger panels.
I can then add other panels if there's space left, with another smaller MPPT.
My challenge when I move into a 6.4m van conversion is to get as much solar power as possible. Ideally, the roof mounts would be tiltable and would swivel to catch the sun directly at any angle, to provide extra yield during the marginal months with a lower sun. But that's a nice to have, not essential, and I can imagine the challenge of safely making that kind of flexible mount is much greater on a vehicle that will regularly reach 60 and maybe 70mph, when compared to a canal boat travelling at 3mph!
For the MH I want at least 600Ah of batteries and a high power (200amp?) alternator, so that if I do a 4 hour drive I would ideally fully recharge my house batteries - which means that even in winter with no solar, I can run the van for about 4 days with no need for any more charging, generators etc.
Obviously a full charge would be the exception. On a day to day basis I only charge my current lithium batteries to about 85%, in an attempt to prolong their lifespan. Keeping them at or near 100% charge for long periods is very stressful for them, as you'll be aware.

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[Intruder]

Back to the original question. . . .

This is what I come up with for Mid-Germany. So, for England would need to be adjusted down a bit for what you could expect. This is for panels installed on MH's, flat mounted.

Sorry about the German, but the Excel Document was done in it.

A. Area of Coverage & Averages of said area.

B. Theoretical Daily Energy per Month

C. Correcting Factors (Temperatures, Cable losses, conversion losses)

D. Corrected Daily Usable Energy

Cheers

 

[Carpmart]

If useful to you, this is my experience last winter in SE Spain…

Folding Solar Panels - Good yield considering time of year!

Just a shout out to angled and directionable solar panels at this time of year; I’m genuinely impressed with the yield! We are at our winter stop over site (3 months) in SE Spain but the days are short, the sun is low, there is often a haze or partial cloud, so it’s the worst time of year for...

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